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

 // SPDX-License-Identifier: GPL-2.0
 /*
  * R-Car PWM Timer driver
  *
  * Copyright (C) 2015 Renesas Electronics Corporation
  *
  * Limitations:
  * - The hardware cannot generate a 0% duty cycle.
  */

 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/log2.h>
 #include <linux/math64.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/pwm.h>
 #include <linux/slab.h>

 #define RCAR_PWM_MAX_DIVISION	24
 #define RCAR_PWM_MAX_CYCLE	1023

 #define RCAR_PWMCR		0x00
 #define  RCAR_PWMCR_CC0_MASK	0x000f0000
 #define  RCAR_PWMCR_CC0_SHIFT	16
 #define  RCAR_PWMCR_CCMD	BIT(15)
 #define  RCAR_PWMCR_SYNC	BIT(11)
 #define  RCAR_PWMCR_SS0		BIT(4)
 #define  RCAR_PWMCR_EN0		BIT(0)

 #define RCAR_PWMCNT		0x04
 #define  RCAR_PWMCNT_CYC0_MASK	0x03ff0000
 #define  RCAR_PWMCNT_CYC0_SHIFT	16
 #define  RCAR_PWMCNT_PH0_MASK	0x000003ff
 #define  RCAR_PWMCNT_PH0_SHIFT	0

 struct rcar_pwm_chip {
 	struct pwm_chip chip;
 	void __iomem *base;
 	struct clk *clk;
 };

 static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip)
 {
 	return container_of(chip, struct rcar_pwm_chip, chip);
 }

 static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data,
 			   unsigned int offset)
 {
 	writel(data, rp->base + offset);
 }

 static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset)
 {
 	return readl(rp->base + offset);
 }

 static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data,
 			    unsigned int offset)
 {
 	u32 value;

 	value = rcar_pwm_read(rp, offset);
 	value &= ~mask;
 	value |= data & mask;
 	rcar_pwm_write(rp, value, offset);
 }

 static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns)
 {
 	unsigned long clk_rate = clk_get_rate(rp->clk);
 	u64 div, tmp;

 	if (clk_rate == 0)
 		return -EINVAL;

 	div = (u64)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE;
 	tmp = (u64)period_ns * clk_rate + div - 1;
 	tmp = div64_u64(tmp, div);
 	div = ilog2(tmp - 1) + 1;

 	return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE;
 }

 static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
 				       unsigned int div)
 {
 	u32 value;

 	value = rcar_pwm_read(rp, RCAR_PWMCR);
 	value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK);

 	if (div & 1)
 		value |= RCAR_PWMCR_CCMD;

 	div >>= 1;

 	value |= div << RCAR_PWMCR_CC0_SHIFT;
 	rcar_pwm_write(rp, value, RCAR_PWMCR);
 }

 static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
 				int period_ns)
 {
 	unsigned long long one_cycle, tmp;	/* 0.01 nanoseconds */
 	unsigned long clk_rate = clk_get_rate(rp->clk);
 	u32 cyc, ph;

 	one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div);
 	do_div(one_cycle, clk_rate);

 	tmp = period_ns * 100ULL;
 	do_div(tmp, one_cycle);
 	cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;

 	tmp = duty_ns * 100ULL;
 	do_div(tmp, one_cycle);
 	ph = tmp & RCAR_PWMCNT_PH0_MASK;

 	/* Avoid prohibited setting */
 	if (cyc == 0 || ph == 0)
 		return -EINVAL;

 	rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT);

 	return 0;
 }

 static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	return pm_runtime_get_sync(chip->dev);
 }

 static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	pm_runtime_put(chip->dev);
 }

 static int rcar_pwm_enable(struct rcar_pwm_chip *rp)
 {
 	u32 value;

 	/* Don't enable the PWM device if CYC0 or PH0 is 0 */
 	value = rcar_pwm_read(rp, RCAR_PWMCNT);
 	if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 ||
 	    (value & RCAR_PWMCNT_PH0_MASK) == 0)
 		return -EINVAL;

 	rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR);

 	return 0;
 }

 static void rcar_pwm_disable(struct rcar_pwm_chip *rp)
 {
 	rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
 }

 static int rcar_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			  const struct pwm_state *state)
 {
 	struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
 	int div, ret;

