linux/drivers/spi/spi.c
Linus Torvalds f9300eaaac ACPI and power management updates for 3.13-rc1
- New power capping framework and the the Intel Running Average Power
    Limit (RAPL) driver using it from Srinivas Pandruvada and Jacob Pan.
 
  - Addition of the in-kernel switching feature to the arm_big_little
    cpufreq driver from Viresh Kumar and Nicolas Pitre.
 
  - cpufreq support for iMac G5 from Aaro Koskinen.
 
  - Baytrail processors support for intel_pstate from Dirk Brandewie.
 
  - cpufreq support for Midway/ECX-2000 from Mark Langsdorf.
 
  - ARM vexpress/TC2 cpufreq support from Sudeep KarkadaNagesha.
 
  - ACPI power management support for the I2C and SPI bus types from
    Mika Westerberg and Lv Zheng.
 
  - cpufreq core fixes and cleanups from Viresh Kumar, Srivatsa S Bhat,
    Stratos Karafotis, Xiaoguang Chen, Lan Tianyu.
 
  - cpufreq drivers updates (mostly fixes and cleanups) from Viresh Kumar,
    Aaro Koskinen, Jungseok Lee, Sudeep KarkadaNagesha, Lukasz Majewski,
    Manish Badarkhe, Hans-Christian Egtvedt, Evgeny Kapaev.
 
  - intel_pstate updates from Dirk Brandewie and Adrian Huang.
 
  - ACPICA update to version 20130927 includig fixes and cleanups and
    some reduction of divergences between the ACPICA code in the kernel
    and ACPICA upstream in order to improve the automatic ACPICA patch
    generation process.  From Bob Moore, Lv Zheng, Tomasz Nowicki,
    Naresh Bhat, Bjorn Helgaas, David E Box.
 
  - ACPI IPMI driver fixes and cleanups from Lv Zheng.
 
  - ACPI hotplug fixes and cleanups from Bjorn Helgaas, Toshi Kani,
    Zhang Yanfei, Rafael J Wysocki.
 
  - Conversion of the ACPI AC driver to the platform bus type and
    multiple driver fixes and cleanups related to ACPI from Zhang Rui.
 
  - ACPI processor driver fixes and cleanups from Hanjun Guo, Jiang Liu,
    Bartlomiej Zolnierkiewicz, Mathieu Rhéaume, Rafael J Wysocki.
 
  - Fixes and cleanups and new blacklist entries related to the ACPI
    video support from Aaron Lu, Felipe Contreras, Lennart Poettering,
    Kirill Tkhai.
 
  - cpuidle core cleanups from Viresh Kumar and Lorenzo Pieralisi.
 
  - cpuidle drivers fixes and cleanups from Daniel Lezcano, Jingoo Han,
    Bartlomiej Zolnierkiewicz, Prarit Bhargava.
 
  - devfreq updates from Sachin Kamat, Dan Carpenter, Manish Badarkhe.
 
  - Operation Performance Points (OPP) core updates from Nishanth Menon.
 
  - Runtime power management core fix from Rafael J Wysocki and update
    from Ulf Hansson.
 
  - Hibernation fixes from Aaron Lu and Rafael J Wysocki.
 
  - Device suspend/resume lockup detection mechanism from Benoit Goby.
 
  - Removal of unused proc directories created for various ACPI drivers
    from Lan Tianyu.
 
  - ACPI LPSS driver fix and new device IDs for the ACPI platform scan
    handler from Heikki Krogerus and Jarkko Nikula.
 
  - New ACPI _OSI blacklist entry for Toshiba NB100 from Levente Kurusa.
 
  - Assorted fixes and cleanups related to ACPI from Andy Shevchenko,
    Al Stone, Bartlomiej Zolnierkiewicz, Colin Ian King, Dan Carpenter,
    Felipe Contreras, Jianguo Wu, Lan Tianyu, Yinghai Lu, Mathias Krause,
    Liu Chuansheng.
 
  - Assorted PM fixes and cleanups from Andy Shevchenko, Thierry Reding,
    Jean-Christophe Plagniol-Villard.
 
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Merge tag 'pm+acpi-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management updates from Rafael J Wysocki:

 - New power capping framework and the the Intel Running Average Power
   Limit (RAPL) driver using it from Srinivas Pandruvada and Jacob Pan.

 - Addition of the in-kernel switching feature to the arm_big_little
   cpufreq driver from Viresh Kumar and Nicolas Pitre.

 - cpufreq support for iMac G5 from Aaro Koskinen.

 - Baytrail processors support for intel_pstate from Dirk Brandewie.

 - cpufreq support for Midway/ECX-2000 from Mark Langsdorf.

 - ARM vexpress/TC2 cpufreq support from Sudeep KarkadaNagesha.

 - ACPI power management support for the I2C and SPI bus types from Mika
   Westerberg and Lv Zheng.

 - cpufreq core fixes and cleanups from Viresh Kumar, Srivatsa S Bhat,
   Stratos Karafotis, Xiaoguang Chen, Lan Tianyu.

 - cpufreq drivers updates (mostly fixes and cleanups) from Viresh
   Kumar, Aaro Koskinen, Jungseok Lee, Sudeep KarkadaNagesha, Lukasz
   Majewski, Manish Badarkhe, Hans-Christian Egtvedt, Evgeny Kapaev.

 - intel_pstate updates from Dirk Brandewie and Adrian Huang.

 - ACPICA update to version 20130927 includig fixes and cleanups and
   some reduction of divergences between the ACPICA code in the kernel
   and ACPICA upstream in order to improve the automatic ACPICA patch
   generation process.  From Bob Moore, Lv Zheng, Tomasz Nowicki, Naresh
   Bhat, Bjorn Helgaas, David E Box.

 - ACPI IPMI driver fixes and cleanups from Lv Zheng.

 - ACPI hotplug fixes and cleanups from Bjorn Helgaas, Toshi Kani, Zhang
   Yanfei, Rafael J Wysocki.

 - Conversion of the ACPI AC driver to the platform bus type and
   multiple driver fixes and cleanups related to ACPI from Zhang Rui.

 - ACPI processor driver fixes and cleanups from Hanjun Guo, Jiang Liu,
   Bartlomiej Zolnierkiewicz, Mathieu Rhéaume, Rafael J Wysocki.

 - Fixes and cleanups and new blacklist entries related to the ACPI
   video support from Aaron Lu, Felipe Contreras, Lennart Poettering,
   Kirill Tkhai.

 - cpuidle core cleanups from Viresh Kumar and Lorenzo Pieralisi.

 - cpuidle drivers fixes and cleanups from Daniel Lezcano, Jingoo Han,
   Bartlomiej Zolnierkiewicz, Prarit Bhargava.

 - devfreq updates from Sachin Kamat, Dan Carpenter, Manish Badarkhe.

 - Operation Performance Points (OPP) core updates from Nishanth Menon.

 - Runtime power management core fix from Rafael J Wysocki and update
   from Ulf Hansson.

 - Hibernation fixes from Aaron Lu and Rafael J Wysocki.

 - Device suspend/resume lockup detection mechanism from Benoit Goby.

 - Removal of unused proc directories created for various ACPI drivers
   from Lan Tianyu.

 - ACPI LPSS driver fix and new device IDs for the ACPI platform scan
   handler from Heikki Krogerus and Jarkko Nikula.

 - New ACPI _OSI blacklist entry for Toshiba NB100 from Levente Kurusa.

