drivers/pwm/pwm-fsl-ftm.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  Freescale FlexTimer Module (FTM) PWM Driver
  *
  *  Copyright 2012-2013 Freescale Semiconductor, Inc.
  */

 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pwm.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/fsl/ftm.h>

 #define FTM_SC_CLK(c)	(((c) + 1) << FTM_SC_CLK_MASK_SHIFT)

 enum fsl_pwm_clk {
 	FSL_PWM_CLK_SYS,
 	FSL_PWM_CLK_FIX,
 	FSL_PWM_CLK_EXT,
 	FSL_PWM_CLK_CNTEN,
 	FSL_PWM_CLK_MAX
 };

 struct fsl_ftm_soc {
 	bool has_enable_bits;
 };

 struct fsl_pwm_periodcfg {
 	enum fsl_pwm_clk clk_select;
 	unsigned int clk_ps;
 	unsigned int mod_period;
 };

 struct fsl_pwm_chip {
 	struct pwm_chip chip;
 	struct mutex lock;
 	struct regmap *regmap;

 	/* This value is valid iff a pwm is running */
 	struct fsl_pwm_periodcfg period;

 	struct clk *ipg_clk;
 	struct clk *clk[FSL_PWM_CLK_MAX];

 	const struct fsl_ftm_soc *soc;
 };

 static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip)
 {
 	return container_of(chip, struct fsl_pwm_chip, chip);
 }

 static void ftm_clear_write_protection(struct fsl_pwm_chip *fpc)
 {
 	u32 val;

 	regmap_read(fpc->regmap, FTM_FMS, &val);
 	if (val & FTM_FMS_WPEN)
 		regmap_update_bits(fpc->regmap, FTM_MODE, FTM_MODE_WPDIS,
 				   FTM_MODE_WPDIS);
 }

 static void ftm_set_write_protection(struct fsl_pwm_chip *fpc)
 {
 	regmap_update_bits(fpc->regmap, FTM_FMS, FTM_FMS_WPEN, FTM_FMS_WPEN);
 }

 static bool fsl_pwm_periodcfg_are_equal(const struct fsl_pwm_periodcfg *a,
 					const struct fsl_pwm_periodcfg *b)
 {
 	if (a->clk_select != b->clk_select)
 		return false;
 	if (a->clk_ps != b->clk_ps)
 		return false;
 	if (a->mod_period != b->mod_period)
 		return false;
 	return true;
 }

 static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	int ret;
 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);

 	ret = clk_prepare_enable(fpc->ipg_clk);
 	if (!ret && fpc->soc->has_enable_bits) {
 		mutex_lock(&fpc->lock);
 		regmap_update_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16),
 				   BIT(pwm->hwpwm + 16));
 		mutex_unlock(&fpc->lock);
 	}

 	return ret;
 }

 static void fsl_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);

 	if (fpc->soc->has_enable_bits) {
 		mutex_lock(&fpc->lock);
 		regmap_update_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16),
 				   0);
 		mutex_unlock(&fpc->lock);
 	}

 	clk_disable_unprepare(fpc->ipg_clk);
 }

 static unsigned int fsl_pwm_ticks_to_ns(struct fsl_pwm_chip *fpc,
 					  unsigned int ticks)
 {
 	unsigned long rate;
 	unsigned long long exval;

 	rate = clk_get_rate(fpc->clk[fpc->period.clk_select]);
 	exval = ticks;
 	exval *= 1000000000UL;
 	do_div(exval, rate >> fpc->period.clk_ps);
 	return exval;
 }

 static bool fsl_pwm_calculate_period_clk(struct fsl_pwm_chip *fpc,
 					 unsigned int period_ns,
 					 enum fsl_pwm_clk index,
 					 struct fsl_pwm_periodcfg *periodcfg
 					 )
 {
 	unsigned long long c;
 	unsigned int ps;

 	c = clk_get_rate(fpc->clk[index]);
 	c = c * period_ns;
 	do_div(c, 1000000000UL);

 	if (c == 0)
 		return false;

 	for (ps = 0; ps < 8 ; ++ps, c >>= 1) {
 		if (c <= 0x10000) {
 			periodcfg->clk_select = index;
 			periodcfg->clk_ps = ps;
 			periodcfg->mod_period = c - 1;
 			return true;
 		}
 	}
 	return false;
 }

 static bool fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
 				     unsigned int period_ns,
 				     struct fsl_pwm_periodcfg *periodcfg)
 {
 	enum fsl_pwm_clk m0, m1;
 	unsigned long fix_rate, ext_rate;
 	bool ret;

