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

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Intel Keem Bay PWM driver
  *
  * Copyright (C) 2020 Intel Corporation
  * Authors: Lai Poey Seng <poey.seng.lai@intel.com>
  *          Vineetha G. Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
  *
  * Limitations:
  * - Upon disabling a channel, the currently running
  *   period will not be completed. However, upon
  *   reconfiguration of the duty cycle/period, the
  *   currently running period will be completed first.
  */

 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/regmap.h>

 #define KMB_TOTAL_PWM_CHANNELS		6
 #define KMB_PWM_COUNT_MAX		U16_MAX
 #define KMB_PWM_EN_BIT			BIT(31)

 /* Mask */
 #define KMB_PWM_HIGH_MASK		GENMASK(31, 16)
 #define KMB_PWM_LOW_MASK		GENMASK(15, 0)
 #define KMB_PWM_LEADIN_MASK		GENMASK(30, 0)

 /* PWM Register offset */
 #define KMB_PWM_LEADIN_OFFSET(ch)	(0x00 + 4 * (ch))
 #define KMB_PWM_HIGHLOW_OFFSET(ch)	(0x20 + 4 * (ch))

 struct keembay_pwm {
 	struct pwm_chip chip;
 	struct device *dev;
 	struct clk *clk;
 	void __iomem *base;
 };

 static inline struct keembay_pwm *to_keembay_pwm_dev(struct pwm_chip *chip)
 {
 	return container_of(chip, struct keembay_pwm, chip);
 }

 static void keembay_clk_unprepare(void *data)
 {
 	clk_disable_unprepare(data);
 }

 static int keembay_clk_enable(struct device *dev, struct clk *clk)
 {
 	int ret;

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

 	return devm_add_action_or_reset(dev, keembay_clk_unprepare, clk);
 }

 /*
  * With gcc 10, CONFIG_CC_OPTIMIZE_FOR_SIZE and only "inline" instead of
  * "__always_inline" this fails to compile because the compiler doesn't notice
  * for all valid masks (e.g. KMB_PWM_LEADIN_MASK) that they are ok.
  */
 static __always_inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask,
 					   u32 val, u32 offset)
 {
 	u32 buff = readl(priv->base + offset);

 	buff = u32_replace_bits(buff, val, mask);
 	writel(buff, priv->base + offset);
 }

 static void keembay_pwm_enable(struct keembay_pwm *priv, int ch)
 {
 	keembay_pwm_update_bits(priv, KMB_PWM_EN_BIT, 1,
 				KMB_PWM_LEADIN_OFFSET(ch));
 }

 static void keembay_pwm_disable(struct keembay_pwm *priv, int ch)
 {
 	keembay_pwm_update_bits(priv, KMB_PWM_EN_BIT, 0,
 				KMB_PWM_LEADIN_OFFSET(ch));
 }

 static void keembay_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 				  struct pwm_state *state)
 {
 	struct keembay_pwm *priv = to_keembay_pwm_dev(chip);
 	unsigned long long high, low;
 	unsigned long clk_rate;
 	u32 highlow;

 	clk_rate = clk_get_rate(priv->clk);

 	/* Read channel enabled status */
 	highlow = readl(priv->base + KMB_PWM_LEADIN_OFFSET(pwm->hwpwm));
 	if (highlow & KMB_PWM_EN_BIT)
 		state->enabled = true;
 	else
 		state->enabled = false;

 	/* Read period and duty cycle */
 	highlow = readl(priv->base + KMB_PWM_HIGHLOW_OFFSET(pwm->hwpwm));
 	low = FIELD_GET(KMB_PWM_LOW_MASK, highlow) * NSEC_PER_SEC;
 	high = FIELD_GET(KMB_PWM_HIGH_MASK, highlow) * NSEC_PER_SEC;
 	state->duty_cycle = DIV_ROUND_UP_ULL(high, clk_rate);
 	state->period = DIV_ROUND_UP_ULL(high + low, clk_rate);
 	state->polarity = PWM_POLARITY_NORMAL;
 }

 static int keembay_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			     const struct pwm_state *state)
 {
 	struct keembay_pwm *priv = to_keembay_pwm_dev(chip);
 	struct pwm_state current_state;
 	unsigned long long div;
 	unsigned long clk_rate;
 	u32 pwm_count = 0;
 	u16 high, low;

 	if (state->polarity != PWM_POLARITY_NORMAL)
 		return -EINVAL;

 	/*
 	 * Configure the pwm repeat count as infinite at (15:0) and leadin
 	 * low time as 0 at (30:16), which is in terms of clock cycles.
 	 */
 	keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0,
 				KMB_PWM_LEADIN_OFFSET(pwm->hwpwm));

 	keembay_pwm_get_state(chip, pwm, &current_state);

 	if (!state->enabled) {
 		if (current_state.enabled)
 			keembay_pwm_disable(priv, pwm->hwpwm);
 		return 0;
 	}