 	/* This HW/driver only supports normal polarity */
 	if (state->polarity != PWM_POLARITY_NORMAL)
 		return -ENOTSUPP;

 	if (!state->enabled) {
 		rcar_pwm_disable(rp);
 		return 0;
 	}

 	div = rcar_pwm_get_clock_division(rp, state->period);
 	if (div < 0)
 		return div;

 	rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);

 	ret = rcar_pwm_set_counter(rp, div, state->duty_cycle, state->period);
 	if (!ret)
 		rcar_pwm_set_clock_control(rp, div);

 	/* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
 	rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);

 	if (!ret)
 		ret = rcar_pwm_enable(rp);

 	return ret;
 }

 static const struct pwm_ops rcar_pwm_ops = {
 	.request = rcar_pwm_request,
 	.free = rcar_pwm_free,
 	.apply = rcar_pwm_apply,
 	.owner = THIS_MODULE,
 };

 static int rcar_pwm_probe(struct platform_device *pdev)
 {
 	struct rcar_pwm_chip *rcar_pwm;
 	struct resource *res;
 	int ret;

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

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

 	rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(rcar_pwm->clk)) {
 		dev_err(&pdev->dev, "cannot get clock\n");
 		return PTR_ERR(rcar_pwm->clk);
 	}

 	platform_set_drvdata(pdev, rcar_pwm);

 	rcar_pwm->chip.dev = &pdev->dev;
 	rcar_pwm->chip.ops = &rcar_pwm_ops;
 	rcar_pwm->chip.base = -1;
 	rcar_pwm->chip.npwm = 1;

 	pm_runtime_enable(&pdev->dev);

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

 	return 0;
 }

 static int rcar_pwm_remove(struct platform_device *pdev)
 {
 	struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev);
 	int ret;

 	ret = pwmchip_remove(&rcar_pwm->chip);

 	pm_runtime_disable(&pdev->dev);

 	return ret;
 }

 static const struct of_device_id rcar_pwm_of_table[] = {
 	{ .compatible = "renesas,pwm-rcar", },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);

 static struct platform_driver rcar_pwm_driver = {
 	.probe = rcar_pwm_probe,
 	.remove = rcar_pwm_remove,
 	.driver = {
 		.name = "pwm-rcar",
 		.of_match_table = of_match_ptr(rcar_pwm_of_table),
 	}
 };
 module_platform_driver(rcar_pwm_driver);

 MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");
 MODULE_DESCRIPTION("Renesas PWM Timer Driver");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:pwm-rcar");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* R-Car PWM Timer driver
	*
	* Copyright (C) 2015 Renesas Electronics Corporation
	*
	* Limitations:
	* - The hardware cannot generate a 0% duty cycle.
	*/

	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/log2.h>
	#include <linux/math64.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>
	#include <linux/pwm.h>
	#include <linux/slab.h>

	#define RCAR_PWM_MAX_DIVISION 24
	#define RCAR_PWM_MAX_CYCLE 1023

	#define RCAR_PWMCR 0x00
	#define RCAR_PWMCR_CC0_MASK 0x000f0000
	#define RCAR_PWMCR_CC0_SHIFT 16
	#define RCAR_PWMCR_CCMD BIT(15)
	#define RCAR_PWMCR_SYNC BIT(11)
	#define RCAR_PWMCR_SS0 BIT(4)
	#define RCAR_PWMCR_EN0 BIT(0)

	#define RCAR_PWMCNT 0x04
	#define RCAR_PWMCNT_CYC0_MASK 0x03ff0000
	#define RCAR_PWMCNT_CYC0_SHIFT 16
	#define RCAR_PWMCNT_PH0_MASK 0x000003ff
	#define RCAR_PWMCNT_PH0_SHIFT 0

	struct rcar_pwm_chip {
	struct pwm_chip chip;
	void __iomem *base;
	struct clk *clk;
	};

	static inline struct rcar_pwm_chip to_rcar_pwm_chip(struct pwm_chip chip)
	{
	return container_of(chip, struct rcar_pwm_chip, chip);
	}

	static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data,
	unsigned int offset)
	{
	writel(data, rp->base + offset);
	}

	static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset)
	{
	return readl(rp->base + offset);
	}

	static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data,
	unsigned int offset)
	{
	u32 value;

	value = rcar_pwm_read(rp, offset);
	value &= ~mask;
	value \|= data & mask;
	rcar_pwm_write(rp, value, offset);
	}

	static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns)
	{
	unsigned long clk_rate = clk_get_rate(rp->clk);
	u64 div, tmp;

	if (clk_rate == 0)
	return -EINVAL;

	div = (u64)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE;
	tmp = (u64)period_ns * clk_rate + div - 1;
	tmp = div64_u64(tmp, div);
	div = ilog2(tmp - 1) + 1;

