linux/drivers/i2c/i2c-core-acpi.c
Hans de Goede 3a4991a986 i2c: acpi: Do not create i2c-clients for LNXVIDEO ACPI devices
ACPI video devices get tagged by the kernel with the custom LNXVIDEO
HID so that normal pnp-id matching can be used and are handled by the
acpi-video driver.

Sometimes the ACPI nodes describing these contain a SERIAL_TYPE_I2C ACPI
resource. Before this commit the presence of this resource would cause the
i2c-core to create a /sys/bus/i2c/devices/i2c-LNXVIDEO:00 device for this
with a modalias of: "i2c:LNXVIDEO:00".

There is no i2c driver for this custom HID, the acpi-video driver binds
directly to the ACPI device /sys/bus/acpi/devices/LNXVIDEO\:00 which has
a modalias of "acpi:LNXVIDEO:" .

Not only is the creation of an i2c-client for this undesirable, it is
actually causing problems. This weird pseudo-resource claims an i2c
speed of 100KHz and typically points to the i2c bus which is used by the
touchscreen controller. Some touchscreen controllers only work properly at
400KHz, at 100KHz they cause errors like these:

i2c_designware 80860F41:03: i2c_dw_handle_tx_abort: lost arbitration
i2c_designware 80860F41:03: i2c_dw_handle_tx_abort: lost arbitration
i2c_designware 80860F41:03: i2c_dw_handle_tx_abort: lost arbitration
i2c_designware 80860F41:03: i2c_dw_handle_tx_abort: lost arbitration
silead_ts i2c-MSSL1680:00: Registers clear error -11

This commit makes the i2c-core ignore LNXVIDEO compatible ACPI devices
which has 2 positive results:

1) The bogus i2c-client for these is no longer created.
2) i2c_acpi_lookup_speed now ignores the 100KHz speed from the pseudo
i2c-resouce and properly returns 400KHz as speed for the touchscreen
i2c bus, fixing the touchscreen not working on various devies.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-07-04 15:57:34 +02:00