 	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, FSL_PWM_CLK_SYS,
 					   periodcfg);
 	if (ret)
 		return true;

 	fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
 	ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);

 	if (fix_rate > ext_rate) {
 		m0 = FSL_PWM_CLK_FIX;
 		m1 = FSL_PWM_CLK_EXT;
 	} else {
 		m0 = FSL_PWM_CLK_EXT;
 		m1 = FSL_PWM_CLK_FIX;
 	}

 	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, m0, periodcfg);
 	if (ret)
 		return true;

 	return fsl_pwm_calculate_period_clk(fpc, period_ns, m1, periodcfg);
 }

 static unsigned int fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
 					   unsigned int duty_ns)
 {
 	unsigned long long duty;

 	unsigned int period = fpc->period.mod_period + 1;
 	unsigned int period_ns = fsl_pwm_ticks_to_ns(fpc, period);

 	duty = (unsigned long long)duty_ns * period;
 	do_div(duty, period_ns);

 	return (unsigned int)duty;
 }

 static bool fsl_pwm_is_any_pwm_enabled(struct fsl_pwm_chip *fpc,
 				       struct pwm_device *pwm)
 {
 	u32 val;

 	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
 	if (~val & 0xFF)
 		return true;
 	else
 		return false;
 }

 static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
 					 struct pwm_device *pwm)
 {
 	u32 val;

 	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
 	if (~(val | BIT(pwm->hwpwm)) & 0xFF)
 		return true;
 	else
 		return false;
 }

 static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
 				struct pwm_device *pwm,
 				const struct pwm_state *newstate)
 {
 	unsigned int duty;
 	u32 reg_polarity;

 	struct fsl_pwm_periodcfg periodcfg;
 	bool do_write_period = false;

 	if (!fsl_pwm_calculate_period(fpc, newstate->period, &periodcfg)) {
 		dev_err(fpc->chip.dev, "failed to calculate new period\n");
 		return -EINVAL;
 	}

 	if (!fsl_pwm_is_any_pwm_enabled(fpc, pwm))
 		do_write_period = true;
 	/*
 	 * The Freescale FTM controller supports only a single period for
 	 * all PWM channels, therefore verify if the newly computed period
 	 * is different than the current period being used. In such case
 	 * we allow to change the period only if no other pwm is running.
 	 */
 	else if (!fsl_pwm_periodcfg_are_equal(&fpc->period, &periodcfg)) {
 		if (fsl_pwm_is_other_pwm_enabled(fpc, pwm)) {
 			dev_err(fpc->chip.dev,
 				"Cannot change period for PWM %u, disable other PWMs first\n",
 				pwm->hwpwm);
 			return -EBUSY;
 		}
 		if (fpc->period.clk_select != periodcfg.clk_select) {
 			int ret;
 			enum fsl_pwm_clk oldclk = fpc->period.clk_select;
 			enum fsl_pwm_clk newclk = periodcfg.clk_select;

 			ret = clk_prepare_enable(fpc->clk[newclk]);
 			if (ret)
 				return ret;
 			clk_disable_unprepare(fpc->clk[oldclk]);
 		}
 		do_write_period = true;
 	}

 	ftm_clear_write_protection(fpc);

 	if (do_write_period) {
 		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
 				   FTM_SC_CLK(periodcfg.clk_select));
 		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
 				   periodcfg.clk_ps);
 		regmap_write(fpc->regmap, FTM_MOD, periodcfg.mod_period);

 		fpc->period = periodcfg;
 	}

 	duty = fsl_pwm_calculate_duty(fpc, newstate->duty_cycle);

 	regmap_write(fpc->regmap, FTM_CSC(pwm->hwpwm),
 		     FTM_CSC_MSB | FTM_CSC_ELSB);
 	regmap_write(fpc->regmap, FTM_CV(pwm->hwpwm), duty);

 	reg_polarity = 0;
 	if (newstate->polarity == PWM_POLARITY_INVERSED)
 		reg_polarity = BIT(pwm->hwpwm);

 	regmap_update_bits(fpc->regmap, FTM_POL, BIT(pwm->hwpwm), reg_polarity);

 	ftm_set_write_protection(fpc);

 	return 0;
 }

 static int fsl_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			 const struct pwm_state *newstate)
 {
 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 	struct pwm_state *oldstate = &pwm->state;
 	int ret = 0;

