Date:   Sat, 21 Sep 2019 20:06:19 +0200
From:   Jacek Anaszewski <jacek.anaszewski@...il.com>
To:     Dan Murphy <dmurphy@...com>, pavel@....cz
Cc:     linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 9/9] leds: Update the lp55xx to use the multi color
 framework

Dan,

On 9/20/19 7:41 PM, Dan Murphy wrote:
> Update the lp5523 to use the multi color framework.
> 
> Signed-off-by: Dan Murphy <dmurphy@...com>
> ---
>  drivers/leds/leds-lp5523.c                |  13 +++
>  drivers/leds/leds-lp55xx-common.c         | 131 ++++++++++++++++++----
>  drivers/leds/leds-lp55xx-common.h         |   9 ++
>  include/linux/platform_data/leds-lp55xx.h |   6 +
>  4 files changed, 137 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/leds/leds-lp5523.c b/drivers/leds/leds-lp5523.c
> index d0b931a136b9..8b2cdb98fed6 100644
> --- a/drivers/leds/leds-lp5523.c
> +++ b/drivers/leds/leds-lp5523.c
> @@ -791,6 +791,18 @@ static ssize_t store_master_fader_leds(struct device *dev,
>  	return ret;
>  }
>  
> +static int lp5523_led_intensity(struct lp55xx_led *led, int chan_num)
> +{
> +	struct lp55xx_chip *chip = led->chip;
> +	int ret;
> +
> +	mutex_lock(&chip->lock);
> +	ret = lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + chan_num,
> +		     led->brightness);
> +	mutex_unlock(&chip->lock);
> +	return ret;
> +}
> +
>  static int lp5523_led_brightness(struct lp55xx_led *led)
>  {
>  	struct lp55xx_chip *chip = led->chip;
> @@ -857,6 +869,7 @@ static struct lp55xx_device_config lp5523_cfg = {
>  	.max_channel  = LP5523_MAX_LEDS,
>  	.post_init_device   = lp5523_post_init_device,
>  	.brightness_fn      = lp5523_led_brightness,
> +	.color_intensity_fn = lp5523_led_intensity,
>  	.set_led_current    = lp5523_set_led_current,
>  	.firmware_cb        = lp5523_firmware_loaded,
>  	.run_engine         = lp5523_run_engine,
> diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c
> index 44ced02b49f9..a5efe2407832 100644
> --- a/drivers/leds/leds-lp55xx-common.c
> +++ b/drivers/leds/leds-lp55xx-common.c
> @@ -136,9 +136,26 @@ static int lp55xx_set_brightness(struct led_classdev *cdev,
>  {
>  	struct lp55xx_led *led = cdev_to_lp55xx_led(cdev);
>  	struct lp55xx_device_config *cfg = led->chip->cfg;
> +	int adj_value[LED_COLOR_ID_MAX];

This looks suboptimal. This array should have only the number
of elements equal to the number of requested colors.

> +	int ret;
> +	int i;
> +
> +	if (led->mc_cdev.num_leds > 1) {
> +		led_mc_calc_brightness(&led->mc_cdev,
> +				       brightness, adj_value);

I still feel uncomfortable with the name of the third
argument for led_mc_calc_brightness().

In the function definition I proposed brightness_val instead of
adj_value, but this is not too informative either.
How about brightness_dimmed ? If you agree then let's change it
also in the definition. Also the type should be enum led_brightness.

Here we would have the following call:

led_mc_calc_brightness(&led->mc_cdev, brightness, brightness_dimmed);

