drivers/pwm/pwm-atmel-tcb.c - kernel/bruno - Git at Google

 /*
  * Copyright (C) Overkiz SAS 2012
  *
  * Author: Boris BREZILLON <b.brezillon@overkiz.com>
  * License terms: GNU General Public License (GPL) version 2
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/clocksource.h>
 #include <linux/clockchips.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>

 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/ioport.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/atmel_tc.h>
 #include <linux/pwm.h>
 #include <linux/of_device.h>
 #include <linux/slab.h>

 #define NPWM	6

 #define ATMEL_TC_ACMR_MASK	(ATMEL_TC_ACPA | ATMEL_TC_ACPC |	\
 				 ATMEL_TC_AEEVT | ATMEL_TC_ASWTRG)

 #define ATMEL_TC_BCMR_MASK	(ATMEL_TC_BCPB | ATMEL_TC_BCPC |	\
 				 ATMEL_TC_BEEVT | ATMEL_TC_BSWTRG)

 struct atmel_tcb_pwm_device {
 	enum pwm_polarity polarity;	/* PWM polarity */
 	unsigned div;			/* PWM clock divider */
 	unsigned duty;			/* PWM duty expressed in clk cycles */
 	unsigned period;		/* PWM period expressed in clk cycles */
 };

 struct atmel_tcb_pwm_chip {
 	struct pwm_chip chip;
 	spinlock_t lock;
 	struct atmel_tc *tc;
 	struct atmel_tcb_pwm_device *pwms[NPWM];
 };

 static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip)
 {
 	return container_of(chip, struct atmel_tcb_pwm_chip, chip);
 }

 static int atmel_tcb_pwm_set_polarity(struct pwm_chip *chip,
 				      struct pwm_device *pwm,
 				      enum pwm_polarity polarity)
 {
 	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);

 	tcbpwm->polarity = polarity;

 	return 0;
 }

 static int atmel_tcb_pwm_request(struct pwm_chip *chip,
 				 struct pwm_device *pwm)
 {
 	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 	struct atmel_tcb_pwm_device *tcbpwm;
 	struct atmel_tc *tc = tcbpwmc->tc;
 	void __iomem *regs = tc->regs;
 	unsigned group = pwm->hwpwm / 2;
 	unsigned index = pwm->hwpwm % 2;
 	unsigned cmr;
 	int ret;

 	tcbpwm = devm_kzalloc(chip->dev, sizeof(*tcbpwm), GFP_KERNEL);
 	if (!tcbpwm)
 		return -ENOMEM;

 	ret = clk_prepare_enable(tc->clk[group]);
 	if (ret) {
 		devm_kfree(chip->dev, tcbpwm);
 		return ret;
 	}

 	pwm_set_chip_data(pwm, tcbpwm);
 	tcbpwm->polarity = PWM_POLARITY_NORMAL;
 	tcbpwm->duty = 0;
 	tcbpwm->period = 0;
 	tcbpwm->div = 0;

 	spin_lock(&tcbpwmc->lock);
 	cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));
 	/*
 	 * Get init config from Timer Counter registers if
 	 * Timer Counter is already configured as a PWM generator.
 	 */
 	if (cmr & ATMEL_TC_WAVE) {
 		if (index == 0)
 			tcbpwm->duty =
 				__raw_readl(regs + ATMEL_TC_REG(group, RA));
 		else
 			tcbpwm->duty =
 				__raw_readl(regs + ATMEL_TC_REG(group, RB));

 		tcbpwm->div = cmr & ATMEL_TC_TCCLKS;
 		tcbpwm->period = __raw_readl(regs + ATMEL_TC_REG(group, RC));
 		cmr &= (ATMEL_TC_TCCLKS | ATMEL_TC_ACMR_MASK |
 			ATMEL_TC_BCMR_MASK);
 	} else
 		cmr = 0;

 	cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0;
 	__raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));
 	spin_unlock(&tcbpwmc->lock);

 	tcbpwmc->pwms[pwm->hwpwm] = tcbpwm;

 	return 0;
 }

 static void atmel_tcb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
 	struct atmel_tc *tc = tcbpwmc->tc;

 	clk_disable_unprepare(tc->clk[pwm->hwpwm / 2]);
 	tcbpwmc->pwms[pwm->hwpwm] = NULL;
 	devm_kfree(chip->dev, tcbpwm);
 }

 static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
 	struct atmel_tc *tc = tcbpwmc->tc;
 	void __iomem *regs = tc->regs;
 	unsigned group = pwm->hwpwm / 2;
 	unsigned index = pwm->hwpwm % 2;
 	unsigned cmr;
 	enum pwm_polarity polarity = tcbpwm->polarity;

