Re: [PATCH 2/2] leds: leds-pca995x: Add support for NXP PCA9956B

[Marek Vasut <marex@denx.de>]

On 7/10/24 8:15 AM, Pieterjan Camerlynck via B4 Relay wrote:
> From: Pieterjan Camerlynck <pieterjanca@gmail.com>
> 
> Add support for PCA9956B chip, which belongs to the same family.
> 
> This chip features 24 instead of 16 outputs, so add a chipdef struct to
> deal with the different register layouts.
> 
> Signed-off-by: Pieterjan Camerlynck <pieterjanca@gmail.com>
> ---
>   drivers/leds/leds-pca995x.c | 88 ++++++++++++++++++++++++++-------------------
>   1 file changed, 52 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/leds/leds-pca995x.c b/drivers/leds/leds-pca995x.c
> index 78215dff1499..4cd2828a3f2d 100644
> --- a/drivers/leds/leds-pca995x.c
> +++ b/drivers/leds/leds-pca995x.c
> @@ -19,10 +19,6 @@
>   #define PCA995X_MODE1			0x00
>   #define PCA995X_MODE2			0x01
>   #define PCA995X_LEDOUT0			0x02
> -#define PCA9955B_PWM0			0x08
> -#define PCA9952_PWM0			0x0A
> -#define PCA9952_IREFALL			0x43
> -#define PCA9955B_IREFALL		0x45
>   
>   /* Auto-increment disabled. Normal mode */
>   #define PCA995X_MODE1_CFG		0x00
> @@ -34,17 +30,43 @@
>   #define PCA995X_LDRX_MASK		0x3
>   #define PCA995X_LDRX_BITS		2
>   
> -#define PCA995X_MAX_OUTPUTS		16
>   #define PCA995X_OUTPUTS_PER_REG		4
>   
>   #define PCA995X_IREFALL_FULL_CFG	0xFF
>   #define PCA995X_IREFALL_HALF_CFG	(PCA995X_IREFALL_FULL_CFG / 2)
>   
> -#define PCA995X_TYPE_NON_B		0
> -#define PCA995X_TYPE_B			1
> -
>   #define ldev_to_led(c)	container_of(c, struct pca995x_led, ldev)
>   
> +enum pca995x_type {
> +	pca9952,
> +	pca9955b,
> +	pca9956b,
> +};

This enum shouldn't be needed (see below).

> +struct pca995x_chipdef {
> +	unsigned int num_leds;
> +	u8 pwm_base;
> +	u8 irefall;
> +};
> +
> +static const struct pca995x_chipdef pca995x_chipdefs[] = {

Define three separate static const struct pca995x_chipdef {} , one for 
each chip type ...