 - Assorted fixes and cleanups related to ACPI from Andy Shevchenko, Al
   Stone, Bartlomiej Zolnierkiewicz, Colin Ian King, Dan Carpenter,
   Felipe Contreras, Jianguo Wu, Lan Tianyu, Yinghai Lu, Mathias Krause,
   Liu Chuansheng.

 - Assorted PM fixes and cleanups from Andy Shevchenko, Thierry Reding,
   Jean-Christophe Plagniol-Villard.

* tag 'pm+acpi-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (386 commits)
  cpufreq: conservative: fix requested_freq reduction issue
  ACPI / hotplug: Consolidate deferred execution of ACPI hotplug routines
  PM / runtime: Use pm_runtime_put_sync() in __device_release_driver()
  ACPI / event: remove unneeded NULL pointer check
  Revert "ACPI / video: Ignore BIOS initial backlight value for HP 250 G1"
  ACPI / video: Quirk initial backlight level 0
  ACPI / video: Fix initial level validity test
  intel_pstate: skip the driver if ACPI has power mgmt option
  PM / hibernate: Avoid overflow in hibernate_preallocate_memory()
  ACPI / hotplug: Do not execute "insert in progress" _OST
  ACPI / hotplug: Carry out PCI root eject directly
  ACPI / hotplug: Merge device hot-removal routines
  ACPI / hotplug: Make acpi_bus_hot_remove_device() internal
  ACPI / hotplug: Simplify device ejection routines
  ACPI / hotplug: Fix handle_root_bridge_removal()
  ACPI / hotplug: Refuse to hot-remove all objects with disabled hotplug
  ACPI / scan: Start matching drivers after trying scan handlers
  ACPI: Remove acpi_pci_slot_init() headers from internal.h
  ACPI / blacklist: fix name of ThinkPad Edge E530
  PowerCap: Fix build error with option -Werror=format-security
  ...

Conflicts:
	arch/arm/mach-omap2/opp.c
	drivers/Kconfig
	drivers/spi/spi.c
2013-11-14 13:41:48 +09:00

