drivers/pwm/pwm-zx.c - linux - Git at Google

 /*
  * Copyright (C) 2017 Sanechips Technology Co., Ltd.
  * Copyright 2017 Linaro Ltd.
  *
  * 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/err.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/slab.h>

 #define ZX_PWM_MODE		0x0
 #define ZX_PWM_CLKDIV_SHIFT	2
 #define ZX_PWM_CLKDIV_MASK	GENMASK(11, 2)
 #define ZX_PWM_CLKDIV(x)	(((x) << ZX_PWM_CLKDIV_SHIFT) & \
 					 ZX_PWM_CLKDIV_MASK)
 #define ZX_PWM_POLAR		BIT(1)
 #define ZX_PWM_EN		BIT(0)
 #define ZX_PWM_PERIOD		0x4
 #define ZX_PWM_DUTY		0x8

 #define ZX_PWM_CLKDIV_MAX	1023
 #define ZX_PWM_PERIOD_MAX	65535

 struct zx_pwm_chip {
 	struct pwm_chip chip;
 	struct clk *pclk;
 	struct clk *wclk;
 	void __iomem *base;
 };

 static inline struct zx_pwm_chip *to_zx_pwm_chip(struct pwm_chip *chip)
 {
 	return container_of(chip, struct zx_pwm_chip, chip);
 }

 static inline u32 zx_pwm_readl(struct zx_pwm_chip *zpc, unsigned int hwpwm,
 			       unsigned int offset)
 {
 	return readl(zpc->base + (hwpwm + 1) * 0x10 + offset);
 }

 static inline void zx_pwm_writel(struct zx_pwm_chip *zpc, unsigned int hwpwm,
 				 unsigned int offset, u32 value)
 {
 	writel(value, zpc->base + (hwpwm + 1) * 0x10 + offset);
 }

 static void zx_pwm_set_mask(struct zx_pwm_chip *zpc, unsigned int hwpwm,
 			    unsigned int offset, u32 mask, u32 value)
 {
 	u32 data;

 	data = zx_pwm_readl(zpc, hwpwm, offset);
 	data &= ~mask;
 	data |= value & mask;
 	zx_pwm_writel(zpc, hwpwm, offset, data);
 }

 static void zx_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 			     struct pwm_state *state)
 {
 	struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip);
 	unsigned long rate;
 	unsigned int div;
 	u32 value;
 	u64 tmp;

 	value = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_MODE);

 	if (value & ZX_PWM_POLAR)
 		state->polarity = PWM_POLARITY_NORMAL;
 	else
 		state->polarity = PWM_POLARITY_INVERSED;

 	if (value & ZX_PWM_EN)
 		state->enabled = true;
 	else
 		state->enabled = false;

 	div = (value & ZX_PWM_CLKDIV_MASK) >> ZX_PWM_CLKDIV_SHIFT;
 	rate = clk_get_rate(zpc->wclk);

 	tmp = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_PERIOD);
 	tmp *= div * NSEC_PER_SEC;
 	state->period = DIV_ROUND_CLOSEST_ULL(tmp, rate);

 	tmp = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_DUTY);
 	tmp *= div * NSEC_PER_SEC;
 	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, rate);
 }

 static int zx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			 unsigned int duty_ns, unsigned int period_ns)
 {
 	struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip);
 	unsigned int period_cycles, duty_cycles;
 	unsigned long long c;
 	unsigned int div = 1;
 	unsigned long rate;

 	/* Find out the best divider */
 	rate = clk_get_rate(zpc->wclk);

 	while (1) {
 		c = rate / div;
 		c = c * period_ns;
 		do_div(c, NSEC_PER_SEC);

 		if (c < ZX_PWM_PERIOD_MAX)
 			break;

 		div++;

 		if (div > ZX_PWM_CLKDIV_MAX)
 			return -ERANGE;
 	}

 	/* Calculate duty cycles */
 	period_cycles = c;
 	c *= duty_ns;
 	do_div(c, period_ns);
 	duty_cycles = c;

 	/*
 	 * If the PWM is being enabled, we have to temporarily disable it
 	 * before configuring the registers.
 	 */
 	if (pwm_is_enabled(pwm))
 		zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_EN, 0);