 	/*
 	 * oldstate to newstate : action
 	 *
 	 * disabled to disabled : ignore
 	 * enabled to disabled : disable
 	 * enabled to enabled : update settings
 	 * disabled to enabled : update settings + enable
 	 */

 	mutex_lock(&fpc->lock);

 	if (!newstate->enabled) {
 		if (oldstate->enabled) {
 			regmap_update_bits(fpc->regmap, FTM_OUTMASK,
 					   BIT(pwm->hwpwm), BIT(pwm->hwpwm));
 			clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
 			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
 		}

 		goto end_mutex;
 	}

 	ret = fsl_pwm_apply_config(fpc, pwm, newstate);
 	if (ret)
 		goto end_mutex;

 	/* check if need to enable */
 	if (!oldstate->enabled) {
 		ret = clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
 		if (ret)
 			goto end_mutex;

 		ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
 		if (ret) {
 			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
 			goto end_mutex;
 		}

 		regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
 				   0);
 	}

 end_mutex:
 	mutex_unlock(&fpc->lock);
 	return ret;
 }

 static const struct pwm_ops fsl_pwm_ops = {
 	.request = fsl_pwm_request,
 	.free = fsl_pwm_free,
 	.apply = fsl_pwm_apply,
 	.owner = THIS_MODULE,
 };

 static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
 {
 	int ret;

 	ret = clk_prepare_enable(fpc->ipg_clk);
 	if (ret)
 		return ret;

 	regmap_write(fpc->regmap, FTM_CNTIN, 0x00);
 	regmap_write(fpc->regmap, FTM_OUTINIT, 0x00);
 	regmap_write(fpc->regmap, FTM_OUTMASK, 0xFF);

 	clk_disable_unprepare(fpc->ipg_clk);

 	return 0;
 }

 static bool fsl_pwm_volatile_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case FTM_FMS:
 	case FTM_MODE:
 	case FTM_CNT:
 		return true;
 	}
 	return false;
 }

 static const struct regmap_config fsl_pwm_regmap_config = {
 	.reg_bits = 32,
 	.reg_stride = 4,
 	.val_bits = 32,

 	.max_register = FTM_PWMLOAD,
 	.volatile_reg = fsl_pwm_volatile_reg,
 	.cache_type = REGCACHE_FLAT,
 };

 static int fsl_pwm_probe(struct platform_device *pdev)
 {
 	struct fsl_pwm_chip *fpc;
 	void __iomem *base;
 	int ret;

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

 	mutex_init(&fpc->lock);

 	fpc->soc = of_device_get_match_data(&pdev->dev);
 	fpc->chip.dev = &pdev->dev;

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

 	fpc->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "ftm_sys", base,
 						&fsl_pwm_regmap_config);
 	if (IS_ERR(fpc->regmap)) {
 		dev_err(&pdev->dev, "regmap init failed\n");
 		return PTR_ERR(fpc->regmap);
 	}

 	fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys");
 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) {
 		dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n");
 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]);
 	}

 	fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX]))
 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]);

 	fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT]))
 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]);

 	fpc->clk[FSL_PWM_CLK_CNTEN] =
 				devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]))
 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]);

 	/*
 	 * ipg_clk is the interface clock for the IP. If not provided, use the
 	 * ftm_sys clock as the default.
 	 */
 	fpc->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
 	if (IS_ERR(fpc->ipg_clk))
 		fpc->ipg_clk = fpc->clk[FSL_PWM_CLK_SYS];


 	fpc->chip.ops = &fsl_pwm_ops;
 	fpc->chip.of_xlate = of_pwm_xlate_with_flags;
 	fpc->chip.of_pwm_n_cells = 3;
 	fpc->chip.base = -1;
 	fpc->chip.npwm = 8;