2053 lines
55 KiB
C

/*
* SPI init/core code
*
* Copyright (C) 2005 David Brownell
* Copyright (C) 2008 Secret Lab Technologies Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/slab.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
#include <linux/of_gpio.h>
#include <linux/pm_runtime.h>
#include <linux/export.h>
#include <linux/sched/rt.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/ioport.h>
#include <linux/acpi.h>
#define CREATE_TRACE_POINTS
#include <trace/events/spi.h>
static void spidev_release(struct device *dev)
{
struct spi_device *spi = to_spi_device(dev);
/* spi masters may cleanup for released devices */
if (spi->master->cleanup)
spi->master->cleanup(spi);
spi_master_put(spi->master);
kfree(spi);
}
static ssize_t
modalias_show(struct device *dev, struct device_attribute *a, char *buf)
{
const struct spi_device *spi = to_spi_device(dev);
return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
}
static DEVICE_ATTR_RO(modalias);
static struct attribute *spi_dev_attrs[] = {
&dev_attr_modalias.attr,
NULL,
};
ATTRIBUTE_GROUPS(spi_dev);
/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
* and the sysfs version makes coldplug work too.
*/
static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
const struct spi_device *sdev)
{
while (id->name[0]) {
if (!strcmp(sdev->modalias, id->name))
return id;
id++;
}
return NULL;
}
const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
{
const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
return spi_match_id(sdrv->id_table, sdev);
}
EXPORT_SYMBOL_GPL(spi_get_device_id);
static int spi_match_device(struct device *dev, struct device_driver *drv)
{
const struct spi_device *spi = to_spi_device(dev);
const struct spi_driver *sdrv = to_spi_driver(drv);
/* Attempt an OF style match */
if (of_driver_match_device(dev, drv))
return 1;
/* Then try ACPI */
if (acpi_driver_match_device(dev, drv))
return 1;
if (sdrv->id_table)
return !!spi_match_id(sdrv->id_table, spi);
return strcmp(spi->modalias, drv->name) == 0;
}
static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
{
const struct spi_device *spi = to_spi_device(dev);
add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int spi_legacy_suspend(struct device *dev, pm_message_t message)
{
int value = 0;
struct spi_driver *drv = to_spi_driver(dev->driver);
/* suspend will stop irqs and dma; no more i/o */
if (drv) {
if (drv->suspend)
value = drv->suspend(to_spi_device(dev), message);
else
dev_dbg(dev, "... can't suspend\n");
}
return value;
}
static int spi_legacy_resume(struct device *dev)
{
int value = 0;
struct spi_driver *drv = to_spi_driver(dev->driver);
/* resume may restart the i/o queue */
if (drv) {
if (drv->resume)
value = drv->resume(to_spi_device(dev));
else
dev_dbg(dev, "... can't resume\n");
}
return value;
}
static int spi_pm_suspend(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm)
return pm_generic_suspend(dev);
else
return spi_legacy_suspend(dev, PMSG_SUSPEND);
}
static int spi_pm_resume(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm)
return pm_generic_resume(dev);
else
return spi_legacy_resume(dev);
}
static int spi_pm_freeze(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm)
return pm_generic_freeze(dev);
else
return spi_legacy_suspend(dev, PMSG_FREEZE);
}
static int spi_pm_thaw(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm)
return pm_generic_thaw(dev);
else
return spi_legacy_resume(dev);
}
static int spi_pm_poweroff(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm)
return pm_generic_poweroff(dev);
else
return spi_legacy_suspend(dev, PMSG_HIBERNATE);
}
static int spi_pm_restore(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm)
return pm_generic_restore(dev);
else
return spi_legacy_resume(dev);
}
#else
#define spi_pm_suspend NULL
#define spi_pm_resume NULL
#define spi_pm_freeze NULL
#define spi_pm_thaw NULL
#define spi_pm_poweroff NULL
#define spi_pm_restore NULL
#endif
static const struct dev_pm_ops spi_pm = {
.suspend = spi_pm_suspend,
.resume = spi_pm_resume,
.freeze = spi_pm_freeze,
.thaw = spi_pm_thaw,
.poweroff = spi_pm_poweroff,
.restore = spi_pm_restore,
SET_RUNTIME_PM_OPS(
pm_generic_runtime_suspend,
pm_generic_runtime_resume,
NULL
)
};
struct bus_type spi_bus_type = {
.name = "spi",
.dev_groups = spi_dev_groups,
.match = spi_match_device,
.uevent = spi_uevent,
.pm = &spi_pm,
};
EXPORT_SYMBOL_GPL(spi_bus_type);
static int spi_drv_probe(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
struct spi_device *spi = to_spi_device(dev);
int ret;
acpi_dev_pm_attach(&spi->dev, true);
ret = sdrv->probe(spi);
if (ret)
acpi_dev_pm_detach(&spi->dev, true);
return ret;
}
static int spi_drv_remove(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
struct spi_device *spi = to_spi_device(dev);
int ret;
ret = sdrv->remove(spi);
acpi_dev_pm_detach(&spi->dev, true);
return ret;
}
static void spi_drv_shutdown(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
sdrv->shutdown(to_spi_device(dev));
}
/**
* spi_register_driver - register a SPI driver
* @sdrv: the driver to register
* Context: can sleep
*/
int spi_register_driver(struct spi_driver *sdrv)
{
sdrv->driver.bus = &spi_bus_type;
if (sdrv->probe)
sdrv->driver.probe = spi_drv_probe;
if (sdrv->remove)
sdrv->driver.remove = spi_drv_remove;
if (sdrv->shutdown)
sdrv->driver.shutdown = spi_drv_shutdown;
return driver_register(&sdrv->driver);
}
EXPORT_SYMBOL_GPL(spi_register_driver);
/*-------------------------------------------------------------------------*/
/* SPI devices should normally not be created by SPI device drivers; that
* would make them board-specific. Similarly with SPI master drivers.
* Device registration normally goes into like arch/.../mach.../board-YYY.c
* with other readonly (flashable) information about mainboard devices.
*/
struct boardinfo {
struct list_head list;
struct spi_board_info board_info;
};
static LIST_HEAD(board_list);
static LIST_HEAD(spi_master_list);
/*
* Used to protect add/del opertion for board_info list and
* spi_master list, and their matching process
*/
static DEFINE_MUTEX(board_lock);
/**
* spi_alloc_device - Allocate a new SPI device
* @master: Controller to which device is connected
* Context: can sleep
*
* Allows a driver to allocate and initialize a spi_device without
* registering it immediately. This allows a driver to directly
* fill the spi_device with device parameters before calling
* spi_add_device() on it.
*
* Caller is responsible to call spi_add_device() on the returned
* spi_device structure to add it to the SPI master. If the caller
* needs to discard the spi_device without adding it, then it should
* call spi_dev_put() on it.
*
* Returns a pointer to the new device, or NULL.
*/
struct spi_device *spi_alloc_device(struct spi_master *master)
{
struct spi_device *spi;
struct device *dev = master->dev.parent;
if (!spi_master_get(master))
return NULL;
spi = kzalloc(sizeof(*spi), GFP_KERNEL);
if (!spi) {
dev_err(dev, "cannot alloc spi_device\n");
spi_master_put(master);
return NULL;
}
spi->master = master;
spi->dev.parent = &master->dev;
spi->dev.bus = &spi_bus_type;
spi->dev.release = spidev_release;
spi->cs_gpio = -ENOENT;
device_initialize(&spi->dev);
return spi;
}
EXPORT_SYMBOL_GPL(spi_alloc_device);
/**
* spi_add_device - Add spi_device allocated with spi_alloc_device
* @spi: spi_device to register
*
* Companion function to spi_alloc_device. Devices allocated with
* spi_alloc_device can be added onto the spi bus with this function.
*
* Returns 0 on success; negative errno on failure
*/
int spi_add_device(struct spi_device *spi)
{
static DEFINE_MUTEX(spi_add_lock);
struct spi_master *master = spi->master;
struct device *dev = master->dev.parent;
struct device *d;
int status;
/* Chipselects are numbered 0..max; validate. */
if (spi->chip_select >= master->num_chipselect) {
dev_err(dev, "cs%d >= max %d\n",
spi->chip_select,
master->num_chipselect);
return -EINVAL;
}
/* Set the bus ID string */
dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
spi->chip_select);
/* We need to make sure there's no other device with this
* chipselect **BEFORE** we call setup(), else we'll trash
* its configuration. Lock against concurrent add() calls.
*/
mutex_lock(&spi_add_lock);
d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
if (d != NULL) {
dev_err(dev, "chipselect %d already in use\n",
spi->chip_select);
put_device(d);
status = -EBUSY;
goto done;
}
if (master->cs_gpios)
spi->cs_gpio = master->cs_gpios[spi->chip_select];
/* Drivers may modify this initial i/o setup, but will