 	/* Set up registers */
 	zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_CLKDIV_MASK,
 			ZX_PWM_CLKDIV(div));
 	zx_pwm_writel(zpc, pwm->hwpwm, ZX_PWM_PERIOD, period_cycles);
 	zx_pwm_writel(zpc, pwm->hwpwm, ZX_PWM_DUTY, duty_cycles);

 	/* Re-enable the PWM if needed */
 	if (pwm_is_enabled(pwm))
 		zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE,
 				ZX_PWM_EN, ZX_PWM_EN);

 	return 0;
 }

 static int zx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			struct pwm_state *state)
 {
 	struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip);
 	struct pwm_state cstate;
 	int ret;

 	pwm_get_state(pwm, &cstate);

 	if (state->polarity != cstate.polarity)
 		zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_POLAR,
 				(state->polarity == PWM_POLARITY_INVERSED) ?
 				 0 : ZX_PWM_POLAR);

 	if (state->period != cstate.period ||
 	    state->duty_cycle != cstate.duty_cycle) {
 		ret = zx_pwm_config(chip, pwm, state->duty_cycle,
 				    state->period);
 		if (ret)
 			return ret;
 	}

 	if (state->enabled != cstate.enabled) {
 		if (state->enabled) {
 			ret = clk_prepare_enable(zpc->wclk);
 			if (ret)
 				return ret;

 			zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE,
 					ZX_PWM_EN, ZX_PWM_EN);
 		} else {
 			zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE,
 					ZX_PWM_EN, 0);
 			clk_disable_unprepare(zpc->wclk);
 		}
 	}

 	return 0;
 }

 static const struct pwm_ops zx_pwm_ops = {
 	.apply = zx_pwm_apply,
 	.get_state = zx_pwm_get_state,
 	.owner = THIS_MODULE,
 };

 static int zx_pwm_probe(struct platform_device *pdev)
 {
 	struct zx_pwm_chip *zpc;
 	struct resource *res;
 	unsigned int i;
 	int ret;

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

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

 	zpc->pclk = devm_clk_get(&pdev->dev, "pclk");
 	if (IS_ERR(zpc->pclk))
 		return PTR_ERR(zpc->pclk);

 	zpc->wclk = devm_clk_get(&pdev->dev, "wclk");
 	if (IS_ERR(zpc->wclk))
 		return PTR_ERR(zpc->wclk);

 	ret = clk_prepare_enable(zpc->pclk);
 	if (ret)
 		return ret;

 	zpc->chip.dev = &pdev->dev;
 	zpc->chip.ops = &zx_pwm_ops;
 	zpc->chip.base = -1;
 	zpc->chip.npwm = 4;
 	zpc->chip.of_xlate = of_pwm_xlate_with_flags;
 	zpc->chip.of_pwm_n_cells = 3;

 	/*
 	 * PWM devices may be enabled by firmware, and let's disable all of
 	 * them initially to save power.
 	 */
 	for (i = 0; i < zpc->chip.npwm; i++)
 		zx_pwm_set_mask(zpc, i, ZX_PWM_MODE, ZX_PWM_EN, 0);

 	ret = pwmchip_add(&zpc->chip);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
 		return ret;
 	}

 	platform_set_drvdata(pdev, zpc);

 	return 0;
 }

 static int zx_pwm_remove(struct platform_device *pdev)
 {
 	struct zx_pwm_chip *zpc = platform_get_drvdata(pdev);
 	int ret;

 	ret = pwmchip_remove(&zpc->chip);
 	clk_disable_unprepare(zpc->pclk);

 	return ret;
 }

 static const struct of_device_id zx_pwm_dt_ids[] = {
 	{ .compatible = "zte,zx296718-pwm", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, zx_pwm_dt_ids);

 static struct platform_driver zx_pwm_driver = {
 	.driver = {
 		.name = "zx-pwm",
 		.of_match_table = zx_pwm_dt_ids,
 	},
 	.probe = zx_pwm_probe,
 	.remove = zx_pwm_remove,
 };
 module_platform_driver(zx_pwm_driver);