666 lines
16 KiB
C

/*
* Linux I2C core ACPI support code
*
* Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
*
* 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.
*/
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "i2c-core.h"
struct i2c_acpi_handler_data {
struct acpi_connection_info info;
struct i2c_adapter *adapter;
};
struct gsb_buffer {
u8 status;
u8 len;
union {
u16 wdata;
u8 bdata;
u8 data[0];
};
} __packed;
struct i2c_acpi_lookup {
struct i2c_board_info *info;
acpi_handle adapter_handle;
acpi_handle device_handle;
acpi_handle search_handle;
int n;
int index;
u32 speed;
u32 min_speed;
};
static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
{
struct i2c_acpi_lookup *lookup = data;
struct i2c_board_info *info = lookup->info;
struct acpi_resource_i2c_serialbus *sb;
acpi_status status;
if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
return 1;
sb = &ares->data.i2c_serial_bus;
if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
return 1;
if (lookup->index != -1 && lookup->n++ != lookup->index)
return 1;
status = acpi_get_handle(lookup->device_handle,
sb->resource_source.string_ptr,
&lookup->adapter_handle);
if (!ACPI_SUCCESS(status))
return 1;
info->addr = sb->slave_address;
lookup->speed = sb->connection_speed;
if (sb->access_mode == ACPI_I2C_10BIT_MODE)
info->flags |= I2C_CLIENT_TEN;
return 1;
}
static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
/*
* ACPI video acpi_devices, which are handled by the acpi-video driver
* sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
*/
{ ACPI_VIDEO_HID, 0 },
{}
};
static int i2c_acpi_do_lookup(struct acpi_device *adev,
struct i2c_acpi_lookup *lookup)
{
struct i2c_board_info *info = lookup->info;
struct list_head resource_list;
int ret;
if (acpi_bus_get_status(adev) || !adev->status.present ||
acpi_device_enumerated(adev))
return -EINVAL;
if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
return -ENODEV;
memset(info, 0, sizeof(*info));
lookup->device_handle = acpi_device_handle(adev);
/* Look up for I2cSerialBus resource */
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_fill_info, lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0 || !info->addr)
return -EINVAL;
return 0;
}
static int i2c_acpi_get_info(struct acpi_device *adev,
struct i2c_board_info *info,
struct i2c_adapter *adapter,
acpi_handle *adapter_handle)
{
struct list_head resource_list;
struct resource_entry *entry;
struct i2c_acpi_lookup lookup;
int ret;
memset(&lookup, 0, sizeof(lookup));
lookup.info = info;
lookup.index = -1;
ret = i2c_acpi_do_lookup(adev, &lookup);
if (ret)
return ret;
if (adapter) {
/* The adapter must match the one in I2cSerialBus() connector */
if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
return -ENODEV;
} else {
struct acpi_device *adapter_adev;
/* The adapter must be present */
if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
return -ENODEV;
if (acpi_bus_get_status(adapter_adev) ||
!adapter_adev->status.present)
return -ENODEV;
}
info->fwnode = acpi_fwnode_handle(adev);
if (adapter_handle)
*adapter_handle = lookup.adapter_handle;
/* Then fill IRQ number if any */
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
if (ret < 0)
return -EINVAL;
resource_list_for_each_entry(entry, &resource_list) {
if (resource_type(entry->res) == IORESOURCE_IRQ) {
info->irq = entry->res->start;
break;
}
}
acpi_dev_free_resource_list(&resource_list);
acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
sizeof(info->type));
return 0;
}
static void i2c_acpi_register_device(struct i2c_adapter *adapter,
struct acpi_device *adev,
struct i2c_board_info *info)
{
adev->power.flags.ignore_parent = true;
acpi_device_set_enumerated(adev);
if (!i2c_new_device(adapter, info)) {
adev->power.flags.ignore_parent = false;
dev_err(&adapter->dev,
"failed to add I2C device %s from ACPI\n",
dev_name(&adev->dev));
}
}
static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct i2c_adapter *adapter = data;
struct acpi_device *adev;
struct i2c_board_info info;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
if (i2c_acpi_get_info(adev, &info, adapter, NULL))
return AE_OK;
i2c_acpi_register_device(adapter, adev, &info);
return AE_OK;
}
#define I2C_ACPI_MAX_SCAN_DEPTH 32
/**
* i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
* @adap: pointer to adapter
*
* Enumerate all I2C slave devices behind this adapter by walking the ACPI
* namespace. When a device is found it will be added to the Linux device
* model and bound to the corresponding ACPI handle.
*/
void i2c_acpi_register_devices(struct i2c_adapter *adap)
{
acpi_status status;
if (!has_acpi_companion(&adap->dev))
return;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
I2C_ACPI_MAX_SCAN_DEPTH,
