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Subject[PATCH] HID: i2c-hid: add ACPI support
Date
The HID over I2C protocol specification states that when the device is
enumerated from ACPI the HID descriptor address can be obtained by
executing "_DSM" for the device with function 1. Enable this.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
drivers/hid/i2c-hid/i2c-hid.c | 73 +++++++++++++++++++++++++++++++++++++++--
1 file changed, 71 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 9ef22244..b2eebb6 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -34,6 +34,7 @@
#include <linux/kernel.h>
#include <linux/hid.h>
#include <linux/mutex.h>
+#include <linux/acpi.h>

#include <linux/i2c/i2c-hid.h>

@@ -810,6 +811,70 @@ static int __devinit i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
return 0;
}

+#ifdef CONFIG_ACPI
+static struct i2c_hid_platform_data *
+i2c_hid_acpi_pdata(struct i2c_client *client)
+{
+ static u8 i2c_hid_guid[] = {
+ 0xF7, 0xF6, 0xDF, 0x3C, 0x67, 0x42, 0x55, 0x45,
+ 0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE,
+ };
+ struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
+ struct i2c_hid_platform_data *pdata = NULL;
+ union acpi_object params[4], *obj;
+ struct acpi_object_list input;
+ struct acpi_device *adev;
+ acpi_handle handle;
+
+ handle = ACPI_HANDLE(&client->dev);
+ if (!handle || acpi_bus_get_device(handle, &adev))
+ return NULL;
+
+ input.count = ARRAY_SIZE(params);
+ input.pointer = params;
+
+ params[0].type = ACPI_TYPE_BUFFER;
+ params[0].buffer.length = sizeof(i2c_hid_guid);
+ params[0].buffer.pointer = i2c_hid_guid;
+ params[1].type = ACPI_TYPE_INTEGER;
+ params[1].integer.value = 1;
+ params[2].type = ACPI_TYPE_INTEGER;
+ params[2].integer.value = 1; /* HID function */
+ params[3].type = ACPI_TYPE_INTEGER;
+ params[3].integer.value = 0;
+
+ if (ACPI_FAILURE(acpi_evaluate_object(handle, "_DSM", &input, &buf)))
+ return NULL;
+
+ obj = (union acpi_object *)buf.pointer;
+ if (obj->type != ACPI_TYPE_INTEGER)
+ goto fail;
+
+ pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ goto fail;
+
+ pdata->hid_descriptor_address = obj->integer.value;
+
+fail:
+ kfree(buf.pointer);
+ return pdata;
+}
+
+static struct acpi_device_id i2c_hid_acpi_match[] = {
+ {"ACPI0C50", 0 },
+ {"PNP0C50", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
+#else
+static inline struct i2c_hid_platform_data *
+i2c_hid_acpi_pdata(struct i2c_client *client)
+{
+ return NULL;
+}
+#endif
+
static int __devinit i2c_hid_probe(struct i2c_client *client,
const struct i2c_device_id *dev_id)
{
@@ -822,8 +887,11 @@ static int __devinit i2c_hid_probe(struct i2c_client *client,
dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);

if (!platform_data) {
- dev_err(&client->dev, "HID register address not provided\n");
- return -EINVAL;
+ platform_data = i2c_hid_acpi_pdata(client);
+ if (!platform_data) {
+ dev_err(&client->dev, "HID register address not provided\n");
+ return -EINVAL;
+ }
}

if (!client->irq) {
@@ -964,6 +1032,7 @@ static struct i2c_driver i2c_hid_driver = {
.name = "i2c_hid",
.owner = THIS_MODULE,
.pm = &i2c_hid_pm,
+ .acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
},

.probe = i2c_hid_probe,
--
1.7.10.4


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