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

 	platform_set_drvdata(pdev, fpc);

 	return fsl_pwm_init(fpc);
 }

 static int fsl_pwm_remove(struct platform_device *pdev)
 {
 	struct fsl_pwm_chip *fpc = platform_get_drvdata(pdev);

 	return pwmchip_remove(&fpc->chip);
 }

 #ifdef CONFIG_PM_SLEEP
 static int fsl_pwm_suspend(struct device *dev)
 {
 	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
 	int i;

 	regcache_cache_only(fpc->regmap, true);
 	regcache_mark_dirty(fpc->regmap);

 	for (i = 0; i < fpc->chip.npwm; i++) {
 		struct pwm_device *pwm = &fpc->chip.pwms[i];

 		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
 			continue;

 		clk_disable_unprepare(fpc->ipg_clk);

 		if (!pwm_is_enabled(pwm))
 			continue;

 		clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
 		clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
 	}

 	return 0;
 }

 static int fsl_pwm_resume(struct device *dev)
 {
 	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
 	int i;

 	for (i = 0; i < fpc->chip.npwm; i++) {
 		struct pwm_device *pwm = &fpc->chip.pwms[i];

 		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
 			continue;

 		clk_prepare_enable(fpc->ipg_clk);

 		if (!pwm_is_enabled(pwm))
 			continue;

 		clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
 		clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
 	}

 	/* restore all registers from cache */
 	regcache_cache_only(fpc->regmap, false);
 	regcache_sync(fpc->regmap);

 	return 0;
 }
 #endif

 static const struct dev_pm_ops fsl_pwm_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(fsl_pwm_suspend, fsl_pwm_resume)
 };

 static const struct fsl_ftm_soc vf610_ftm_pwm = {
 	.has_enable_bits = false,
 };

 static const struct fsl_ftm_soc imx8qm_ftm_pwm = {
 	.has_enable_bits = true,
 };

 static const struct of_device_id fsl_pwm_dt_ids[] = {
 	{ .compatible = "fsl,vf610-ftm-pwm", .data = &vf610_ftm_pwm },
 	{ .compatible = "fsl,imx8qm-ftm-pwm", .data = &imx8qm_ftm_pwm },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids);

 static struct platform_driver fsl_pwm_driver = {
 	.driver = {
 		.name = "fsl-ftm-pwm",
 		.of_match_table = fsl_pwm_dt_ids,
 		.pm = &fsl_pwm_pm_ops,
 	},
 	.probe = fsl_pwm_probe,
 	.remove = fsl_pwm_remove,
 };
 module_platform_driver(fsl_pwm_driver);

 MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver");
 MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>");
 MODULE_ALIAS("platform:fsl-ftm-pwm");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Freescale FlexTimer Module (FTM) PWM Driver
	*
	* Copyright 2012-2013 Freescale Semiconductor, Inc.
	*/

	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of_address.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/pm.h>
	#include <linux/pwm.h>
	#include <linux/regmap.h>
	#include <linux/slab.h>
	#include <linux/fsl/ftm.h>

	#define FTM_SC_CLK(c) (((c) + 1) << FTM_SC_CLK_MASK_SHIFT)

	enum fsl_pwm_clk {
	FSL_PWM_CLK_SYS,
	FSL_PWM_CLK_FIX,
	FSL_PWM_CLK_EXT,
	FSL_PWM_CLK_CNTEN,
	FSL_PWM_CLK_MAX
	};

	struct fsl_ftm_soc {
	bool has_enable_bits;
	};

	struct fsl_pwm_periodcfg {
	enum fsl_pwm_clk clk_select;
	unsigned int clk_ps;
	unsigned int mod_period;
	};

	struct fsl_pwm_chip {
	struct pwm_chip chip;
	struct mutex lock;
	struct regmap *regmap;

	/* This value is valid iff a pwm is running */
	struct fsl_pwm_periodcfg period;

	struct clk *ipg_clk;
	struct clk *clk[FSL_PWM_CLK_MAX];

	const struct fsl_ftm_soc *soc;
	};

	static inline struct fsl_pwm_chip to_fsl_chip(struct pwm_chip chip)
	{
	return container_of(chip, struct fsl_pwm_chip, chip);
	}

	static void ftm_clear_write_protection(struct fsl_pwm_chip *fpc)
	{
	u32 val;

	regmap_read(fpc->regmap, FTM_FMS, &val);
	if (val & FTM_FMS_WPEN)
	regmap_update_bits(fpc->regmap, FTM_MODE, FTM_MODE_WPDIS,
	FTM_MODE_WPDIS);
	}

