src/kernel/linux/v4.19/drivers/pwm/pwm-rockchip.c - T800 - Gitiles

 /*
  * PWM driver for Rockchip SoCs
  *
  * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
  * Copyright (C) 2014 ROCKCHIP, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  */

 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/time.h>

 #define PWM_CTRL_TIMER_EN	(1 << 0)
 #define PWM_CTRL_OUTPUT_EN	(1 << 3)

 #define PWM_ENABLE		(1 << 0)
 #define PWM_CONTINUOUS		(1 << 1)
 #define PWM_DUTY_POSITIVE	(1 << 3)
 #define PWM_DUTY_NEGATIVE	(0 << 3)
 #define PWM_INACTIVE_NEGATIVE	(0 << 4)
 #define PWM_INACTIVE_POSITIVE	(1 << 4)
 #define PWM_POLARITY_MASK	(PWM_DUTY_POSITIVE | PWM_INACTIVE_POSITIVE)
 #define PWM_OUTPUT_LEFT		(0 << 5)
 #define PWM_LOCK_EN		(1 << 6)
 #define PWM_LP_DISABLE		(0 << 8)

 struct rockchip_pwm_chip {
 	struct pwm_chip chip;
 	struct clk *clk;
 	struct clk *pclk;
 	const struct rockchip_pwm_data *data;
 	void __iomem *base;
 };

 struct rockchip_pwm_regs {
 	unsigned long duty;
 	unsigned long period;
 	unsigned long cntr;
 	unsigned long ctrl;
 };

 struct rockchip_pwm_data {
 	struct rockchip_pwm_regs regs;
 	unsigned int prescaler;
 	bool supports_polarity;
 	bool supports_lock;
 	u32 enable_conf;
 };

 static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
 {
 	return container_of(c, struct rockchip_pwm_chip, chip);
 }

 static void rockchip_pwm_get_state(struct pwm_chip *chip,
 				   struct pwm_device *pwm,
 				   struct pwm_state *state)
 {
 	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 	u32 enable_conf = pc->data->enable_conf;
 	unsigned long clk_rate;
 	u64 tmp;
 	u32 val;
 	int ret;

 	ret = clk_enable(pc->pclk);
 	if (ret)
 		return;

 	clk_rate = clk_get_rate(pc->clk);

 	tmp = readl_relaxed(pc->base + pc->data->regs.period);
 	tmp *= pc->data->prescaler * NSEC_PER_SEC;
 	state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);

 	tmp = readl_relaxed(pc->base + pc->data->regs.duty);
 	tmp *= pc->data->prescaler * NSEC_PER_SEC;
 	state->duty_cycle =  DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);

 	val = readl_relaxed(pc->base + pc->data->regs.ctrl);
 	if (pc->data->supports_polarity)
 		state->enabled = ((val & enable_conf) != enable_conf) ?
 				 false : true;
 	else
 		state->enabled = ((val & enable_conf) == enable_conf) ?
 				 true : false;

 	if (pc->data->supports_polarity) {
 		if (!(val & PWM_DUTY_POSITIVE))
 			state->polarity = PWM_POLARITY_INVERSED;
 	}

 	clk_disable(pc->pclk);
 }

 static void rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			       struct pwm_state *state)
 {
 	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 	unsigned long period, duty;
 	u64 clk_rate, div;
 	u32 ctrl;

 	clk_rate = clk_get_rate(pc->clk);

 	/*
 	 * Since period and duty cycle registers have a width of 32
 	 * bits, every possible input period can be obtained using the
 	 * default prescaler value for all practical clock rate values.
 	 */
 	div = clk_rate * state->period;
 	period = DIV_ROUND_CLOSEST_ULL(div,
 				       pc->data->prescaler * NSEC_PER_SEC);

 	div = clk_rate * state->duty_cycle;
 	duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);

 	/*
 	 * Lock the period and duty of previous configuration, then
 	 * change the duty and period, that would not be effective.
 	 */
 	ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
 	if (pc->data->supports_lock) {
 		ctrl |= PWM_LOCK_EN;
 		writel_relaxed(ctrl, pc->base + pc->data->regs.ctrl);
 	}

 	writel(period, pc->base + pc->data->regs.period);
 	writel(duty, pc->base + pc->data->regs.duty);

 	if (pc->data->supports_polarity) {
 		ctrl &= ~PWM_POLARITY_MASK;
 		if (state->polarity == PWM_POLARITY_INVERSED)
 			ctrl |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
 		else
 			ctrl |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
 	}

