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

 /*
  * Broadcom BCM7038 PWM driver
  * Author: Florian Fainelli
  *
  * Copyright (C) 2015 Broadcom Corporation
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

 #include <linux/clk.h>
 #include <linux/export.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/spinlock.h>

 #define PWM_CTRL		0x00
 #define  CTRL_START		BIT(0)
 #define  CTRL_OEB		BIT(1)
 #define  CTRL_FORCE_HIGH	BIT(2)
 #define  CTRL_OPENDRAIN		BIT(3)
 #define  CTRL_CHAN_OFFS		4

 #define PWM_CTRL2		0x04
 #define  CTRL2_OUT_SELECT	BIT(0)

 #define PWM_CH_SIZE		0x8

 #define PWM_CWORD_MSB(ch)	(0x08 + ((ch) * PWM_CH_SIZE))
 #define PWM_CWORD_LSB(ch)	(0x0c + ((ch) * PWM_CH_SIZE))

 /* Number of bits for the CWORD value */
 #define CWORD_BIT_SIZE		16

 /*
  * Maximum control word value allowed when variable-frequency PWM is used as a
  * clock for the constant-frequency PMW.
  */
 #define CONST_VAR_F_MAX		32768
 #define CONST_VAR_F_MIN		1

 #define PWM_ON(ch)		(0x18 + ((ch) * PWM_CH_SIZE))
 #define  PWM_ON_MIN		1
 #define PWM_PERIOD(ch)		(0x1c + ((ch) * PWM_CH_SIZE))
 #define  PWM_PERIOD_MIN		0

 #define PWM_ON_PERIOD_MAX	0xff

 struct brcmstb_pwm {
 	void __iomem *base;
 	spinlock_t lock;
 	struct clk *clk;
 	struct pwm_chip chip;
 };

 static inline u32 brcmstb_pwm_readl(struct brcmstb_pwm *p,
 				    unsigned int offset)
 {
 	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
 		return __raw_readl(p->base + offset);
 	else
 		return readl_relaxed(p->base + offset);
 }

 static inline void brcmstb_pwm_writel(struct brcmstb_pwm *p, u32 value,
 				      unsigned int offset)
 {
 	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
 		__raw_writel(value, p->base + offset);
 	else
 		writel_relaxed(value, p->base + offset);
 }

 static inline struct brcmstb_pwm *to_brcmstb_pwm(struct pwm_chip *chip)
 {
 	return container_of(chip, struct brcmstb_pwm, chip);
 }

 /*
  * Fv is derived from the variable frequency output. The variable frequency
  * output is configured using this formula:
  *
  * W = cword, if cword < 2 ^ 15 else 16-bit 2's complement of cword
  *
  * Fv = W x 2 ^ -16 x 27Mhz (reference clock)
  *
  * The period is: (period + 1) / Fv and "on" time is on / (period + 1)
  *
  * The PWM core framework specifies that the "duty_ns" parameter is in fact the
  * "on" time, so this translates directly into our HW programming here.
  */
 static int brcmstb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			      int duty_ns, int period_ns)
 {
 	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);
 	unsigned long pc, dc, cword = CONST_VAR_F_MAX;
 	unsigned int channel = pwm->hwpwm;
 	u32 value;

 	/*
 	 * If asking for a duty_ns equal to period_ns, we need to substract
 	 * the period value by 1 to make it shorter than the "on" time and
 	 * produce a flat 100% duty cycle signal, and max out the "on" time
 	 */
 	if (duty_ns == period_ns) {
 		dc = PWM_ON_PERIOD_MAX;
 		pc = PWM_ON_PERIOD_MAX - 1;
 		goto done;
 	}

 	while (1) {
 		u64 rate, tmp;

