leds-pca9633: Add mutex to the ledout register

To update an LED a register has to be read, updated and writen. If
another LED whas been updated at the same time, this could lead into
wrong updates.

This patch adds a common mutex to all the leds of the same chip to
protect the ledout register.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

1 files changed, 55 insertions, 31 deletions

diff --git a/drivers/leds/leds-pca9633.c b/drivers/leds/leds-pca9633.c
index 7dd48f896d4e..aaa1c4a0dbc5 100644
--- a/drivers/leds/leds-pca9633.c
+++ b/drivers/leds/leds-pca9633.c
@@ -93,9 +93,17 @@ enum pca9633_cmd {
         BLINK_SET,
 };
 
-struct pca9633_led {
-        struct i2c_client *client;
+struct pca9633_led;
+
+struct pca9633 {
         struct pca9633_chipdef *chipdef;
+        struct mutex mutex;
+        struct i2c_client *client;
+        struct pca9633_led *leds;
+};
+
+struct pca9633_led {
+        struct pca9633 *chip;
         struct work_struct work;
         enum led_brightness brightness;
         struct led_classdev led_cdev;
@@ -108,52 +116,60 @@ struct pca9633_led {
 
 static void pca9633_brightness_work(struct pca9633_led *pca9633)
 {
-        u8 ledout_addr = pca9633->chipdef->ledout_base + (pca9633->led_num / 4);
+        u8 ledout_addr = pca9633->chip->chipdef->ledout_base
+                + (pca9633->led_num / 4);
         u8 ledout;
         int shift = 2 * (pca9633->led_num % 4);
         u8 mask = 0x3 << shift;
 
-        ledout = i2c_smbus_read_byte_data(pca9633->client, ledout_addr);
+        mutex_lock(&pca9633->chip->mutex);
+        ledout = i2c_smbus_read_byte_data(pca9633->chip->client, ledout_addr);
         switch (pca9633->brightness) {
         case LED_FULL:
-                i2c_smbus_write_byte_data(pca9633->client, ledout_addr,
+                i2c_smbus_write_byte_data(pca9633->chip->client, ledout_addr,
                         (ledout & ~mask) | (PCA9633_LED_ON << shift));
                 break;
         case LED_OFF:
-                i2c_smbus_write_byte_data(pca9633->client, ledout_addr,
+                i2c_smbus_write_byte_data(pca9633->chip->client, ledout_addr,
                         ledout & ~mask);
                 break;
         default:
-                i2c_smbus_write_byte_data(pca9633->client,
+                i2c_smbus_write_byte_data(pca9633->chip->client,
                         PCA9633_PWM_BASE + pca9633->led_num,
                         pca9633->brightness);
-                i2c_smbus_write_byte_data(pca9633->client, ledout_addr,
+                i2c_smbus_write_byte_data(pca9633->chip->client, ledout_addr,
                         (ledout & ~mask) | (PCA9633_LED_PWM << shift));
                 break;
         }
+        mutex_unlock(&pca9633->chip->mutex);
 }
 
 static void pca9633_blink_work(struct pca9633_led *pca9633)
 {
-        u8 ledout_addr = pca9633->chipdef->ledout_base + (pca9633->led_num / 4);
-        u8 ledout = i2c_smbus_read_byte_data(pca9633->client, ledout_addr);
-        u8 mode2 = i2c_smbus_read_byte_data(pca9633->client, PCA9633_MODE2);
+        u8 ledout_addr = pca9633->chip->chipdef->ledout_base +
+                (pca9633->led_num / 4);
+        u8 ledout;
+        u8 mode2 = i2c_smbus_read_byte_data(pca9633->chip->client,
+                                                        PCA9633_MODE2);
         int shift = 2 * (pca9633->led_num % 4);
         u8 mask = 0x3 << shift;
 
-        i2c_smbus_write_byte_data(pca9633->client, pca9633->chipdef->grppwm,
-                pca9633->gdc);
+        i2c_smbus_write_byte_data(pca9633->chip->client,
+                        pca9633->chip->chipdef->grppwm, pca9633->gdc);
 