* normally rely on the device being setup. Devices
* using SPI_CS_HIGH can't coexist well otherwise...
*/
status = spi_setup(spi);
if (status < 0) {
dev_err(dev, "can't setup %s, status %d\n",
dev_name(&spi->dev), status);
goto done;
}
/* Device may be bound to an active driver when this returns */
status = device_add(&spi->dev);
if (status < 0)
dev_err(dev, "can't add %s, status %d\n",
dev_name(&spi->dev), status);
else
dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
done:
mutex_unlock(&spi_add_lock);
return status;
}
EXPORT_SYMBOL_GPL(spi_add_device);
/**
* spi_new_device - instantiate one new SPI device
* @master: Controller to which device is connected
* @chip: Describes the SPI device
* Context: can sleep
*
* On typical mainboards, this is purely internal; and it's not needed
* after board init creates the hard-wired devices. Some development
* platforms may not be able to use spi_register_board_info though, and
* this is exported so that for example a USB or parport based adapter
* driver could add devices (which it would learn about out-of-band).
*
* Returns the new device, or NULL.
*/
struct spi_device *spi_new_device(struct spi_master *master,
struct spi_board_info *chip)
{
struct spi_device *proxy;
int status;
/* NOTE: caller did any chip->bus_num checks necessary.
*
* Also, unless we change the return value convention to use
* error-or-pointer (not NULL-or-pointer), troubleshootability
* suggests syslogged diagnostics are best here (ugh).
*/
proxy = spi_alloc_device(master);
if (!proxy)
return NULL;
WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
proxy->chip_select = chip->chip_select;
proxy->max_speed_hz = chip->max_speed_hz;
proxy->mode = chip->mode;
proxy->irq = chip->irq;
strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
proxy->dev.platform_data = (void *) chip->platform_data;
proxy->controller_data = chip->controller_data;
proxy->controller_state = NULL;
status = spi_add_device(proxy);
if (status < 0) {
spi_dev_put(proxy);
return NULL;
}
return proxy;
}
EXPORT_SYMBOL_GPL(spi_new_device);
static void spi_match_master_to_boardinfo(struct spi_master *master,
struct spi_board_info *bi)
{
struct spi_device *dev;
if (master->bus_num != bi->bus_num)
return;
dev = spi_new_device(master, bi);
if (!dev)
dev_err(master->dev.parent, "can't create new device for %s\n",
bi->modalias);
}
/**
* spi_register_board_info - register SPI devices for a given board
* @info: array of chip descriptors
* @n: how many descriptors are provided
* Context: can sleep
*
* Board-specific early init code calls this (probably during arch_initcall)
* with segments of the SPI device table. Any device nodes are created later,
* after the relevant parent SPI controller (bus_num) is defined. We keep
* this table of devices forever, so that reloading a controller driver will
* not make Linux forget about these hard-wired devices.
*
* Other code can also call this, e.g. a particular add-on board might provide
* SPI devices through its expansion connector, so code initializing that board
* would naturally declare its SPI devices.
*
* The board info passed can safely be __initdata ... but be careful of
* any embedded pointers (platform_data, etc), they're copied as-is.
*/
int spi_register_board_info(struct spi_board_info const *info, unsigned n)
{
struct boardinfo *bi;
int i;
bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
if (!bi)
return -ENOMEM;
for (i = 0; i < n; i++, bi++, info++) {
struct spi_master *master;
memcpy(&bi->board_info, info, sizeof(*info));
mutex_lock(&board_lock);
list_add_tail(&bi->list, &board_list);
list_for_each_entry(master, &spi_master_list, list)
spi_match_master_to_boardinfo(master, &bi->board_info);
mutex_unlock(&board_lock);
}
return 0;
}
/*-------------------------------------------------------------------------*/
static void spi_set_cs(struct spi_device *spi, bool enable)
{
if (spi->mode & SPI_CS_HIGH)
enable = !enable;
if (spi->cs_gpio >= 0)
gpio_set_value(spi->cs_gpio, !enable);
else if (spi->master->set_cs)
spi->master->set_cs(spi, !enable);
}
/*
* spi_transfer_one_message - Default implementation of transfer_one_message()
*
* This is a standard implementation of transfer_one_message() for
* drivers which impelment a transfer_one() operation. It provides
* standard handling of delays and chip select management.
*/
static int spi_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct spi_transfer *xfer;
bool cur_cs = true;
bool keep_cs = false;
int ret = 0;
spi_set_cs(msg->spi, true);
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
trace_spi_transfer_start(msg, xfer);
INIT_COMPLETION(master->xfer_completion);
ret = master->transfer_one(master, msg->spi, xfer);
if (ret < 0) {
dev_err(&msg->spi->dev,
"SPI transfer failed: %d\n", ret);
goto out;
}
if (ret > 0)
wait_for_completion(&master->xfer_completion);
trace_spi_transfer_stop(msg, xfer);
if (msg->status != -EINPROGRESS)
goto out;
if (xfer->delay_usecs)
udelay(xfer->delay_usecs);
if (xfer->cs_change) {
if (list_is_last(&xfer->transfer_list,
&msg->transfers)) {
keep_cs = true;
} else {
cur_cs = !cur_cs;
spi_set_cs(msg->spi, cur_cs);
}
}
msg->actual_length += xfer->len;
}
out:
if (ret != 0 || !keep_cs)
spi_set_cs(msg->spi, false);
if (msg->status == -EINPROGRESS)
msg->status = ret;
spi_finalize_current_message(master);
return ret;
}
/**
* spi_finalize_current_transfer - report completion of a transfer
*
* Called by SPI drivers using the core transfer_one_message()
* implementation to notify it that the current interrupt driven
* transfer has finised and the next one may be scheduled.
*/
void spi_finalize_current_transfer(struct spi_master *master)
{
complete(&master->xfer_completion);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
/**
* spi_pump_messages - kthread work function which processes spi message queue
* @work: pointer to kthread work struct contained in the master struct
*
* This function checks if there is any spi message in the queue that
* needs processing and if so call out to the driver to initialize hardware
* and transfer each message.
*
*/
static void spi_pump_messages(struct kthread_work *work)
{
struct spi_master *master =
container_of(work, struct spi_master, pump_messages);
unsigned long flags;
bool was_busy = false;
int ret;
/* Lock queue and check for queue work */
spin_lock_irqsave(&master->queue_lock, flags);
if (list_empty(&master->queue) || !master->running) {
if (!master->busy) {
spin_unlock_irqrestore(&master->queue_lock, flags);
return;
}
master->busy = false;
spin_unlock_irqrestore(&master->queue_lock, flags);
if (master->unprepare_transfer_hardware &&
master->unprepare_transfer_hardware(master))
dev_err(&master->dev,
"failed to unprepare transfer hardware\n");
if (master->auto_runtime_pm) {
pm_runtime_mark_last_busy(master->dev.parent);
pm_runtime_put_autosuspend(master->dev.parent);
}
trace_spi_master_idle(master);
return;
}
/* Make sure we are not already running a message */
if (master->cur_msg) {
spin_unlock_irqrestore(&master->queue_lock, flags);
return;
}
/* Extract head of queue */
master->cur_msg =
list_entry(master->queue.next, struct spi_message, queue);
list_del_init(&master->cur_msg->queue);
if (master->busy)
was_busy = true;
else
master->busy = true;
spin_unlock_irqrestore(&master->queue_lock, flags);
if (!was_busy && master->auto_runtime_pm) {
ret = pm_runtime_get_sync(master->dev.parent);
if (ret < 0) {
dev_err(&master->dev, "Failed to power device: %d\n",
ret);
return;
}
}
if (!was_busy)
trace_spi_master_busy(master);
if (!was_busy && master->prepare_transfer_hardware) {
ret = master->prepare_transfer_hardware(master);
if (ret) {
dev_err(&master->dev,
"failed to prepare transfer hardware\n");
if (master->auto_runtime_pm)
pm_runtime_put(master->dev.parent);
return;
}
}
trace_spi_message_start(master->cur_msg);
if (master->prepare_message) {
ret = master->prepare_message(master, master->cur_msg);
if (ret) {
dev_err(&master->dev,
"failed to prepare message: %d\n", ret);
master->cur_msg->status = ret;
spi_finalize_current_message(master);
return;
}
master->cur_msg_prepared = true;
}
ret = master->transfer_one_message(master, master->cur_msg);
if (ret) {
dev_err(&master->dev,
"failed to transfer one message from queue\n");
return;
}
}
static int spi_init_queue(struct spi_master *master)
{
struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
INIT_LIST_HEAD(&master->queue);
spin_lock_init(&master->queue_lock);
master->running = false;
master->busy = false;
init_kthread_worker(&master->kworker);
master->kworker_task = kthread_run(kthread_worker_fn,