 	/*
 	 * If duty is 0 the timer will be stopped and we have to
 	 * configure the output correctly on software trigger:
 	 *  - set output to high if PWM_POLARITY_INVERSED
 	 *  - set output to low if PWM_POLARITY_NORMAL
 	 *
 	 * This is why we're reverting polarity in this case.
 	 */
 	if (tcbpwm->duty == 0)
 		polarity = !polarity;

 	spin_lock(&tcbpwmc->lock);
 	cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));

 	/* flush old setting and set the new one */
 	if (index == 0) {
 		cmr &= ~ATMEL_TC_ACMR_MASK;
 		if (polarity == PWM_POLARITY_INVERSED)
 			cmr |= ATMEL_TC_ASWTRG_CLEAR;
 		else
 			cmr |= ATMEL_TC_ASWTRG_SET;
 	} else {
 		cmr &= ~ATMEL_TC_BCMR_MASK;
 		if (polarity == PWM_POLARITY_INVERSED)
 			cmr |= ATMEL_TC_BSWTRG_CLEAR;
 		else
 			cmr |= ATMEL_TC_BSWTRG_SET;
 	}

 	__raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));

 	/*
 	 * Use software trigger to apply the new setting.
 	 * If both PWM devices in this group are disabled we stop the clock.
 	 */
 	if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC)))
 		__raw_writel(ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS,
 			     regs + ATMEL_TC_REG(group, CCR));
 	else
 		__raw_writel(ATMEL_TC_SWTRG, regs +
 			     ATMEL_TC_REG(group, CCR));

 	spin_unlock(&tcbpwmc->lock);
 }

 static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
 	struct atmel_tc *tc = tcbpwmc->tc;
 	void __iomem *regs = tc->regs;
 	unsigned group = pwm->hwpwm / 2;
 	unsigned index = pwm->hwpwm % 2;
 	u32 cmr;
 	enum pwm_polarity polarity = tcbpwm->polarity;

 	/*
 	 * If duty is 0 the timer will be stopped and we have to
 	 * configure the output correctly on software trigger:
 	 *  - set output to high if PWM_POLARITY_INVERSED
 	 *  - set output to low if PWM_POLARITY_NORMAL
 	 *
 	 * This is why we're reverting polarity in this case.
 	 */
 	if (tcbpwm->duty == 0)
 		polarity = !polarity;

 	spin_lock(&tcbpwmc->lock);
 	cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));

 	/* flush old setting and set the new one */
 	cmr &= ~ATMEL_TC_TCCLKS;

 	if (index == 0) {
 		cmr &= ~ATMEL_TC_ACMR_MASK;

 		/* Set CMR flags according to given polarity */
 		if (polarity == PWM_POLARITY_INVERSED)
 			cmr |= ATMEL_TC_ASWTRG_CLEAR;
 		else
 			cmr |= ATMEL_TC_ASWTRG_SET;
 	} else {
 		cmr &= ~ATMEL_TC_BCMR_MASK;
 		if (polarity == PWM_POLARITY_INVERSED)
 			cmr |= ATMEL_TC_BSWTRG_CLEAR;
 		else
 			cmr |= ATMEL_TC_BSWTRG_SET;
 	}

 	/*
 	 * If duty is 0 or equal to period there's no need to register
 	 * a specific action on RA/RB and RC compare.
 	 * The output will be configured on software trigger and keep
 	 * this config till next config call.
 	 */
 	if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) {
 		if (index == 0) {
 			if (polarity == PWM_POLARITY_INVERSED)
 				cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR;
 			else
 				cmr |= ATMEL_TC_ACPA_CLEAR | ATMEL_TC_ACPC_SET;
 		} else {
 			if (polarity == PWM_POLARITY_INVERSED)
 				cmr |= ATMEL_TC_BCPB_SET | ATMEL_TC_BCPC_CLEAR;
 			else
 				cmr |= ATMEL_TC_BCPB_CLEAR | ATMEL_TC_BCPC_SET;
 		}
 	}

 	cmr |= (tcbpwm->div & ATMEL_TC_TCCLKS);