 		/*
 		 * Calculate the base rate from base frequency and current
 		 * cword
 		 */
 		rate = (u64)clk_get_rate(p->clk) * (u64)cword;
 		do_div(rate, 1 << CWORD_BIT_SIZE);

 		tmp = period_ns * rate;
 		do_div(tmp, NSEC_PER_SEC);
 		pc = tmp;

 		tmp = (duty_ns + 1) * rate;
 		do_div(tmp, NSEC_PER_SEC);
 		dc = tmp;

 		/*
 		 * We can be called with separate duty and period updates,
 		 * so do not reject dc == 0 right away
 		 */
 		if (pc == PWM_PERIOD_MIN || (dc < PWM_ON_MIN && duty_ns))
 			return -EINVAL;

 		/* We converged on a calculation */
 		if (pc <= PWM_ON_PERIOD_MAX && dc <= PWM_ON_PERIOD_MAX)
 			break;

 		/*
 		 * The cword needs to be a power of 2 for the variable
 		 * frequency generator to output a 50% duty cycle variable
 		 * frequency which is used as input clock to the fixed
 		 * frequency generator.
 		 */
 		cword >>= 1;

 		/*
 		 * Desired periods are too large, we do not have a divider
 		 * for them
 		 */
 		if (cword < CONST_VAR_F_MIN)
 			return -EINVAL;
 	}

 done:
 	/*
 	 * Configure the defined "cword" value to have the variable frequency
 	 * generator output a base frequency for the constant frequency
 	 * generator to derive from.
 	 */
 	spin_lock(&p->lock);
 	brcmstb_pwm_writel(p, cword >> 8, PWM_CWORD_MSB(channel));
 	brcmstb_pwm_writel(p, cword & 0xff, PWM_CWORD_LSB(channel));

 	/* Select constant frequency signal output */
 	value = brcmstb_pwm_readl(p, PWM_CTRL2);
 	value |= CTRL2_OUT_SELECT << (channel * CTRL_CHAN_OFFS);
 	brcmstb_pwm_writel(p, value, PWM_CTRL2);

 	/* Configure on and period value */
 	brcmstb_pwm_writel(p, pc, PWM_PERIOD(channel));
 	brcmstb_pwm_writel(p, dc, PWM_ON(channel));
 	spin_unlock(&p->lock);

 	return 0;
 }

 static inline void brcmstb_pwm_enable_set(struct brcmstb_pwm *p,
 					  unsigned int channel, bool enable)
 {
 	unsigned int shift = channel * CTRL_CHAN_OFFS;
 	u32 value;

 	spin_lock(&p->lock);
 	value = brcmstb_pwm_readl(p, PWM_CTRL);

 	if (enable) {
 		value &= ~(CTRL_OEB << shift);
 		value |= (CTRL_START | CTRL_OPENDRAIN) << shift;
 	} else {
 		value &= ~((CTRL_START | CTRL_OPENDRAIN) << shift);
 		value |= CTRL_OEB << shift;
 	}

 	brcmstb_pwm_writel(p, value, PWM_CTRL);
 	spin_unlock(&p->lock);
 }

 static int brcmstb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);

 	brcmstb_pwm_enable_set(p, pwm->hwpwm, true);

 	return 0;
 }

 static void brcmstb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);

 	brcmstb_pwm_enable_set(p, pwm->hwpwm, false);
 }

 static const struct pwm_ops brcmstb_pwm_ops = {
 	.config = brcmstb_pwm_config,
 	.enable = brcmstb_pwm_enable,
 	.disable = brcmstb_pwm_disable,
 	.owner = THIS_MODULE,
 };

 static const struct of_device_id brcmstb_pwm_of_match[] = {
 	{ .compatible = "brcm,bcm7038-pwm", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, brcmstb_pwm_of_match);

 static int brcmstb_pwm_probe(struct platform_device *pdev)
 {
 	struct brcmstb_pwm *p;
 	struct resource *res;
 	int ret;