i2c_acpi_add_device, NULL,
adap, NULL);
if (ACPI_FAILURE(status))
dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
}
static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct i2c_acpi_lookup *lookup = data;
struct acpi_device *adev;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
if (i2c_acpi_do_lookup(adev, lookup))
return AE_OK;
if (lookup->search_handle != lookup->adapter_handle)
return AE_OK;
if (lookup->speed <= lookup->min_speed)
lookup->min_speed = lookup->speed;
return AE_OK;
}
/**
* i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
* @dev: The device owning the bus
*
* Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
* devices connected to this bus and use the speed of slowest device.
*
* Returns the speed in Hz or zero
*/
u32 i2c_acpi_find_bus_speed(struct device *dev)
{
struct i2c_acpi_lookup lookup;
struct i2c_board_info dummy;
acpi_status status;
if (!has_acpi_companion(dev))
return 0;
memset(&lookup, 0, sizeof(lookup));
lookup.search_handle = ACPI_HANDLE(dev);
lookup.min_speed = UINT_MAX;
lookup.info = &dummy;
lookup.index = -1;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
I2C_ACPI_MAX_SCAN_DEPTH,
i2c_acpi_lookup_speed, NULL,
&lookup, NULL);
if (ACPI_FAILURE(status)) {
dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
return 0;
}
return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
}
EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
static int i2c_acpi_match_adapter(struct device *dev, void *data)
{
struct i2c_adapter *adapter = i2c_verify_adapter(dev);
if (!adapter)
return 0;
return ACPI_HANDLE(dev) == (acpi_handle)data;
}
static int i2c_acpi_match_device(struct device *dev, void *data)
{
return ACPI_COMPANION(dev) == data;
}
static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
{
struct device *dev;
dev = bus_find_device(&i2c_bus_type, NULL, handle,
i2c_acpi_match_adapter);
return dev ? i2c_verify_adapter(dev) : NULL;
}
static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
{
struct device *dev;
dev = bus_find_device(&i2c_bus_type, NULL, adev, i2c_acpi_match_device);
return dev ? i2c_verify_client(dev) : NULL;
}
static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
void *arg)
{
struct acpi_device *adev = arg;
struct i2c_board_info info;
acpi_handle adapter_handle;
struct i2c_adapter *adapter;
struct i2c_client *client;
switch (value) {
case ACPI_RECONFIG_DEVICE_ADD:
if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
break;
adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
if (!adapter)
break;
i2c_acpi_register_device(adapter, adev, &info);
break;
case ACPI_RECONFIG_DEVICE_REMOVE:
if (!acpi_device_enumerated(adev))
break;
client = i2c_acpi_find_client_by_adev(adev);
if (!client)
break;
i2c_unregister_device(client);
put_device(&client->dev);
break;
}
return NOTIFY_OK;
}
struct notifier_block i2c_acpi_notifier = {
.notifier_call = i2c_acpi_notify,
};
/**
* i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
* @dev: Device owning the ACPI resources to get the client from
* @index: Index of ACPI resource to get
* @info: describes the I2C device; note this is modified (addr gets set)
* Context: can sleep
*
* By default the i2c subsys creates an i2c-client for the first I2cSerialBus
* resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
* resources, in that case this function can be used to create an i2c-client
* for other I2cSerialBus resources in the Current Resource Settings table.
*
* Also see i2c_new_device, which this function calls to create the i2c-client.
*
* Returns a pointer to the new i2c-client, or NULL if the adapter is not found.
*/
struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
struct i2c_board_info *info)
{
struct i2c_acpi_lookup lookup;
struct i2c_adapter *adapter;
struct acpi_device *adev;
LIST_HEAD(resource_list);
int ret;
adev = ACPI_COMPANION(dev);
if (!adev)
return NULL;
memset(&lookup, 0, sizeof(lookup));
lookup.info = info;
lookup.device_handle = acpi_device_handle(adev);
lookup.index = index;
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_fill_info, &lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0 || !info->addr)
return NULL;
adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
if (!adapter)
return NULL;
return i2c_new_device(adapter, info);
}
EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
#ifdef CONFIG_ACPI_I2C_OPREGION
static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
u8 cmd, u8 *data, u8 data_len)
{
struct i2c_msg msgs[2];
int ret;
u8 *buffer;
buffer = kzalloc(data_len, GFP_KERNEL);
if (!buffer)
return AE_NO_MEMORY;
msgs[0].addr = client->addr;
msgs[0].flags = client->flags;
msgs[0].len = 1;
msgs[0].buf = &cmd;
msgs[1].addr = client->addr;