&master->kworker, "%s",
dev_name(&master->dev));
if (IS_ERR(master->kworker_task)) {
dev_err(&master->dev, "failed to create message pump task\n");
return -ENOMEM;
}
init_kthread_work(&master->pump_messages, spi_pump_messages);
/*
* Master config will indicate if this controller should run the
* message pump with high (realtime) priority to reduce the transfer
* latency on the bus by minimising the delay between a transfer
* request and the scheduling of the message pump thread. Without this
* setting the message pump thread will remain at default priority.
*/
if (master->rt) {
dev_info(&master->dev,
"will run message pump with realtime priority\n");
sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
}
return 0;
}
/**
* spi_get_next_queued_message() - called by driver to check for queued
* messages
* @master: the master to check for queued messages
*
* If there are more messages in the queue, the next message is returned from
* this call.
*/
struct spi_message *spi_get_next_queued_message(struct spi_master *master)
{
struct spi_message *next;
unsigned long flags;
/* get a pointer to the next message, if any */
spin_lock_irqsave(&master->queue_lock, flags);
if (list_empty(&master->queue))
next = NULL;
else
next = list_entry(master->queue.next,
struct spi_message, queue);
spin_unlock_irqrestore(&master->queue_lock, flags);
return next;
}
EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
/**
* spi_finalize_current_message() - the current message is complete
* @master: the master to return the message to
*
* Called by the driver to notify the core that the message in the front of the
* queue is complete and can be removed from the queue.
*/
void spi_finalize_current_message(struct spi_master *master)
{
struct spi_message *mesg;
unsigned long flags;
int ret;
spin_lock_irqsave(&master->queue_lock, flags);
mesg = master->cur_msg;
master->cur_msg = NULL;
queue_kthread_work(&master->kworker, &master->pump_messages);
spin_unlock_irqrestore(&master->queue_lock, flags);
if (master->cur_msg_prepared && master->unprepare_message) {
ret = master->unprepare_message(master, mesg);
if (ret) {
dev_err(&master->dev,
"failed to unprepare message: %d\n", ret);
}
}
master->cur_msg_prepared = false;
mesg->state = NULL;
if (mesg->complete)
mesg->complete(mesg->context);
trace_spi_message_done(mesg);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_message);
static int spi_start_queue(struct spi_master *master)
{
unsigned long flags;
spin_lock_irqsave(&master->queue_lock, flags);
if (master->running || master->busy) {
spin_unlock_irqrestore(&master->queue_lock, flags);
return -EBUSY;
}
master->running = true;
master->cur_msg = NULL;
spin_unlock_irqrestore(&master->queue_lock, flags);
queue_kthread_work(&master->kworker, &master->pump_messages);
return 0;
}
static int spi_stop_queue(struct spi_master *master)
{
unsigned long flags;
unsigned limit = 500;
int ret = 0;
spin_lock_irqsave(&master->queue_lock, flags);
/*
* This is a bit lame, but is optimized for the common execution path.
* A wait_queue on the master->busy could be used, but then the common
* execution path (pump_messages) would be required to call wake_up or
* friends on every SPI message. Do this instead.
*/
while ((!list_empty(&master->queue) || master->busy) && limit--) {
spin_unlock_irqrestore(&master->queue_lock, flags);
msleep(10);
spin_lock_irqsave(&master->queue_lock, flags);
}
if (!list_empty(&master->queue) || master->busy)
ret = -EBUSY;
else
master->running = false;
spin_unlock_irqrestore(&master->queue_lock, flags);
if (ret) {
dev_warn(&master->dev,
"could not stop message queue\n");
return ret;
}
return ret;
}
static int spi_destroy_queue(struct spi_master *master)
{
int ret;
ret = spi_stop_queue(master);
/*
* flush_kthread_worker will block until all work is done.
* If the reason that stop_queue timed out is that the work will never
* finish, then it does no good to call flush/stop thread, so
* return anyway.
*/
if (ret) {
dev_err(&master->dev, "problem destroying queue\n");
return ret;
}
flush_kthread_worker(&master->kworker);
kthread_stop(master->kworker_task);
return 0;
}
/**
* spi_queued_transfer - transfer function for queued transfers
* @spi: spi device which is requesting transfer
* @msg: spi message which is to handled is queued to driver queue
*/
static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
{
struct spi_master *master = spi->master;
unsigned long flags;
spin_lock_irqsave(&master->queue_lock, flags);
if (!master->running) {
spin_unlock_irqrestore(&master->queue_lock, flags);
return -ESHUTDOWN;
}
msg->actual_length = 0;
msg->status = -EINPROGRESS;
list_add_tail(&msg->queue, &master->queue);
if (!master->busy)
queue_kthread_work(&master->kworker, &master->pump_messages);
spin_unlock_irqrestore(&master->queue_lock, flags);
return 0;
}
static int spi_master_initialize_queue(struct spi_master *master)
{
int ret;
master->queued = true;
master->transfer = spi_queued_transfer;
if (!master->transfer_one_message)
master->transfer_one_message = spi_transfer_one_message;
/* Initialize and start queue */
ret = spi_init_queue(master);
if (ret) {
dev_err(&master->dev, "problem initializing queue\n");
goto err_init_queue;
}
ret = spi_start_queue(master);
if (ret) {
dev_err(&master->dev, "problem starting queue\n");
goto err_start_queue;
}
return 0;
err_start_queue:
err_init_queue:
spi_destroy_queue(master);
return ret;
}
/*-------------------------------------------------------------------------*/
#if defined(CONFIG_OF)
/**
* of_register_spi_devices() - Register child devices onto the SPI bus
* @master: Pointer to spi_master device
*
* Registers an spi_device for each child node of master node which has a 'reg'
* property.
*/
static void of_register_spi_devices(struct spi_master *master)
{
struct spi_device *spi;
struct device_node *nc;
int rc;
u32 value;
if (!master->dev.of_node)
return;
for_each_available_child_of_node(master->dev.of_node, nc) {
/* Alloc an spi_device */
spi = spi_alloc_device(master);
if (!spi) {
dev_err(&master->dev, "spi_device alloc error for %s\n",
nc->full_name);
spi_dev_put(spi);
continue;
}
/* Select device driver */
if (of_modalias_node(nc, spi->modalias,
sizeof(spi->modalias)) < 0) {
dev_err(&master->dev, "cannot find modalias for %s\n",
nc->full_name);
spi_dev_put(spi);
continue;
}
/* Device address */
rc = of_property_read_u32(nc, "reg", &value);
if (rc) {
dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
nc->full_name, rc);
spi_dev_put(spi);
continue;
}
spi->chip_select = value;
/* Mode (clock phase/polarity/etc.) */
if (of_find_property(nc, "spi-cpha", NULL))
spi->mode |= SPI_CPHA;
if (of_find_property(nc, "spi-cpol", NULL))
spi->mode |= SPI_CPOL;
if (of_find_property(nc, "spi-cs-high", NULL))
spi->mode |= SPI_CS_HIGH;
if (of_find_property(nc, "spi-3wire", NULL))
spi->mode |= SPI_3WIRE;
/* Device DUAL/QUAD mode */
if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
switch (value) {
case 1:
break;
case 2:
spi->mode |= SPI_TX_DUAL;
break;
case 4:
spi->mode |= SPI_TX_QUAD;
break;
default:
dev_err(&master->dev,
"spi-tx-bus-width %d not supported\n",
value);
spi_dev_put(spi);
continue;
}
}
if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
switch (value) {
case 1:
break;
case 2:
spi->mode |= SPI_RX_DUAL;
break;
case 4:
spi->mode |= SPI_RX_QUAD;
break;
default:
dev_err(&master->dev,
"spi-rx-bus-width %d not supported\n",
value);
spi_dev_put(spi);
continue;
}
}
/* Device speed */
rc = of_property_read_u32(nc, "spi-max-frequency", &value);
if (rc) {
dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
nc->full_name, rc);
spi_dev_put(spi);
continue;
}
spi->max_speed_hz = value;
/* IRQ */
spi->irq = irq_of_parse_and_map(nc, 0);
/* Store a pointer to the node in the device structure */
of_node_get(nc);
spi->dev.of_node = nc;
/* Register the new device */
request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
rc = spi_add_device(spi);
if (rc) {
dev_err(&master->dev, "spi_device register error %s\n",
nc->full_name);
spi_dev_put(spi);
}
}
}
#else
static void of_register_spi_devices(struct spi_master *master) { }
#endif
#ifdef CONFIG_ACPI
static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
{
struct spi_device *spi = data;
if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
struct acpi_resource_spi_serialbus *sb;
sb = &ares->data.spi_serial_bus;
if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
spi->chip_select = sb->device_selection;
spi->max_speed_hz = sb->connection_speed;
if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