> +		for (i = 0; i < led->mc_cdev.num_leds; i++) {
> +			led->brightness = adj_value[i];
> +			ret = cfg->color_intensity_fn(led,
> +						      led->grouped_channels[i]);
> +			if (ret)
> +				break;
> +		}
> +	} else {
> +		led->brightness = (u8)brightness;
> +		ret = cfg->brightness_fn(led);
> +	}
>  
> -	led->brightness = (u8)brightness;
> -	return cfg->brightness_fn(led);
> +	return ret;
>  }
>  
>  static int lp55xx_init_led(struct lp55xx_led *led,
> @@ -147,9 +164,9 @@ static int lp55xx_init_led(struct lp55xx_led *led,
>  	struct lp55xx_platform_data *pdata = chip->pdata;
>  	struct lp55xx_device_config *cfg = chip->cfg;
>  	struct device *dev = &chip->cl->dev;
> +	int max_channel = cfg->max_channel;
>  	char name[32];
>  	int ret;
> -	int max_channel = cfg->max_channel;
>  
>  	if (chan >= max_channel) {
>  		dev_err(dev, "invalid channel: %d / %d\n", chan, max_channel);
> @@ -159,10 +176,35 @@ static int lp55xx_init_led(struct lp55xx_led *led,
>  	if (pdata->led_config[chan].led_current == 0)
>  		return 0;
>  
> +	if (pdata->led_config[chan].name) {
> +		led->cdev.name = pdata->led_config[chan].name;
> +	} else {
> +		snprintf(name, sizeof(name), "%s:channel%d",
> +			pdata->label ? : chip->cl->name, chan);
> +		led->cdev.name = name;
> +	}
> +
> +	if (pdata->led_config[chan].num_colors > 1) {> +		led->mc_cdev.led_cdev = &led->cdev;
> +		led->cdev.brightness_set_blocking = lp55xx_set_brightness;
> +		led->cdev.groups = lp55xx_led_groups;
> +		led->mc_cdev.num_leds = pdata->led_config[chan].num_colors;
> +		led->mc_cdev.available_colors = pdata->led_config[chan].available_colors;
> +		memcpy(led->channel_color,
> +		       pdata->led_config[chan].channel_color,
> +		       sizeof(led->channel_color));
> +		memcpy(led->grouped_channels,
> +		       pdata->led_config[chan].grouped_channels,
> +		       sizeof(led->grouped_channels));
> +	} else {
> +
> +		led->cdev.default_trigger = pdata->led_config[chan].default_trigger;
> +		led->cdev.brightness_set_blocking = lp55xx_set_brightness;
> +	}	led->cdev.groups = lp55xx_led_groups;
> +
>  	led->led_current = pdata->led_config[chan].led_current;
>  	led->max_current = pdata->led_config[chan].max_current;
>  	led->chan_nr = pdata->led_config[chan].chan_nr;
> -	led->cdev.default_trigger = pdata->led_config[chan].default_trigger;
>  
>  	if (led->chan_nr >= max_channel) {
>  		dev_err(dev, "Use channel numbers between 0 and %d\n",
> @@ -170,18 +212,11 @@ static int lp55xx_init_led(struct lp55xx_led *led,
>  		return -EINVAL;
>  	}
>  
> -	led->cdev.brightness_set_blocking = lp55xx_set_brightness;
> -	led->cdev.groups = lp55xx_led_groups;
> +	if (pdata->led_config[chan].num_colors > 1)
> +		ret = led_classdev_multicolor_register(dev, &led->mc_cdev);
> +	else
> +		ret = led_classdev_register(dev, &led->cdev);
>  
> -	if (pdata->led_config[chan].name) {
> -		led->cdev.name = pdata->led_config[chan].name;
> -	} else {
> -		snprintf(name, sizeof(name), "%s:channel%d",
> -			pdata->label ? : chip->cl->name, chan);
> -		led->cdev.name = name;
> -	}
> -
> -	ret = led_classdev_register(dev, &led->cdev);
>  	if (ret) {
>  		dev_err(dev, "led register err: %d\n", ret);
>  		return ret;
> @@ -466,7 +501,6 @@ int lp55xx_register_leds(struct lp55xx_led *led, struct lp55xx_chip *chip)
>  		dev_err(&chip->cl->dev, "empty brightness configuration\n");
>  		return -EINVAL;
>  	}
> -
>  	for (i = 0; i < num_channels; i++) {
>  
>  		/* do not initialize channels that are not connected */
> @@ -538,6 +572,38 @@ void lp55xx_unregister_sysfs(struct lp55xx_chip *chip)
>  }
>  EXPORT_SYMBOL_GPL(lp55xx_unregister_sysfs);
>  
> +static int lp5xx_parse_channel_child(struct device_node *np,
> +				     struct lp55xx_led_config *cfg,
> +				     int chan_num)
> +{
> +	struct device_node *child;
> +	int num_colors = 0;
> +	u32 color_id;
> +	u32 led_number;
> +	int ret;
> +
> +	cfg[chan_num].default_trigger =
> +			of_get_property(np, "linux,default-trigger", NULL);
> +
> +	for_each_child_of_node(np, child) {
> +		of_property_read_string(child, "chan-name",
> +					&cfg[chan_num].name);
> +		of_property_read_u8(child, "led-cur",
> +				    &cfg[chan_num].led_current);
> +		of_property_read_u8(child, "max-cur",
> +				    &cfg[chan_num].max_current);
> +		of_property_read_u32(child, "color", &color_id);
> +		cfg[chan_num].channel_color[num_colors] = color_id;
> +		set_bit(color_id, &cfg[chan_num].available_colors);
> +		ret = of_property_read_u32(child, "reg", &led_number);
> +		cfg[chan_num].grouped_channels[num_colors] = led_number;
> +		num_colors++;

We have similar parser snippet below in lp55xx_of_populate_pdata().
Why this duplication is needed? We also need an update to DT bindings.
Now I don't know what's the multicolor DT design for this driver
family.

