Input: egalax_ts - get gpio from devicetree

The irq_to_gpio() is old, most platforms use GENERIC_GPIO framework
and don't support this API anymore.

The i.MX6q sabrelite platform equips an egalax touchscreen controller,
and this platform already transfered to GENERIC_GPIO framework, to
support this driver, we use a more generic way to get gpio.

Add a return value checking for waking up the controller in the probe
function, this guarantee only a workable device can pass init.

[[e-mail]: Make driver depend on CONFIG_OF as it is
now required.]

Acked-by Zhang Jiejing <[e-mail]>
Reviewed-by: Shawn Guo <[e-mail]>
Signed-off-by: Hui Wang <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/touchscreen/egalax-ts.txt

···
+* EETI eGalax Multiple Touch Controller
+
+Required properties:
+- compatible: must be "eeti,egalax_ts"
+- reg: i2c slave address
+- interrupt-parent: the phandle for the interrupt controller
+- interrupts: touch controller interrupt
+- wakeup-gpios: the gpio pin to be used for waking up the controller
+  as well as uased as irq pin
+
+Example:
+
+	egalax_ts@04 {
+		compatible = "eeti,egalax_ts";
+		reg = <0x04>;
+		interrupt-parent = <&gpio1>;
+		interrupts = <9 2>;
+		wakeup-gpios = <&gpio1 9 0>;
+	};

drivers/input/touchscreen/Kconfig

···
 
 config TOUCHSCREEN_EGALAX
 	tristate "EETI eGalax multi-touch panel support"
-	depends on I2C
+	depends on I2C && OF
 	help
 	  Say Y here to enable support for I2C connected EETI
 	  eGalax multi-touch panels.

drivers/input/touchscreen/egalax_ts.c

···
 #include <linux/slab.h>
 #include <linux/bitops.h>
 #include <linux/input/mt.h>
+#include <linux/of_gpio.h>
 
 /*
  * Mouse Mode: some panel may configure the controller to mouse mode,
···
 /* wake up controller by an falling edge of interrupt gpio.  */
 static int egalax_wake_up_device(struct i2c_client *client)
 {
-	int gpio = irq_to_gpio(client->irq);
+	struct device_node *np = client->dev.of_node;
+	int gpio;
 	int ret;
+
+	if (!np)
+		return -ENODEV;
+
+	gpio = of_get_named_gpio(np, "wakeup-gpios", 0);
+	if (!gpio_is_valid(gpio))
+		return -ENODEV;
 
 	ret = gpio_request(gpio, "egalax_irq");
 	if (ret < 0) {
···
 	ts->input_dev = input_dev;
 
 	/* controller may be in sleep, wake it up. */
-	egalax_wake_up_device(client);
+	error = egalax_wake_up_device(client);
+	if (error) {
+		dev_err(&client->dev, "Failed to wake up the controller\n");
+		goto err_free_dev;
+	}
 
 	ret = egalax_firmware_version(client);
 	if (ret < 0) {
···
 
 static SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops, egalax_ts_suspend, egalax_ts_resume);
 
+static struct of_device_id egalax_ts_dt_ids[] = {
+	{ .compatible = "eeti,egalax_ts" },
+	{ /* sentinel */ }
+};
+
 static struct i2c_driver egalax_ts_driver = {
 	.driver = {
 		.name	= "egalax_ts",
 		.owner	= THIS_MODULE,
 		.pm	= &egalax_ts_pm_ops,
+		.of_match_table	= of_match_ptr(egalax_ts_dt_ids),
 	},
 	.id_table	= egalax_ts_id,
 	.probe		= egalax_ts_probe,