 	/*
 	 * Unlock and set polarity at the same time,
 	 * the configuration of duty, period and polarity
 	 * would be effective together at next period.
 	 */
 	if (pc->data->supports_lock)
 		ctrl &= ~PWM_LOCK_EN;

 	writel(ctrl, pc->base + pc->data->regs.ctrl);
 }

 static int rockchip_pwm_enable(struct pwm_chip *chip,
 			       struct pwm_device *pwm,
 			       bool enable)
 {
 	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 	u32 enable_conf = pc->data->enable_conf;
 	int ret;
 	u32 val;

 	if (enable) {
 		ret = clk_enable(pc->clk);
 		if (ret)
 			return ret;
 	}

 	val = readl_relaxed(pc->base + pc->data->regs.ctrl);

 	if (enable)
 		val |= enable_conf;
 	else
 		val &= ~enable_conf;

 	writel_relaxed(val, pc->base + pc->data->regs.ctrl);

 	if (!enable)
 		clk_disable(pc->clk);

 	return 0;
 }

 static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			      struct pwm_state *state)
 {
 	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 	struct pwm_state curstate;
 	bool enabled;
 	int ret = 0;

 	ret = clk_enable(pc->pclk);
 	if (ret)
 		return ret;

 	pwm_get_state(pwm, &curstate);
 	enabled = curstate.enabled;

 	if (state->polarity != curstate.polarity && enabled &&
 	    !pc->data->supports_lock) {
 		ret = rockchip_pwm_enable(chip, pwm, false);
 		if (ret)
 			goto out;
 		enabled = false;
 	}

 	rockchip_pwm_config(chip, pwm, state);
 	if (state->enabled != enabled) {
 		ret = rockchip_pwm_enable(chip, pwm, state->enabled);
 		if (ret)
 			goto out;
 	}

 	/*
 	 * Update the state with the real hardware, which can differ a bit
 	 * because of period/duty_cycle approximation.
 	 */
 	rockchip_pwm_get_state(chip, pwm, state);

 out:
 	clk_disable(pc->pclk);

 	return ret;
 }

 static const struct pwm_ops rockchip_pwm_ops = {
 	.get_state = rockchip_pwm_get_state,
 	.apply = rockchip_pwm_apply,
 	.owner = THIS_MODULE,
 };

 static const struct rockchip_pwm_data pwm_data_v1 = {
 	.regs = {
 		.duty = 0x04,
 		.period = 0x08,
 		.cntr = 0x00,
 		.ctrl = 0x0c,
 	},
 	.prescaler = 2,
 	.supports_polarity = false,
 	.supports_lock = false,
 	.enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN,
 };

 static const struct rockchip_pwm_data pwm_data_v2 = {
 	.regs = {
 		.duty = 0x08,
 		.period = 0x04,
 		.cntr = 0x00,
 		.ctrl = 0x0c,
 	},
 	.prescaler = 1,
 	.supports_polarity = true,
 	.supports_lock = false,
 	.enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
 		       PWM_CONTINUOUS,
 };

 static const struct rockchip_pwm_data pwm_data_vop = {
 	.regs = {
 		.duty = 0x08,
 		.period = 0x04,
 		.cntr = 0x0c,
 		.ctrl = 0x00,
 	},
 	.prescaler = 1,
 	.supports_polarity = true,
 	.supports_lock = false,
 	.enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
 		       PWM_CONTINUOUS,
 };

 static const struct rockchip_pwm_data pwm_data_v3 = {
 	.regs = {
 		.duty = 0x08,
 		.period = 0x04,
 		.cntr = 0x00,
 		.ctrl = 0x0c,
 	},
 	.prescaler = 1,
 	.supports_polarity = true,
 	.supports_lock = true,
 	.enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
 		       PWM_CONTINUOUS,
 };

 static const struct of_device_id rockchip_pwm_dt_ids[] = {
 	{ .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
 	{ .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
 	{ .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
 	{ .compatible = "rockchip,rk3328-pwm", .data = &pwm_data_v3},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);

 static int rockchip_pwm_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *id;
 	struct rockchip_pwm_chip *pc;
 	struct resource *r;
 	int ret, count;

 	id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
 	if (!id)
 		return -EINVAL;

