iio: tsl2772: add support for reading proximity led settings from device tree

This patch adds support for optionally reading the proximity led diode
and current settings from device tree. This was tested using a LG
Nexus 5 (hammerhead) which requires a different diode than the driver
default for the IR LED.
Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/light/tsl2772.c

@@ -107,6 +107,8 @@
 #define TSL2772_ALS_GAIN_TRIM_MIN	250
 #define TSL2772_ALS_GAIN_TRIM_MAX	4000
 
+#define TSL2772_MAX_PROX_LEDS		2
+
 /* Device family members */
 enum {
 	tsl2571,
@@ -141,6 +143,14 @@ struct tsl2772_chip_info {
 	const struct iio_info *info;
 };
 
+static const int tsl2772_led_currents[][2] = {
+	{ 100000, TSL2772_100_mA },
+	{  50000, TSL2772_50_mA },
+	{  25000, TSL2772_25_mA },
+	{  13000, TSL2772_13_mA },
+	{      0, 0 }
+};
+
 struct tsl2772_chip {
 	kernel_ulong_t id;
 	struct mutex prox_mutex;
@@ -515,6 +525,75 @@ static int tsl2772_get_prox(struct iio_dev *indio_dev)
 	return ret;
 }
 
+static int tsl2772_read_prox_led_current(struct tsl2772_chip *chip)
+{
+	struct device_node *of_node = chip->client->dev.of_node;
+	int ret, tmp, i;
+
+	ret = of_property_read_u32(of_node, "led-max-microamp", &tmp);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; tsl2772_led_currents[i][0] != 0; i++) {
+		if (tmp == tsl2772_led_currents[i][0]) {
+			chip->settings.prox_power = tsl2772_led_currents[i][1];
+			return 0;
+		}
+	}
+
+	dev_err(&chip->client->dev, "Invalid value %d for led-max-microamp\n",
+		tmp);
+
+	return -EINVAL;
+
+}
+
+static int tsl2772_read_prox_diodes(struct tsl2772_chip *chip)
+{
+	struct device_node *of_node = chip->client->dev.of_node;
+	int i, ret, num_leds, prox_diode_mask;
+	u32 leds[TSL2772_MAX_PROX_LEDS];
+
+	ret = of_property_count_u32_elems(of_node, "amstaos,proximity-diodes");
+	if (ret < 0)
+		return ret;
+
+	num_leds = ret;
+	if (num_leds > TSL2772_MAX_PROX_LEDS)
+		num_leds = TSL2772_MAX_PROX_LEDS;
+
+	ret = of_property_read_u32_array(of_node, "amstaos,proximity-diodes",
+					 leds, num_leds);
+	if (ret < 0) {
+		dev_err(&chip->client->dev,
+			"Invalid value for amstaos,proximity-diodes: %d.\n",
+			ret);
+		return ret;
+	}
+
+	prox_diode_mask = 0;
+	for (i = 0; i < num_leds; i++) {
+		if (leds[i] == 0)
+			prox_diode_mask |= TSL2772_DIODE0;
+		else if (leds[i] == 1)
+			prox_diode_mask |= TSL2772_DIODE1;
+		else {
+			dev_err(&chip->client->dev,
+				"Invalid value %d in amstaos,proximity-diodes.\n",
+				leds[i]);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static void tsl2772_parse_dt(struct tsl2772_chip *chip)
+{
+	tsl2772_read_prox_led_current(chip);
+	tsl2772_read_prox_diodes(chip);
+}
+
 /**
  * tsl2772_defaults() - Populates the device nominal operating parameters
  *                      with those provided by a 'platform' data struct or
@@ -541,6 +620,8 @@ static void tsl2772_defaults(struct tsl2772_chip *chip)
 		memcpy(chip->tsl2772_device_lux,
 		       tsl2772_default_lux_table_group[chip->id],
 		       TSL2772_DEFAULT_TABLE_BYTES);
+
+	tsl2772_parse_dt(chip);
 }
 
 /**