> +	[pca9952] = {
> +		.num_leds	= 16,
> +		.pwm_base	= 0x0a,
> +		.irefall	= 0x43,
> +	},
> +	[pca9955b] = {
> +		.num_leds	= 16,
> +		.pwm_base	= 0x08,
> +		.irefall	= 0x45,
> +	},
> +	[pca9956b] = {
> +		.num_leds	= 24,
> +		.pwm_base	= 0x0a,
> +		.irefall	= 0x40,
> +	},
> +};
> +
>   struct pca995x_led {
>   	unsigned int led_no;
>   	struct led_classdev ldev;
> @@ -52,9 +74,9 @@ struct pca995x_led {
>   };
>   
>   struct pca995x_chip {
> +	const struct pca995x_chipdef *chipdef;
>   	struct regmap *regmap;
> -	struct pca995x_led leds[PCA995X_MAX_OUTPUTS];
> -	int btype;
> +	struct pca995x_led leds[];
>   };
>   
>   static int pca995x_brightness_set(struct led_classdev *led_cdev,
> @@ -62,10 +84,11 @@ static int pca995x_brightness_set(struct led_classdev *led_cdev,
>   {
>   	struct pca995x_led *led = ldev_to_led(led_cdev);
>   	struct pca995x_chip *chip = led->chip;
> +	const struct pca995x_chipdef *chipdef = chip->chipdef;
>   	u8 ledout_addr, pwmout_addr;
>   	int shift, ret;
>   
> -	pwmout_addr = (chip->btype ? PCA9955B_PWM0 : PCA9952_PWM0) + led->led_no;
> +	pwmout_addr = (chipdef->pwm_base) + led->led_no;
>   	ledout_addr = PCA995X_LEDOUT0 + (led->led_no / PCA995X_OUTPUTS_PER_REG);
>   	shift = PCA995X_LDRX_BITS * (led->led_no % PCA995X_OUTPUTS_PER_REG);
>   
> @@ -101,24 +124,24 @@ static const struct regmap_config pca995x_regmap = {
>   
>   static int pca995x_probe(struct i2c_client *client)
>   {
> -	struct fwnode_handle *led_fwnodes[PCA995X_MAX_OUTPUTS] = { 0 };
>   	struct fwnode_handle *np, *child;
>   	struct device *dev = &client->dev;
> +	const struct pca995x_chipdef *chipdef;
>   	struct pca995x_chip *chip;
>   	struct pca995x_led *led;
> -	int i, btype, reg, ret;
> +	int reg, ret;
>   
> -	btype = (unsigned long)device_get_match_data(&client->dev);
> +	chipdef = device_get_match_data(&client->dev);
>   
>   	np = dev_fwnode(dev);
>   	if (!np)
>   		return -ENODEV;
>   
> -	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
> +	chip = devm_kzalloc(dev, struct_size(chip, leds, chipdef->num_leds), GFP_KERNEL);
>   	if (!chip)
>   		return -ENOMEM;
>   
> -	chip->btype = btype;
> +	chip->chipdef = chipdef;
>   	chip->regmap = devm_regmap_init_i2c(client, &pca995x_regmap);
>   	if (IS_ERR(chip->regmap))
>   		return PTR_ERR(chip->regmap);
> @@ -126,41 +149,34 @@ static int pca995x_probe(struct i2c_client *client)
>   	i2c_set_clientdata(client, chip);
>   
>   	fwnode_for_each_available_child_node(np, child) {
> +		struct led_init_data init_data = {};
> +
>   		ret = fwnode_property_read_u32(child, "reg", &reg);
>   		if (ret) {
>   			fwnode_handle_put(child);
>   			return ret;
>   		}
>   
> -		if (reg < 0 || reg >= PCA995X_MAX_OUTPUTS || led_fwnodes[reg]) {
> +		if (reg < 0 || reg >= chipdef->num_leds) {
>   			fwnode_handle_put(child);
>   			return -EINVAL;
>   		}
>   
>   		led = &chip->leds[reg];
> -		led_fwnodes[reg] = child;
>   		led->chip = chip;
>   		led->led_no = reg;
>   		led->ldev.brightness_set_blocking = pca995x_brightness_set;
>   		led->ldev.max_brightness = 255;
> -	}
> -
> -	for (i = 0; i < PCA995X_MAX_OUTPUTS; i++) {
> -		struct led_init_data init_data = {};
> -
> -		if (!led_fwnodes[i])
> -			continue;
> -
> -		init_data.fwnode = led_fwnodes[i];
> +		init_data.fwnode = child;
>   
>   		ret = devm_led_classdev_register_ext(dev,
> -						     &chip->leds[i].ldev,
> +						     &led->ldev,
>   						     &init_data);
>   		if (ret < 0) {
>   			fwnode_handle_put(child);
>   			return dev_err_probe(dev, ret,
>   					     "Could not register LED %s\n",
> -					     chip->leds[i].ldev.name);
> +					     led->ldev.name);
>   		}
>   	}
>   
> @@ -170,21 +186,21 @@ static int pca995x_probe(struct i2c_client *client)
>   		return ret;
>   
>   	/* IREF Output current value for all LEDn outputs */
> -	return regmap_write(chip->regmap,
> -			    btype ? PCA9955B_IREFALL : PCA9952_IREFALL,
> -			    PCA995X_IREFALL_HALF_CFG);
> +	return regmap_write(chip->regmap, chipdef->irefall, PCA995X_IREFALL_HALF_CFG);
>   }
>   
>   static const struct i2c_device_id pca995x_id[] = {
> -	{ "pca9952", .driver_data = (kernel_ulong_t)PCA995X_TYPE_NON_B },
> -	{ "pca9955b", .driver_data = (kernel_ulong_t)PCA995X_TYPE_B },
> +	{ "pca9952", .driver_data = (kernel_ulong_t)&pca995x_chipdefs[pca9952] },
> +	{ "pca9955b", .driver_data = (kernel_ulong_t)&pca995x_chipdefs[pca9955b] },
> +	{ "pca9956b", .driver_data = (kernel_ulong_t)&pca995x_chipdefs[pca9956b] },

... pass pointer to each (separate) chip type structure here ...

>   	{}
>   };
>   MODULE_DEVICE_TABLE(i2c, pca995x_id);
>   
>   static const struct of_device_id pca995x_of_match[] = {
> -	{ .compatible = "nxp,pca9952",  .data = (void *)PCA995X_TYPE_NON_B },
> -	{ .compatible = "nxp,pca9955b", .data = (void *)PCA995X_TYPE_B },
> +	{ .compatible = "nxp,pca9952", .data = &pca995x_chipdefs[pca9952] },
> +	{ .compatible = "nxp,pca9955b", . data = &pca995x_chipdefs[pca9955b] },
> +	{ .compatible = "nxp,pca9956b", .data = &pca995x_chipdefs[pca9956b] },

... and here.

In pca995x_probe() , cache pointer to the whole struct pca995x_chipdef 
and use its members all over the driver. That's how you can get rid of 
the enum .