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

 	spin_lock_init(&p->lock);

 	p->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(p->clk)) {
 		dev_err(&pdev->dev, "failed to obtain clock\n");
 		return PTR_ERR(p->clk);
 	}

 	ret = clk_prepare_enable(p->clk);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
 		return ret;
 	}

 	platform_set_drvdata(pdev, p);

 	p->chip.dev = &pdev->dev;
 	p->chip.ops = &brcmstb_pwm_ops;
 	p->chip.base = -1;
 	p->chip.npwm = 2;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	p->base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(p->base)) {
 		ret = PTR_ERR(p->base);
 		goto out_clk;
 	}

 	ret = pwmchip_add(&p->chip);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
 		goto out_clk;
 	}

 	return 0;

 out_clk:
 	clk_disable_unprepare(p->clk);
 	return ret;
 }

 static int brcmstb_pwm_remove(struct platform_device *pdev)
 {
 	struct brcmstb_pwm *p = platform_get_drvdata(pdev);
 	int ret;

 	ret = pwmchip_remove(&p->chip);
 	clk_disable_unprepare(p->clk);

 	return ret;
 }

 #ifdef CONFIG_PM_SLEEP
 static int brcmstb_pwm_suspend(struct device *dev)
 {
 	struct brcmstb_pwm *p = dev_get_drvdata(dev);

 	clk_disable(p->clk);

 	return 0;
 }

 static int brcmstb_pwm_resume(struct device *dev)
 {
 	struct brcmstb_pwm *p = dev_get_drvdata(dev);

 	clk_enable(p->clk);

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(brcmstb_pwm_pm_ops, brcmstb_pwm_suspend,
 			 brcmstb_pwm_resume);

 static struct platform_driver brcmstb_pwm_driver = {
 	.probe = brcmstb_pwm_probe,
 	.remove = brcmstb_pwm_remove,
 	.driver = {
 		.name = "pwm-brcmstb",
 		.of_match_table = brcmstb_pwm_of_match,
 		.pm = &brcmstb_pwm_pm_ops,
 	},
 };
 module_platform_driver(brcmstb_pwm_driver);

 MODULE_AUTHOR("Florian Fainelli <f.fainelli@gmail.com>");
 MODULE_DESCRIPTION("Broadcom STB PWM driver");
 MODULE_ALIAS("platform:pwm-brcmstb");
 MODULE_LICENSE("GPL");
	/*
	* Broadcom BCM7038 PWM driver
	* Author: Florian Fainelli
	*
	* Copyright (C) 2015 Broadcom Corporation
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/clk.h>
	#include <linux/export.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/pwm.h>
	#include <linux/spinlock.h>

	#define PWM_CTRL 0x00
	#define CTRL_START BIT(0)
	#define CTRL_OEB BIT(1)
	#define CTRL_FORCE_HIGH BIT(2)
	#define CTRL_OPENDRAIN BIT(3)
	#define CTRL_CHAN_OFFS 4

	#define PWM_CTRL2 0x04
	#define CTRL2_OUT_SELECT BIT(0)

	#define PWM_CH_SIZE 0x8

	#define PWM_CWORD_MSB(ch) (0x08 + ((ch) * PWM_CH_SIZE))
	#define PWM_CWORD_LSB(ch) (0x0c + ((ch) * PWM_CH_SIZE))

	/* Number of bits for the CWORD value */
	#define CWORD_BIT_SIZE 16

	/*
	* Maximum control word value allowed when variable-frequency PWM is used as a
	* clock for the constant-frequency PMW.
	*/
	#define CONST_VAR_F_MAX 32768
	#define CONST_VAR_F_MIN 1

	#define PWM_ON(ch) (0x18 + ((ch) * PWM_CH_SIZE))
	#define PWM_ON_MIN 1
	#define PWM_PERIOD(ch) (0x1c + ((ch) * PWM_CH_SIZE))
	#define PWM_PERIOD_MIN 0

