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

 /*
  * Copyright (C) 2014 Free Electrons
  * Copyright (C) 2014 Atmel
  *
  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  *
  * 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.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/mfd/atmel-hlcdc.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/regmap.h>

 #define ATMEL_HLCDC_PWMCVAL_MASK	GENMASK(15, 8)
 #define ATMEL_HLCDC_PWMCVAL(x)		(((x) << 8) & ATMEL_HLCDC_PWMCVAL_MASK)
 #define ATMEL_HLCDC_PWMPOL		BIT(4)
 #define ATMEL_HLCDC_PWMPS_MASK		GENMASK(2, 0)
 #define ATMEL_HLCDC_PWMPS_MAX		0x6
 #define ATMEL_HLCDC_PWMPS(x)		((x) & ATMEL_HLCDC_PWMPS_MASK)

 struct atmel_hlcdc_pwm_errata {
 	bool slow_clk_erratum;
 	bool div1_clk_erratum;
 };

 struct atmel_hlcdc_pwm {
 	struct pwm_chip chip;
 	struct atmel_hlcdc *hlcdc;
 	struct clk *cur_clk;
 	const struct atmel_hlcdc_pwm_errata *errata;
 };

 static inline struct atmel_hlcdc_pwm *to_atmel_hlcdc_pwm(struct pwm_chip *chip)
 {
 	return container_of(chip, struct atmel_hlcdc_pwm, chip);
 }

 static int atmel_hlcdc_pwm_config(struct pwm_chip *c,
 				  struct pwm_device *pwm,
 				  int duty_ns, int period_ns)
 {
 	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
 	struct atmel_hlcdc *hlcdc = chip->hlcdc;
 	struct clk *new_clk = hlcdc->slow_clk;
 	u64 pwmcval = duty_ns * 256;
 	unsigned long clk_freq;
 	u64 clk_period_ns;
 	u32 pwmcfg;
 	int pres;

 	if (!chip->errata || !chip->errata->slow_clk_erratum) {
 		clk_freq = clk_get_rate(new_clk);
 		clk_period_ns = (u64)NSEC_PER_SEC * 256;
 		do_div(clk_period_ns, clk_freq);
 	}

 	/* Errata: cannot use slow clk on some IP revisions */
 	if ((chip->errata && chip->errata->slow_clk_erratum) ||
 	    clk_period_ns > period_ns) {
 		new_clk = hlcdc->sys_clk;
 		clk_freq = clk_get_rate(new_clk);
 		clk_period_ns = (u64)NSEC_PER_SEC * 256;
 		do_div(clk_period_ns, clk_freq);
 	}

 	for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++) {
 		/* Errata: cannot divide by 1 on some IP revisions */
 		if (!pres && chip->errata && chip->errata->div1_clk_erratum)
 			continue;

 		if ((clk_period_ns << pres) >= period_ns)
 			break;
 	}

 	if (pres > ATMEL_HLCDC_PWMPS_MAX)
 		return -EINVAL;

 	pwmcfg = ATMEL_HLCDC_PWMPS(pres);

 	if (new_clk != chip->cur_clk) {
 		u32 gencfg = 0;
 		int ret;

 		ret = clk_prepare_enable(new_clk);
 		if (ret)
 			return ret;

 		clk_disable_unprepare(chip->cur_clk);
 		chip->cur_clk = new_clk;

 		if (new_clk == hlcdc->sys_clk)
 			gencfg = ATMEL_HLCDC_CLKPWMSEL;

 		ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(0),
 					 ATMEL_HLCDC_CLKPWMSEL, gencfg);
 		if (ret)
 			return ret;
 	}

 	do_div(pwmcval, period_ns);

 	/*
 	 * The PWM duty cycle is configurable from 0/256 to 255/256 of the
 	 * period cycle. Hence we can't set a duty cycle occupying the
 	 * whole period cycle if we're asked to.
 	 * Set it to 255 if pwmcval is greater than 256.
 	 */
 	if (pwmcval > 255)
 		pwmcval = 255;

 	pwmcfg |= ATMEL_HLCDC_PWMCVAL(pwmcval);

 	return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
 				  ATMEL_HLCDC_PWMCVAL_MASK |
 				  ATMEL_HLCDC_PWMPS_MASK,
 				  pwmcfg);
 }

 static int atmel_hlcdc_pwm_set_polarity(struct pwm_chip *c,
 					struct pwm_device *pwm,
 					enum pwm_polarity polarity)
 {
 	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
 	struct atmel_hlcdc *hlcdc = chip->hlcdc;
 	u32 cfg = 0;

 	if (polarity == PWM_POLARITY_NORMAL)
 		cfg = ATMEL_HLCDC_PWMPOL;

 	return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
 				  ATMEL_HLCDC_PWMPOL, cfg);
 }

 static int atmel_hlcdc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
 {
 	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
 	struct atmel_hlcdc *hlcdc = chip->hlcdc;
 	u32 status;
 	int ret;