spi->mode |= SPI_CPHA;
if (sb->clock_polarity == ACPI_SPI_START_HIGH)
spi->mode |= SPI_CPOL;
if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
spi->mode |= SPI_CS_HIGH;
}
} else if (spi->irq < 0) {
struct resource r;
if (acpi_dev_resource_interrupt(ares, 0, &r))
spi->irq = r.start;
}
/* Always tell the ACPI core to skip this resource */
return 1;
}
static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct spi_master *master = data;
struct list_head resource_list;
struct acpi_device *adev;
struct spi_device *spi;
int ret;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
if (acpi_bus_get_status(adev) || !adev->status.present)
return AE_OK;
spi = spi_alloc_device(master);
if (!spi) {
dev_err(&master->dev, "failed to allocate SPI device for %s\n",
dev_name(&adev->dev));
return AE_NO_MEMORY;
}
ACPI_HANDLE_SET(&spi->dev, handle);
spi->irq = -1;
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
acpi_spi_add_resource, spi);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0 || !spi->max_speed_hz) {
spi_dev_put(spi);
return AE_OK;
}
adev->power.flags.ignore_parent = true;
strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
if (spi_add_device(spi)) {
adev->power.flags.ignore_parent = false;
dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
dev_name(&adev->dev));
spi_dev_put(spi);
}
return AE_OK;
}
static void acpi_register_spi_devices(struct spi_master *master)
{
acpi_status status;
acpi_handle handle;
handle = ACPI_HANDLE(master->dev.parent);
if (!handle)
return;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
acpi_spi_add_device, NULL,
master, NULL);
if (ACPI_FAILURE(status))
dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
}
#else
static inline void acpi_register_spi_devices(struct spi_master *master) {}
#endif /* CONFIG_ACPI */
static void spi_master_release(struct device *dev)
{
struct spi_master *master;
master = container_of(dev, struct spi_master, dev);
kfree(master);
}
static struct class spi_master_class = {
.name = "spi_master",
.owner = THIS_MODULE,
.dev_release = spi_master_release,
};
/**
* spi_alloc_master - allocate SPI master controller
* @dev: the controller, possibly using the platform_bus
* @size: how much zeroed driver-private data to allocate; the pointer to this
* memory is in the driver_data field of the returned device,
* accessible with spi_master_get_devdata().
* Context: can sleep
*
* This call is used only by SPI master controller drivers, which are the
* only ones directly touching chip registers. It's how they allocate
* an spi_master structure, prior to calling spi_register_master().
*
* This must be called from context that can sleep. It returns the SPI
* master structure on success, else NULL.
*
* The caller is responsible for assigning the bus number and initializing
* the master's methods before calling spi_register_master(); and (after errors
* adding the device) calling spi_master_put() and kfree() to prevent a memory
* leak.
*/
struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
{
struct spi_master *master;
if (!dev)
return NULL;
master = kzalloc(size + sizeof(*master), GFP_KERNEL);
if (!master)
return NULL;
device_initialize(&master->dev);
master->bus_num = -1;
master->num_chipselect = 1;
master->dev.class = &spi_master_class;
master->dev.parent = get_device(dev);
spi_master_set_devdata(master, &master[1]);
return master;
}
EXPORT_SYMBOL_GPL(spi_alloc_master);
#ifdef CONFIG_OF
static int of_spi_register_master(struct spi_master *master)
{
int nb, i, *cs;
struct device_node *np = master->dev.of_node;
if (!np)
return 0;
nb = of_gpio_named_count(np, "cs-gpios");
master->num_chipselect = max_t(int, nb, master->num_chipselect);
/* Return error only for an incorrectly formed cs-gpios property */
if (nb == 0 || nb == -ENOENT)
return 0;
else if (nb < 0)
return nb;
cs = devm_kzalloc(&master->dev,
sizeof(int) * master->num_chipselect,
GFP_KERNEL);
master->cs_gpios = cs;
if (!master->cs_gpios)
return -ENOMEM;
for (i = 0; i < master->num_chipselect; i++)
cs[i] = -ENOENT;
for (i = 0; i < nb; i++)
cs[i] = of_get_named_gpio(np, "cs-gpios", i);
return 0;
}
#else
static int of_spi_register_master(struct spi_master *master)
{
return 0;
}
#endif
/**
* spi_register_master - register SPI master controller
* @master: initialized master, originally from spi_alloc_master()
* Context: can sleep
*
* SPI master controllers connect to their drivers using some non-SPI bus,
* such as the platform bus. The final stage of probe() in that code
* includes calling spi_register_master() to hook up to this SPI bus glue.
*
* SPI controllers use board specific (often SOC specific) bus numbers,
* and board-specific addressing for SPI devices combines those numbers
* with chip select numbers. Since SPI does not directly support dynamic
* device identification, boards need configuration tables telling which
* chip is at which address.
*
* This must be called from context that can sleep. It returns zero on
* success, else a negative error code (dropping the master's refcount).
* After a successful return, the caller is responsible for calling
* spi_unregister_master().
*/
int spi_register_master(struct spi_master *master)
{
static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
struct device *dev = master->dev.parent;
struct boardinfo *bi;
int status = -ENODEV;
int dynamic = 0;
if (!dev)
return -ENODEV;
status = of_spi_register_master(master);
if (status)
return status;
/* even if it's just one always-selected device, there must
* be at least one chipselect
*/
if (master->num_chipselect == 0)
return -EINVAL;
if ((master->bus_num < 0) && master->dev.of_node)
master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
/* convention: dynamically assigned bus IDs count down from the max */
if (master->bus_num < 0) {
/* FIXME switch to an IDR based scheme, something like
* I2C now uses, so we can't run out of "dynamic" IDs
*/
master->bus_num = atomic_dec_return(&dyn_bus_id);
dynamic = 1;
}
spin_lock_init(&master->bus_lock_spinlock);
mutex_init(&master->bus_lock_mutex);
master->bus_lock_flag = 0;
init_completion(&master->xfer_completion);
/* register the device, then userspace will see it.
* registration fails if the bus ID is in use.
*/
dev_set_name(&master->dev, "spi%u", master->bus_num);
status = device_add(&master->dev);
if (status < 0)
goto done;
dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
dynamic ? " (dynamic)" : "");
/* If we're using a queued driver, start the queue */
if (master->transfer)
dev_info(dev, "master is unqueued, this is deprecated\n");
else {
status = spi_master_initialize_queue(master);
if (status) {
device_del(&master->dev);
goto done;
}
}
mutex_lock(&board_lock);
list_add_tail(&master->list, &spi_master_list);
list_for_each_entry(bi, &board_list, list)
spi_match_master_to_boardinfo(master, &bi->board_info);
mutex_unlock(&board_lock);
/* Register devices from the device tree and ACPI */
of_register_spi_devices(master);
acpi_register_spi_devices(master);
done:
return status;
}
EXPORT_SYMBOL_GPL(spi_register_master);
static void devm_spi_unregister(struct device *dev, void *res)
{
spi_unregister_master(*(struct spi_master **)res);
}
/**
* dev_spi_register_master - register managed SPI master controller
* @dev: device managing SPI master
* @master: initialized master, originally from spi_alloc_master()
* Context: can sleep
*
* Register a SPI device as with spi_register_master() which will
* automatically be unregister
*/
int devm_spi_register_master(struct device *dev, struct spi_master *master)
{
struct spi_master **ptr;
int ret;
ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return -ENOMEM;
ret = spi_register_master(master);
if (ret != 0) {
*ptr = master;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return ret;
}
EXPORT_SYMBOL_GPL(devm_spi_register_master);
static int __unregister(struct device *dev, void *null)
{
spi_unregister_device(to_spi_device(dev));
return 0;
}
/**
* spi_unregister_master - unregister SPI master controller
* @master: the master being unregistered
* Context: can sleep
*
* This call is used only by SPI master controller drivers, which are the
* only ones directly touching chip registers.
*
* This must be called from context that can sleep.
*/
void spi_unregister_master(struct spi_master *master)
{
int dummy;
if (master->queued) {
if (spi_destroy_queue(master))
dev_err(&master->dev, "queue remove failed\n");
}
mutex_lock(&board_lock);
list_del(&master->list);
mutex_unlock(&board_lock);
dummy = device_for_each_child(&master->dev, NULL, __unregister);
