[U-Boot] [PATCH 3/7] power: regulator: add pwm regulator

[Simon Glass]

Hi Kever,

On 29 August 2016 at 21:02, Kever Yang <kever.yang at rock-chips.com> wrote:
> This driver add support for pwm regulator.
>
> Signed-off-by: Elaine Zhang <zhangqing at rock-chips.com>
> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
> ---
>
>  drivers/power/regulator/Kconfig         |   9 ++
>  drivers/power/regulator/Makefile        |   1 +
>  drivers/power/regulator/pwm_regulator.c | 157 ++++++++++++++++++++++++++++++++
>  3 files changed, 167 insertions(+)
>  create mode 100644 drivers/power/regulator/pwm_regulator.c
>
> diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
> index 17f22dd..c2eaa84 100644
> --- a/drivers/power/regulator/Kconfig
> +++ b/drivers/power/regulator/Kconfig
> @@ -42,6 +42,15 @@ config DM_REGULATOR_PFUZE100
>         features for REGULATOR PFUZE100. The driver implements get/set api for:
>         value, enable and mode.
>
> +config REGULATOR_PWM
> +       bool "Enable driver for PWM regulators"
> +       depends on DM_REGULATOR
> +       ---help---
> +       Enable support for the regulator functions of the PWM. The

Does a PWM have regulator functions? Do you mean a board that uses a
PWM to control a regulator?

> +       driver implements get/set api for the various BUCKS.
> +       This driver is controlled by a device tree node
> +       which includes voltage limits.
> +
>  config DM_REGULATOR_MAX77686
>         bool "Enable Driver Model for REGULATOR MAX77686"
>         depends on DM_REGULATOR && DM_PMIC_MAX77686
> diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
> index 1590d85..ab461ec 100644
> --- a/drivers/power/regulator/Makefile
> +++ b/drivers/power/regulator/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_$(SPL_)DM_REGULATOR) += regulator-uclass.o
>  obj-$(CONFIG_REGULATOR_ACT8846) += act8846.o
>  obj-$(CONFIG_DM_REGULATOR_MAX77686) += max77686.o
>  obj-$(CONFIG_DM_REGULATOR_PFUZE100) += pfuze100.o
> +obj-$(CONFIG_REGULATOR_PWM) += pwm_regulator.o
>  obj-$(CONFIG_$(SPL_)DM_REGULATOR_FIXED) += fixed.o
>  obj-$(CONFIG_REGULATOR_RK808) += rk808.o
>  obj-$(CONFIG_REGULATOR_S5M8767) += s5m8767.o
> diff --git a/drivers/power/regulator/pwm_regulator.c b/drivers/power/regulator/pwm_regulator.c
> new file mode 100644
> index 0000000..f75731b
> --- /dev/null
> +++ b/drivers/power/regulator/pwm_regulator.c
> @@ -0,0 +1,157 @@
> +/*
> + * Copyright (C) 2016 Rockchip Electronics Co., Ltd
> + *
> + * Based on kernel drivers/regulator/pwm-regulator.c
> + * Copyright (C) 2014 - STMicroelectronics Inc.
> + * Author: Lee Jones <lee.jones at linaro.org>
> + *
> + * SPDX-License-Identifier:    GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <errno.h>
> +#include <pwm.h>
> +#include <power/regulator.h>
> +#include <libfdt.h>
> +#include <fdt_support.h>
> +#include <fdtdec.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +struct pwm_regulator_info {
> +       int pwm_id;

Please add a comment for members

> +       int period;

period_ms is better, if this is milliseconds. Or period_us?

> +       struct udevice *pwm;
> +       unsigned int init_voltage;
> +       unsigned int max_voltage;
> +       unsigned int min_voltage;
> +       unsigned int boot_on;

bool?