-        i2c_smbus_write_byte_data(pca9633->client, pca9633->chipdef->grpfreq,
-                pca9633->gfrq);
+        i2c_smbus_write_byte_data(pca9633->chip->client,
+                        pca9633->chip->chipdef->grpfreq, pca9633->gfrq);
 
         if (!(mode2 & PCA9633_MODE2_DMBLNK))
-                i2c_smbus_write_byte_data(pca9633->client, PCA9633_MODE2,
+                i2c_smbus_write_byte_data(pca9633->chip->client, PCA9633_MODE2,
                         mode2 | PCA9633_MODE2_DMBLNK);
 
+        mutex_lock(&pca9633->chip->mutex);
+        ledout = i2c_smbus_read_byte_data(pca9633->chip->client, ledout_addr);
         if ((ledout & mask) != (PCA9633_LED_GRP_PWM << shift))
-                i2c_smbus_write_byte_data(pca9633->client, ledout_addr,
+                i2c_smbus_write_byte_data(pca9633->chip->client, ledout_addr,
                         (ledout & ~mask) | (PCA9633_LED_GRP_PWM << shift));
+        mutex_unlock(&pca9633->chip->mutex);
 }
 
 static void pca9633_work(struct work_struct *work)
@@ -318,6 +334,7 @@ pca9633_dt_init(struct i2c_client *client, struct pca9633_chipdef *chip)
 static int pca9633_probe(struct i2c_client *client,
                                         const struct i2c_device_id *id)
 {
+        struct pca9633 *pca9633_chip;
         struct pca9633_led *pca9633;
         struct pca9633_platform_data *pdata;
         struct pca9633_chipdef *chip;
@@ -341,17 +358,30 @@ static int pca9633_probe(struct i2c_client *client,
                 return -EINVAL;
         }
 
+        pca9633_chip = devm_kzalloc(&client->dev, sizeof(*pca9633_chip),
+                                                                GFP_KERNEL);
+        if (!pca9633_chip)
+                return -ENOMEM;
         pca9633 = devm_kzalloc(&client->dev, chip->n_leds * sizeof(*pca9633),
                                                                 GFP_KERNEL);
         if (!pca9633)
                 return -ENOMEM;
 
-        i2c_set_clientdata(client, pca9633);
+        i2c_set_clientdata(client, pca9633_chip);
+
+        mutex_init(&pca9633_chip->mutex);
+        pca9633_chip->chipdef = chip;
+        pca9633_chip->client = client;
+        pca9633_chip->leds = pca9633;
+
+        /* Turn off LEDs by default*/
+        i2c_smbus_write_byte_data(client, chip->ledout_base, 0x00);
+        if (chip->n_leds > 4)
+                i2c_smbus_write_byte_data(client, chip->ledout_base + 1, 0x00);
 
         for (i = 0; i < chip->n_leds; i++) {
-                pca9633[i].client = client;
                 pca9633[i].led_num = i;
-                pca9633[i].chipdef = chip;
+                pca9633[i].chip = pca9633_chip;
 
                 /* Platform data can specify LED names and default triggers */
                 if (pdata && i < pdata->leds.num_leds) {
@@ -389,11 +419,6 @@ static int pca9633_probe(struct i2c_client *client,
         if (pdata && pdata->outdrv == PCA9633_OPEN_DRAIN)
                 i2c_smbus_write_byte_data(client, PCA9633_MODE2, 0x01);
 
-        /* Turn off LEDs */
-        i2c_smbus_write_byte_data(client, chip->ledout_base, 0x00);
-        if (chip->n_leds > 4)
-                i2c_smbus_write_byte_data(client, chip->ledout_base + 1, 0x00);
-
         return 0;
 
 exit:
@@ -407,14 +432,13 @@ exit:
 
 static int pca9633_remove(struct i2c_client *client)
 {
-        struct pca9633_led *pca9633 = i2c_get_clientdata(client);
+        struct pca9633 *pca9633 = i2c_get_clientdata(client);
         int i;
 
-        for (i = 0; i < pca9633->chipdef->n_leds; i++)
-                if (pca9633[i].client != NULL) {
-                        led_classdev_unregister(&pca9633[i].led_cdev);
-                        cancel_work_sync(&pca9633[i].work);
-                }
+        for (i = 0; i < pca9633->chipdef->n_leds; i++) {
+                led_classdev_unregister(&pca9633->leds[i].led_cdev);
+                cancel_work_sync(&pca9633->leds[i].work);
+        }
 
         return 0;
 }