Re: [PATCH] cap11xx: add LED support

[Daniel Mack <daniel@zonque.org>]

Hi Matt,

On 06/09/2015 05:46 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 | 102 +++++++++++++++++++++++++++++++++++++--
>  1 file changed, 99 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/input/keyboard/cap11xx.c b/drivers/input/keyboard/cap11xx.c
> index f07461a..dc48936 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 +48,8 @@
>  #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_SENSOR_CALIB	(0xb1 + (X))
>  #define CAP11XX_REG_SENSOR_CALIB_LSB1	0xb9
>  #define CAP11XX_REG_SENSOR_CALIB_LSB2	0xba
> @@ -56,10 +59,25 @@
>  
>  #define CAP11XX_MANUFACTURER_ID	0x5d
>  
> +#ifdef CONFIG_LEDS_CLASS
> +struct cap11xx_led {
> +	struct cap11xx_priv *priv;
> +	struct led_classdev cdev;
> +	struct work_struct work;
> +	char name[32];
> +	int id;
> +	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 +85,7 @@ struct cap11xx_priv {
>  struct cap11xx_hw_model {
>  	u8 product_id;
>  	unsigned int num_channels;
> +	unsigned int num_leds;
>  };
>  
>  enum {
> @@ -76,9 +95,9 @@ 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 +130,8 @@ 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_LED_OUTPUT_CONTROL,	0x00 },
>  	{ CAP11XX_REG_SENSOR_CALIB_LSB1,	0x00 },
>  	{ CAP11XX_REG_SENSOR_CALIB_LSB2,	0x00 },
>  };
> @@ -196,6 +217,69 @@ 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;
> +
> +	regmap_update_bits(priv->regmap, CAP11XX_REG_LED_OUTPUT_CONTROL,
> +				BIT(led->id), !!value ? BIT(led->id) : 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_register_leds(struct device *dev, struct cap11xx_priv *priv)
> +{
> +	int ret;
> +	int i;
> +
> +	for (i = 0; i < priv->num_leds; i++) {
> +		struct cap11xx_led *led = &priv->leds[i];
> +
> +		snprintf(led->name, sizeof(led->name), "cap11xx:led%d", i + 1);
> +		led->cdev.name = led->name;
> +		led->cdev.brightness_set = cap11xx_led_set;

Use the .brightness_set_sync callback, so you don't have to dance around
with the workers at all.

> +		led->cdev.brightness = LED_OFF;
> +		led->cdev.max_brightness = 1;
> +		led->id = i;
> +		led->priv = priv;
> +
> +		ret = led_classdev_register(dev, &led->cdev);

You can use the devm_variant of this function. That will solve the
tricky part of unwinding if registration of only one LED fails.

> +		if (ret < 0)
> +			return ret;
> +
> +		INIT_WORK(&led->work, cap11xx_led_work);
> +	};
> +	return 0;
> +}
> +
> +static int cap11xx_i2c_remove(struct i2c_client *client)
> +{
> +	struct cap11xx_priv *priv = i2c_get_clientdata(client);
> +	int i;
> +
> +	for (i = 0; i < priv->num_leds; i++) {
> +		led_classdev_unregister(&priv->leds[i].cdev);
> +		cancel_work_sync(&priv->leds[i].work);
> +	}

With the two changes from above, this code can go away.

> +	regmap_update_bits(priv->regmap,
> +		CAP11XX_REG_LED_OUTPUT_CONTROL, 0xff, 0);

Well, we don't reset the other registers either, so I don't know if it's
worth it. After all, the entire function can go away if you left this
register untouched on removal time.

> +
> +	return 0;
> +}
> +#else
> +#define cap11xx_i2c_remove	NULL
> +#endif
> +
>  static int cap11xx_i2c_probe(struct i2c_client *i2c_client,
>  			     const struct i2c_device_id *id)
>  {
> @@ -316,6 +400,17 @@ 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
> +	if (cap->num_leds > 0) {
> +		priv->leds = devm_kzalloc(dev,
> +				cap->num_leds * sizeof(struct cap11xx_led),
> +				GFP_KERNEL);

There's devm_kcalloc(), but that's nitpicking.

> +		if (!priv->leds)
> +			return -ENOMEM;
> +		priv->num_leds = cap->num_leds;
> +		cap11xx_register_leds(dev, priv);

You need to check the return value here and bail.



Thanks,
Daniel