 MODULE_ALIAS("platform:zx-pwm");
 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 MODULE_DESCRIPTION("ZTE ZX PWM Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Copyright (C) 2017 Sanechips Technology Co., Ltd.
	* Copyright 2017 Linaro Ltd.
	*
	* 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/err.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/pwm.h>
	#include <linux/slab.h>

	#define ZX_PWM_MODE 0x0
	#define ZX_PWM_CLKDIV_SHIFT 2
	#define ZX_PWM_CLKDIV_MASK GENMASK(11, 2)
	#define ZX_PWM_CLKDIV(x) (((x) << ZX_PWM_CLKDIV_SHIFT) & \
	ZX_PWM_CLKDIV_MASK)
	#define ZX_PWM_POLAR BIT(1)
	#define ZX_PWM_EN BIT(0)
	#define ZX_PWM_PERIOD 0x4
	#define ZX_PWM_DUTY 0x8

	#define ZX_PWM_CLKDIV_MAX 1023
	#define ZX_PWM_PERIOD_MAX 65535

	struct zx_pwm_chip {
	struct pwm_chip chip;
	struct clk *pclk;
	struct clk *wclk;
	void __iomem *base;
	};

	static inline struct zx_pwm_chip to_zx_pwm_chip(struct pwm_chip chip)
	{
	return container_of(chip, struct zx_pwm_chip, chip);
	}

	static inline u32 zx_pwm_readl(struct zx_pwm_chip *zpc, unsigned int hwpwm,
	unsigned int offset)
	{
	return readl(zpc->base + (hwpwm + 1) * 0x10 + offset);
	}

	static inline void zx_pwm_writel(struct zx_pwm_chip *zpc, unsigned int hwpwm,
	unsigned int offset, u32 value)
	{
	writel(value, zpc->base + (hwpwm + 1) * 0x10 + offset);
	}

	static void zx_pwm_set_mask(struct zx_pwm_chip *zpc, unsigned int hwpwm,
	unsigned int offset, u32 mask, u32 value)
	{
	u32 data;

	data = zx_pwm_readl(zpc, hwpwm, offset);
	data &= ~mask;
	data \|= value & mask;
	zx_pwm_writel(zpc, hwpwm, offset, data);
	}

	static void zx_pwm_get_state(struct pwm_chip chip, struct pwm_device pwm,
	struct pwm_state *state)
	{
	struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip);
	unsigned long rate;
	unsigned int div;
	u32 value;
	u64 tmp;

	value = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_MODE);

	if (value & ZX_PWM_POLAR)
	state->polarity = PWM_POLARITY_NORMAL;
	else
	state->polarity = PWM_POLARITY_INVERSED;

	if (value & ZX_PWM_EN)
	state->enabled = true;
	else
	state->enabled = false;

	div = (value & ZX_PWM_CLKDIV_MASK) >> ZX_PWM_CLKDIV_SHIFT;
	rate = clk_get_rate(zpc->wclk);

	tmp = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_PERIOD);
	tmp = div NSEC_PER_SEC;
	state->period = DIV_ROUND_CLOSEST_ULL(tmp, rate);

	tmp = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_DUTY);
	tmp = div NSEC_PER_SEC;
	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, rate);
	}

	static int zx_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	unsigned int duty_ns, unsigned int period_ns)
	{
	struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip);
	unsigned int period_cycles, duty_cycles;
	unsigned long long c;
	unsigned int div = 1;
	unsigned long rate;

	/* Find out the best divider */
	rate = clk_get_rate(zpc->wclk);

	while (1) {
	c = rate / div;
	c = c * period_ns;
	do_div(c, NSEC_PER_SEC);

	if (c < ZX_PWM_PERIOD_MAX)
	break;

	div++;

	if (div > ZX_PWM_CLKDIV_MAX)
	return -ERANGE;
	}

	/* Calculate duty cycles */
	period_cycles = c;
	c *= duty_ns;
	do_div(c, period_ns);
	duty_cycles = c;

	/*
	* If the PWM is being enabled, we have to temporarily disable it
	* before configuring the registers.
	*/
	if (pwm_is_enabled(pwm))
	zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_EN, 0);

