HID: i2c-hid: add DT bindings

Add device tree based support for HID over I2C devices.

Tested on an Odroid-X board with a Synaptics touchpad.

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

1 files changed, 43 insertions, 1 deletions

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 879b0ed701a3..fc9d92cb3f39 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -35,6 +35,7 @@
 #include <linux/hid.h>
 #include <linux/mutex.h>
 #include <linux/acpi.h>
+#include <linux/of.h>
 
 #include <linux/i2c/i2c-hid.h>
 
@@ -933,6 +934,42 @@ static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
 }
 #endif
 
+#ifdef CONFIG_OF
+static int i2c_hid_of_probe(struct i2c_client *client,
+                struct i2c_hid_platform_data *pdata)
+{
+        struct device *dev = &client->dev;
+        u32 val;
+        int ret;
+
+        ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
+        if (ret) {
+                dev_err(&client->dev, "HID register address not provided\n");
+                return -ENODEV;
+        }
+        if (val >> 16) {
+                dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
+                        val);
+                return -EINVAL;
+        }
+        pdata->hid_descriptor_address = val;
+
+        return 0;
+}
+
+static const struct of_device_id i2c_hid_of_match[] = {
+        { .compatible = "hid-over-i2c" },
+        {},
+};
+MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
+#else
+static inline int i2c_hid_of_probe(struct i2c_client *client,
+                struct i2c_hid_platform_data *pdata)
+{
+        return -ENODEV;
+}
+#endif
+
 static int i2c_hid_probe(struct i2c_client *client,
                          const struct i2c_device_id *dev_id)
 {
@@ -954,7 +991,11 @@ static int i2c_hid_probe(struct i2c_client *client,
         if (!ihid)
                 return -ENOMEM;
 
-        if (!platform_data) {
+        if (client->dev.of_node) {
+                ret = i2c_hid_of_probe(client, &ihid->pdata);
+                if (ret)
+                        goto err;
+        } else if (!platform_data) {
                 ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
                 if (ret) {
                         dev_err(&client->dev,
@@ -1095,6 +1136,7 @@ static struct i2c_driver i2c_hid_driver = {
                 .owner  = THIS_MODULE,
                 .pm     = &i2c_hid_pm,
                 .acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
+                .of_match_table = of_match_ptr(i2c_hid_of_match),
         },
 
         .probe          = i2c_hid_probe,