	static void ftm_set_write_protection(struct fsl_pwm_chip *fpc)
	{
	regmap_update_bits(fpc->regmap, FTM_FMS, FTM_FMS_WPEN, FTM_FMS_WPEN);
	}

	static bool fsl_pwm_periodcfg_are_equal(const struct fsl_pwm_periodcfg *a,
	const struct fsl_pwm_periodcfg *b)
	{
	if (a->clk_select != b->clk_select)
	return false;
	if (a->clk_ps != b->clk_ps)
	return false;
	if (a->mod_period != b->mod_period)
	return false;
	return true;
	}

	static int fsl_pwm_request(struct pwm_chip chip, struct pwm_device pwm)
	{
	int ret;
	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);

	ret = clk_prepare_enable(fpc->ipg_clk);
	if (!ret && fpc->soc->has_enable_bits) {
	mutex_lock(&fpc->lock);
	regmap_update_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16),
	BIT(pwm->hwpwm + 16));
	mutex_unlock(&fpc->lock);
	}

	return ret;
	}

	static void fsl_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);

	if (fpc->soc->has_enable_bits) {
	mutex_lock(&fpc->lock);
	regmap_update_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16),
	0);
	mutex_unlock(&fpc->lock);
	}

	clk_disable_unprepare(fpc->ipg_clk);
	}

	static unsigned int fsl_pwm_ticks_to_ns(struct fsl_pwm_chip *fpc,
	unsigned int ticks)
	{
	unsigned long rate;
	unsigned long long exval;

	rate = clk_get_rate(fpc->clk[fpc->period.clk_select]);
	exval = ticks;
	exval *= 1000000000UL;
	do_div(exval, rate >> fpc->period.clk_ps);
	return exval;
	}

	static bool fsl_pwm_calculate_period_clk(struct fsl_pwm_chip *fpc,
	unsigned int period_ns,
	enum fsl_pwm_clk index,
	struct fsl_pwm_periodcfg *periodcfg
	)
	{
	unsigned long long c;
	unsigned int ps;

	c = clk_get_rate(fpc->clk[index]);
	c = c * period_ns;
	do_div(c, 1000000000UL);

	if (c == 0)
	return false;

	for (ps = 0; ps < 8 ; ++ps, c >>= 1) {
	if (c <= 0x10000) {
	periodcfg->clk_select = index;
	periodcfg->clk_ps = ps;
	periodcfg->mod_period = c - 1;
	return true;
	}
	}
	return false;
	}

	static bool fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
	unsigned int period_ns,
	struct fsl_pwm_periodcfg *periodcfg)
	{
	enum fsl_pwm_clk m0, m1;
	unsigned long fix_rate, ext_rate;
	bool ret;

	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, FSL_PWM_CLK_SYS,
	periodcfg);
	if (ret)
	return true;

	fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
	ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);

	if (fix_rate > ext_rate) {
	m0 = FSL_PWM_CLK_FIX;
	m1 = FSL_PWM_CLK_EXT;
	} else {
	m0 = FSL_PWM_CLK_EXT;
	m1 = FSL_PWM_CLK_FIX;
	}

	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, m0, periodcfg);
	if (ret)
	return true;

	return fsl_pwm_calculate_period_clk(fpc, period_ns, m1, periodcfg);
	}

	static unsigned int fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
	unsigned int duty_ns)
	{
	unsigned long long duty;

	unsigned int period = fpc->period.mod_period + 1;
	unsigned int period_ns = fsl_pwm_ticks_to_ns(fpc, period);

	duty = (unsigned long long)duty_ns * period;
	do_div(duty, period_ns);

	return (unsigned int)duty;
	}

	static bool fsl_pwm_is_any_pwm_enabled(struct fsl_pwm_chip *fpc,
	struct pwm_device *pwm)
	{
	u32 val;

	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
	if (~val & 0xFF)
	return true;
	else
	return false;
	}

	static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
	struct pwm_device *pwm)
	{
	u32 val;