	#define PWM_ON_PERIOD_MAX 0xff

	struct brcmstb_pwm {
	void __iomem *base;
	spinlock_t lock;
	struct clk *clk;
	struct pwm_chip chip;
	};

	static inline u32 brcmstb_pwm_readl(struct brcmstb_pwm *p,
	unsigned int offset)
	{
	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
	return __raw_readl(p->base + offset);
	else
	return readl_relaxed(p->base + offset);
	}

	static inline void brcmstb_pwm_writel(struct brcmstb_pwm *p, u32 value,
	unsigned int offset)
	{
	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
	__raw_writel(value, p->base + offset);
	else
	writel_relaxed(value, p->base + offset);
	}

	static inline struct brcmstb_pwm to_brcmstb_pwm(struct pwm_chip chip)
	{
	return container_of(chip, struct brcmstb_pwm, chip);
	}

	/*
	* Fv is derived from the variable frequency output. The variable frequency
	* output is configured using this formula:
	*
	* W = cword, if cword < 2 ^ 15 else 16-bit 2's complement of cword
	*
	* Fv = W x 2 ^ -16 x 27Mhz (reference clock)
	*
	* The period is: (period + 1) / Fv and "on" time is on / (period + 1)
	*
	* The PWM core framework specifies that the "duty_ns" parameter is in fact the
	* "on" time, so this translates directly into our HW programming here.
	*/
	static int brcmstb_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	int duty_ns, int period_ns)
	{
	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);
	unsigned long pc, dc, cword = CONST_VAR_F_MAX;
	unsigned int channel = pwm->hwpwm;
	u32 value;

	/*
	* If asking for a duty_ns equal to period_ns, we need to substract
	* the period value by 1 to make it shorter than the "on" time and
	* produce a flat 100% duty cycle signal, and max out the "on" time
	*/
	if (duty_ns == period_ns) {
	dc = PWM_ON_PERIOD_MAX;
	pc = PWM_ON_PERIOD_MAX - 1;
	goto done;
	}

	while (1) {
	u64 rate, tmp;

	/*
	* Calculate the base rate from base frequency and current
	* cword
	*/
	rate = (u64)clk_get_rate(p->clk) * (u64)cword;
	do_div(rate, 1 << CWORD_BIT_SIZE);

	tmp = period_ns * rate;
	do_div(tmp, NSEC_PER_SEC);
	pc = tmp;

	tmp = (duty_ns + 1) * rate;
	do_div(tmp, NSEC_PER_SEC);
	dc = tmp;

	/*
	* We can be called with separate duty and period updates,
	* so do not reject dc == 0 right away
	*/
	if (pc == PWM_PERIOD_MIN \|\| (dc < PWM_ON_MIN && duty_ns))
	return -EINVAL;

	/* We converged on a calculation */
	if (pc <= PWM_ON_PERIOD_MAX && dc <= PWM_ON_PERIOD_MAX)
	break;

	/*
	* The cword needs to be a power of 2 for the variable
	* frequency generator to output a 50% duty cycle variable
	* frequency which is used as input clock to the fixed
	* frequency generator.
	*/
	cword >>= 1;

	/*
	* Desired periods are too large, we do not have a divider
	* for them
	*/
	if (cword < CONST_VAR_F_MIN)
	return -EINVAL;
	}

	done:
	/*
	* Configure the defined "cword" value to have the variable frequency
	* generator output a base frequency for the constant frequency
	* generator to derive from.
	*/
	spin_lock(&p->lock);
	brcmstb_pwm_writel(p, cword >> 8, PWM_CWORD_MSB(channel));
	brcmstb_pwm_writel(p, cword & 0xff, PWM_CWORD_LSB(channel));

	/* Select constant frequency signal output */
	value = brcmstb_pwm_readl(p, PWM_CTRL2);
	value \|= CTRL2_OUT_SELECT << (channel * CTRL_CHAN_OFFS);
	brcmstb_pwm_writel(p, value, PWM_CTRL2);