	/* Set up registers */
	zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_CLKDIV_MASK,
	ZX_PWM_CLKDIV(div));
	zx_pwm_writel(zpc, pwm->hwpwm, ZX_PWM_PERIOD, period_cycles);
	zx_pwm_writel(zpc, pwm->hwpwm, ZX_PWM_DUTY, duty_cycles);

	/* Re-enable the PWM if needed */
	if (pwm_is_enabled(pwm))
	zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE,
	ZX_PWM_EN, ZX_PWM_EN);

	return 0;
	}

	static int zx_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	struct pwm_state *state)
	{
	struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip);
	struct pwm_state cstate;
	int ret;

	pwm_get_state(pwm, &cstate);

	if (state->polarity != cstate.polarity)
	zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_POLAR,
	(state->polarity == PWM_POLARITY_INVERSED) ?
	0 : ZX_PWM_POLAR);

	if (state->period != cstate.period \|\|
	state->duty_cycle != cstate.duty_cycle) {
	ret = zx_pwm_config(chip, pwm, state->duty_cycle,
	state->period);
	if (ret)
	return ret;
	}

	if (state->enabled != cstate.enabled) {
	if (state->enabled) {
	ret = clk_prepare_enable(zpc->wclk);
	if (ret)
	return ret;

	zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE,
	ZX_PWM_EN, ZX_PWM_EN);
	} else {
	zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE,
	ZX_PWM_EN, 0);
	clk_disable_unprepare(zpc->wclk);
	}
	}

	return 0;
	}

	static const struct pwm_ops zx_pwm_ops = {
	.apply = zx_pwm_apply,
	.get_state = zx_pwm_get_state,
	.owner = THIS_MODULE,
	};

	static int zx_pwm_probe(struct platform_device *pdev)
	{
	struct zx_pwm_chip *zpc;
	struct resource *res;
	unsigned int i;
	int ret;

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

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

	zpc->pclk = devm_clk_get(&pdev->dev, "pclk");
	if (IS_ERR(zpc->pclk))
	return PTR_ERR(zpc->pclk);

	zpc->wclk = devm_clk_get(&pdev->dev, "wclk");
	if (IS_ERR(zpc->wclk))
	return PTR_ERR(zpc->wclk);

	ret = clk_prepare_enable(zpc->pclk);
	if (ret)
	return ret;

	zpc->chip.dev = &pdev->dev;
	zpc->chip.ops = &zx_pwm_ops;
	zpc->chip.base = -1;
	zpc->chip.npwm = 4;
	zpc->chip.of_xlate = of_pwm_xlate_with_flags;
	zpc->chip.of_pwm_n_cells = 3;

	/*
	* PWM devices may be enabled by firmware, and let's disable all of
	* them initially to save power.
	*/
	for (i = 0; i < zpc->chip.npwm; i++)
	zx_pwm_set_mask(zpc, i, ZX_PWM_MODE, ZX_PWM_EN, 0);

	ret = pwmchip_add(&zpc->chip);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
	return ret;
	}

	platform_set_drvdata(pdev, zpc);

	return 0;
	}

	static int zx_pwm_remove(struct platform_device *pdev)
	{
	struct zx_pwm_chip *zpc = platform_get_drvdata(pdev);
	int ret;

	ret = pwmchip_remove(&zpc->chip);
	clk_disable_unprepare(zpc->pclk);

	return ret;
	}

	static const struct of_device_id zx_pwm_dt_ids[] = {
	{ .compatible = "zte,zx296718-pwm", },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, zx_pwm_dt_ids);

	static struct platform_driver zx_pwm_driver = {
	.driver = {
	.name = "zx-pwm",
	.of_match_table = zx_pwm_dt_ids,
	},
	.probe = zx_pwm_probe,
	.remove = zx_pwm_remove,
	};
	module_platform_driver(zx_pwm_driver);

	MODULE_ALIAS("platform:zx-pwm");
	MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
	MODULE_DESCRIPTION("ZTE ZX PWM Driver");
	MODULE_LICENSE("GPL v2");