	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
	if (~(val \| BIT(pwm->hwpwm)) & 0xFF)
	return true;
	else
	return false;
	}

	static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
	struct pwm_device *pwm,
	const struct pwm_state *newstate)
	{
	unsigned int duty;
	u32 reg_polarity;

	struct fsl_pwm_periodcfg periodcfg;
	bool do_write_period = false;

	if (!fsl_pwm_calculate_period(fpc, newstate->period, &periodcfg)) {
	dev_err(fpc->chip.dev, "failed to calculate new period\n");
	return -EINVAL;
	}

	if (!fsl_pwm_is_any_pwm_enabled(fpc, pwm))
	do_write_period = true;
	/*
	* The Freescale FTM controller supports only a single period for
	* all PWM channels, therefore verify if the newly computed period
	* is different than the current period being used. In such case
	* we allow to change the period only if no other pwm is running.
	*/
	else if (!fsl_pwm_periodcfg_are_equal(&fpc->period, &periodcfg)) {
	if (fsl_pwm_is_other_pwm_enabled(fpc, pwm)) {
	dev_err(fpc->chip.dev,
	"Cannot change period for PWM %u, disable other PWMs first\n",
	pwm->hwpwm);
	return -EBUSY;
	}
	if (fpc->period.clk_select != periodcfg.clk_select) {
	int ret;
	enum fsl_pwm_clk oldclk = fpc->period.clk_select;
	enum fsl_pwm_clk newclk = periodcfg.clk_select;

	ret = clk_prepare_enable(fpc->clk[newclk]);
	if (ret)
	return ret;
	clk_disable_unprepare(fpc->clk[oldclk]);
	}
	do_write_period = true;
	}

	ftm_clear_write_protection(fpc);

	if (do_write_period) {
	regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
	FTM_SC_CLK(periodcfg.clk_select));
	regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
	periodcfg.clk_ps);
	regmap_write(fpc->regmap, FTM_MOD, periodcfg.mod_period);

	fpc->period = periodcfg;
	}

	duty = fsl_pwm_calculate_duty(fpc, newstate->duty_cycle);

	regmap_write(fpc->regmap, FTM_CSC(pwm->hwpwm),
	FTM_CSC_MSB \| FTM_CSC_ELSB);
	regmap_write(fpc->regmap, FTM_CV(pwm->hwpwm), duty);

	reg_polarity = 0;
	if (newstate->polarity == PWM_POLARITY_INVERSED)
	reg_polarity = BIT(pwm->hwpwm);

	regmap_update_bits(fpc->regmap, FTM_POL, BIT(pwm->hwpwm), reg_polarity);

	ftm_set_write_protection(fpc);

	return 0;
	}

	static int fsl_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	const struct pwm_state *newstate)
	{
	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
	struct pwm_state *oldstate = &pwm->state;
	int ret = 0;

	/*
	* oldstate to newstate : action
	*
	* disabled to disabled : ignore
	* enabled to disabled : disable
	* enabled to enabled : update settings
	* disabled to enabled : update settings + enable
	*/

	mutex_lock(&fpc->lock);

	if (!newstate->enabled) {
	if (oldstate->enabled) {
	regmap_update_bits(fpc->regmap, FTM_OUTMASK,
	BIT(pwm->hwpwm), BIT(pwm->hwpwm));
	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
	clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
	}

	goto end_mutex;
	}

	ret = fsl_pwm_apply_config(fpc, pwm, newstate);
	if (ret)
	goto end_mutex;

	/* check if need to enable */
	if (!oldstate->enabled) {
	ret = clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
	if (ret)
	goto end_mutex;

	ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
	if (ret) {
	clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
	goto end_mutex;
	}

	regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
	0);
	}

	end_mutex:
	mutex_unlock(&fpc->lock);
	return ret;
	}

	static const struct pwm_ops fsl_pwm_ops = {
	.request = fsl_pwm_request,
	.free = fsl_pwm_free,
	.apply = fsl_pwm_apply,
	.owner = THIS_MODULE,
	};

	static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
	{
	int ret;

	ret = clk_prepare_enable(fpc->ipg_clk);
	if (ret)
	return ret;

	regmap_write(fpc->regmap, FTM_CNTIN, 0x00);
	regmap_write(fpc->regmap, FTM_OUTINIT, 0x00);
	regmap_write(fpc->regmap, FTM_OUTMASK, 0xFF);

	clk_disable_unprepare(fpc->ipg_clk);

	return 0;
	}

	static bool fsl_pwm_volatile_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case FTM_FMS:
	case FTM_MODE:
	case FTM_CNT:
	return true;
	}
	return false;
	}

	static const struct regmap_config fsl_pwm_regmap_config = {
	.reg_bits = 32,
	.reg_stride = 4,
	.val_bits = 32,

