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

[Doug Anderson]

Chris,

On Wed, Sep 17, 2014 at 6:07 AM, Chris Zhong <zyw@xxxxxxxxxxxxxx> wrote:
> 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>

Why didn't you CC Lee Jones on your patches?  He's the author of the
driver and should certainly be involved in reviewing your patches.

CCed him now.


>  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

Seems like you should add some wording saying that this driver is also
useful for other PWM-based voltage regulators.


>         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. */

I wonder if this warning should be transferred to the device tree (if
it's generally a problem for anyone using the b2105)?


> -};
> -
> -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" },
>         { },
>  };
>  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);
>         }

-Doug
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