 	__raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));

 	if (index == 0)
 		__raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RA));
 	else
 		__raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RB));

 	__raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(group, RC));

 	/* Use software trigger to apply the new setting */
 	__raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
 		     regs + ATMEL_TC_REG(group, CCR));
 	spin_unlock(&tcbpwmc->lock);
 	return 0;
 }

 static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 				int duty_ns, int period_ns)
 {
 	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
 	unsigned group = pwm->hwpwm / 2;
 	unsigned index = pwm->hwpwm % 2;
 	struct atmel_tcb_pwm_device *atcbpwm = NULL;
 	struct atmel_tc *tc = tcbpwmc->tc;
 	int i;
 	int slowclk = 0;
 	unsigned period;
 	unsigned duty;
 	unsigned rate = clk_get_rate(tc->clk[group]);
 	unsigned long long min;
 	unsigned long long max;

 	/*
 	 * Find best clk divisor:
 	 * the smallest divisor which can fulfill the period_ns requirements.
 	 */
 	for (i = 0; i < 5; ++i) {
 		if (atmel_tc_divisors[i] == 0) {
 			slowclk = i;
 			continue;
 		}
 		min = div_u64((u64)NSEC_PER_SEC * atmel_tc_divisors[i], rate);
 		max = min << tc->tcb_config->counter_width;
 		if (max >= period_ns)
 			break;
 	}

 	/*
 	 * If none of the divisor are small enough to represent period_ns
 	 * take slow clock (32KHz).
 	 */
 	if (i == 5) {
 		i = slowclk;
 		rate = clk_get_rate(tc->slow_clk);
 		min = div_u64(NSEC_PER_SEC, rate);
 		max = min << tc->tcb_config->counter_width;

 		/* If period is too big return ERANGE error */
 		if (max < period_ns)
 			return -ERANGE;
 	}

 	duty = div_u64(duty_ns, min);
 	period = div_u64(period_ns, min);

 	if (index == 0)
 		atcbpwm = tcbpwmc->pwms[pwm->hwpwm + 1];
 	else
 		atcbpwm = tcbpwmc->pwms[pwm->hwpwm - 1];

 	/*
 	 * PWM devices provided by TCB driver are grouped by 2:
 	 * - group 0: PWM 0 & 1
 	 * - group 1: PWM 2 & 3
 	 * - group 2: PWM 4 & 5
 	 *
 	 * PWM devices in a given group must be configured with the
 	 * same period_ns.
 	 *
 	 * We're checking the period value of the second PWM device
 	 * in this group before applying the new config.
 	 */
 	if ((atcbpwm && atcbpwm->duty > 0 &&
 			atcbpwm->duty != atcbpwm->period) &&
 		(atcbpwm->div != i || atcbpwm->period != period)) {
 		dev_err(chip->dev,
 			"failed to configure period_ns: PWM group already configured with a different value\n");
 		return -EINVAL;
 	}

 	tcbpwm->period = period;
 	tcbpwm->div = i;
 	tcbpwm->duty = duty;

 	/* If the PWM is enabled, call enable to apply the new conf */
 	if (pwm_is_enabled(pwm))
 		atmel_tcb_pwm_enable(chip, pwm);

 	return 0;
 }

 static const struct pwm_ops atmel_tcb_pwm_ops = {
 	.request = atmel_tcb_pwm_request,
 	.free = atmel_tcb_pwm_free,
 	.config = atmel_tcb_pwm_config,
 	.set_polarity = atmel_tcb_pwm_set_polarity,
 	.enable = atmel_tcb_pwm_enable,
 	.disable = atmel_tcb_pwm_disable,
 	.owner = THIS_MODULE,
 };

 static int atmel_tcb_pwm_probe(struct platform_device *pdev)
 {
 	struct atmel_tcb_pwm_chip *tcbpwm;
 	struct device_node *np = pdev->dev.of_node;
 	struct atmel_tc *tc;
 	int err;
 	int tcblock;

 	err = of_property_read_u32(np, "tc-block", &tcblock);
 	if (err < 0) {
 		dev_err(&pdev->dev,
 			"failed to get Timer Counter Block number from device tree (error: %d)\n",
 			err);
 		return err;
 	}