	.max_register = FTM_PWMLOAD,
	.volatile_reg = fsl_pwm_volatile_reg,
	.cache_type = REGCACHE_FLAT,
	};

	static int fsl_pwm_probe(struct platform_device *pdev)
	{
	struct fsl_pwm_chip *fpc;
	void __iomem *base;
	int ret;

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

	mutex_init(&fpc->lock);

	fpc->soc = of_device_get_match_data(&pdev->dev);
	fpc->chip.dev = &pdev->dev;

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

	fpc->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "ftm_sys", base,
	&fsl_pwm_regmap_config);
	if (IS_ERR(fpc->regmap)) {
	dev_err(&pdev->dev, "regmap init failed\n");
	return PTR_ERR(fpc->regmap);
	}

	fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys");
	if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) {
	dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n");
	return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]);
	}

	fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
	if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX]))
	return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]);

	fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
	if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT]))
	return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]);

	fpc->clk[FSL_PWM_CLK_CNTEN] =
	devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
	if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]))
	return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]);

	/*
	* ipg_clk is the interface clock for the IP. If not provided, use the
	* ftm_sys clock as the default.
	*/
	fpc->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
	if (IS_ERR(fpc->ipg_clk))
	fpc->ipg_clk = fpc->clk[FSL_PWM_CLK_SYS];


	fpc->chip.ops = &fsl_pwm_ops;
	fpc->chip.of_xlate = of_pwm_xlate_with_flags;
	fpc->chip.of_pwm_n_cells = 3;
	fpc->chip.base = -1;
	fpc->chip.npwm = 8;

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

	platform_set_drvdata(pdev, fpc);

	return fsl_pwm_init(fpc);
	}

	static int fsl_pwm_remove(struct platform_device *pdev)
	{
	struct fsl_pwm_chip *fpc = platform_get_drvdata(pdev);

	return pwmchip_remove(&fpc->chip);
	}

	#ifdef CONFIG_PM_SLEEP
	static int fsl_pwm_suspend(struct device *dev)
	{
	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
	int i;

	regcache_cache_only(fpc->regmap, true);
	regcache_mark_dirty(fpc->regmap);

	for (i = 0; i < fpc->chip.npwm; i++) {
	struct pwm_device *pwm = &fpc->chip.pwms[i];

	if (!test_bit(PWMF_REQUESTED, &pwm->flags))
	continue;

	clk_disable_unprepare(fpc->ipg_clk);

	if (!pwm_is_enabled(pwm))
	continue;

	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
	clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
	}

	return 0;
	}

	static int fsl_pwm_resume(struct device *dev)
	{
	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
	int i;

	for (i = 0; i < fpc->chip.npwm; i++) {
	struct pwm_device *pwm = &fpc->chip.pwms[i];

	if (!test_bit(PWMF_REQUESTED, &pwm->flags))
	continue;

	clk_prepare_enable(fpc->ipg_clk);

	if (!pwm_is_enabled(pwm))
	continue;

	clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
	clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
	}

	/* restore all registers from cache */
	regcache_cache_only(fpc->regmap, false);
	regcache_sync(fpc->regmap);

	return 0;
	}
	#endif

	static const struct dev_pm_ops fsl_pwm_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(fsl_pwm_suspend, fsl_pwm_resume)
	};

	static const struct fsl_ftm_soc vf610_ftm_pwm = {
	.has_enable_bits = false,
	};

	static const struct fsl_ftm_soc imx8qm_ftm_pwm = {
	.has_enable_bits = true,
	};

	static const struct of_device_id fsl_pwm_dt_ids[] = {
	{ .compatible = "fsl,vf610-ftm-pwm", .data = &vf610_ftm_pwm },
	{ .compatible = "fsl,imx8qm-ftm-pwm", .data = &imx8qm_ftm_pwm },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids);

	static struct platform_driver fsl_pwm_driver = {
	.driver = {
	.name = "fsl-ftm-pwm",
	.of_match_table = fsl_pwm_dt_ids,
	.pm = &fsl_pwm_pm_ops,
	},
	.probe = fsl_pwm_probe,
	.remove = fsl_pwm_remove,
	};
	module_platform_driver(fsl_pwm_driver);

	MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver");
	MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>");
	MODULE_ALIAS("platform:fsl-ftm-pwm");
	MODULE_LICENSE("GPL");