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

 /*
  * Marvell Berlin PWM driver
  *
  * Copyright (C) 2015 Marvell Technology Group Ltd.
  *
  * Author: Antoine Tenart <antoine.tenart@free-electrons.com>
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  */

 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/slab.h>

 #define BERLIN_PWM_EN			0x0
 #define  BERLIN_PWM_ENABLE		BIT(0)
 #define BERLIN_PWM_CONTROL		0x4
 /*
  * The prescaler claims to support 8 different moduli, configured using the
  * low three bits of PWM_CONTROL. (Sequentially, they are 1, 4, 8, 16, 64,
  * 256, 1024, and 4096.)  However, the moduli from 4 to 1024 appear to be
  * implemented by internally shifting TCNT left without adding additional
  * bits. So, the max TCNT that actually works for a modulus of 4 is 0x3fff;
  * for 8, 0x1fff; and so on. This means that those moduli are entirely
  * useless, as we could just do the shift ourselves. The 4096 modulus is
  * implemented with a real prescaler, so we do use that, but we treat it
  * as a flag instead of pretending the modulus is actually configurable.
  */
 #define  BERLIN_PWM_PRESCALE_4096	0x7
 #define  BERLIN_PWM_INVERT_POLARITY	BIT(3)
 #define BERLIN_PWM_DUTY			0x8
 #define BERLIN_PWM_TCNT			0xc
 #define  BERLIN_PWM_MAX_TCNT		65535

 struct berlin_pwm_channel {
 	u32 enable;
 	u32 ctrl;
 	u32 duty;
 	u32 tcnt;
 };

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

 static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip)
 {
 	return container_of(chip, struct berlin_pwm_chip, chip);
 }

 static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *bpc,
 				   unsigned int channel, unsigned long offset)
 {
 	return readl_relaxed(bpc->base + channel * 0x10 + offset);
 }

 static inline void berlin_pwm_writel(struct berlin_pwm_chip *bpc,
 				     unsigned int channel, u32 value,
 				     unsigned long offset)
 {
 	writel_relaxed(value, bpc->base + channel * 0x10 + offset);
 }

 static int berlin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct berlin_pwm_channel *channel;

 	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 	if (!channel)
 		return -ENOMEM;

 	return pwm_set_chip_data(pwm, channel);
 }

 static void berlin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm);

 	kfree(channel);
 }

 static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			     u64 duty_ns, u64 period_ns)
 {
 	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
 	bool prescale_4096 = false;
 	u32 value, duty, period;
 	u64 cycles;

 	cycles = clk_get_rate(bpc->clk);
 	cycles *= period_ns;
 	do_div(cycles, NSEC_PER_SEC);

 	if (cycles > BERLIN_PWM_MAX_TCNT) {
 		prescale_4096 = true;
 		cycles >>= 12; // Prescaled by 4096

 		if (cycles > BERLIN_PWM_MAX_TCNT)
 			return -ERANGE;
 	}

 	period = cycles;
 	cycles *= duty_ns;
 	do_div(cycles, period_ns);
 	duty = cycles;

 	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_CONTROL);
 	if (prescale_4096)
 		value |= BERLIN_PWM_PRESCALE_4096;
 	else
 		value &= ~BERLIN_PWM_PRESCALE_4096;
 	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_CONTROL);

 	berlin_pwm_writel(bpc, pwm->hwpwm, duty, BERLIN_PWM_DUTY);
 	berlin_pwm_writel(bpc, pwm->hwpwm, period, BERLIN_PWM_TCNT);

 	return 0;
 }

 static int berlin_pwm_set_polarity(struct pwm_chip *chip,
 				   struct pwm_device *pwm,
 				   enum pwm_polarity polarity)
 {
 	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
 	u32 value;

 	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_CONTROL);

 	if (polarity == PWM_POLARITY_NORMAL)
 		value &= ~BERLIN_PWM_INVERT_POLARITY;
 	else
 		value |= BERLIN_PWM_INVERT_POLARITY;

 	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_CONTROL);

 	return 0;
 }

 static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
 	u32 value;

 	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_EN);
 	value |= BERLIN_PWM_ENABLE;
 	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_EN);

 	return 0;
 }

 static void berlin_pwm_disable(struct pwm_chip *chip,
 			       struct pwm_device *pwm)
 {
 	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
 	u32 value;