 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 	if (!pc)
 		return -ENOMEM;

 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	pc->base = devm_ioremap_resource(&pdev->dev, r);
 	if (IS_ERR(pc->base))
 		return PTR_ERR(pc->base);

 	pc->clk = devm_clk_get(&pdev->dev, "pwm");
 	if (IS_ERR(pc->clk)) {
 		pc->clk = devm_clk_get(&pdev->dev, NULL);
 		if (IS_ERR(pc->clk)) {
 			ret = PTR_ERR(pc->clk);
 			if (ret != -EPROBE_DEFER)
 				dev_err(&pdev->dev, "Can't get bus clk: %d\n",
 					ret);
 			return ret;
 		}
 	}

 	count = of_count_phandle_with_args(pdev->dev.of_node,
 					   "clocks", "#clock-cells");
 	if (count == 2)
 		pc->pclk = devm_clk_get(&pdev->dev, "pclk");
 	else
 		pc->pclk = pc->clk;

 	if (IS_ERR(pc->pclk)) {
 		ret = PTR_ERR(pc->pclk);
 		if (ret != -EPROBE_DEFER)
 			dev_err(&pdev->dev, "Can't get APB clk: %d\n", ret);
 		return ret;
 	}

 	ret = clk_prepare_enable(pc->clk);
 	if (ret) {
 		dev_err(&pdev->dev, "Can't prepare enable bus clk: %d\n", ret);
 		return ret;
 	}

 	ret = clk_prepare(pc->pclk);
 	if (ret) {
 		dev_err(&pdev->dev, "Can't prepare APB clk: %d\n", ret);
 		goto err_clk;
 	}

 	platform_set_drvdata(pdev, pc);

 	pc->data = id->data;
 	pc->chip.dev = &pdev->dev;
 	pc->chip.ops = &rockchip_pwm_ops;
 	pc->chip.base = -1;
 	pc->chip.npwm = 1;

 	if (pc->data->supports_polarity) {
 		pc->chip.of_xlate = of_pwm_xlate_with_flags;
 		pc->chip.of_pwm_n_cells = 3;
 	}

 	ret = pwmchip_add(&pc->chip);
 	if (ret < 0) {
 		clk_unprepare(pc->clk);
 		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 		goto err_pclk;
 	}

 	/* Keep the PWM clk enabled if the PWM appears to be up and running. */
 	if (!pwm_is_enabled(pc->chip.pwms))
 		clk_disable(pc->clk);

 	return 0;

 err_pclk:
 	clk_unprepare(pc->pclk);
 err_clk:
 	clk_disable_unprepare(pc->clk);

 	return ret;
 }

 static int rockchip_pwm_remove(struct platform_device *pdev)
 {
 	struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);

 	/*
 	 * Disable the PWM clk before unpreparing it if the PWM device is still
 	 * running. This should only happen when the last PWM user left it
 	 * enabled, or when nobody requested a PWM that was previously enabled
 	 * by the bootloader.
 	 *
 	 * FIXME: Maybe the core should disable all PWM devices in
 	 * pwmchip_remove(). In this case we'd only have to call
 	 * clk_unprepare() after pwmchip_remove().
 	 *
 	 */
 	if (pwm_is_enabled(pc->chip.pwms))
 		clk_disable(pc->clk);

 	clk_unprepare(pc->pclk);
 	clk_unprepare(pc->clk);

 	return pwmchip_remove(&pc->chip);
 }

 static struct platform_driver rockchip_pwm_driver = {
 	.driver = {
 		.name = "rockchip-pwm",
 		.of_match_table = rockchip_pwm_dt_ids,
 	},
 	.probe = rockchip_pwm_probe,
 	.remove = rockchip_pwm_remove,
 };
 module_platform_driver(rockchip_pwm_driver);