	/* Configure on and period value */
	brcmstb_pwm_writel(p, pc, PWM_PERIOD(channel));
	brcmstb_pwm_writel(p, dc, PWM_ON(channel));
	spin_unlock(&p->lock);

	return 0;
	}

	static inline void brcmstb_pwm_enable_set(struct brcmstb_pwm *p,
	unsigned int channel, bool enable)
	{
	unsigned int shift = channel * CTRL_CHAN_OFFS;
	u32 value;

	spin_lock(&p->lock);
	value = brcmstb_pwm_readl(p, PWM_CTRL);

	if (enable) {
	value &= ~(CTRL_OEB << shift);
	value \|= (CTRL_START \| CTRL_OPENDRAIN) << shift;
	} else {
	value &= ~((CTRL_START \| CTRL_OPENDRAIN) << shift);
	value \|= CTRL_OEB << shift;
	}

	brcmstb_pwm_writel(p, value, PWM_CTRL);
	spin_unlock(&p->lock);
	}

	static int brcmstb_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);

	brcmstb_pwm_enable_set(p, pwm->hwpwm, true);

	return 0;
	}

	static void brcmstb_pwm_disable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);

	brcmstb_pwm_enable_set(p, pwm->hwpwm, false);
	}

	static const struct pwm_ops brcmstb_pwm_ops = {
	.config = brcmstb_pwm_config,
	.enable = brcmstb_pwm_enable,
	.disable = brcmstb_pwm_disable,
	.owner = THIS_MODULE,
	};

	static const struct of_device_id brcmstb_pwm_of_match[] = {
	{ .compatible = "brcm,bcm7038-pwm", },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, brcmstb_pwm_of_match);

	static int brcmstb_pwm_probe(struct platform_device *pdev)
	{
	struct brcmstb_pwm *p;
	struct resource *res;
	int ret;

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

	spin_lock_init(&p->lock);

	p->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(p->clk)) {
	dev_err(&pdev->dev, "failed to obtain clock\n");
	return PTR_ERR(p->clk);
	}

	ret = clk_prepare_enable(p->clk);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
	return ret;
	}

	platform_set_drvdata(pdev, p);

	p->chip.dev = &pdev->dev;
	p->chip.ops = &brcmstb_pwm_ops;
	p->chip.base = -1;
	p->chip.npwm = 2;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	p->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(p->base)) {
	ret = PTR_ERR(p->base);
	goto out_clk;
	}

	ret = pwmchip_add(&p->chip);
	if (ret) {
	dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
	goto out_clk;
	}

	return 0;

	out_clk:
	clk_disable_unprepare(p->clk);
	return ret;
	}

	static int brcmstb_pwm_remove(struct platform_device *pdev)
	{
	struct brcmstb_pwm *p = platform_get_drvdata(pdev);
	int ret;

	ret = pwmchip_remove(&p->chip);
	clk_disable_unprepare(p->clk);

	return ret;
	}

	#ifdef CONFIG_PM_SLEEP
	static int brcmstb_pwm_suspend(struct device *dev)
	{
	struct brcmstb_pwm *p = dev_get_drvdata(dev);

	clk_disable(p->clk);

	return 0;
	}

	static int brcmstb_pwm_resume(struct device *dev)
	{
	struct brcmstb_pwm *p = dev_get_drvdata(dev);

	clk_enable(p->clk);

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(brcmstb_pwm_pm_ops, brcmstb_pwm_suspend,
	brcmstb_pwm_resume);

	static struct platform_driver brcmstb_pwm_driver = {
	.probe = brcmstb_pwm_probe,
	.remove = brcmstb_pwm_remove,
	.driver = {
	.name = "pwm-brcmstb",
	.of_match_table = brcmstb_pwm_of_match,
	.pm = &brcmstb_pwm_pm_ops,
	},
	};
	module_platform_driver(brcmstb_pwm_driver);

	MODULE_AUTHOR("Florian Fainelli <f.fainelli@gmail.com>");
	MODULE_DESCRIPTION("Broadcom STB PWM driver");
	MODULE_ALIAS("platform:pwm-brcmstb");
	MODULE_LICENSE("GPL");