> +       unsigned int volt_uV;
> +};
> +
> +static int pwm_regulator_enable(struct udevice *dev, bool enable)
> +{
> +       struct pwm_regulator_info *priv = dev_get_priv(dev);
> +
> +       return pwm_set_enable(priv->pwm, priv->pwm_id, enable);
> +}
> +
> +static int pwm_voltage_to_duty_cycle_percentage(struct udevice *dev, int req_uV)
> +{
> +       struct pwm_regulator_info *priv = dev_get_priv(dev);
> +       int min_uV = priv->min_voltage;
> +       int max_uV = priv->max_voltage;
> +       int diff = max_uV - min_uV;
> +
> +       return 100 - (((req_uV * 100) - (min_uV * 100)) / diff);
> +}
> +
> +static int pwm_regulator_get_voltage(struct udevice *dev)
> +{
> +       struct pwm_regulator_info *priv = dev_get_priv(dev);
> +
> +       return priv->volt_uV;
> +}
> +
> +static int pwm_regulator_set_voltage(struct udevice *dev, int uvolt)
> +{
> +       struct pwm_regulator_info *priv = dev_get_priv(dev);
> +       int duty_cycle;
> +       int ret = 0;
> +
> +       duty_cycle = pwm_voltage_to_duty_cycle_percentage(dev, uvolt);
> +
> +       ret = pwm_set_config(priv->pwm, priv->pwm_id,
> +                       (priv->period / 100) * duty_cycle, priv->period);
> +       if (ret) {
> +               dev_err(dev, "Failed to configure PWM\n");
> +               return ret;
> +       }
> +
> +       ret = pwm_set_enable(priv->pwm, priv->pwm_id, true);
> +       if (ret) {
> +               dev_err(dev, "Failed to enable PWM\n");
> +               return ret;
> +       }
> +       priv->volt_uV = uvolt;
> +       return ret;
> +}
> +
> +static int pwm_regulator_ofdata_to_platdata(struct udevice *dev)
> +{
> +       struct pwm_regulator_info *priv = dev_get_priv(dev);
> +       struct fdtdec_phandle_args args;
> +       const void *blob = gd->fdt_blob;
> +       int node = dev->of_offset;
> +       int ret;
> +
> +       ret = fdtdec_parse_phandle_with_args(blob, node, "pwms", "#pwm-cells",
> +                                            0, 0, &args);
> +       if (ret) {
> +               debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret);
> +               return ret;
> +       }
> +
> +       priv->period = args.args[1];
> +
> +       /* rkpwm do not use the pwm_id, set it to 0 */
> +       priv->pwm_id = 0;

But this is not a rockchip driver. Also private data starts at 0 so
you can skip this.

> +
> +       priv->init_voltage = fdtdec_get_int(blob, node,
> +                       "regulator-init-microvolt", 0);
> +       if (priv->init_voltage < 0)
> +               printf("Cannot find regulator pwm init_voltage\n");

debug()

If that is an error, please return -EINVAL. The error seems wrong
also. If the property is missing then fdtdec_get_int() will return
your default value (0). So perhaps the error should be 'invalid
voltage < 0'. But actually I cannot see why such a check is useful.
People should not make such mistakes in device-tree data.

> +
> +       ret = uclass_get_device_by_of_offset(UCLASS_PWM, args.node, &priv->pwm);
> +       if (ret) {
> +               debug("%s: Cannot get PWM: ret=%d\n", __func__, ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int pwm_regulator_probe(struct udevice *dev)
> +{
> +       struct pwm_regulator_info *priv = dev_get_priv(dev);
> +       struct dm_regulator_uclass_platdata *uc_pdata;
> +
> +       uc_pdata = dev_get_uclass_platdata(dev);
> +
> +       uc_pdata->type = REGULATOR_TYPE_BUCK;
> +       uc_pdata->mode_count = 0;
> +       priv->max_voltage = uc_pdata->max_uV;
> +       priv->min_voltage = uc_pdata->min_uV;
> +
> +       if (priv->init_voltage)
> +               pwm_regulator_set_voltage(dev, priv->init_voltage);
> +
> +       if (priv->boot_on)
> +               pwm_regulator_enable(dev, 1);
> +
> +       return 0;
> +}
> +
> +static const struct dm_regulator_ops pwm_regulator_ops = {
> +       .get_value  = pwm_regulator_get_voltage,
> +       .set_value  = pwm_regulator_set_voltage,
> +       .set_enable = pwm_regulator_enable,
> +};
> +
> +static const struct udevice_id pwm_regulator_ids[] = {
> +       { .compatible = "pwm-regulator" },
> +       { .compatible = "rockchip_pwm_regulator" },

Should that be rockchip,pwm-regulator ?

> +       { }
> +};
> +
> +U_BOOT_DRIVER(pwm_regulator) = {
> +       .name = "pwm_regulator",
> +       .id = UCLASS_REGULATOR,
> +       .ops = &pwm_regulator_ops,
> +       .probe = pwm_regulator_probe,
> +       .of_match = pwm_regulator_ids,
> +       .ofdata_to_platdata     = pwm_regulator_ofdata_to_platdata,
> +       .priv_auto_alloc_size   = sizeof(struct pwm_regulator_info),
> +};
> +
> --
> 1.9.1
>

Regards,
Simon