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>

1 files changed, 81 insertions, 6 deletions

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 9ef222442ca0..9e46e4295bd9 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>
 
@@ -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,