 	tc = atmel_tc_alloc(tcblock);
 	if (tc == NULL) {
 		dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n");
 		return -ENOMEM;
 	}

 	tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL);
 	if (tcbpwm == NULL) {
 		err = -ENOMEM;
 		dev_err(&pdev->dev, "failed to allocate memory\n");
 		goto err_free_tc;
 	}

 	tcbpwm->chip.dev = &pdev->dev;
 	tcbpwm->chip.ops = &atmel_tcb_pwm_ops;
 	tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags;
 	tcbpwm->chip.of_pwm_n_cells = 3;
 	tcbpwm->chip.base = -1;
 	tcbpwm->chip.npwm = NPWM;
 	tcbpwm->tc = tc;

 	err = clk_prepare_enable(tc->slow_clk);
 	if (err)
 		goto err_free_tc;

 	spin_lock_init(&tcbpwm->lock);

 	err = pwmchip_add(&tcbpwm->chip);
 	if (err < 0)
 		goto err_disable_clk;

 	platform_set_drvdata(pdev, tcbpwm);

 	return 0;

 err_disable_clk:
 	clk_disable_unprepare(tcbpwm->tc->slow_clk);

 err_free_tc:
 	atmel_tc_free(tc);

 	return err;
 }

 static int atmel_tcb_pwm_remove(struct platform_device *pdev)
 {
 	struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
 	int err;

 	clk_disable_unprepare(tcbpwm->tc->slow_clk);

 	err = pwmchip_remove(&tcbpwm->chip);
 	if (err < 0)
 		return err;

 	atmel_tc_free(tcbpwm->tc);

 	return 0;
 }

 static const struct of_device_id atmel_tcb_pwm_dt_ids[] = {
 	{ .compatible = "atmel,tcb-pwm", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids);

 static struct platform_driver atmel_tcb_pwm_driver = {
 	.driver = {
 		.name = "atmel-tcb-pwm",
 		.of_match_table = atmel_tcb_pwm_dt_ids,
 	},
 	.probe = atmel_tcb_pwm_probe,
 	.remove = atmel_tcb_pwm_remove,
 };
 module_platform_driver(atmel_tcb_pwm_driver);

 MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>");
 MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Copyright (C) Overkiz SAS 2012
	*
	* Author: Boris BREZILLON <b.brezillon@overkiz.com>
	* License terms: GNU General Public License (GPL) version 2
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/clocksource.h>
	#include <linux/clockchips.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>

	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/ioport.h>
	#include <linux/io.h>
	#include <linux/platform_device.h>
	#include <linux/atmel_tc.h>
	#include <linux/pwm.h>
	#include <linux/of_device.h>
	#include <linux/slab.h>

	#define NPWM 6

	#define ATMEL_TC_ACMR_MASK (ATMEL_TC_ACPA \| ATMEL_TC_ACPC \| \
	ATMEL_TC_AEEVT \| ATMEL_TC_ASWTRG)

	#define ATMEL_TC_BCMR_MASK (ATMEL_TC_BCPB \| ATMEL_TC_BCPC \| \
	ATMEL_TC_BEEVT \| ATMEL_TC_BSWTRG)

	struct atmel_tcb_pwm_device {
	enum pwm_polarity polarity; /* PWM polarity */
	unsigned div; /* PWM clock divider */
	unsigned duty; /* PWM duty expressed in clk cycles */
	unsigned period; /* PWM period expressed in clk cycles */
	};

	struct atmel_tcb_pwm_chip {
	struct pwm_chip chip;
	spinlock_t lock;
	struct atmel_tc *tc;
	struct atmel_tcb_pwm_device *pwms[NPWM];
	};

	static inline struct atmel_tcb_pwm_chip to_tcb_chip(struct pwm_chip chip)
	{
	return container_of(chip, struct atmel_tcb_pwm_chip, chip);
	}

	static int atmel_tcb_pwm_set_polarity(struct pwm_chip *chip,
	struct pwm_device *pwm,
	enum pwm_polarity polarity)
	{
	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);

	tcbpwm->polarity = polarity;