 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
 MODULE_DESCRIPTION("Rockchip SoC PWM driver");
 MODULE_LICENSE("GPL v2");
	/*
	* PWM driver for Rockchip SoCs
	*
	* Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
	* Copyright (C) 2014 ROCKCHIP, Inc.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*/

	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/pwm.h>
	#include <linux/time.h>

	#define PWM_CTRL_TIMER_EN (1 << 0)
	#define PWM_CTRL_OUTPUT_EN (1 << 3)

	#define PWM_ENABLE (1 << 0)
	#define PWM_CONTINUOUS (1 << 1)
	#define PWM_DUTY_POSITIVE (1 << 3)
	#define PWM_DUTY_NEGATIVE (0 << 3)
	#define PWM_INACTIVE_NEGATIVE (0 << 4)
	#define PWM_INACTIVE_POSITIVE (1 << 4)
	#define PWM_POLARITY_MASK (PWM_DUTY_POSITIVE \| PWM_INACTIVE_POSITIVE)
	#define PWM_OUTPUT_LEFT (0 << 5)
	#define PWM_LOCK_EN (1 << 6)
	#define PWM_LP_DISABLE (0 << 8)

	struct rockchip_pwm_chip {
	struct pwm_chip chip;
	struct clk *clk;
	struct clk *pclk;
	const struct rockchip_pwm_data *data;
	void __iomem *base;
	};

	struct rockchip_pwm_regs {
	unsigned long duty;
	unsigned long period;
	unsigned long cntr;
	unsigned long ctrl;
	};

	struct rockchip_pwm_data {
	struct rockchip_pwm_regs regs;
	unsigned int prescaler;
	bool supports_polarity;
	bool supports_lock;
	u32 enable_conf;
	};

	static inline struct rockchip_pwm_chip to_rockchip_pwm_chip(struct pwm_chip c)
	{
	return container_of(c, struct rockchip_pwm_chip, chip);
	}

	static void rockchip_pwm_get_state(struct pwm_chip *chip,
	struct pwm_device *pwm,
	struct pwm_state *state)
	{
	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
	u32 enable_conf = pc->data->enable_conf;
	unsigned long clk_rate;
	u64 tmp;
	u32 val;
	int ret;

	ret = clk_enable(pc->pclk);
	if (ret)
	return;

	clk_rate = clk_get_rate(pc->clk);

	tmp = readl_relaxed(pc->base + pc->data->regs.period);
	tmp = pc->data->prescaler NSEC_PER_SEC;
	state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);

	tmp = readl_relaxed(pc->base + pc->data->regs.duty);
	tmp = pc->data->prescaler NSEC_PER_SEC;
	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);

	val = readl_relaxed(pc->base + pc->data->regs.ctrl);
	if (pc->data->supports_polarity)
	state->enabled = ((val & enable_conf) != enable_conf) ?
	false : true;
	else
	state->enabled = ((val & enable_conf) == enable_conf) ?
	true : false;

	if (pc->data->supports_polarity) {
	if (!(val & PWM_DUTY_POSITIVE))
	state->polarity = PWM_POLARITY_INVERSED;
	}

	clk_disable(pc->pclk);
	}

	static void rockchip_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	struct pwm_state *state)
	{
	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
	unsigned long period, duty;
	u64 clk_rate, div;
	u32 ctrl;

	clk_rate = clk_get_rate(pc->clk);

	/*
	* Since period and duty cycle registers have a width of 32
	* bits, every possible input period can be obtained using the
	* default prescaler value for all practical clock rate values.
	*/
	div = clk_rate * state->period;
	period = DIV_ROUND_CLOSEST_ULL(div,
	pc->data->prescaler * NSEC_PER_SEC);

	div = clk_rate * state->duty_cycle;
	duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);

	/*
	* Lock the period and duty of previous configuration, then
	* change the duty and period, that would not be effective.
	*/
	ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
	if (pc->data->supports_lock) {
	ctrl \|= PWM_LOCK_EN;
	writel_relaxed(ctrl, pc->base + pc->data->regs.ctrl);
	}

	writel(period, pc->base + pc->data->regs.period);
	writel(duty, pc->base + pc->data->regs.duty);

	if (pc->data->supports_polarity) {
	ctrl &= ~PWM_POLARITY_MASK;
	if (state->polarity == PWM_POLARITY_INVERSED)
	ctrl \|= PWM_DUTY_NEGATIVE \| PWM_INACTIVE_POSITIVE;
	else
	ctrl \|= PWM_DUTY_POSITIVE \| PWM_INACTIVE_NEGATIVE;
	}