> +	}
> +	cfg[chan_num].num_colors = num_colors;
> +
> +	return 0;
> +}
> +
>  struct lp55xx_platform_data *lp55xx_of_populate_pdata(struct device *dev,
>  						      struct device_node *np)
>  {
> @@ -545,7 +611,10 @@ struct lp55xx_platform_data *lp55xx_of_populate_pdata(struct device *dev,
>  	struct lp55xx_platform_data *pdata;
>  	struct lp55xx_led_config *cfg;
>  	int num_channels;
> +	int channel_color;
> +	u32 led_number;
>  	int i = 0;
> +	int ret;
>  
>  	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
>  	if (!pdata)
> @@ -565,13 +634,31 @@ struct lp55xx_platform_data *lp55xx_of_populate_pdata(struct device *dev,
>  	pdata->num_channels = num_channels;
>  
>  	for_each_child_of_node(np, child) {
> -		cfg[i].chan_nr = i;
> +		ret = of_property_read_u32(child, "color", &channel_color);
> +		if (ret) {
> +			dev_err(dev,"Missing color property setting white\n");
> +			channel_color = LED_COLOR_ID_WHITE;
> +		}
>  
> -		of_property_read_string(child, "chan-name", &cfg[i].name);
> -		of_property_read_u8(child, "led-cur", &cfg[i].led_current);
> -		of_property_read_u8(child, "max-cur", &cfg[i].max_current);
> -		cfg[i].default_trigger =
> -			of_get_property(child, "linux,default-trigger", NULL);
> +		if (channel_color == LED_COLOR_ID_MULTI)
> +			lp5xx_parse_channel_child(child, cfg, i);
> +		else {
> +			of_property_read_string(child, "chan-name",
> +						&cfg[i].name);
> +			of_property_read_u8(child, "led-cur",
> +					    &cfg[i].led_current);
> +			of_property_read_u8(child, "max-cur",
> +					    &cfg[i].max_current);
> +			cfg[i].default_trigger =
> +				of_get_property(child, "linux,default-trigger",
> +						NULL);
> +			of_property_read_u32(child, "reg", &led_number);
> +
> +			if (led_number < 0 || led_number > 6)
> +				return ERR_PTR(EINVAL);
> +
> +			cfg[i].chan_nr = led_number;
> +		}
>  
>  		i++;
>  	}
> diff --git a/drivers/leds/leds-lp55xx-common.h b/drivers/leds/leds-lp55xx-common.h
> index 783ed5103ce5..d9c114259dcb 100644
> --- a/drivers/leds/leds-lp55xx-common.h
> +++ b/drivers/leds/leds-lp55xx-common.h
> @@ -12,6 +12,8 @@
>  #ifndef _LEDS_LP55XX_COMMON_H
>  #define _LEDS_LP55XX_COMMON_H
>  
> +#include <linux/led-class-multicolor.h>
> +
>  enum lp55xx_engine_index {
>  	LP55XX_ENGINE_INVALID,
>  	LP55XX_ENGINE_1,
> @@ -109,6 +111,9 @@ struct lp55xx_device_config {
>  	/* access brightness register */
>  	int (*brightness_fn)(struct lp55xx_led *led);
>  
> +	/* access specific brightness register */
> +	int (*color_intensity_fn)(struct lp55xx_led *led, int chan_num);
> +
>  	/* current setting function */
>  	void (*set_led_current) (struct lp55xx_led *led, u8 led_current);
>  
> @@ -159,6 +164,7 @@ struct lp55xx_chip {
>   * struct lp55xx_led
>   * @chan_nr         : Channel number
>   * @cdev            : LED class device
> + * @mc_cdev	    : Multi color class device
>   * @led_current     : Current setting at each led channel
>   * @max_current     : Maximun current at each led channel
>   * @brightness      : Brightness value
> @@ -167,9 +173,12 @@ struct lp55xx_chip {
>  struct lp55xx_led {
>  	int chan_nr;
>  	struct led_classdev cdev;
> +	struct led_classdev_mc mc_cdev;
>  	u8 led_current;
>  	u8 max_current;
>  	u8 brightness;
> +	int channel_color[LED_COLOR_ID_MAX];
> +	int grouped_channels[LED_COLOR_ID_MAX];
>  	struct lp55xx_chip *chip;
>  };
>  
> diff --git a/include/linux/platform_data/leds-lp55xx.h b/include/linux/platform_data/leds-lp55xx.h
> index 96a787100fda..0ac29f537ab6 100644
> --- a/include/linux/platform_data/leds-lp55xx.h
> +++ b/include/linux/platform_data/leds-lp55xx.h
> @@ -12,6 +12,8 @@
>  #ifndef _LEDS_LP55XX_H
>  #define _LEDS_LP55XX_H
>  
> +#include <linux/led-class-multicolor.h>
> +
>  /* Clock configuration */
>  #define LP55XX_CLOCK_AUTO	0
>  #define LP55XX_CLOCK_INT	1
> @@ -23,6 +25,10 @@ struct lp55xx_led_config {
>  	u8 chan_nr;
>  	u8 led_current; /* mA x10, 0 if led is not connected */
>  	u8 max_current;
> +	int num_colors;
> +	unsigned long available_colors;
> +	u32 channel_color[LED_COLOR_ID_MAX];
> +	int grouped_channels[LED_COLOR_ID_MAX];

We can do with three-element arrays here.

>  };
>  
>  struct lp55xx_predef_pattern {
> 

-- 
Best regards,
Jacek Anaszewski

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