msgs[1].flags = client->flags | I2C_M_RD;
msgs[1].len = data_len;
msgs[1].buf = buffer;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0)
dev_err(&client->adapter->dev, "i2c read failed\n");
else
memcpy(data, buffer, data_len);
kfree(buffer);
return ret;
}
static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
u8 cmd, u8 *data, u8 data_len)
{
struct i2c_msg msgs[1];
u8 *buffer;
int ret = AE_OK;
buffer = kzalloc(data_len + 1, GFP_KERNEL);
if (!buffer)
return AE_NO_MEMORY;
buffer[0] = cmd;
memcpy(buffer + 1, data, data_len);
msgs[0].addr = client->addr;
msgs[0].flags = client->flags;
msgs[0].len = data_len + 1;
msgs[0].buf = buffer;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0)
dev_err(&client->adapter->dev, "i2c write failed\n");
kfree(buffer);
return ret;
}
static acpi_status
i2c_acpi_space_handler(u32 function, acpi_physical_address command,
u32 bits, u64 *value64,
void *handler_context, void *region_context)
{
struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
struct i2c_acpi_handler_data *data = handler_context;
struct acpi_connection_info *info = &data->info;
struct acpi_resource_i2c_serialbus *sb;
struct i2c_adapter *adapter = data->adapter;
struct i2c_client *client;
struct acpi_resource *ares;
u32 accessor_type = function >> 16;
u8 action = function & ACPI_IO_MASK;
acpi_status ret;
int status;
ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
if (ACPI_FAILURE(ret))
return ret;
client = kzalloc(sizeof(*client), GFP_KERNEL);
if (!client) {
ret = AE_NO_MEMORY;
goto err;
}
if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
ret = AE_BAD_PARAMETER;
goto err;
}
sb = &ares->data.i2c_serial_bus;
if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
ret = AE_BAD_PARAMETER;
goto err;
}
client->adapter = adapter;
client->addr = sb->slave_address;
if (sb->access_mode == ACPI_I2C_10BIT_MODE)
client->flags |= I2C_CLIENT_TEN;
switch (accessor_type) {
case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
if (action == ACPI_READ) {
status = i2c_smbus_read_byte(client);
if (status >= 0) {
gsb->bdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_byte(client, gsb->bdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_BYTE:
if (action == ACPI_READ) {
status = i2c_smbus_read_byte_data(client, command);
if (status >= 0) {
gsb->bdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_byte_data(client, command,
gsb->bdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_WORD:
if (action == ACPI_READ) {
status = i2c_smbus_read_word_data(client, command);
if (status >= 0) {
gsb->wdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_word_data(client, command,
gsb->wdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
if (action == ACPI_READ) {
status = i2c_smbus_read_block_data(client, command,
gsb->data);
if (status >= 0) {
gsb->len = status;
status = 0;
}
} else {
status = i2c_smbus_write_block_data(client, command,
gsb->len, gsb->data);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
if (action == ACPI_READ) {
status = acpi_gsb_i2c_read_bytes(client, command,
gsb->data, info->access_length);
if (status > 0)
status = 0;
} else {
status = acpi_gsb_i2c_write_bytes(client, command,
gsb->data, info->access_length);
}
break;
default:
dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
accessor_type, client->addr);
ret = AE_BAD_PARAMETER;
goto err;
}
gsb->status = status;
err:
kfree(client);
ACPI_FREE(ares);
return ret;
}
int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
{
acpi_handle handle;
struct i2c_acpi_handler_data *data;
acpi_status status;
if (!adapter->dev.parent)
return -ENODEV;
handle = ACPI_HANDLE(adapter->dev.parent);
if (!handle)
return -ENODEV;
data = kzalloc(sizeof(struct i2c_acpi_handler_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
data->adapter = adapter;
status = acpi_bus_attach_private_data(handle, (void *)data);
if (ACPI_FAILURE(status)) {
kfree(data);
return -ENOMEM;
}
status = acpi_install_address_space_handler(handle,
ACPI_ADR_SPACE_GSBUS,
&i2c_acpi_space_handler,
NULL,
data);
if (ACPI_FAILURE(status)) {
dev_err(&adapter->dev, "Error installing i2c space handler\n");
acpi_bus_detach_private_data(handle);
kfree(data);
return -ENOMEM;
}
acpi_walk_dep_device_list(handle);
return 0;
}
void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
{
acpi_handle handle;
struct i2c_acpi_handler_data *data;
acpi_status status;
if (!adapter->dev.parent)
return;
handle = ACPI_HANDLE(adapter->dev.parent);
if (!handle)
return;
acpi_remove_address_space_handler(handle,
ACPI_ADR_SPACE_GSBUS,
&i2c_acpi_space_handler);
status = acpi_bus_get_private_data(handle, (void **)&data);
if (ACPI_SUCCESS(status))
kfree(data);
acpi_bus_detach_private_data(handle);
}
#endif /* CONFIG_ACPI_I2C_OPREGION */