Re: [PATCH 1/2] regulator: st-pwm: get voltage and duty table from dts

[Heiko Stübner]

Hi Chris,

Am Mittwoch, 17. September 2014, 21:07:59 schrieb Chris Zhong:
> Get voltage & duty table from device tree might be better, other platforms
> can also use this driver without any modify.
> 
> Signed-off-by: Chris Zhong <zyw@xxxxxxxxxxxxxx>
> ---
> 
>  drivers/regulator/Kconfig  |    1 -
>  drivers/regulator/st-pwm.c |   80
> +++++++++++++++++++++++--------------------- 2 files changed, 42
> insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
> index fb32bab..06a9632 100644
> --- a/drivers/regulator/Kconfig
> +++ b/drivers/regulator/Kconfig
> @@ -495,7 +495,6 @@ config REGULATOR_S5M8767
> 
>  config REGULATOR_ST_PWM
>  	tristate "STMicroelectronics PWM voltage regulator"
> -	depends on ARCH_STI
>  	help
>  	 This driver supports ST's PWM controlled voltage regulators.
> 
> diff --git a/drivers/regulator/st-pwm.c b/drivers/regulator/st-pwm.c
> index 5ea78df..877381b 100644
> --- a/drivers/regulator/st-pwm.c
> +++ b/drivers/regulator/st-pwm.c
> @@ -20,16 +20,11 @@
>  #include <linux/of_device.h>
>  #include <linux/pwm.h>
> 
> -#define ST_PWM_REG_PERIOD 8448
> -
> -struct st_pwm_regulator_pdata {
> -	const struct regulator_desc *desc;
> -	struct st_pwm_voltages *duty_cycle_table;
> -};
> -
>  struct st_pwm_regulator_data {
> -	const struct st_pwm_regulator_pdata *pdata;
> +	struct regulator_desc *desc;
> +	struct st_pwm_voltages *duty_cycle_table;
>  	struct pwm_device *pwm;
> +	int pwm_reg_period;
>  	bool enabled;
>  	int state;
>  };
> @@ -53,10 +48,10 @@ static int st_pwm_regulator_set_voltage_sel(struct
> regulator_dev *dev, int dutycycle;
>  	int ret;
> 
> -	dutycycle = (ST_PWM_REG_PERIOD / 100) *
> -		drvdata->pdata->duty_cycle_table[selector].dutycycle;
> +	dutycycle = (drvdata->pwm_reg_period / 100) *
> +		    drvdata->duty_cycle_table[selector].dutycycle;
> 
> -	ret = pwm_config(drvdata->pwm, dutycycle, ST_PWM_REG_PERIOD);
> +	ret = pwm_config(drvdata->pwm, dutycycle, drvdata->pwm_reg_period);
>  	if (ret) {
>  		dev_err(&dev->dev, "Failed to configure PWM\n");
>  		return ret;
> @@ -84,7 +79,7 @@ static int st_pwm_regulator_list_voltage(struct
> regulator_dev *dev, if (selector >= dev->desc->n_voltages)
>  		return -EINVAL;
> 
> -	return drvdata->pdata->duty_cycle_table[selector].uV;
> +	return drvdata->duty_cycle_table[selector].uV;
>  }
> 
>  static struct regulator_ops st_pwm_regulator_voltage_ops = {
> @@ -94,32 +89,16 @@ static struct regulator_ops st_pwm_regulator_voltage_ops
> = { .map_voltage     = regulator_map_voltage_iterate,
>  };
> 
> -static struct st_pwm_voltages b2105_duty_cycle_table[] = {
> -	{ .uV = 1114000, .dutycycle = 0,  },
> -	{ .uV = 1095000, .dutycycle = 10, },
> -	{ .uV = 1076000, .dutycycle = 20, },
> -	{ .uV = 1056000, .dutycycle = 30, },
> -	{ .uV = 1036000, .dutycycle = 40, },
> -	{ .uV = 1016000, .dutycycle = 50, },
> -	/* WARNING: Values above 50% duty-cycle cause boot failures. */
> -};
> -
> -static const struct regulator_desc b2105_desc = {
> +static struct regulator_desc b2105_desc = {
>  	.name		= "b2105-pwm-regulator",
>  	.ops		= &st_pwm_regulator_voltage_ops,
>  	.type		= REGULATOR_VOLTAGE,
>  	.owner		= THIS_MODULE,
> -	.n_voltages	= ARRAY_SIZE(b2105_duty_cycle_table),
>  	.supply_name    = "pwm",
>  };
> 
> -static const struct st_pwm_regulator_pdata b2105_info = {
> -	.desc		  = &b2105_desc,
> -	.duty_cycle_table = b2105_duty_cycle_table,
> -};
> -
>  static const struct of_device_id st_pwm_of_match[] = {
> -	{ .compatible = "st,b2105-pwm-regulator", .data = &b2105_info, },
> +	{ .compatible = "st,b2105-pwm-regulator" },