	return 0;
	}

	static int atmel_tcb_pwm_request(struct pwm_chip *chip,
	struct pwm_device *pwm)
	{
	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
	struct atmel_tcb_pwm_device *tcbpwm;
	struct atmel_tc *tc = tcbpwmc->tc;
	void __iomem *regs = tc->regs;
	unsigned group = pwm->hwpwm / 2;
	unsigned index = pwm->hwpwm % 2;
	unsigned cmr;
	int ret;

	tcbpwm = devm_kzalloc(chip->dev, sizeof(*tcbpwm), GFP_KERNEL);
	if (!tcbpwm)
	return -ENOMEM;

	ret = clk_prepare_enable(tc->clk[group]);
	if (ret) {
	devm_kfree(chip->dev, tcbpwm);
	return ret;
	}

	pwm_set_chip_data(pwm, tcbpwm);
	tcbpwm->polarity = PWM_POLARITY_NORMAL;
	tcbpwm->duty = 0;
	tcbpwm->period = 0;
	tcbpwm->div = 0;

	spin_lock(&tcbpwmc->lock);
	cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));
	/*
	* Get init config from Timer Counter registers if
	* Timer Counter is already configured as a PWM generator.
	*/
	if (cmr & ATMEL_TC_WAVE) {
	if (index == 0)
	tcbpwm->duty =
	__raw_readl(regs + ATMEL_TC_REG(group, RA));
	else
	tcbpwm->duty =
	__raw_readl(regs + ATMEL_TC_REG(group, RB));

	tcbpwm->div = cmr & ATMEL_TC_TCCLKS;
	tcbpwm->period = __raw_readl(regs + ATMEL_TC_REG(group, RC));
	cmr &= (ATMEL_TC_TCCLKS \| ATMEL_TC_ACMR_MASK \|
	ATMEL_TC_BCMR_MASK);
	} else
	cmr = 0;

	cmr \|= ATMEL_TC_WAVE \| ATMEL_TC_WAVESEL_UP_AUTO \| ATMEL_TC_EEVT_XC0;
	__raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));
	spin_unlock(&tcbpwmc->lock);

	tcbpwmc->pwms[pwm->hwpwm] = tcbpwm;

	return 0;
	}

	static void atmel_tcb_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
	struct atmel_tc *tc = tcbpwmc->tc;

	clk_disable_unprepare(tc->clk[pwm->hwpwm / 2]);
	tcbpwmc->pwms[pwm->hwpwm] = NULL;
	devm_kfree(chip->dev, tcbpwm);
	}

	static void atmel_tcb_pwm_disable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
	struct atmel_tc *tc = tcbpwmc->tc;
	void __iomem *regs = tc->regs;
	unsigned group = pwm->hwpwm / 2;
	unsigned index = pwm->hwpwm % 2;
	unsigned cmr;
	enum pwm_polarity polarity = tcbpwm->polarity;

	/*
	* If duty is 0 the timer will be stopped and we have to
	* configure the output correctly on software trigger:
	* - set output to high if PWM_POLARITY_INVERSED
	* - set output to low if PWM_POLARITY_NORMAL
	*
	* This is why we're reverting polarity in this case.
	*/
	if (tcbpwm->duty == 0)
	polarity = !polarity;

	spin_lock(&tcbpwmc->lock);
	cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));

	/* flush old setting and set the new one */
	if (index == 0) {
	cmr &= ~ATMEL_TC_ACMR_MASK;
	if (polarity == PWM_POLARITY_INVERSED)
	cmr \|= ATMEL_TC_ASWTRG_CLEAR;
	else
	cmr \|= ATMEL_TC_ASWTRG_SET;
	} else {
	cmr &= ~ATMEL_TC_BCMR_MASK;
	if (polarity == PWM_POLARITY_INVERSED)
	cmr \|= ATMEL_TC_BSWTRG_CLEAR;
	else
	cmr \|= ATMEL_TC_BSWTRG_SET;
	}

	__raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));

	/*
	* Use software trigger to apply the new setting.
	* If both PWM devices in this group are disabled we stop the clock.
	*/
	if (!(cmr & (ATMEL_TC_ACPC \| ATMEL_TC_BCPC)))
	__raw_writel(ATMEL_TC_SWTRG \| ATMEL_TC_CLKDIS,
	regs + ATMEL_TC_REG(group, CCR));
	else
	__raw_writel(ATMEL_TC_SWTRG, regs +
	ATMEL_TC_REG(group, CCR));

	spin_unlock(&tcbpwmc->lock);
	}

	static int atmel_tcb_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
	struct atmel_tc *tc = tcbpwmc->tc;
	void __iomem *regs = tc->regs;
	unsigned group = pwm->hwpwm / 2;
	unsigned index = pwm->hwpwm % 2;
	u32 cmr;
	enum pwm_polarity polarity = tcbpwm->polarity;

