[PATCH v4 2/2] cap11xx: add LED support

[Matt Ranostay <mranostay@gmail.com>]

Several cap11xx variants have LEDs that be can be controlled, this
patchset implements this functionality.

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
---
 drivers/input/keyboard/cap11xx.c | 128 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 125 insertions(+), 3 deletions(-)

diff --git a/drivers/input/keyboard/cap11xx.c b/drivers/input/keyboard/cap11xx.c
index f07461a..fc8d365 100644
--- a/drivers/input/keyboard/cap11xx.c
+++ b/drivers/input/keyboard/cap11xx.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/input.h>
+#include <linux/leds.h>
 #include <linux/of_irq.h>
 #include <linux/regmap.h>
 #include <linux/i2c.h>
@@ -47,6 +48,20 @@
 #define CAP11XX_REG_CONFIG2		0x44
 #define CAP11XX_REG_CONFIG2_ALT_POL	BIT(6)
 #define CAP11XX_REG_SENSOR_BASE_CNT(X)	(0x50 + (X))
+#define CAP11XX_REG_LED_POLARITY	0x73
+#define CAP11XX_REG_LED_OUTPUT_CONTROL	0x74
+
+#define CAP11XX_REG_LED_DUTY_CYCLE_1	0x90
+#define CAP11XX_REG_LED_DUTY_CYCLE_2	0x91
+#define CAP11XX_REG_LED_DUTY_CYCLE_3	0x92
+#define CAP11XX_REG_LED_DUTY_CYCLE_4	0x93
+
+#define CAP11XX_REG_LED_DUTY_MIN_MASK	(0x0f)
+#define CAP11XX_REG_LED_DUTY_MIN_MASK_SHIFT	(0)
+#define CAP11XX_REG_LED_DUTY_MAX_MASK	(0xf0)
+#define CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT	(4)
+#define CAP11XX_REG_LED_DUTY_MAX_VALUE	(15)
+
 #define CAP11XX_REG_SENSOR_CALIB	(0xb1 + (X))
 #define CAP11XX_REG_SENSOR_CALIB_LSB1	0xb9
 #define CAP11XX_REG_SENSOR_CALIB_LSB2	0xba
@@ -56,10 +71,24 @@
 
 #define CAP11XX_MANUFACTURER_ID	0x5d
 
+#ifdef CONFIG_LEDS_CLASS
+struct cap11xx_led {
+	struct cap11xx_priv *priv;
+	struct led_classdev cdev;
+	struct work_struct work;
+	u32 reg;
+	enum led_brightness new_brightness;
+};
+#endif
+
 struct cap11xx_priv {
 	struct regmap *regmap;
 	struct input_dev *idev;
 
+#ifdef CONFIG_LEDS_CLASS
+	struct cap11xx_led *leds;
+	int num_leds;
+#endif
 	/* config */
 	u32 keycodes[];
 };
@@ -67,6 +96,7 @@ struct cap11xx_priv {
 struct cap11xx_hw_model {
 	u8 product_id;
 	unsigned int num_channels;
+	unsigned int num_leds;
 };
 
 enum {
@@ -76,9 +106,9 @@ enum {
 };
 
 static const struct cap11xx_hw_model cap11xx_devices[] = {
-	[CAP1106] = { .product_id = 0x55, .num_channels = 6 },
-	[CAP1126] = { .product_id = 0x53, .num_channels = 6 },
-	[CAP1188] = { .product_id = 0x50, .num_channels = 8 },
+	[CAP1106] = { .product_id = 0x55, .num_channels = 6, .num_leds = 0 },
+	[CAP1126] = { .product_id = 0x53, .num_channels = 6, .num_leds = 2 },
+	[CAP1188] = { .product_id = 0x50, .num_channels = 8, .num_leds = 8 },
 };
 
 static const struct reg_default cap11xx_reg_defaults[] = {
@@ -111,6 +141,7 @@ static const struct reg_default cap11xx_reg_defaults[] = {
 	{ CAP11XX_REG_STANDBY_SENSITIVITY,	0x02 },
 	{ CAP11XX_REG_STANDBY_THRESH,		0x40 },
 	{ CAP11XX_REG_CONFIG2,			0x40 },
+	{ CAP11XX_REG_LED_POLARITY,		0x00 },
 	{ CAP11XX_REG_SENSOR_CALIB_LSB1,	0x00 },
 	{ CAP11XX_REG_SENSOR_CALIB_LSB2,	0x00 },
 };
@@ -196,6 +227,91 @@ static void cap11xx_input_close(struct input_dev *idev)
 	cap11xx_set_sleep(priv, true);
 }
 
