Input: qt2160 - add support for LEDs

Outputs x8..x0 of the qt2160 can have leds attached to it.
This patch handles those outputs using the generic LED
framework.

The PWM controls available in the chip are used to achieve
different levels of brightness.

Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/qt2160.c

@@ -20,6 +20,7 @@
 
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/jiffies.h>
@@ -39,6 +40,11 @@
 #define QT2160_CMD_GPIOS      6
 #define QT2160_CMD_SUBVER     7
 #define QT2160_CMD_CALIBRATE  10
+#define QT2160_CMD_DRIVE_X    70
+#define QT2160_CMD_PWMEN_X    74
+#define QT2160_CMD_PWM_DUTY   76
+
+#define QT2160_NUM_LEDS_X	8
 
 #define QT2160_CYCLE_INTERVAL	(2*HZ)
 
@@ -49,15 +55,79 @@ static unsigned char qt2160_key2code[] = {
 	KEY_C, KEY_D, KEY_E, KEY_F,
 };
 
+#ifdef CONFIG_LEDS_CLASS
+struct qt2160_led {
+	struct qt2160_data *qt2160;
+	struct led_classdev cdev;
+	struct work_struct work;
+	char name[32];
+	int id;
+	enum led_brightness new_brightness;
+};
+#endif
+
 struct qt2160_data {
 	struct i2c_client *client;
 	struct input_dev *input;
 	struct delayed_work dwork;
 	spinlock_t lock;        /* Protects canceling/rescheduling of dwork */
 	unsigned short keycodes[ARRAY_SIZE(qt2160_key2code)];
 	u16 key_matrix;
+#ifdef CONFIG_LEDS_CLASS
+	struct qt2160_led leds[QT2160_NUM_LEDS_X];
+	struct mutex led_lock;
+#endif
 };
 
+static int qt2160_read(struct i2c_client *client, u8 reg);
+static int qt2160_write(struct i2c_client *client, u8 reg, u8 data);
+
+#ifdef CONFIG_LEDS_CLASS
+
+static void qt2160_led_work(struct work_struct *work)
+{
+	struct qt2160_led *led = container_of(work, struct qt2160_led, work);
+	struct qt2160_data *qt2160 = led->qt2160;
+	struct i2c_client *client = qt2160->client;
+	int value = led->new_brightness;
+	u32 drive, pwmen;
+
+	mutex_lock(&qt2160->led_lock);
+
+	drive = qt2160_read(client, QT2160_CMD_DRIVE_X);
+	pwmen = qt2160_read(client, QT2160_CMD_PWMEN_X);
+	if (value != LED_OFF) {
+		drive |= (1 << led->id);
+		pwmen |= (1 << led->id);
+
+	} else {
+		drive &= ~(1 << led->id);
+		pwmen &= ~(1 << led->id);
+	}
+	qt2160_write(client, QT2160_CMD_DRIVE_X, drive);
+	qt2160_write(client, QT2160_CMD_PWMEN_X, pwmen);
+
+	/*
+	 * Changing this register will change the brightness
+	 * of every LED in the qt2160. It's a HW limitation.
+	 */
+	if (value != LED_OFF)
+		qt2160_write(client, QT2160_CMD_PWM_DUTY, value);
+
+	mutex_unlock(&qt2160->led_lock);
+}
+
+static void qt2160_led_set(struct led_classdev *cdev,
+			   enum led_brightness value)
+{
+	struct qt2160_led *led = container_of(cdev, struct qt2160_led, cdev);
+
+	led->new_brightness = value;
+	schedule_work(&led->work);
+}
+
+#endif /* CONFIG_LEDS_CLASS */
+
 static int qt2160_read_block(struct i2c_client *client,
 			     u8 inireg, u8 *buffer, unsigned int count)
 {
@@ -216,6 +286,63 @@ static int qt2160_write(struct i2c_client *client, u8 reg, u8 data)
 	return ret;
 }
 
+#ifdef CONFIG_LEDS_CLASS
+
+static int qt2160_register_leds(struct qt2160_data *qt2160)
+{
+	struct i2c_client *client = qt2160->client;
+	int ret;
+	int i;
+
+	mutex_init(&qt2160->led_lock);
+
+	for (i = 0; i < QT2160_NUM_LEDS_X; i++) {
+		struct qt2160_led *led = &qt2160->leds[i];
+
+		snprintf(led->name, sizeof(led->name), "qt2160:x%d", i);
+		led->cdev.name = led->name;
+		led->cdev.brightness_set = qt2160_led_set;
+		led->cdev.brightness = LED_OFF;
+		led->id = i;
+		led->qt2160 = qt2160;
+
+		INIT_WORK(&led->work, qt2160_led_work);
+
+		ret = led_classdev_register(&client->dev, &led->cdev);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Tur off LEDs */
+	qt2160_write(client, QT2160_CMD_DRIVE_X, 0);
+	qt2160_write(client, QT2160_CMD_PWMEN_X, 0);
+	qt2160_write(client, QT2160_CMD_PWM_DUTY, 0);
+
+	return 0;
+}
+
+static void qt2160_unregister_leds(struct qt2160_data *qt2160)
+{
+	int i;
+
+	for (i = 0; i < QT2160_NUM_LEDS_X; i++) {
+		led_classdev_unregister(&qt2160->leds[i].cdev);
+		cancel_work_sync(&qt2160->leds[i].work);
+	}
+}
+
+#else
+
+static inline int qt2160_register_leds(struct qt2160_data *qt2160)
+{
+	return 0;
+}
+
+static inline void qt2160_unregister_leds(struct qt2160_data *qt2160)
+{
+}
+
+#endif
 
 static bool qt2160_identify(struct i2c_client *client)
 {
@@ -249,7 +376,7 @@ static bool qt2160_identify(struct i2c_client *client)
 }
 
 static int qt2160_probe(struct i2c_client *client,
-				  const struct i2c_device_id *id)
+			const struct i2c_device_id *id)
 {
 	struct qt2160_data *qt2160;
 	struct input_dev *input;
@@ -314,18 +441,26 @@ static int qt2160_probe(struct i2c_client *client,
 		}
 	}
 
+	error = qt2160_register_leds(qt2160);
+	if (error) {
+		dev_err(&client->dev, "Failed to register leds\n");
+		goto err_free_irq;
+	}
+
 	error = input_register_device(qt2160->input);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to register input device\n");
-		goto err_free_irq;
+		goto err_unregister_leds;
 	}
 
 	i2c_set_clientdata(client, qt2160);
 	qt2160_schedule_read(qt2160);
 
 	return 0;
 
+err_unregister_leds:
+	qt2160_unregister_leds(qt2160);
 err_free_irq:
 	if (client->irq)
 		free_irq(client->irq, qt2160);
@@ -339,6 +474,8 @@ static int qt2160_remove(struct i2c_client *client)
 {
 	struct qt2160_data *qt2160 = i2c_get_clientdata(client);
 
+	qt2160_unregister_leds(qt2160);
+
 	/* Release IRQ so no queue will be scheduled */
 	if (client->irq)
 		free_irq(client->irq, qt2160);