 	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_EN);
 	value &= ~BERLIN_PWM_ENABLE;
 	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_EN);
 }

 static int berlin_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			    const struct pwm_state *state)
 {
 	int err;
 	bool enabled = pwm->state.enabled;

 	if (state->polarity != pwm->state.polarity) {
 		if (enabled) {
 			berlin_pwm_disable(chip, pwm);
 			enabled = false;
 		}

 		err = berlin_pwm_set_polarity(chip, pwm, state->polarity);
 		if (err)
 			return err;
 	}

 	if (!state->enabled) {
 		if (enabled)
 			berlin_pwm_disable(chip, pwm);
 		return 0;
 	}

 	err = berlin_pwm_config(chip, pwm, state->duty_cycle, state->period);
 	if (err)
 		return err;

 	if (!enabled)
 		return berlin_pwm_enable(chip, pwm);

 	return 0;
 }

 static const struct pwm_ops berlin_pwm_ops = {
 	.request = berlin_pwm_request,
 	.free = berlin_pwm_free,
 	.apply = berlin_pwm_apply,
 	.owner = THIS_MODULE,
 };

 static const struct of_device_id berlin_pwm_match[] = {
 	{ .compatible = "marvell,berlin-pwm" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, berlin_pwm_match);

 static int berlin_pwm_probe(struct platform_device *pdev)
 {
 	struct berlin_pwm_chip *bpc;
 	int ret;

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

 	bpc->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(bpc->base))
 		return PTR_ERR(bpc->base);

 	bpc->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(bpc->clk))
 		return PTR_ERR(bpc->clk);

 	ret = clk_prepare_enable(bpc->clk);
 	if (ret)
 		return ret;

 	bpc->chip.dev = &pdev->dev;
 	bpc->chip.ops = &berlin_pwm_ops;
 	bpc->chip.npwm = 4;

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

 	platform_set_drvdata(pdev, bpc);

 	return 0;
 }

 static void berlin_pwm_remove(struct platform_device *pdev)
 {
 	struct berlin_pwm_chip *bpc = platform_get_drvdata(pdev);

 	pwmchip_remove(&bpc->chip);

 	clk_disable_unprepare(bpc->clk);
 }

 #ifdef CONFIG_PM_SLEEP
 static int berlin_pwm_suspend(struct device *dev)
 {
 	struct berlin_pwm_chip *bpc = dev_get_drvdata(dev);
 	unsigned int i;

 	for (i = 0; i < bpc->chip.npwm; i++) {
 		struct berlin_pwm_channel *channel;

 		channel = pwm_get_chip_data(&bpc->chip.pwms[i]);
 		if (!channel)
 			continue;

 		channel->enable = berlin_pwm_readl(bpc, i, BERLIN_PWM_ENABLE);
 		channel->ctrl = berlin_pwm_readl(bpc, i, BERLIN_PWM_CONTROL);
 		channel->duty = berlin_pwm_readl(bpc, i, BERLIN_PWM_DUTY);
 		channel->tcnt = berlin_pwm_readl(bpc, i, BERLIN_PWM_TCNT);
 	}

 	clk_disable_unprepare(bpc->clk);

 	return 0;
 }

 static int berlin_pwm_resume(struct device *dev)
 {
 	struct berlin_pwm_chip *bpc = dev_get_drvdata(dev);
 	unsigned int i;
 	int ret;

 	ret = clk_prepare_enable(bpc->clk);
 	if (ret)
 		return ret;

 	for (i = 0; i < bpc->chip.npwm; i++) {
 		struct berlin_pwm_channel *channel;

 		channel = pwm_get_chip_data(&bpc->chip.pwms[i]);
 		if (!channel)
 			continue;

 		berlin_pwm_writel(bpc, i, channel->ctrl, BERLIN_PWM_CONTROL);
 		berlin_pwm_writel(bpc, i, channel->duty, BERLIN_PWM_DUTY);
 		berlin_pwm_writel(bpc, i, channel->tcnt, BERLIN_PWM_TCNT);
 		berlin_pwm_writel(bpc, i, channel->enable, BERLIN_PWM_ENABLE);
 	}

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend,
 			 berlin_pwm_resume);

 static struct platform_driver berlin_pwm_driver = {
 	.probe = berlin_pwm_probe,
 	.remove_new = berlin_pwm_remove,
 	.driver = {
 		.name = "berlin-pwm",
 		.of_match_table = berlin_pwm_match,
 		.pm = &berlin_pwm_pm_ops,
 	},
 };
 module_platform_driver(berlin_pwm_driver);

 MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
 MODULE_DESCRIPTION("Marvell Berlin PWM driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Marvell Berlin PWM driver
	*
	* Copyright (C) 2015 Marvell Technology Group Ltd.
	*
	* Author: Antoine Tenart <antoine.tenart@free-electrons.com>
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*/

	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/mod_devicetable.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/pwm.h>
	#include <linux/slab.h>

	#define BERLIN_PWM_EN 0x0
	#define BERLIN_PWM_ENABLE BIT(0)
	#define BERLIN_PWM_CONTROL 0x4
	/*
	* The prescaler claims to support 8 different moduli, configured using the
	* low three bits of PWM_CONTROL. (Sequentially, they are 1, 4, 8, 16, 64,
	* 256, 1024, and 4096.) However, the moduli from 4 to 1024 appear to be
	* implemented by internally shifting TCNT left without adding additional
	* bits. So, the max TCNT that actually works for a modulus of 4 is 0x3fff;
	* for 8, 0x1fff; and so on. This means that those moduli are entirely
	* useless, as we could just do the shift ourselves. The 4096 modulus is
	* implemented with a real prescaler, so we do use that, but we treat it
	* as a flag instead of pretending the modulus is actually configurable.
	*/
	#define BERLIN_PWM_PRESCALE_4096 0x7
	#define BERLIN_PWM_INVERT_POLARITY BIT(3)
	#define BERLIN_PWM_DUTY 0x8
	#define BERLIN_PWM_TCNT 0xc
	#define BERLIN_PWM_MAX_TCNT 65535

	struct berlin_pwm_channel {
	u32 enable;
	u32 ctrl;
	u32 duty;
	u32 tcnt;
	};

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

	static inline struct berlin_pwm_chip to_berlin_pwm_chip(struct pwm_chip chip)
	{
	return container_of(chip, struct berlin_pwm_chip, chip);
	}

	static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *bpc,
	unsigned int channel, unsigned long offset)
	{
	return readl_relaxed(bpc->base + channel * 0x10 + offset);
	}

	static inline void berlin_pwm_writel(struct berlin_pwm_chip *bpc,
	unsigned int channel, u32 value,
	unsigned long offset)
	{
	writel_relaxed(value, bpc->base + channel * 0x10 + offset);
	}

	static int berlin_pwm_request(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct berlin_pwm_channel *channel;

	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
	if (!channel)
	return -ENOMEM;

	return pwm_set_chip_data(pwm, channel);
	}

	static void berlin_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm);

	kfree(channel);
	}

	static int berlin_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	u64 duty_ns, u64 period_ns)
	{
	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
	bool prescale_4096 = false;
	u32 value, duty, period;
	u64 cycles;

	cycles = clk_get_rate(bpc->clk);
	cycles *= period_ns;
	do_div(cycles, NSEC_PER_SEC);

	if (cycles > BERLIN_PWM_MAX_TCNT) {
	prescale_4096 = true;
	cycles >>= 12; // Prescaled by 4096

	if (cycles > BERLIN_PWM_MAX_TCNT)
	return -ERANGE;
	}

	period = cycles;
	cycles *= duty_ns;
	do_div(cycles, period_ns);
	duty = cycles;

	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_CONTROL);
	if (prescale_4096)
	value \|= BERLIN_PWM_PRESCALE_4096;
	else
	value &= ~BERLIN_PWM_PRESCALE_4096;
	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_CONTROL);

	berlin_pwm_writel(bpc, pwm->hwpwm, duty, BERLIN_PWM_DUTY);
	berlin_pwm_writel(bpc, pwm->hwpwm, period, BERLIN_PWM_TCNT);

	return 0;
	}

	static int berlin_pwm_set_polarity(struct pwm_chip *chip,
	struct pwm_device *pwm,
	enum pwm_polarity polarity)
	{
	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
	u32 value;

	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_CONTROL);

	if (polarity == PWM_POLARITY_NORMAL)
	value &= ~BERLIN_PWM_INVERT_POLARITY;
	else
	value \|= BERLIN_PWM_INVERT_POLARITY;

	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_CONTROL);

	return 0;
	}

	static int berlin_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
	u32 value;

	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_EN);
	value \|= BERLIN_PWM_ENABLE;
	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_EN);

	return 0;
	}

	static void berlin_pwm_disable(struct pwm_chip *chip,
	struct pwm_device *pwm)
	{
	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
	u32 value;