 	ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_PWM);
 	if (ret)
 		return ret;

 	while (true) {
 		ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status);
 		if (ret)
 			return ret;

 		if ((status & ATMEL_HLCDC_PWM) != 0)
 			break;

 		usleep_range(1, 10);
 	}

 	return 0;
 }

 static void atmel_hlcdc_pwm_disable(struct pwm_chip *c,
 				    struct pwm_device *pwm)
 {
 	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
 	struct atmel_hlcdc *hlcdc = chip->hlcdc;
 	u32 status;
 	int ret;

 	ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_PWM);
 	if (ret)
 		return;

 	while (true) {
 		ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status);
 		if (ret)
 			return;

 		if ((status & ATMEL_HLCDC_PWM) == 0)
 			break;

 		usleep_range(1, 10);
 	}
 }

 static const struct pwm_ops atmel_hlcdc_pwm_ops = {
 	.config = atmel_hlcdc_pwm_config,
 	.set_polarity = atmel_hlcdc_pwm_set_polarity,
 	.enable = atmel_hlcdc_pwm_enable,
 	.disable = atmel_hlcdc_pwm_disable,
 	.owner = THIS_MODULE,
 };

 static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_at91sam9x5_errata = {
 	.slow_clk_erratum = true,
 };

 static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_sama5d3_errata = {
 	.div1_clk_erratum = true,
 };

 static const struct of_device_id atmel_hlcdc_dt_ids[] = {
 	{
 		.compatible = "atmel,at91sam9x5-hlcdc",
 		.data = &atmel_hlcdc_pwm_at91sam9x5_errata,
 	},
 	{
 		.compatible = "atmel,sama5d3-hlcdc",
 		.data = &atmel_hlcdc_pwm_sama5d3_errata,
 	},
 	{ /* sentinel */ },
 };

 static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *match;
 	struct device *dev = &pdev->dev;
 	struct atmel_hlcdc_pwm *chip;
 	struct atmel_hlcdc *hlcdc;
 	int ret;

 	hlcdc = dev_get_drvdata(dev->parent);

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

 	ret = clk_prepare_enable(hlcdc->periph_clk);
 	if (ret)
 		return ret;

 	match = of_match_node(atmel_hlcdc_dt_ids, dev->parent->of_node);
 	if (match)
 		chip->errata = match->data;

 	chip->hlcdc = hlcdc;
 	chip->chip.ops = &atmel_hlcdc_pwm_ops;
 	chip->chip.dev = dev;
 	chip->chip.base = -1;
 	chip->chip.npwm = 1;
 	chip->chip.of_xlate = of_pwm_xlate_with_flags;
 	chip->chip.of_pwm_n_cells = 3;
 	chip->chip.can_sleep = 1;

 	ret = pwmchip_add(&chip->chip);
 	if (ret) {
 		clk_disable_unprepare(hlcdc->periph_clk);
 		return ret;
 	}

 	platform_set_drvdata(pdev, chip);

 	return 0;
 }

 static int atmel_hlcdc_pwm_remove(struct platform_device *pdev)
 {
 	struct atmel_hlcdc_pwm *chip = platform_get_drvdata(pdev);
 	int ret;

 	ret = pwmchip_remove(&chip->chip);
 	if (ret)
 		return ret;

 	clk_disable_unprepare(chip->hlcdc->periph_clk);

 	return 0;
 }

 static const struct of_device_id atmel_hlcdc_pwm_dt_ids[] = {
 	{ .compatible = "atmel,hlcdc-pwm" },
 	{ /* sentinel */ },
 };

 static struct platform_driver atmel_hlcdc_pwm_driver = {
 	.driver = {
 		.name = "atmel-hlcdc-pwm",
 		.of_match_table = atmel_hlcdc_pwm_dt_ids,
 	},
 	.probe = atmel_hlcdc_pwm_probe,
 	.remove = atmel_hlcdc_pwm_remove,
 };
 module_platform_driver(atmel_hlcdc_pwm_driver);

