leds: pca963x: enable low-power state

Allow chip to enter low power state when no LEDs are being lit or in
blink mode.

Cc: Peter Meerwald <p.meerwald@bct-electronic.com>,
Cc: Ricardo Ribalda <ricardo.ribalda@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

1 files changed, 33 insertions, 7 deletions

diff --git a/drivers/leds/leds-pca963x.c b/drivers/leds/leds-pca963x.c
index b6ce1f2ec33e..46fbf935944a 100644
--- a/drivers/leds/leds-pca963x.c
+++ b/drivers/leds/leds-pca963x.c
@@ -103,6 +103,7 @@ struct pca963x {
         struct mutex mutex;
         struct i2c_client *client;
         struct pca963x_led *leds;
+        unsigned long leds_on;
 };
 
 struct pca963x_led {
@@ -124,7 +125,6 @@ static int pca963x_brightness(struct pca963x_led *pca963x,
         u8 mask = 0x3 << shift;
         int ret;
 
-        mutex_lock(&pca963x->chip->mutex);
         ledout = i2c_smbus_read_byte_data(pca963x->chip->client, ledout_addr);
         switch (brightness) {
         case LED_FULL:
@@ -141,14 +141,13 @@ static int pca963x_brightness(struct pca963x_led *pca963x,
                         PCA963X_PWM_BASE + pca963x->led_num,
                         brightness);
                 if (ret < 0)
-                        goto unlock;
+                        return ret;
                 ret = i2c_smbus_write_byte_data(pca963x->chip->client,
                         ledout_addr,
                         (ledout & ~mask) | (PCA963X_LED_PWM << shift));
                 break;
         }
-unlock:
-        mutex_unlock(&pca963x->chip->mutex);
+
         return ret;
 }
 
@@ -180,14 +179,41 @@ static void pca963x_blink(struct pca963x_led *pca963x)
         mutex_unlock(&pca963x->chip->mutex);
 }
 
+static int pca963x_power_state(struct pca963x_led *pca963x)
+{
+        unsigned long *leds_on = &pca963x->chip->leds_on;
+        unsigned long cached_leds = pca963x->chip->leds_on;
+
+        if (pca963x->led_cdev.brightness)
+                set_bit(pca963x->led_num, leds_on);
+        else
+                clear_bit(pca963x->led_num, leds_on);
+
+        if (!(*leds_on) != !cached_leds)
+                return i2c_smbus_write_byte_data(pca963x->chip->client,
+                        PCA963X_MODE1, *leds_on ? 0 : BIT(4));
+
+        return 0;
+}
+
 static int pca963x_led_set(struct led_classdev *led_cdev,
         enum led_brightness value)
 {
         struct pca963x_led *pca963x;
+        int ret;
 
         pca963x = container_of(led_cdev, struct pca963x_led, led_cdev);
 
-        return pca963x_brightness(pca963x, value);
+        mutex_lock(&pca963x->chip->mutex);
+
+        ret = pca963x_brightness(pca963x, value);
+        if (ret < 0)
+                goto unlock;
+        ret = pca963x_power_state(pca963x);
+
+unlock:
+        mutex_unlock(&pca963x->chip->mutex);
+        return ret;
 }
 
 static unsigned int pca963x_period_scale(struct pca963x_led *pca963x,
@@ -403,8 +429,8 @@ static int pca963x_probe(struct i2c_client *client,
                         goto exit;
         }
 
-        /* Disable LED all-call address and set normal mode */
-        i2c_smbus_write_byte_data(client, PCA963X_MODE1, 0x00);
+        /* Disable LED all-call address, and power down initially */
+        i2c_smbus_write_byte_data(client, PCA963X_MODE1, BIT(4));
 
         if (pdata) {
                 /* Configure output: open-drain or totem pole (push-pull) */