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

[Jacek Anaszewski <j.anaszewski@samsung.com>]

On 06/16/2015 04:46 AM, Matt Ranostay wrote:
> 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);

You don't need '!!' before value. Any non-zero value is evaluated
to true in conditions.

> +}
> +
> +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);

Why do you schedule work here? It should be done only in brightness_set op.

> +		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);
>
>   	/*
>


-- 
Best Regards,
Jacek Anaszewski