	/*
	* Unlock and set polarity at the same time,
	* the configuration of duty, period and polarity
	* would be effective together at next period.
	*/
	if (pc->data->supports_lock)
	ctrl &= ~PWM_LOCK_EN;

	writel(ctrl, pc->base + pc->data->regs.ctrl);
	}

	static int rockchip_pwm_enable(struct pwm_chip *chip,
	struct pwm_device *pwm,
	bool enable)
	{
	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
	u32 enable_conf = pc->data->enable_conf;
	int ret;
	u32 val;

	if (enable) {
	ret = clk_enable(pc->clk);
	if (ret)
	return ret;
	}

	val = readl_relaxed(pc->base + pc->data->regs.ctrl);

	if (enable)
	val \|= enable_conf;
	else
	val &= ~enable_conf;

	writel_relaxed(val, pc->base + pc->data->regs.ctrl);

	if (!enable)
	clk_disable(pc->clk);

	return 0;
	}

	static int rockchip_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	struct pwm_state *state)
	{
	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
	struct pwm_state curstate;
	bool enabled;
	int ret = 0;

	ret = clk_enable(pc->pclk);
	if (ret)
	return ret;

	pwm_get_state(pwm, &curstate);
	enabled = curstate.enabled;

	if (state->polarity != curstate.polarity && enabled &&
	!pc->data->supports_lock) {
	ret = rockchip_pwm_enable(chip, pwm, false);
	if (ret)
	goto out;
	enabled = false;
	}

	rockchip_pwm_config(chip, pwm, state);
	if (state->enabled != enabled) {
	ret = rockchip_pwm_enable(chip, pwm, state->enabled);
	if (ret)
	goto out;
	}

	/*
	* Update the state with the real hardware, which can differ a bit
	* because of period/duty_cycle approximation.
	*/
	rockchip_pwm_get_state(chip, pwm, state);

	out:
	clk_disable(pc->pclk);

	return ret;
	}

	static const struct pwm_ops rockchip_pwm_ops = {
	.get_state = rockchip_pwm_get_state,
	.apply = rockchip_pwm_apply,
	.owner = THIS_MODULE,
	};

	static const struct rockchip_pwm_data pwm_data_v1 = {
	.regs = {
	.duty = 0x04,
	.period = 0x08,
	.cntr = 0x00,
	.ctrl = 0x0c,
	},
	.prescaler = 2,
	.supports_polarity = false,
	.supports_lock = false,
	.enable_conf = PWM_CTRL_OUTPUT_EN \| PWM_CTRL_TIMER_EN,
	};

	static const struct rockchip_pwm_data pwm_data_v2 = {
	.regs = {
	.duty = 0x08,
	.period = 0x04,
	.cntr = 0x00,
	.ctrl = 0x0c,
	},
	.prescaler = 1,
	.supports_polarity = true,
	.supports_lock = false,
	.enable_conf = PWM_OUTPUT_LEFT \| PWM_LP_DISABLE \| PWM_ENABLE \|
	PWM_CONTINUOUS,
	};

	static const struct rockchip_pwm_data pwm_data_vop = {
	.regs = {
	.duty = 0x08,
	.period = 0x04,
	.cntr = 0x0c,
	.ctrl = 0x00,
	},
	.prescaler = 1,
	.supports_polarity = true,
	.supports_lock = false,
	.enable_conf = PWM_OUTPUT_LEFT \| PWM_LP_DISABLE \| PWM_ENABLE \|
	PWM_CONTINUOUS,
	};

	static const struct rockchip_pwm_data pwm_data_v3 = {
	.regs = {
	.duty = 0x08,
	.period = 0x04,
	.cntr = 0x00,
	.ctrl = 0x0c,
	},
	.prescaler = 1,
	.supports_polarity = true,
	.supports_lock = true,
	.enable_conf = PWM_OUTPUT_LEFT \| PWM_LP_DISABLE \| PWM_ENABLE \|
	PWM_CONTINUOUS,
	};

	static const struct of_device_id rockchip_pwm_dt_ids[] = {
	{ .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
	{ .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
	{ .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
	{ .compatible = "rockchip,rk3328-pwm", .data = &pwm_data_v3},
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);

	static int rockchip_pwm_probe(struct platform_device *pdev)
	{
	const struct of_device_id *id;
	struct rockchip_pwm_chip *pc;
	struct resource *r;
	int ret, count;

	id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
	if (!id)
	return -EINVAL;

