drivers/power/regulator/pwm_regulator.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * 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@linaro.org>
 */

#include <dm.h>
#include <errno.h>
#include <log.h>
#include <pwm.h>
#include <asm/global_data.h>
#include <dm/device_compat.h>
#include <power/regulator.h>

DECLARE_GLOBAL_DATA_PTR;

struct pwm_regulator_info {
	/* pwm id corresponding to the PWM driver */
	int pwm_id;
	/* the period of one PWM cycle */
	int period_ns;
	/*
	 * the polarity of one PWM
	 * 0: normal polarity
	 * 1: inverted polarity
	 */
	bool polarity;
	struct udevice *pwm;
	/* initialize voltage of regulator */
	int init_voltage;
	/* the maximum voltage of regulator */
	int max_voltage;
	/* the minimum voltage of regulator */
	int min_voltage;
	/* the current voltage of regulator */
	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 ((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_invert(priv->pwm, priv->pwm_id, priv->polarity);
	if (ret) {
		dev_err(dev, "Failed to init PWM\n");
		return ret;
	}

	ret = pwm_set_config(priv->pwm, priv->pwm_id,
			priv->period_ns, (priv->period_ns / 100) * duty_cycle);
	if (ret) {
		dev_err(dev, "Failed to configure PWM\n");
		return ret;
	}

	priv->volt_uV = uvolt;

	return ret;
}

static int pwm_regulator_of_to_plat(struct udevice *dev)
{
	struct pwm_regulator_info *priv = dev_get_priv(dev);
	struct ofnode_phandle_args args;
	int ret;

	ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0, &args);
	if (ret) {
		debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret);
		return ret;
	}

	priv->period_ns = args.args[1];
	priv->polarity = args.args[2];

	priv->init_voltage = dev_read_u32_default(dev, "regulator-init-microvolt", -1);
	if (priv->init_voltage < 0) {
		printf("Cannot find regulator pwm init_voltage\n");
		return -EINVAL;
	}

	ret = uclass_get_device_by_ofnode(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_plat *uc_pdata;

	uc_pdata = dev_get_uclass_plat(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);

	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" },
	{ }
};

U_BOOT_DRIVER(pwm_regulator) = {
	.name = "pwm_regulator",
	.id = UCLASS_REGULATOR,
	.ops = &pwm_regulator_ops,
	.probe = pwm_regulator_probe,
	.of_match = pwm_regulator_ids,
	.of_to_plat	= pwm_regulator_of_to_plat,
	.priv_auto	= sizeof(struct pwm_regulator_info),
};