From 3d7d248cf484fe37595698e0ca31a9bcecc85a42 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date: Thu, 13 Jun 2013 09:50:35 +0200
Subject: 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>
---
 drivers/hid/i2c-hid/i2c-hid.c | 44 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

(limited to 'drivers')

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 879b0ed701a..fc9d92cb3f3 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,
-- 
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