linux/drivers/soundwire/slave.c
Pierre-Louis Bossart 0173f525b2 soundwire: sysfs: add slave status and device number before probe
The MIPI DisCo device properties that are read by the driver from
platform firmware, or hard-coded in the driver, should only be
provided as sysfs entries when a driver probes successfully.

However the device status and device number is updated even when there
is no driver present, and hence can be updated when a Slave device is
detected on the bus without being described in platform firmware and
without any driver registered/probed.

As suggested by GregKH, the attribute group for Slave status and
device number is is added by default upon device registration.

Credits to Vinod Koul for the status_show() function, shared in a
separate patch and used as is here. The status table was modified to
remove an unnecessary enum and status_show() is handled in a different
group attribute than what was suggested by Vinod.

Tested-by: Srinivas Kandgatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Co-developed-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200924194430.121058-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-09-28 11:17:43 +05:30

244 lines
5.6 KiB
C

// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
// Copyright(c) 2015-17 Intel Corporation.
#include <linux/acpi.h>
#include <linux/of.h>
#include <linux/soundwire/sdw.h>
#include <linux/soundwire/sdw_type.h>
#include "bus.h"
#include "sysfs_local.h"
static void sdw_slave_release(struct device *dev)
{
struct sdw_slave *slave = dev_to_sdw_dev(dev);
kfree(slave);
}
struct device_type sdw_slave_type = {
.name = "sdw_slave",
.release = sdw_slave_release,
.uevent = sdw_slave_uevent,
};
int sdw_slave_add(struct sdw_bus *bus,
struct sdw_slave_id *id, struct fwnode_handle *fwnode)
{
struct sdw_slave *slave;
int ret;
int i;
slave = kzalloc(sizeof(*slave), GFP_KERNEL);
if (!slave)
return -ENOMEM;
/* Initialize data structure */
memcpy(&slave->id, id, sizeof(*id));
slave->dev.parent = bus->dev;
slave->dev.fwnode = fwnode;
if (id->unique_id == SDW_IGNORED_UNIQUE_ID) {
/* name shall be sdw:link:mfg:part:class */
dev_set_name(&slave->dev, "sdw:%x:%x:%x:%x",
bus->link_id, id->mfg_id, id->part_id,
id->class_id);
} else {
/* name shall be sdw:link:mfg:part:class:unique */
dev_set_name(&slave->dev, "sdw:%x:%x:%x:%x:%x",
bus->link_id, id->mfg_id, id->part_id,
id->class_id, id->unique_id);
}
slave->dev.bus = &sdw_bus_type;
slave->dev.of_node = of_node_get(to_of_node(fwnode));
slave->dev.type = &sdw_slave_type;
slave->dev.groups = sdw_slave_status_attr_groups;
slave->bus = bus;
slave->status = SDW_SLAVE_UNATTACHED;
init_completion(&slave->enumeration_complete);
init_completion(&slave->initialization_complete);
slave->dev_num = 0;
init_completion(&slave->probe_complete);
slave->probed = false;
slave->first_interrupt_done = false;
for (i = 0; i < SDW_MAX_PORTS; i++)
init_completion(&slave->port_ready[i]);
mutex_lock(&bus->bus_lock);
list_add_tail(&slave->node, &bus->slaves);
mutex_unlock(&bus->bus_lock);
ret = device_register(&slave->dev);
if (ret) {
dev_err(bus->dev, "Failed to add slave: ret %d\n", ret);
/*
* On err, don't free but drop ref as this will be freed
* when release method is invoked.
*/
mutex_lock(&bus->bus_lock);
list_del(&slave->node);
mutex_unlock(&bus->bus_lock);
put_device(&slave->dev);
return ret;
}
sdw_slave_debugfs_init(slave);
return ret;
}
#if IS_ENABLED(CONFIG_ACPI)
static bool find_slave(struct sdw_bus *bus,
struct acpi_device *adev,
struct sdw_slave_id *id)
{
unsigned long long addr;
unsigned int link_id;
acpi_status status;
status = acpi_evaluate_integer(adev->handle,
METHOD_NAME__ADR, NULL, &addr);
if (ACPI_FAILURE(status)) {
dev_err(bus->dev, "_ADR resolution failed: %x\n",
status);
return false;
}
/* Extract link id from ADR, Bit 51 to 48 (included) */
link_id = SDW_DISCO_LINK_ID(addr);
/* Check for link_id match */
if (link_id != bus->link_id)
return false;
sdw_extract_slave_id(bus, addr, id);
return true;
}
/*
* sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
* @bus: SDW bus instance
*
* Scans Master ACPI node for SDW child Slave devices and registers it.
*/
int sdw_acpi_find_slaves(struct sdw_bus *bus)
{
struct acpi_device *adev, *parent;
struct acpi_device *adev2, *parent2;
parent = ACPI_COMPANION(bus->dev);
if (!parent) {
dev_err(bus->dev, "Can't find parent for acpi bind\n");
return -ENODEV;
}
list_for_each_entry(adev, &parent->children, node) {
struct sdw_slave_id id;
struct sdw_slave_id id2;
bool ignore_unique_id = true;
if (!find_slave(bus, adev, &id))
continue;
/* brute-force O(N^2) search for duplicates */
parent2 = parent;
list_for_each_entry(adev2, &parent2->children, node) {
if (adev == adev2)
continue;
if (!find_slave(bus, adev2, &id2))
continue;
if (id.sdw_version != id2.sdw_version ||
id.mfg_id != id2.mfg_id ||
id.part_id != id2.part_id ||
id.class_id != id2.class_id)
continue;
if (id.unique_id != id2.unique_id) {
dev_dbg(bus->dev,
"Valid unique IDs %x %x for Slave mfg %x part %d\n",
id.unique_id, id2.unique_id,
id.mfg_id, id.part_id);
ignore_unique_id = false;
} else {
dev_err(bus->dev,
"Invalid unique IDs %x %x for Slave mfg %x part %d\n",
id.unique_id, id2.unique_id,
id.mfg_id, id.part_id);
return -ENODEV;
}
}
if (ignore_unique_id)
id.unique_id = SDW_IGNORED_UNIQUE_ID;
/*
* don't error check for sdw_slave_add as we want to continue
* adding Slaves
*/
sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
}
return 0;
}
#endif
/*
* sdw_of_find_slaves() - Find Slave devices in master device tree node
* @bus: SDW bus instance
*
* Scans Master DT node for SDW child Slave devices and registers it.
*/
int sdw_of_find_slaves(struct sdw_bus *bus)
{
struct device *dev = bus->dev;
struct device_node *node;
for_each_child_of_node(bus->dev->of_node, node) {
int link_id, ret, len;
unsigned int sdw_version;
const char *compat = NULL;
struct sdw_slave_id id;
const __be32 *addr;
compat = of_get_property(node, "compatible", NULL);
if (!compat)
continue;
ret = sscanf(compat, "sdw%01x%04hx%04hx%02hhx", &sdw_version,
&id.mfg_id, &id.part_id, &id.class_id);
if (ret != 4) {
dev_err(dev, "Invalid compatible string found %s\n",
compat);
continue;
}
addr = of_get_property(node, "reg", &len);
if (!addr || (len < 2 * sizeof(u32))) {
dev_err(dev, "Invalid Link and Instance ID\n");
continue;
}
link_id = be32_to_cpup(addr++);
id.unique_id = be32_to_cpup(addr);
id.sdw_version = sdw_version;
/* Check for link_id match */
if (link_id != bus->link_id)
continue;
sdw_slave_add(bus, &id, of_fwnode_handle(node));
}
return 0;
}