device_unregister(&master->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_master);
int spi_master_suspend(struct spi_master *master)
{
int ret;
/* Basically no-ops for non-queued masters */
if (!master->queued)
return 0;
ret = spi_stop_queue(master);
if (ret)
dev_err(&master->dev, "queue stop failed\n");
return ret;
}
EXPORT_SYMBOL_GPL(spi_master_suspend);
int spi_master_resume(struct spi_master *master)
{
int ret;
if (!master->queued)
return 0;
ret = spi_start_queue(master);
if (ret)
dev_err(&master->dev, "queue restart failed\n");
return ret;
}
EXPORT_SYMBOL_GPL(spi_master_resume);
static int __spi_master_match(struct device *dev, const void *data)
{
struct spi_master *m;
const u16 *bus_num = data;
m = container_of(dev, struct spi_master, dev);
return m->bus_num == *bus_num;
}
/**
* spi_busnum_to_master - look up master associated with bus_num
* @bus_num: the master's bus number
* Context: can sleep
*
* This call may be used with devices that are registered after
* arch init time. It returns a refcounted pointer to the relevant
* spi_master (which the caller must release), or NULL if there is
* no such master registered.
*/
struct spi_master *spi_busnum_to_master(u16 bus_num)
{
struct device *dev;
struct spi_master *master = NULL;
dev = class_find_device(&spi_master_class, NULL, &bus_num,
__spi_master_match);
if (dev)
master = container_of(dev, struct spi_master, dev);
/* reference got in class_find_device */
return master;
}
EXPORT_SYMBOL_GPL(spi_busnum_to_master);
/*-------------------------------------------------------------------------*/
/* Core methods for SPI master protocol drivers. Some of the
* other core methods are currently defined as inline functions.
*/
/**
* spi_setup - setup SPI mode and clock rate
* @spi: the device whose settings are being modified
* Context: can sleep, and no requests are queued to the device
*
* SPI protocol drivers may need to update the transfer mode if the
* device doesn't work with its default. They may likewise need
* to update clock rates or word sizes from initial values. This function
* changes those settings, and must be called from a context that can sleep.
* Except for SPI_CS_HIGH, which takes effect immediately, the changes take
* effect the next time the device is selected and data is transferred to
* or from it. When this function returns, the spi device is deselected.
*
* Note that this call will fail if the protocol driver specifies an option
* that the underlying controller or its driver does not support. For
* example, not all hardware supports wire transfers using nine bit words,
* LSB-first wire encoding, or active-high chipselects.
*/
int spi_setup(struct spi_device *spi)
{
unsigned bad_bits;
int status = 0;
/* check mode to prevent that DUAL and QUAD set at the same time
*/
if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
dev_err(&spi->dev,
"setup: can not select dual and quad at the same time\n");
return -EINVAL;
}
/* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
*/
if ((spi->mode & SPI_3WIRE) && (spi->mode &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
return -EINVAL;
/* help drivers fail *cleanly* when they need options
* that aren't supported with their current master
*/
bad_bits = spi->mode & ~spi->master->mode_bits;
if (bad_bits) {
dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
bad_bits);
return -EINVAL;
}
if (!spi->bits_per_word)
spi->bits_per_word = 8;
if (spi->master->setup)
status = spi->master->setup(spi);
dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
(spi->mode & SPI_3WIRE) ? "3wire, " : "",
(spi->mode & SPI_LOOP) ? "loopback, " : "",
spi->bits_per_word, spi->max_speed_hz,
status);
return status;
}
EXPORT_SYMBOL_GPL(spi_setup);
static int __spi_async(struct spi_device *spi, struct spi_message *message)
{
struct spi_master *master = spi->master;
struct spi_transfer *xfer;
message->spi = spi;
trace_spi_message_submit(message);
if (list_empty(&message->transfers))
return -EINVAL;
if (!message->complete)
return -EINVAL;
/* Half-duplex links include original MicroWire, and ones with
* only one data pin like SPI_3WIRE (switches direction) or where
* either MOSI or MISO is missing. They can also be caused by
* software limitations.
*/
if ((master->flags & SPI_MASTER_HALF_DUPLEX)
|| (spi->mode & SPI_3WIRE)) {
unsigned flags = master->flags;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
if (xfer->rx_buf && xfer->tx_buf)
return -EINVAL;
if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
return -EINVAL;
if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
return -EINVAL;
}
}
/**
* Set transfer bits_per_word and max speed as spi device default if
* it is not set for this transfer.
* Set transfer tx_nbits and rx_nbits as single transfer default
* (SPI_NBITS_SINGLE) if it is not set for this transfer.
*/
list_for_each_entry(xfer, &message->transfers, transfer_list) {
message->frame_length += xfer->len;
if (!xfer->bits_per_word)
xfer->bits_per_word = spi->bits_per_word;
if (!xfer->speed_hz) {
xfer->speed_hz = spi->max_speed_hz;
if (master->max_speed_hz &&
xfer->speed_hz > master->max_speed_hz)
xfer->speed_hz = master->max_speed_hz;
}
if (master->bits_per_word_mask) {
/* Only 32 bits fit in the mask */
if (xfer->bits_per_word > 32)
return -EINVAL;
if (!(master->bits_per_word_mask &
BIT(xfer->bits_per_word - 1)))
return -EINVAL;
}
if (xfer->speed_hz && master->min_speed_hz &&
xfer->speed_hz < master->min_speed_hz)
return -EINVAL;
if (xfer->speed_hz && master->max_speed_hz &&
xfer->speed_hz > master->max_speed_hz)
return -EINVAL;
if (xfer->tx_buf && !xfer->tx_nbits)
xfer->tx_nbits = SPI_NBITS_SINGLE;
if (xfer->rx_buf && !xfer->rx_nbits)
xfer->rx_nbits = SPI_NBITS_SINGLE;
/* check transfer tx/rx_nbits:
* 1. keep the value is not out of single, dual and quad
* 2. keep tx/rx_nbits is contained by mode in spi_device
* 3. if SPI_3WIRE, tx/rx_nbits should be in single
*/
if (xfer->tx_buf) {
if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
xfer->tx_nbits != SPI_NBITS_DUAL &&
xfer->tx_nbits != SPI_NBITS_QUAD)
return -EINVAL;
if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
return -EINVAL;
if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
!(spi->mode & SPI_TX_QUAD))
return -EINVAL;
if ((spi->mode & SPI_3WIRE) &&
(xfer->tx_nbits != SPI_NBITS_SINGLE))
return -EINVAL;
}
/* check transfer rx_nbits */
if (xfer->rx_buf) {
if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
xfer->rx_nbits != SPI_NBITS_DUAL &&
xfer->rx_nbits != SPI_NBITS_QUAD)
return -EINVAL;
if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
return -EINVAL;
if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
!(spi->mode & SPI_RX_QUAD))
return -EINVAL;
if ((spi->mode & SPI_3WIRE) &&
(xfer->rx_nbits != SPI_NBITS_SINGLE))
return -EINVAL;
}
}
message->status = -EINPROGRESS;
return master->transfer(spi, message);
}
/**
* spi_async - asynchronous SPI transfer
* @spi: device with which data will be exchanged
* @message: describes the data transfers, including completion callback
* Context: any (irqs may be blocked, etc)
*
* This call may be used in_irq and other contexts which can't sleep,
* as well as from task contexts which can sleep.
*
* The completion callback is invoked in a context which can't sleep.
* Before that invocation, the value of message->status is undefined.
* When the callback is issued, message->status holds either zero (to
* indicate complete success) or a negative error code. After that
* callback returns, the driver which issued the transfer request may
* deallocate the associated memory; it's no longer in use by any SPI
* core or controller driver code.
*
* Note that although all messages to a spi_device are handled in
* FIFO order, messages may go to different devices in other orders.
* Some device might be higher priority, or have various "hard" access
* time requirements, for example.
*
* On detection of any fault during the transfer, processing of
* the entire message is aborted, and the device is deselected.
* Until returning from the associated message completion callback,
* no other spi_message queued to that device will be processed.
* (This rule applies equally to all the synchronous transfer calls,
* which are wrappers around this core asynchronous primitive.)
*/
int spi_async(struct spi_device *spi, struct spi_message *message)
{
struct spi_master *master = spi->master;
int ret;
unsigned long flags;
spin_lock_irqsave(&master->bus_lock_spinlock, flags);
if (master->bus_lock_flag)
ret = -EBUSY;
else
ret = __spi_async(spi, message);
spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(spi_async);
/**
* spi_async_locked - version of spi_async with exclusive bus usage
* @spi: device with which data will be exchanged
* @message: describes the data transfers, including completion callback
* Context: any (irqs may be blocked, etc)
*
* This call may be used in_irq and other contexts which can't sleep,
* as well as from task contexts which can sleep.
*
* The completion callback is invoked in a context which can't sleep.
* Before that invocation, the value of message->status is undefined.
* When the callback is issued, message->status holds either zero (to
* indicate complete success) or a negative error code. After that
* callback returns, the driver which issued the transfer request may
* deallocate the associated memory; it's no longer in use by any SPI
* core or controller driver code.
*
* Note that although all messages to a spi_device are handled in
* FIFO order, messages may go to different devices in other orders.
* Some device might be higher priority, or have various "hard" access
* time requirements, for example.
*
* On detection of any fault during the transfer, processing of
* the entire message is aborted, and the device is deselected.
* Until returning from the associated message completion callback,
* no other spi_message queued to that device will be processed.
* (This rule applies equally to all the synchronous transfer calls,
* which are wrappers around this core asynchronous primitive.)
*/
int spi_async_locked(struct spi_device *spi, struct spi_message *message)
{
struct spi_master *master = spi->master;
int ret;
unsigned long flags;
spin_lock_irqsave(&master->bus_lock_spinlock, flags);
ret = __spi_async(spi, message);
spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(spi_async_locked);
/*-------------------------------------------------------------------------*/
/* Utility methods for SPI master protocol drivers, layered on
* top of the core. Some other utility methods are defined as
* inline functions.
*/
static void spi_complete(void *arg)
{
complete(arg);
}
static int __spi_sync(struct spi_device *spi, struct spi_message *message,
int bus_locked)
{
DECLARE_COMPLETION_ONSTACK(done);
int status;
struct spi_master *master = spi->master;
message->complete = spi_complete;
message->context = &done;
if (!bus_locked)
mutex_lock(&master->bus_lock_mutex);
status = spi_async_locked(spi, message);
if (!bus_locked)
mutex_unlock(&master->bus_lock_mutex);
if (status == 0) {
wait_for_completion(&done);
status = message->status;
}
message->context = NULL;
return status;
}
/**
* spi_sync - blocking/synchronous SPI data transfers
* @spi: device with which data will be exchanged
* @message: describes the data transfers
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout. Low-overhead controller
* drivers may DMA directly into and out of the message buffers.
*
* Note that the SPI device's chip select is active during the message,
* and then is normally disabled between messages. Drivers for some
* frequently-used devices may want to minimize costs of selecting a chip,
* by leaving it selected in anticipation that the next message will go
* to the same chip. (That may increase power usage.)
*
* Also, the caller is guaranteeing that the memory associated with the
* message will not be freed before this call returns.
*
* It returns zero on success, else a negative error code.
*/
int spi_sync(struct spi_device *spi, struct spi_message *message)
{
return __spi_sync(spi, message, 0);
}
EXPORT_SYMBOL_GPL(spi_sync);
/**
* spi_sync_locked - version of spi_sync with exclusive bus usage
* @spi: device with which data will be exchanged
* @message: describes the data transfers
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout. Low-overhead controller
* drivers may DMA directly into and out of the message buffers.
*
* This call should be used by drivers that require exclusive access to the
* SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
* be released by a spi_bus_unlock call when the exclusive access is over.
*
* It returns zero on success, else a negative error code.
*/
int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
{
return __spi_sync(spi, message, 1);
}
EXPORT_SYMBOL_GPL(spi_sync_locked);
/**
* spi_bus_lock - obtain a lock for exclusive SPI bus usage
* @master: SPI bus master that should be locked for exclusive bus access
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout.
*
* This call should be used by drivers that require exclusive access to the
* SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
* exclusive access is over. Data transfer must be done by spi_sync_locked
* and spi_async_locked calls when the SPI bus lock is held.
*
* It returns zero on success, else a negative error code.
*/
int spi_bus_lock(struct spi_master *master)
{
unsigned long flags;
mutex_lock(&master->bus_lock_mutex);
spin_lock_irqsave(&master->bus_lock_spinlock, flags);
master->bus_lock_flag = 1;
spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
/* mutex remains locked until spi_bus_unlock is called */
return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_lock);
/**
* spi_bus_unlock - release the lock for exclusive SPI bus usage
* @master: SPI bus master that was locked for exclusive bus access
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout.
*
* This call releases an SPI bus lock previously obtained by an spi_bus_lock
* call.
*
* It returns zero on success, else a negative error code.
*/
int spi_bus_unlock(struct spi_master *master)
{
master->bus_lock_flag = 0;
mutex_unlock(&master->bus_lock_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_unlock);
/* portable code must never pass more than 32 bytes */
#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
static u8 *buf;
/**
* spi_write_then_read - SPI synchronous write followed by read
* @spi: device with which data will be exchanged
* @txbuf: data to be written (need not be dma-safe)
* @n_tx: size of txbuf, in bytes
* @rxbuf: buffer into which data will be read (need not be dma-safe)
* @n_rx: size of rxbuf, in bytes
* Context: can sleep
*
* This performs a half duplex MicroWire style transaction with the
* device, sending txbuf and then reading rxbuf. The return value
* is zero for success, else a negative errno status code.
* This call may only be used from a context that may sleep.
*
* Parameters to this routine are always copied using a small buffer;
* portable code should never use this for more than 32 bytes.
* Performance-sensitive or bulk transfer code should instead use
* spi_{async,sync}() calls with dma-safe buffers.
*/
int spi_write_then_read(struct spi_device *spi,
const void *txbuf, unsigned n_tx,
void *rxbuf, unsigned n_rx)
{
static DEFINE_MUTEX(lock);
int status;
struct spi_message message;
struct spi_transfer x[2];
u8 *local_buf;
/* Use preallocated DMA-safe buffer if we can. We can't avoid
* copying here, (as a pure convenience thing), but we can
* keep heap costs out of the hot path unless someone else is
* using the pre-allocated buffer or the transfer is too large.
*/
if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
GFP_KERNEL | GFP_DMA);
if (!local_buf)
return -ENOMEM;
} else {
local_buf = buf;
}
spi_message_init(&message);
memset(x, 0, sizeof(x));
if (n_tx) {
x[0].len = n_tx;
spi_message_add_tail(&x[0], &message);
}
if (n_rx) {
x[1].len = n_rx;
spi_message_add_tail(&x[1], &message);
}
memcpy(local_buf, txbuf, n_tx);
x[0].tx_buf = local_buf;
x[1].rx_buf = local_buf + n_tx;
/* do the i/o */
status = spi_sync(spi, &message);
if (status == 0)
memcpy(rxbuf, x[1].rx_buf, n_rx);
if (x[0].tx_buf == buf)
mutex_unlock(&lock);
else
kfree(local_buf);
return status;
}
EXPORT_SYMBOL_GPL(spi_write_then_read);
/*-------------------------------------------------------------------------*/
static int __init spi_init(void)
{
int status;
buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
if (!buf) {
status = -ENOMEM;
goto err0;
}
status = bus_register(&spi_bus_type);
if (status < 0)
goto err1;
status = class_register(&spi_master_class);
if (status < 0)
goto err2;
return 0;
err2:
bus_unregister(&spi_bus_type);
err1:
kfree(buf);
buf = NULL;
err0:
return status;
}
/* board_info is normally registered in arch_initcall(),
* but even essential drivers wait till later
*
* REVISIT only boardinfo really needs static linking. the rest (device and
* driver registration) _could_ be dynamically linked (modular) ... costs
* include needing to have boardinfo data structures be much more public.
*/
postcore_initcall(spi_init);