[PATCH v3 2/2] input: qt2160: Add support for LEDs.

[PATCH v3 2/2] input: qt2160: Add support for LEDs.

[Javier Martin]

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>
---
Changes since v2:
 - Make sure LEDS_CLASS is selected.

---
 drivers/input/keyboard/Kconfig  |    2 +-
 drivers/input/keyboard/qt2160.c |   97 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 96 insertions(+), 3 deletions(-)

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index c50fa75..89c792c 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -134,7 +134,7 @@ config KEYBOARD_QT1070
 
 config KEYBOARD_QT2160
 	tristate "Atmel AT42QT2160 Touch Sensor Chip"
-	depends on I2C && EXPERIMENTAL
+	depends on I2C && EXPERIMENTAL && LEDS_CLASS
 	help
 	  If you say yes here you get support for Atmel AT42QT2160 Touch
 	  Sensor chip as a keyboard input.
diff --git a/drivers/input/keyboard/qt2160.c b/drivers/input/keyboard/qt2160.c
index 73ea4b0..e9ce2c5 100644
--- a/drivers/input/keyboard/qt2160.c
+++ b/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)
 
@@ -49,6 +55,15 @@ static unsigned char qt2160_key2code[] = {
 	KEY_C, KEY_D, KEY_E, KEY_F,
 };
 
+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;
+};
+
 struct qt2160_data {
 	struct i2c_client *client;
 	struct input_dev *input;
@@ -56,8 +71,55 @@ struct qt2160_data {
 	spinlock_t lock;        /* Protects canceling/rescheduling of dwork */
 	unsigned short keycodes[ARRAY_SIZE(qt2160_key2code)];
 	u16 key_matrix;
+	struct qt2160_led leds[QT2160_NUM_LEDS_X];
+	struct mutex led_lock;
 };
 
+static int qt2160_read(struct i2c_client *client, u8 reg);
+static int qt2160_write(struct i2c_client *client, u8 reg, u8 data);
+
+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);
+}
+
 static int qt2160_read_block(struct i2c_client *client,
 			     u8 inireg, u8 *buffer, unsigned int count)
 {
@@ -184,7 +246,7 @@ static void qt2160_worker(struct work_struct *work)
 	qt2160_schedule_read(qt2160);
 }
 
-static int __devinit qt2160_read(struct i2c_client *client, u8 reg)
+static int qt2160_read(struct i2c_client *client, u8 reg)
 {
 	int ret;
 
@@ -205,7 +267,7 @@ static int __devinit qt2160_read(struct i2c_client *client, u8 reg)
 	return ret;
 }
 
-static int __devinit qt2160_write(struct i2c_client *client, u8 reg, u8 data)
+static int qt2160_write(struct i2c_client *client, u8 reg, u8 data)
 {
 	int ret;
 
@@ -324,9 +386,34 @@ static int __devinit qt2160_probe(struct i2c_client *client,
 
 	i2c_set_clientdata(client, qt2160);
 	qt2160_schedule_read(qt2160);
+	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);
+
+		error = led_classdev_register(&client->dev, &led->cdev);
+		if (error < 0)
+			goto err_unreg_input;
+	}
+
+	/* 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;
 
+err_unreg_input:
+	input_unregister_device(input);
 err_free_irq:
 	if (client->irq)
 		free_irq(client->irq, qt2160);
@@ -339,6 +426,12 @@ err_free_mem:
 static int __devexit qt2160_remove(struct i2c_client *client)
 {
 	struct qt2160_data *qt2160 = i2c_get_clientdata(client);
+	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);
+	}
 
 	/* Release IRQ so no queue will be scheduled */
 	if (client->irq)
-- 
1.7.9.5

Re: [PATCH v3 2/2] input: qt2160: Add support for LEDs.

[Dmitry Torokhov]

On Fri, Oct 19, 2012 at 11:21:10AM +0200, Javier Martin wrote:
> 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>
> ---
> Changes since v2:
>  - Make sure LEDS_CLASS is selected.

I think that if user does not want LEDs the driver shoudl still be
useful so please just guard LED code with #ifdefs and provide dummy
stubs when not in use.

Thanks.

-- 
Dmitry