	/*
	* If duty is 0 the timer will be stopped and we have to
	* configure the output correctly on software trigger:
	* - set output to high if PWM_POLARITY_INVERSED
	* - set output to low if PWM_POLARITY_NORMAL
	*
	* This is why we're reverting polarity in this case.
	*/
	if (tcbpwm->duty == 0)
	polarity = !polarity;

	spin_lock(&tcbpwmc->lock);
	cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));

	/* flush old setting and set the new one */
	cmr &= ~ATMEL_TC_TCCLKS;

	if (index == 0) {
	cmr &= ~ATMEL_TC_ACMR_MASK;

	/* Set CMR flags according to given polarity */
	if (polarity == PWM_POLARITY_INVERSED)
	cmr \|= ATMEL_TC_ASWTRG_CLEAR;
	else
	cmr \|= ATMEL_TC_ASWTRG_SET;
	} else {
	cmr &= ~ATMEL_TC_BCMR_MASK;
	if (polarity == PWM_POLARITY_INVERSED)
	cmr \|= ATMEL_TC_BSWTRG_CLEAR;
	else
	cmr \|= ATMEL_TC_BSWTRG_SET;
	}

	/*
	* If duty is 0 or equal to period there's no need to register
	* a specific action on RA/RB and RC compare.
	* The output will be configured on software trigger and keep
	* this config till next config call.
	*/
	if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) {
	if (index == 0) {
	if (polarity == PWM_POLARITY_INVERSED)
	cmr \|= ATMEL_TC_ACPA_SET \| ATMEL_TC_ACPC_CLEAR;
	else
	cmr \|= ATMEL_TC_ACPA_CLEAR \| ATMEL_TC_ACPC_SET;
	} else {
	if (polarity == PWM_POLARITY_INVERSED)
	cmr \|= ATMEL_TC_BCPB_SET \| ATMEL_TC_BCPC_CLEAR;
	else
	cmr \|= ATMEL_TC_BCPB_CLEAR \| ATMEL_TC_BCPC_SET;
	}
	}

	cmr \|= (tcbpwm->div & ATMEL_TC_TCCLKS);

	__raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));

	if (index == 0)
	__raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RA));
	else
	__raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RB));

	__raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(group, RC));

	/* Use software trigger to apply the new setting */
	__raw_writel(ATMEL_TC_CLKEN \| ATMEL_TC_SWTRG,
	regs + ATMEL_TC_REG(group, CCR));
	spin_unlock(&tcbpwmc->lock);
	return 0;
	}

	static int atmel_tcb_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	int duty_ns, int period_ns)
	{
	struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
	struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
	unsigned group = pwm->hwpwm / 2;
	unsigned index = pwm->hwpwm % 2;
	struct atmel_tcb_pwm_device *atcbpwm = NULL;
	struct atmel_tc *tc = tcbpwmc->tc;
	int i;
	int slowclk = 0;
	unsigned period;
	unsigned duty;
	unsigned rate = clk_get_rate(tc->clk[group]);
	unsigned long long min;
	unsigned long long max;

	/*
	* Find best clk divisor:
	* the smallest divisor which can fulfill the period_ns requirements.
	*/
	for (i = 0; i < 5; ++i) {
	if (atmel_tc_divisors[i] == 0) {
	slowclk = i;
	continue;
	}
	min = div_u64((u64)NSEC_PER_SEC * atmel_tc_divisors[i], rate);
	max = min << tc->tcb_config->counter_width;
	if (max >= period_ns)
	break;
	}

	/*
	* If none of the divisor are small enough to represent period_ns
	* take slow clock (32KHz).
	*/
	if (i == 5) {
	i = slowclk;
	rate = clk_get_rate(tc->slow_clk);
	min = div_u64(NSEC_PER_SEC, rate);
	max = min << tc->tcb_config->counter_width;

