leds: lp5523: add master_fader support

This patch introduces 4 new attributes:
  master_fader_leds
  master_fader1
  master_fader2
  master_fader3

Fo example, to map channel 0,6 to master_fader1,
map channel 1,7 to master_fader2,
map channel 2,8 to master_fader3, and
map channel 3,4,5 to none

  echo "123000123" > master_fader_leds

A different factor can be set to each master_fader:

  echo 255 > master_fader1
  echo 100 > master_fader2
  echo 0 > master_fader3

Signed-off-by: Toshi Kikuchi <toshik@chromium.org>
Acked-by: Milo Kim <milo.kim@ti.com>
Tested-by: Milo Kim <milo.kim@ti.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/leds-lp5523.c

@@ -50,6 +50,7 @@
 #define LP5523_REG_OP_MODE		0x01
 #define LP5523_REG_ENABLE_LEDS_MSB	0x04
 #define LP5523_REG_ENABLE_LEDS_LSB	0x05
+#define LP5523_REG_LED_CTRL_BASE	0x06
 #define LP5523_REG_LED_PWM_BASE		0x16
 #define LP5523_REG_LED_CURRENT_BASE	0x26
 #define LP5523_REG_CONFIG		0x36
@@ -57,6 +58,7 @@
 #define LP5523_REG_RESET		0x3D
 #define LP5523_REG_LED_TEST_CTRL	0x41
 #define LP5523_REG_LED_TEST_ADC		0x42
+#define LP5523_REG_MASTER_FADER_BASE	0x48
 #define LP5523_REG_CH1_PROG_START	0x4C
 #define LP5523_REG_CH2_PROG_START	0x4D
 #define LP5523_REG_CH3_PROG_START	0x4E
@@ -78,6 +80,9 @@
 #define LP5523_EXT_CLK_USED		0x08
 #define LP5523_ENG_STATUS_MASK		0x07
 
+#define LP5523_FADER_MAPPING_MASK	0xC0
+#define LP5523_FADER_MAPPING_SHIFT	6
+
 /* Memory Page Selection */
 #define LP5523_PAGE_ENG1		0
 #define LP5523_PAGE_ENG2		1
@@ -666,6 +671,137 @@ release_lock:
 	return pos;
 }
 
+#define show_fader(nr)						\
+static ssize_t show_master_fader##nr(struct device *dev,	\
+			    struct device_attribute *attr,	\
+			    char *buf)				\
+{								\
+	return show_master_fader(dev, attr, buf, nr);		\
+}
+
+#define store_fader(nr)						\
+static ssize_t store_master_fader##nr(struct device *dev,	\
+			     struct device_attribute *attr,	\
+			     const char *buf, size_t len)	\
+{								\
+	return store_master_fader(dev, attr, buf, len, nr);	\
+}
+
+static ssize_t show_master_fader(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf, int nr)
+{
+	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
+	struct lp55xx_chip *chip = led->chip;
+	int ret;
+	u8 val;
+
+	mutex_lock(&chip->lock);
+	ret = lp55xx_read(chip, LP5523_REG_MASTER_FADER_BASE + nr - 1, &val);
+	mutex_unlock(&chip->lock);
+
+	if (ret == 0)
+		ret = sprintf(buf, "%u\n", val);
+
+	return ret;
+}
+show_fader(1)
+show_fader(2)
+show_fader(3)
+
+static ssize_t store_master_fader(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t len, int nr)
+{
+	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
+	struct lp55xx_chip *chip = led->chip;
+	int ret;
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	if (val > 0xff)
+		return -EINVAL;
+
+	mutex_lock(&chip->lock);
+	ret = lp55xx_write(chip, LP5523_REG_MASTER_FADER_BASE + nr - 1,
+			   (u8)val);
+	mutex_unlock(&chip->lock);
+
+	if (ret == 0)
+		ret = len;
+
+	return ret;
+}
+store_fader(1)
+store_fader(2)
+store_fader(3)
+
+static ssize_t show_master_fader_leds(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
+	struct lp55xx_chip *chip = led->chip;
+	int i, ret, pos = 0;
+	u8 val;
+
+	mutex_lock(&chip->lock);
+
+	for (i = 0; i < LP5523_MAX_LEDS; i++) {
+		ret = lp55xx_read(chip, LP5523_REG_LED_CTRL_BASE + i, &val);
+		if (ret)
+			goto leave;
+
+		val = (val & LP5523_FADER_MAPPING_MASK)
+			>> LP5523_FADER_MAPPING_SHIFT;
+		if (val > 3) {
+			ret = -EINVAL;
+			goto leave;
+		}
+		buf[pos++] = val + '0';
+	}
+	buf[pos++] = '\n';
+	ret = pos;
+leave:
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+
+static ssize_t store_master_fader_leds(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t len)
+{
+	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
+	struct lp55xx_chip *chip = led->chip;
+	int i, n, ret;
+	u8 val;
+
+	n = min_t(int, len, LP5523_MAX_LEDS);
+
+	mutex_lock(&chip->lock);
+
+	for (i = 0; i < n; i++) {
+		if (buf[i] >= '0' && buf[i] <= '3') {
+			val = (buf[i] - '0') << LP5523_FADER_MAPPING_SHIFT;
+			ret = lp55xx_update_bits(chip,
+						 LP5523_REG_LED_CTRL_BASE + i,
+						 LP5523_FADER_MAPPING_MASK,
+						 val);
+			if (ret)
+				goto leave;
+		} else {
+			ret = -EINVAL;
+			goto leave;
+		}
+	}
+	ret = len;
+leave:
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+
 static void lp5523_led_brightness_work(struct work_struct *work)
 {
 	struct lp55xx_led *led = container_of(work, struct lp55xx_led,
@@ -688,6 +824,14 @@ static LP55XX_DEV_ATTR_WO(engine1_load, store_engine1_load);
 static LP55XX_DEV_ATTR_WO(engine2_load, store_engine2_load);
 static LP55XX_DEV_ATTR_WO(engine3_load, store_engine3_load);
 static LP55XX_DEV_ATTR_RO(selftest, lp5523_selftest);
+static LP55XX_DEV_ATTR_RW(master_fader1, show_master_fader1,
+			  store_master_fader1);
+static LP55XX_DEV_ATTR_RW(master_fader2, show_master_fader2,
+			  store_master_fader2);
+static LP55XX_DEV_ATTR_RW(master_fader3, show_master_fader3,
+			  store_master_fader3);
+static LP55XX_DEV_ATTR_RW(master_fader_leds, show_master_fader_leds,
+			  store_master_fader_leds);
 
 static struct attribute *lp5523_attributes[] = {
 	&dev_attr_engine1_mode.attr,
@@ -700,6 +844,10 @@ static struct attribute *lp5523_attributes[] = {
 	&dev_attr_engine2_leds.attr,
 	&dev_attr_engine3_leds.attr,
 	&dev_attr_selftest.attr,
+	&dev_attr_master_fader1.attr,
+	&dev_attr_master_fader2.attr,
+	&dev_attr_master_fader3.attr,
+	&dev_attr_master_fader_leds.attr,
 	NULL,
 };