This is breaking compatibility with the existing binding for the b2105-pwm-
regulator - which has to stay intact. Please add a separate compatiblity like 
"pwm-regulator" that reads the table from the dt and let the b2105 keep it's 
voltage<->duty_cycle table in the driver as it is now.


Heiko


>  	{ },
>  };
>  MODULE_DEVICE_TABLE(of, st_pwm_of_match);
> @@ -127,10 +106,11 @@ MODULE_DEVICE_TABLE(of, st_pwm_of_match);
>  static int st_pwm_regulator_probe(struct platform_device *pdev)
>  {
>  	struct st_pwm_regulator_data *drvdata;
> +	struct property *prop;
>  	struct regulator_dev *regulator;
>  	struct regulator_config config = { };
>  	struct device_node *np = pdev->dev.of_node;
> -	const struct of_device_id *of_match;
> +	int length, ret;
> 
>  	if (!np) {
>  		dev_err(&pdev->dev, "Device Tree node missing\n");
> @@ -141,12 +121,36 @@ static int st_pwm_regulator_probe(struct
> platform_device *pdev) if (!drvdata)
>  		return -ENOMEM;
> 
> -	of_match = of_match_device(st_pwm_of_match, &pdev->dev);
> -	if (!of_match) {
> -		dev_err(&pdev->dev, "failed to match of device\n");
> -		return -ENODEV;
> +	drvdata->desc = &b2105_desc;
> +
> +	/* determine the number of voltage-table */
> +	prop = of_find_property(np, "voltage-table", &length);
> +	if (!prop)
> +		return -EINVAL;
> +
> +	drvdata->desc->n_voltages = length / sizeof(*drvdata->duty_cycle_table);
> +
> +	/* read voltage table from DT property */
> +	if (length > 0) {
> +		size_t size = sizeof(*drvdata->duty_cycle_table) *
> +			      drvdata->desc->n_voltages;
> +
> +		drvdata->duty_cycle_table = devm_kzalloc(&pdev->dev,
> +							 size, GFP_KERNEL);
> +		if (!drvdata->duty_cycle_table)
> +			return -ENOMEM;
> +
> +		ret = of_property_read_u32_array(np, "voltage-table",
> +				(u32 *)drvdata->duty_cycle_table,
> +				length / sizeof(u32));
> +		if (ret < 0)
> +			return ret;
>  	}
> -	drvdata->pdata = of_match->data;
> +
> +	ret = of_property_read_u32(np, "pwm-reg-period",
> +				   &drvdata->pwm_reg_period);
> +	if (ret)
> +		return -EINVAL;
> 
>  	config.init_data = of_get_regulator_init_data(&pdev->dev, np);
>  	if (!config.init_data)
> @@ -163,10 +167,10 @@ static int st_pwm_regulator_probe(struct
> platform_device *pdev) }
> 
>  	regulator = devm_regulator_register(&pdev->dev,
> -					    drvdata->pdata->desc, &config);
> +					    drvdata->desc, &config);
>  	if (IS_ERR(regulator)) {
>  		dev_err(&pdev->dev, "Failed to register regulator %s\n",
> -			drvdata->pdata->desc->name);
> +			drvdata->desc->name);
>  		return PTR_ERR(regulator);
>  	}

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