 MODULE_ALIAS("platform:atmel-hlcdc-pwm");
 MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");
 MODULE_DESCRIPTION("Atmel HLCDC PWM driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Copyright (C) 2014 Free Electrons
	* Copyright (C) 2014 Atmel
	*
	* Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*
	* 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.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/mfd/atmel-hlcdc.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/pwm.h>
	#include <linux/regmap.h>

	#define ATMEL_HLCDC_PWMCVAL_MASK GENMASK(15, 8)
	#define ATMEL_HLCDC_PWMCVAL(x) (((x) << 8) & ATMEL_HLCDC_PWMCVAL_MASK)
	#define ATMEL_HLCDC_PWMPOL BIT(4)
	#define ATMEL_HLCDC_PWMPS_MASK GENMASK(2, 0)
	#define ATMEL_HLCDC_PWMPS_MAX 0x6
	#define ATMEL_HLCDC_PWMPS(x) ((x) & ATMEL_HLCDC_PWMPS_MASK)

	struct atmel_hlcdc_pwm_errata {
	bool slow_clk_erratum;
	bool div1_clk_erratum;
	};

	struct atmel_hlcdc_pwm {
	struct pwm_chip chip;
	struct atmel_hlcdc *hlcdc;
	struct clk *cur_clk;
	const struct atmel_hlcdc_pwm_errata *errata;
	};

	static inline struct atmel_hlcdc_pwm to_atmel_hlcdc_pwm(struct pwm_chip chip)
	{
	return container_of(chip, struct atmel_hlcdc_pwm, chip);
	}

	static int atmel_hlcdc_pwm_config(struct pwm_chip *c,
	struct pwm_device *pwm,
	int duty_ns, int period_ns)
	{
	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
	struct atmel_hlcdc *hlcdc = chip->hlcdc;
	struct clk *new_clk = hlcdc->slow_clk;
	u64 pwmcval = duty_ns * 256;
	unsigned long clk_freq;
	u64 clk_period_ns;
	u32 pwmcfg;
	int pres;

	if (!chip->errata \|\| !chip->errata->slow_clk_erratum) {
	clk_freq = clk_get_rate(new_clk);
	clk_period_ns = (u64)NSEC_PER_SEC * 256;
	do_div(clk_period_ns, clk_freq);
	}

	/* Errata: cannot use slow clk on some IP revisions */
	if ((chip->errata && chip->errata->slow_clk_erratum) \|\|
	clk_period_ns > period_ns) {
	new_clk = hlcdc->sys_clk;
	clk_freq = clk_get_rate(new_clk);
	clk_period_ns = (u64)NSEC_PER_SEC * 256;
	do_div(clk_period_ns, clk_freq);
	}

	for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++) {
	/* Errata: cannot divide by 1 on some IP revisions */
	if (!pres && chip->errata && chip->errata->div1_clk_erratum)
	continue;

	if ((clk_period_ns << pres) >= period_ns)
	break;
	}

	if (pres > ATMEL_HLCDC_PWMPS_MAX)
	return -EINVAL;

	pwmcfg = ATMEL_HLCDC_PWMPS(pres);

	if (new_clk != chip->cur_clk) {
	u32 gencfg = 0;
	int ret;

	ret = clk_prepare_enable(new_clk);
	if (ret)
	return ret;

	clk_disable_unprepare(chip->cur_clk);
	chip->cur_clk = new_clk;

	if (new_clk == hlcdc->sys_clk)
	gencfg = ATMEL_HLCDC_CLKPWMSEL;

	ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(0),
	ATMEL_HLCDC_CLKPWMSEL, gencfg);
	if (ret)
	return ret;
	}

	do_div(pwmcval, period_ns);

	/*
	* The PWM duty cycle is configurable from 0/256 to 255/256 of the
	* period cycle. Hence we can't set a duty cycle occupying the
	* whole period cycle if we're asked to.
	* Set it to 255 if pwmcval is greater than 256.
	*/
	if (pwmcval > 255)
	pwmcval = 255;

	pwmcfg \|= ATMEL_HLCDC_PWMCVAL(pwmcval);

	return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
	ATMEL_HLCDC_PWMCVAL_MASK \|
	ATMEL_HLCDC_PWMPS_MASK,
	pwmcfg);
	}

	static int atmel_hlcdc_pwm_set_polarity(struct pwm_chip *c,
	struct pwm_device *pwm,
	enum pwm_polarity polarity)
	{
	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
	struct atmel_hlcdc *hlcdc = chip->hlcdc;
	u32 cfg = 0;

	if (polarity == PWM_POLARITY_NORMAL)
	cfg = ATMEL_HLCDC_PWMPOL;

	return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
	ATMEL_HLCDC_PWMPOL, cfg);
	}

	static int atmel_hlcdc_pwm_enable(struct pwm_chip c, struct pwm_device pwm)
	{
	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
	struct atmel_hlcdc *hlcdc = chip->hlcdc;
	u32 status;
	int ret;

	ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_PWM);
	if (ret)
	return ret;

	while (true) {
	ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status);
	if (ret)
	return ret;

	if ((status & ATMEL_HLCDC_PWM) != 0)
	break;

	usleep_range(1, 10);
	}

	return 0;
	}

	static void atmel_hlcdc_pwm_disable(struct pwm_chip *c,
	struct pwm_device *pwm)
	{
	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
	struct atmel_hlcdc *hlcdc = chip->hlcdc;
	u32 status;
	int ret;

	ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_PWM);
	if (ret)
	return;

	while (true) {
	ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status);
	if (ret)
	return;

	if ((status & ATMEL_HLCDC_PWM) == 0)
	break;

	usleep_range(1, 10);
	}
	}

	static const struct pwm_ops atmel_hlcdc_pwm_ops = {
	.config = atmel_hlcdc_pwm_config,
	.set_polarity = atmel_hlcdc_pwm_set_polarity,
	.enable = atmel_hlcdc_pwm_enable,
	.disable = atmel_hlcdc_pwm_disable,
	.owner = THIS_MODULE,
	};

	static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_at91sam9x5_errata = {
	.slow_clk_erratum = true,
	};

	static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_sama5d3_errata = {
	.div1_clk_erratum = true,
	};

	static const struct of_device_id atmel_hlcdc_dt_ids[] = {
	{
	.compatible = "atmel,at91sam9x5-hlcdc",
	.data = &atmel_hlcdc_pwm_at91sam9x5_errata,
	},
	{
	.compatible = "atmel,sama5d3-hlcdc",
	.data = &atmel_hlcdc_pwm_sama5d3_errata,
	},
	{ /* sentinel */ },
	};

	static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
	{
	const struct of_device_id *match;
	struct device *dev = &pdev->dev;
	struct atmel_hlcdc_pwm *chip;
	struct atmel_hlcdc *hlcdc;
	int ret;

	hlcdc = dev_get_drvdata(dev->parent);

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

	ret = clk_prepare_enable(hlcdc->periph_clk);
	if (ret)
	return ret;

	match = of_match_node(atmel_hlcdc_dt_ids, dev->parent->of_node);
	if (match)
	chip->errata = match->data;

	chip->hlcdc = hlcdc;
	chip->chip.ops = &atmel_hlcdc_pwm_ops;
	chip->chip.dev = dev;
	chip->chip.base = -1;
	chip->chip.npwm = 1;
	chip->chip.of_xlate = of_pwm_xlate_with_flags;
	chip->chip.of_pwm_n_cells = 3;
	chip->chip.can_sleep = 1;

	ret = pwmchip_add(&chip->chip);
	if (ret) {
	clk_disable_unprepare(hlcdc->periph_clk);
	return ret;
	}

	platform_set_drvdata(pdev, chip);

	return 0;
	}

	static int atmel_hlcdc_pwm_remove(struct platform_device *pdev)
	{
	struct atmel_hlcdc_pwm *chip = platform_get_drvdata(pdev);
	int ret;

	ret = pwmchip_remove(&chip->chip);
	if (ret)
	return ret;

	clk_disable_unprepare(chip->hlcdc->periph_clk);

	return 0;
	}

	static const struct of_device_id atmel_hlcdc_pwm_dt_ids[] = {
	{ .compatible = "atmel,hlcdc-pwm" },
	{ /* sentinel */ },
	};

	static struct platform_driver atmel_hlcdc_pwm_driver = {
	.driver = {
	.name = "atmel-hlcdc-pwm",
	.of_match_table = atmel_hlcdc_pwm_dt_ids,
	},
	.probe = atmel_hlcdc_pwm_probe,
	.remove = atmel_hlcdc_pwm_remove,
	};
	module_platform_driver(atmel_hlcdc_pwm_driver);

	MODULE_ALIAS("platform:atmel-hlcdc-pwm");
	MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");
	MODULE_DESCRIPTION("Atmel HLCDC PWM driver");
	MODULE_LICENSE("GPL v2");