	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_EN);
	value &= ~BERLIN_PWM_ENABLE;
	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_EN);
	}

	static int berlin_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	const struct pwm_state *state)
	{
	int err;
	bool enabled = pwm->state.enabled;

	if (state->polarity != pwm->state.polarity) {
	if (enabled) {
	berlin_pwm_disable(chip, pwm);
	enabled = false;
	}

	err = berlin_pwm_set_polarity(chip, pwm, state->polarity);
	if (err)
	return err;
	}

	if (!state->enabled) {
	if (enabled)
	berlin_pwm_disable(chip, pwm);
	return 0;
	}

	err = berlin_pwm_config(chip, pwm, state->duty_cycle, state->period);
	if (err)
	return err;

	if (!enabled)
	return berlin_pwm_enable(chip, pwm);

	return 0;
	}

	static const struct pwm_ops berlin_pwm_ops = {
	.request = berlin_pwm_request,
	.free = berlin_pwm_free,
	.apply = berlin_pwm_apply,
	.owner = THIS_MODULE,
	};

	static const struct of_device_id berlin_pwm_match[] = {
	{ .compatible = "marvell,berlin-pwm" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, berlin_pwm_match);

	static int berlin_pwm_probe(struct platform_device *pdev)
	{
	struct berlin_pwm_chip *bpc;
	int ret;

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

	bpc->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(bpc->base))
	return PTR_ERR(bpc->base);

	bpc->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(bpc->clk))
	return PTR_ERR(bpc->clk);

	ret = clk_prepare_enable(bpc->clk);
	if (ret)
	return ret;

	bpc->chip.dev = &pdev->dev;
	bpc->chip.ops = &berlin_pwm_ops;
	bpc->chip.npwm = 4;

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

	platform_set_drvdata(pdev, bpc);

	return 0;
	}

	static void berlin_pwm_remove(struct platform_device *pdev)
	{
	struct berlin_pwm_chip *bpc = platform_get_drvdata(pdev);

	pwmchip_remove(&bpc->chip);

	clk_disable_unprepare(bpc->clk);
	}

	#ifdef CONFIG_PM_SLEEP
	static int berlin_pwm_suspend(struct device *dev)
	{
	struct berlin_pwm_chip *bpc = dev_get_drvdata(dev);
	unsigned int i;

	for (i = 0; i < bpc->chip.npwm; i++) {
	struct berlin_pwm_channel *channel;

	channel = pwm_get_chip_data(&bpc->chip.pwms[i]);
	if (!channel)
	continue;

	channel->enable = berlin_pwm_readl(bpc, i, BERLIN_PWM_ENABLE);
	channel->ctrl = berlin_pwm_readl(bpc, i, BERLIN_PWM_CONTROL);
	channel->duty = berlin_pwm_readl(bpc, i, BERLIN_PWM_DUTY);
	channel->tcnt = berlin_pwm_readl(bpc, i, BERLIN_PWM_TCNT);
	}

	clk_disable_unprepare(bpc->clk);

	return 0;
	}

	static int berlin_pwm_resume(struct device *dev)
	{
	struct berlin_pwm_chip *bpc = dev_get_drvdata(dev);
	unsigned int i;
	int ret;

	ret = clk_prepare_enable(bpc->clk);
	if (ret)
	return ret;

	for (i = 0; i < bpc->chip.npwm; i++) {
	struct berlin_pwm_channel *channel;

	channel = pwm_get_chip_data(&bpc->chip.pwms[i]);
	if (!channel)
	continue;

	berlin_pwm_writel(bpc, i, channel->ctrl, BERLIN_PWM_CONTROL);
	berlin_pwm_writel(bpc, i, channel->duty, BERLIN_PWM_DUTY);
	berlin_pwm_writel(bpc, i, channel->tcnt, BERLIN_PWM_TCNT);
	berlin_pwm_writel(bpc, i, channel->enable, BERLIN_PWM_ENABLE);
	}

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend,
	berlin_pwm_resume);

	static struct platform_driver berlin_pwm_driver = {
	.probe = berlin_pwm_probe,
	.remove_new = berlin_pwm_remove,
	.driver = {
	.name = "berlin-pwm",
	.of_match_table = berlin_pwm_match,
	.pm = &berlin_pwm_pm_ops,
	},
	};
	module_platform_driver(berlin_pwm_driver);

	MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
	MODULE_DESCRIPTION("Marvell Berlin PWM driver");
	MODULE_LICENSE("GPL v2");