	return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE;
	}

	static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
	unsigned int div)
	{
	u32 value;

	value = rcar_pwm_read(rp, RCAR_PWMCR);
	value &= ~(RCAR_PWMCR_CCMD \| RCAR_PWMCR_CC0_MASK);

	if (div & 1)
	value \|= RCAR_PWMCR_CCMD;

	div >>= 1;

	value \|= div << RCAR_PWMCR_CC0_SHIFT;
	rcar_pwm_write(rp, value, RCAR_PWMCR);
	}

	static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
	int period_ns)
	{
	unsigned long long one_cycle, tmp; /* 0.01 nanoseconds */
	unsigned long clk_rate = clk_get_rate(rp->clk);
	u32 cyc, ph;

	one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div);
	do_div(one_cycle, clk_rate);

	tmp = period_ns * 100ULL;
	do_div(tmp, one_cycle);
	cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;

	tmp = duty_ns * 100ULL;
	do_div(tmp, one_cycle);
	ph = tmp & RCAR_PWMCNT_PH0_MASK;

	/* Avoid prohibited setting */
	if (cyc == 0 \|\| ph == 0)
	return -EINVAL;

	rcar_pwm_write(rp, cyc \| ph, RCAR_PWMCNT);

	return 0;
	}

	static int rcar_pwm_request(struct pwm_chip chip, struct pwm_device pwm)
	{
	return pm_runtime_get_sync(chip->dev);
	}

	static void rcar_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
	{
	pm_runtime_put(chip->dev);
	}

	static int rcar_pwm_enable(struct rcar_pwm_chip *rp)
	{
	u32 value;

	/* Don't enable the PWM device if CYC0 or PH0 is 0 */
	value = rcar_pwm_read(rp, RCAR_PWMCNT);
	if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 \|\|
	(value & RCAR_PWMCNT_PH0_MASK) == 0)
	return -EINVAL;

	rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR);

	return 0;
	}

	static void rcar_pwm_disable(struct rcar_pwm_chip *rp)
	{
	rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
	}

	static int rcar_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	const struct pwm_state *state)
	{
	struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
	int div, ret;

	/* This HW/driver only supports normal polarity */
	if (state->polarity != PWM_POLARITY_NORMAL)
	return -ENOTSUPP;

	if (!state->enabled) {
	rcar_pwm_disable(rp);
	return 0;
	}

	div = rcar_pwm_get_clock_division(rp, state->period);
	if (div < 0)
	return div;

	rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);

	ret = rcar_pwm_set_counter(rp, div, state->duty_cycle, state->period);
	if (!ret)
	rcar_pwm_set_clock_control(rp, div);

	/* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
	rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);

	if (!ret)
	ret = rcar_pwm_enable(rp);

	return ret;
	}

	static const struct pwm_ops rcar_pwm_ops = {
	.request = rcar_pwm_request,
	.free = rcar_pwm_free,
	.apply = rcar_pwm_apply,
	.owner = THIS_MODULE,
	};

	static int rcar_pwm_probe(struct platform_device *pdev)
	{
	struct rcar_pwm_chip *rcar_pwm;
	struct resource *res;
	int ret;

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

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

	rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(rcar_pwm->clk)) {
	dev_err(&pdev->dev, "cannot get clock\n");
	return PTR_ERR(rcar_pwm->clk);
	}

	platform_set_drvdata(pdev, rcar_pwm);

	rcar_pwm->chip.dev = &pdev->dev;
	rcar_pwm->chip.ops = &rcar_pwm_ops;
	rcar_pwm->chip.base = -1;
	rcar_pwm->chip.npwm = 1;

	pm_runtime_enable(&pdev->dev);

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

	return 0;
	}

	static int rcar_pwm_remove(struct platform_device *pdev)
	{
	struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev);
	int ret;

	ret = pwmchip_remove(&rcar_pwm->chip);

	pm_runtime_disable(&pdev->dev);

	return ret;
	}

	static const struct of_device_id rcar_pwm_of_table[] = {
	{ .compatible = "renesas,pwm-rcar", },
	{ },
	};
	MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);

	static struct platform_driver rcar_pwm_driver = {
	.probe = rcar_pwm_probe,
	.remove = rcar_pwm_remove,
	.driver = {
	.name = "pwm-rcar",
	.of_match_table = of_match_ptr(rcar_pwm_of_table),
	}
	};
	module_platform_driver(rcar_pwm_driver);

	MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");
	MODULE_DESCRIPTION("Renesas PWM Timer Driver");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:pwm-rcar");