+#ifdef CONFIG_LEDS_CLASS
+static void cap11xx_led_work(struct work_struct *work)
+{
+	struct cap11xx_led *led = container_of(work, struct cap11xx_led, work);
+	struct cap11xx_priv *priv = led->priv;
+	int value = led->new_brightness;
+
+	/*
+	 * All LEDs share the same duty cycle as this is a HW limitation.
+	 * Brightness levels per LED are either 0 (OFF) and 1 (ON).
+	 *
+	 * Actual brightness level for the ON state for all LEDS is set via the
+	 * "linux,led-brightness" DT property.
+	 */
+	regmap_update_bits(priv->regmap, CAP11XX_REG_LED_OUTPUT_CONTROL,
+				BIT(led->reg), !!value ? BIT(led->reg) : 0);
+}
+
+static void cap11xx_led_set(struct led_classdev *cdev,
+			   enum led_brightness value)
+{
+	struct cap11xx_led *led = container_of(cdev, struct cap11xx_led, cdev);
+
+	led->new_brightness = value;
+	schedule_work(&led->work);
+}
+
+static int cap11xx_init_leds(struct device *dev, struct cap11xx_priv *priv)
+{
+	struct device_node *node = dev->of_node, *child;
+	struct cap11xx_led *led;
+	int cnt = of_get_child_count(node);
+	u32 reg = 0;
+	int error;
+
+	if (!priv->num_leds || !cnt)
+		return 0;
+	if (cnt > priv->num_leds)
+		return -EINVAL;
+
+	led = devm_kcalloc(dev, cnt,
+		sizeof(struct cap11xx_led), GFP_KERNEL);
+	if (!led)
+		return -ENOMEM;
+
+	priv->leds = led;
+	error = of_property_read_u32(node, "linux,led-brightness", &reg);
+	if (error || reg == 0 || reg > CAP11XX_REG_LED_DUTY_MAX_VALUE)
+		reg = CAP11XX_REG_LED_DUTY_MAX_VALUE;
+
+	error = regmap_update_bits(priv->regmap, CAP11XX_REG_LED_DUTY_CYCLE_4,
+				CAP11XX_REG_LED_DUTY_MAX_MASK,
+				reg << CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT);
+	if (error)
+		return error;
+
+	for_each_child_of_node(node, child) {
+		led->cdev.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		led->cdev.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);
+		led->cdev.flags = 0;
+		led->cdev.brightness_set = cap11xx_led_set;
+		led->cdev.max_brightness = 1;
+		led->cdev.brightness = LED_OFF;
+
+		error = of_property_read_u32(child, "reg", &reg);
+		if (error != 0 || reg >= priv->num_leds)
+			continue;
+		led->reg = reg;
+		led->priv = priv;
+
+		INIT_WORK(&led->work, cap11xx_led_work);
+		error = devm_led_classdev_register(dev, &led->cdev);
+		if (error < 0)
+			return -EINVAL;
+
+		schedule_work(&led->work);
+		led++;
+	};
+
+	return 0;
+}
+#endif
+
 static int cap11xx_i2c_probe(struct i2c_client *i2c_client,
 			     const struct i2c_device_id *id)
 {
@@ -316,6 +432,12 @@ static int cap11xx_i2c_probe(struct i2c_client *i2c_client,
 	priv->idev->open = cap11xx_input_open;
 	priv->idev->close = cap11xx_input_close;
 
+#ifdef CONFIG_LEDS_CLASS
+	priv->num_leds = cap->num_leds;
+	error = cap11xx_init_leds(dev, priv);
+	if (error)
+		return error;
+#endif
 	input_set_drvdata(priv->idev, priv);
 
 	/*
-- 
1.9.1