leds: leds-pcs9532 - Move i2c work to a workqueque

Apparently these might be called under atomic context,
and i2c operations may sleep. BUG found by
Ross Burton <ross@burtonini.com>
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

drivers/leds/leds-pca9532.c

@@ -16,6 +16,7 @@
 #include <linux/leds.h>
 #include <linux/input.h>
 #include <linux/mutex.h>
+#include <linux/workqueue.h>
 #include <linux/leds-pca9532.h>
 
 static const unsigned short normal_i2c[] = { /*0x60,*/ I2C_CLIENT_END};
@@ -34,6 +35,7 @@ struct pca9532_data {
 	struct pca9532_led leds[16];
 	struct mutex update_lock;
 	struct input_dev    *idev;
+       struct work_struct work;
 	u8 pwm[2];
 	u8 psc[2];
 };
@@ -63,7 +65,7 @@ static struct i2c_driver pca9532_driver = {
  * as a compromise we average one pwm to the values requested by all
  * leds that are not ON/OFF.
  * */
-static int pca9532_setpwm(struct i2c_client *client, int pwm, int blink,
+static int pca9532_calcpwm(struct i2c_client *client, int pwm, int blink,
 	enum led_brightness value)
 {
 	int a = 0, b = 0, i = 0;
@@ -84,11 +86,17 @@ static int pca9532_setpwm(struct i2c_client *client, int pwm, int blink,
 	b = b/a;
 	if (b > 0xFF)
 		return -EINVAL;
-	mutex_lock(&data->update_lock);
 	data->pwm[pwm] = b;
+       data->psc[pwm] = blink;
+       return 0;
+}
+
+static int pca9532_setpwm(struct i2c_client *client, int pwm)
+{
+       struct pca9532_data *data = i2c_get_clientdata(client);
+       mutex_lock(&data->update_lock);
 	i2c_smbus_write_byte_data(client, PCA9532_REG_PWM(pwm),
 		data->pwm[pwm]);
-	data->psc[pwm] = blink;
 	i2c_smbus_write_byte_data(client, PCA9532_REG_PSC(pwm),
 		data->psc[pwm]);
 	mutex_unlock(&data->update_lock);
@@ -124,11 +132,11 @@ static void pca9532_set_brightness(struct led_classdev *led_cdev,
 		led->state = PCA9532_ON;
 	else {
 		led->state = PCA9532_PWM0; /* Thecus: hardcode one pwm */
-		err = pca9532_setpwm(led->client, 0, 0, value);
+               err = pca9532_calcpwm(led->client, 0, 0, value);
 		if (err)
 			return; /* XXX: led api doesn't allow error code? */
 	}
-	pca9532_setled(led);
+       schedule_work(&led->work);
 }
 
 static int pca9532_set_blink(struct led_classdev *led_cdev,
@@ -137,6 +145,7 @@ static int pca9532_set_blink(struct led_classdev *led_cdev,
 	struct pca9532_led *led = ldev_to_led(led_cdev);
 	struct i2c_client *client = led->client;
 	int psc;
+       int err = 0;
 
 	if (*delay_on == 0 && *delay_off == 0) {
 	/* led subsystem ask us for a blink rate */
@@ -148,7 +157,11 @@ static int pca9532_set_blink(struct led_classdev *led_cdev,
 
 	/* Thecus specific: only use PSC/PWM 0 */
 	psc = (*delay_on * 152-1)/1000;
-	return pca9532_setpwm(client, 0, psc, led_cdev->brightness);
+       err = pca9532_calcpwm(client, 0, psc, led_cdev->brightness);
+       if (err)
+               return err;
+       schedule_work(&led->work);
+       return 0;
 }
 
 static int pca9532_event(struct input_dev *dev, unsigned int type,
@@ -165,13 +178,28 @@ static int pca9532_event(struct input_dev *dev, unsigned int type,
 	else
 		data->pwm[1] = 0;
 
-	dev_info(&dev->dev, "setting beep to %d \n", data->pwm[1]);
+       schedule_work(&data->work);
+
+       return 0;
+}
+
+static void pca9532_input_work(struct work_struct *work)
+{
+       struct pca9532_data *data;
+       data = container_of(work, struct pca9532_data, work);
 	mutex_lock(&data->update_lock);
 	i2c_smbus_write_byte_data(data->client, PCA9532_REG_PWM(1),
 		data->pwm[1]);
 	mutex_unlock(&data->update_lock);
+}
 
-	return 0;
+static void pca9532_led_work(struct work_struct *work)
+{
+       struct pca9532_led *led;
+       led = container_of(work, struct pca9532_led, work);
+       if (led->state == PCA9532_PWM0)
+               pca9532_setpwm(led->client, 0);
+       pca9532_setled(led);
 }
 
 static int pca9532_configure(struct i2c_client *client,
@@ -204,6 +232,7 @@ static int pca9532_configure(struct i2c_client *client,
 			led->ldev.brightness = LED_OFF;
 			led->ldev.brightness_set = pca9532_set_brightness;
 			led->ldev.blink_set = pca9532_set_blink;
+                       INIT_WORK(&led->work, pca9532_led_work);
 			err = led_classdev_register(&client->dev, &led->ldev);
 			if (err < 0) {
 				dev_err(&client->dev,
@@ -233,9 +262,11 @@ static int pca9532_configure(struct i2c_client *client,
 						BIT_MASK(SND_TONE);
 			data->idev->event = pca9532_event;
 			input_set_drvdata(data->idev, data);
+                       INIT_WORK(&data->work, pca9532_input_work);
 			err = input_register_device(data->idev);
 			if (err) {
 				input_free_device(data->idev);
+                               cancel_work_sync(&data->work);
 				data->idev = NULL;
 				goto exit;
 			}
@@ -252,11 +283,13 @@ exit:
 				break;
 			case PCA9532_TYPE_LED:
 				led_classdev_unregister(&data->leds[i].ldev);
+                               cancel_work_sync(&data->leds[i].work);
 				break;
 			case PCA9532_TYPE_N2100_BEEP:
 				if (data->idev != NULL) {
 					input_unregister_device(data->idev);
 					input_free_device(data->idev);
+                                       cancel_work_sync(&data->work);
 					data->idev = NULL;
 				}
 				break;
@@ -307,11 +340,13 @@ static int pca9532_remove(struct i2c_client *client)
 			break;
 		case PCA9532_TYPE_LED:
 			led_classdev_unregister(&data->leds[i].ldev);
+                       cancel_work_sync(&data->leds[i].work);
 			break;
 		case PCA9532_TYPE_N2100_BEEP:
 			if (data->idev != NULL) {
 				input_unregister_device(data->idev);
 				input_free_device(data->idev);
+                               cancel_work_sync(&data->work);
 				data->idev = NULL;
 			}
 			break;

include/linux/leds-pca9532.h

@@ -15,6 +15,7 @@
 #define __LINUX_PCA9532_H
 
 #include <linux/leds.h>
+#include <linux/workqueue.h>
 
 enum pca9532_state {
 	PCA9532_OFF  = 0x0,
@@ -31,6 +32,7 @@ struct pca9532_led {
 	struct i2c_client *client;
 	char *name;
 	struct led_classdev ldev;
+       struct work_struct work;
 	enum pca9532_type type;
 	enum pca9532_state state;
 };