	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
	if (!pc)
	return -ENOMEM;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	pc->base = devm_ioremap_resource(&pdev->dev, r);
	if (IS_ERR(pc->base))
	return PTR_ERR(pc->base);

	pc->clk = devm_clk_get(&pdev->dev, "pwm");
	if (IS_ERR(pc->clk)) {
	pc->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(pc->clk)) {
	ret = PTR_ERR(pc->clk);
	if (ret != -EPROBE_DEFER)
	dev_err(&pdev->dev, "Can't get bus clk: %d\n",
	ret);
	return ret;
	}
	}

	count = of_count_phandle_with_args(pdev->dev.of_node,
	"clocks", "#clock-cells");
	if (count == 2)
	pc->pclk = devm_clk_get(&pdev->dev, "pclk");
	else
	pc->pclk = pc->clk;

	if (IS_ERR(pc->pclk)) {
	ret = PTR_ERR(pc->pclk);
	if (ret != -EPROBE_DEFER)
	dev_err(&pdev->dev, "Can't get APB clk: %d\n", ret);
	return ret;
	}

	ret = clk_prepare_enable(pc->clk);
	if (ret) {
	dev_err(&pdev->dev, "Can't prepare enable bus clk: %d\n", ret);
	return ret;
	}

	ret = clk_prepare(pc->pclk);
	if (ret) {
	dev_err(&pdev->dev, "Can't prepare APB clk: %d\n", ret);
	goto err_clk;
	}

	platform_set_drvdata(pdev, pc);

	pc->data = id->data;
	pc->chip.dev = &pdev->dev;
	pc->chip.ops = &rockchip_pwm_ops;
	pc->chip.base = -1;
	pc->chip.npwm = 1;

	if (pc->data->supports_polarity) {
	pc->chip.of_xlate = of_pwm_xlate_with_flags;
	pc->chip.of_pwm_n_cells = 3;
	}

	ret = pwmchip_add(&pc->chip);
	if (ret < 0) {
	clk_unprepare(pc->clk);
	dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
	goto err_pclk;
	}

	/* Keep the PWM clk enabled if the PWM appears to be up and running. */
	if (!pwm_is_enabled(pc->chip.pwms))
	clk_disable(pc->clk);

	return 0;

	err_pclk:
	clk_unprepare(pc->pclk);
	err_clk:
	clk_disable_unprepare(pc->clk);

	return ret;
	}

	static int rockchip_pwm_remove(struct platform_device *pdev)
	{
	struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);

	/*
	* Disable the PWM clk before unpreparing it if the PWM device is still
	* running. This should only happen when the last PWM user left it
	* enabled, or when nobody requested a PWM that was previously enabled
	* by the bootloader.
	*
	* FIXME: Maybe the core should disable all PWM devices in
	* pwmchip_remove(). In this case we'd only have to call
	* clk_unprepare() after pwmchip_remove().
	*
	*/
	if (pwm_is_enabled(pc->chip.pwms))
	clk_disable(pc->clk);

	clk_unprepare(pc->pclk);
	clk_unprepare(pc->clk);

	return pwmchip_remove(&pc->chip);
	}

	static struct platform_driver rockchip_pwm_driver = {
	.driver = {
	.name = "rockchip-pwm",
	.of_match_table = rockchip_pwm_dt_ids,
	},
	.probe = rockchip_pwm_probe,
	.remove = rockchip_pwm_remove,
	};
	module_platform_driver(rockchip_pwm_driver);

	MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
	MODULE_DESCRIPTION("Rockchip SoC PWM driver");
	MODULE_LICENSE("GPL v2");