HID: i2c-hid: add ACPI support

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>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 9ef222442ca0e989438ec3695ab473fc427339f3..9e46e4295bd9006addbb92ea136f7d98d0e1d093 100644 (file)
--- 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>
 
@@ -139,6 +140,8 @@ struct i2c_hid {
        unsigned long           flags;          /* device flags */
 
        wait_queue_head_t       wait;           /* For waiting the interrupt */
+
+       struct i2c_hid_platform_data pdata;
 };
 
 static int __i2c_hid_command(struct i2c_client *client,
@@ -810,6 +813,70 @@ static int __devinit i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
        return 0;
 }
 
+#ifdef CONFIG_ACPI
+static int i2c_hid_acpi_pdata(struct i2c_client *client,
+               struct i2c_hid_platform_data *pdata)
+{
+       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 };
+       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 -ENODEV;
+
+       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))) {
+               dev_err(&client->dev, "device _DSM execution failed\n");
+               return -ENODEV;
+       }
+
+       obj = (union acpi_object *)buf.pointer;
+       if (obj->type != ACPI_TYPE_INTEGER) {
+               dev_err(&client->dev, "device _DSM returned invalid type: %d\n",
+                       obj->type);
+               kfree(buf.pointer);
+               return -EINVAL;
+       }
+
+       pdata->hid_descriptor_address = obj->integer.value;
+
+       kfree(buf.pointer);
+       return 0;
+}
+
+static const struct acpi_device_id i2c_hid_acpi_match[] = {
+       {"ACPI0C50", 0 },
+       {"PNP0C50", 0 },
+       { },
+};
+MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
+#else
+static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
+               struct i2c_hid_platform_data *pdata)
+{
+       return -ENODEV;
+}
+#endif
+
 static int __devinit i2c_hid_probe(struct i2c_client *client,
                const struct i2c_device_id *dev_id)
 {
@@ -821,11 +888,6 @@ 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;
-       }
-
        if (!client->irq) {
                dev_err(&client->dev,
                        "HID over i2c has not been provided an Int IRQ\n");
@@ -836,11 +898,22 @@ static int __devinit i2c_hid_probe(struct i2c_client *client,
        if (!ihid)
                return -ENOMEM;
 
+       if (!platform_data) {
+               ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
+               if (ret) {
+                       dev_err(&client->dev,
+                               "HID register address not provided\n");
+                       goto err;
+               }
+       } else {
+               ihid->pdata = *platform_data;
+       }
+
        i2c_set_clientdata(client, ihid);
 
        ihid->client = client;
 
-       hidRegister = platform_data->hid_descriptor_address;
+       hidRegister = ihid->pdata.hid_descriptor_address;
        ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
 
        init_waitqueue_head(&ihid->wait);
@@ -873,6 +946,7 @@ static int __devinit i2c_hid_probe(struct i2c_client *client,
        hid->hid_get_raw_report = i2c_hid_get_raw_report;
        hid->hid_output_raw_report = i2c_hid_output_raw_report;
        hid->dev.parent = &client->dev;
+       ACPI_HANDLE_SET(&hid->dev, ACPI_HANDLE(&client->dev));
        hid->bus = BUS_I2C;
        hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
        hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
@@ -964,6 +1038,7 @@ 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,