	/* If period is too big return ERANGE error */
	if (max < period_ns)
	return -ERANGE;
	}

	duty = div_u64(duty_ns, min);
	period = div_u64(period_ns, min);

	if (index == 0)
	atcbpwm = tcbpwmc->pwms[pwm->hwpwm + 1];
	else
	atcbpwm = tcbpwmc->pwms[pwm->hwpwm - 1];

	/*
	* PWM devices provided by TCB driver are grouped by 2:
	* - group 0: PWM 0 & 1
	* - group 1: PWM 2 & 3
	* - group 2: PWM 4 & 5
	*
	* PWM devices in a given group must be configured with the
	* same period_ns.
	*
	* We're checking the period value of the second PWM device
	* in this group before applying the new config.
	*/
	if ((atcbpwm && atcbpwm->duty > 0 &&
	atcbpwm->duty != atcbpwm->period) &&
	(atcbpwm->div != i \|\| atcbpwm->period != period)) {
	dev_err(chip->dev,
	"failed to configure period_ns: PWM group already configured with a different value\n");
	return -EINVAL;
	}

	tcbpwm->period = period;
	tcbpwm->div = i;
	tcbpwm->duty = duty;

	/* If the PWM is enabled, call enable to apply the new conf */
	if (pwm_is_enabled(pwm))
	atmel_tcb_pwm_enable(chip, pwm);

	return 0;
	}

	static const struct pwm_ops atmel_tcb_pwm_ops = {
	.request = atmel_tcb_pwm_request,
	.free = atmel_tcb_pwm_free,
	.config = atmel_tcb_pwm_config,
	.set_polarity = atmel_tcb_pwm_set_polarity,
	.enable = atmel_tcb_pwm_enable,
	.disable = atmel_tcb_pwm_disable,
	.owner = THIS_MODULE,
	};

	static int atmel_tcb_pwm_probe(struct platform_device *pdev)
	{
	struct atmel_tcb_pwm_chip *tcbpwm;
	struct device_node *np = pdev->dev.of_node;
	struct atmel_tc *tc;
	int err;
	int tcblock;

	err = of_property_read_u32(np, "tc-block", &tcblock);
	if (err < 0) {
	dev_err(&pdev->dev,
	"failed to get Timer Counter Block number from device tree (error: %d)\n",
	err);
	return err;
	}

	tc = atmel_tc_alloc(tcblock);
	if (tc == NULL) {
	dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n");
	return -ENOMEM;
	}

	tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL);
	if (tcbpwm == NULL) {
	err = -ENOMEM;
	dev_err(&pdev->dev, "failed to allocate memory\n");
	goto err_free_tc;
	}

	tcbpwm->chip.dev = &pdev->dev;
	tcbpwm->chip.ops = &atmel_tcb_pwm_ops;
	tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags;
	tcbpwm->chip.of_pwm_n_cells = 3;
	tcbpwm->chip.base = -1;
	tcbpwm->chip.npwm = NPWM;
	tcbpwm->tc = tc;

	err = clk_prepare_enable(tc->slow_clk);
	if (err)
	goto err_free_tc;

	spin_lock_init(&tcbpwm->lock);

	err = pwmchip_add(&tcbpwm->chip);
	if (err < 0)
	goto err_disable_clk;

	platform_set_drvdata(pdev, tcbpwm);

	return 0;

	err_disable_clk:
	clk_disable_unprepare(tcbpwm->tc->slow_clk);

	err_free_tc:
	atmel_tc_free(tc);

	return err;
	}

	static int atmel_tcb_pwm_remove(struct platform_device *pdev)
	{
	struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
	int err;

	clk_disable_unprepare(tcbpwm->tc->slow_clk);

	err = pwmchip_remove(&tcbpwm->chip);
	if (err < 0)
	return err;

	atmel_tc_free(tcbpwm->tc);

	return 0;
	}

	static const struct of_device_id atmel_tcb_pwm_dt_ids[] = {
	{ .compatible = "atmel,tcb-pwm", },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids);

	static struct platform_driver atmel_tcb_pwm_driver = {
	.driver = {
	.name = "atmel-tcb-pwm",
	.of_match_table = atmel_tcb_pwm_dt_ids,
	},
	.probe = atmel_tcb_pwm_probe,
	.remove = atmel_tcb_pwm_remove,
	};
	module_platform_driver(atmel_tcb_pwm_driver);

	MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>");
	MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver");
	MODULE_LICENSE("GPL v2");