 	/*
 	 * The upper 16 bits and lower 16 bits of the KMB_PWM_HIGHLOW_OFFSET
 	 * register contain the high time and low time of waveform accordingly.
 	 * All the values are in terms of clock cycles.
 	 */

 	clk_rate = clk_get_rate(priv->clk);
 	div = clk_rate * state->duty_cycle;
 	div = DIV_ROUND_DOWN_ULL(div, NSEC_PER_SEC);
 	if (div > KMB_PWM_COUNT_MAX)
 		return -ERANGE;

 	high = div;
 	div = clk_rate * state->period;
 	div = DIV_ROUND_DOWN_ULL(div, NSEC_PER_SEC);
 	div = div - high;
 	if (div > KMB_PWM_COUNT_MAX)
 		return -ERANGE;

 	low = div;

 	pwm_count = FIELD_PREP(KMB_PWM_HIGH_MASK, high) |
 		    FIELD_PREP(KMB_PWM_LOW_MASK, low);

 	writel(pwm_count, priv->base + KMB_PWM_HIGHLOW_OFFSET(pwm->hwpwm));

 	if (state->enabled && !current_state.enabled)
 		keembay_pwm_enable(priv, pwm->hwpwm);

 	return 0;
 }

 static const struct pwm_ops keembay_pwm_ops = {
 	.owner = THIS_MODULE,
 	.apply = keembay_pwm_apply,
 	.get_state = keembay_pwm_get_state,
 };

 static int keembay_pwm_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct keembay_pwm *priv;
 	int ret;

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

 	priv->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(priv->clk))
 		return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to get clock\n");

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

 	ret = keembay_clk_enable(dev, priv->clk);
 	if (ret)
 		return ret;

 	priv->chip.dev = dev;
 	priv->chip.ops = &keembay_pwm_ops;
 	priv->chip.npwm = KMB_TOTAL_PWM_CHANNELS;

 	ret = pwmchip_add(&priv->chip);
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to add PWM chip\n");

 	platform_set_drvdata(pdev, priv);

 	return 0;
 }

 static int keembay_pwm_remove(struct platform_device *pdev)
 {
 	struct keembay_pwm *priv = platform_get_drvdata(pdev);

 	return pwmchip_remove(&priv->chip);
 }

 static const struct of_device_id keembay_pwm_of_match[] = {
 	{ .compatible = "intel,keembay-pwm" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, keembay_pwm_of_match);

 static struct platform_driver keembay_pwm_driver = {
 	.probe	= keembay_pwm_probe,
 	.remove	= keembay_pwm_remove,
 	.driver	= {
 		.name = "pwm-keembay",
 		.of_match_table = keembay_pwm_of_match,
 	},
 };
 module_platform_driver(keembay_pwm_driver);

 MODULE_ALIAS("platform:pwm-keembay");
 MODULE_DESCRIPTION("Intel Keem Bay PWM driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Intel Keem Bay PWM driver
	*
	* Copyright (C) 2020 Intel Corporation
	* Authors: Lai Poey Seng <poey.seng.lai@intel.com>
	* Vineetha G. Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
	*
	* Limitations:
	* - Upon disabling a channel, the currently running
	* period will not be completed. However, upon
	* reconfiguration of the duty cycle/period, the
	* currently running period will be completed first.
	*/

	#include <linux/bitfield.h>
	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/mod_devicetable.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/pwm.h>
	#include <linux/regmap.h>

	#define KMB_TOTAL_PWM_CHANNELS 6
	#define KMB_PWM_COUNT_MAX U16_MAX
	#define KMB_PWM_EN_BIT BIT(31)

	/* Mask */
	#define KMB_PWM_HIGH_MASK GENMASK(31, 16)
	#define KMB_PWM_LOW_MASK GENMASK(15, 0)
	#define KMB_PWM_LEADIN_MASK GENMASK(30, 0)

	/* PWM Register offset */
	#define KMB_PWM_LEADIN_OFFSET(ch) (0x00 + 4 * (ch))
	#define KMB_PWM_HIGHLOW_OFFSET(ch) (0x20 + 4 * (ch))

	struct keembay_pwm {
	struct pwm_chip chip;
	struct device *dev;
	struct clk *clk;
	void __iomem *base;
	};

	static inline struct keembay_pwm to_keembay_pwm_dev(struct pwm_chip chip)
	{
	return container_of(chip, struct keembay_pwm, chip);
	}

	static void keembay_clk_unprepare(void *data)
	{
	clk_disable_unprepare(data);
	}

	static int keembay_clk_enable(struct device dev, struct clk clk)
	{
	int ret;

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

	return devm_add_action_or_reset(dev, keembay_clk_unprepare, clk);
	}

	/*
	* With gcc 10, CONFIG_CC_OPTIMIZE_FOR_SIZE and only "inline" instead of
	* "__always_inline" this fails to compile because the compiler doesn't notice
	* for all valid masks (e.g. KMB_PWM_LEADIN_MASK) that they are ok.
	*/
	static __always_inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask,
	u32 val, u32 offset)
	{
	u32 buff = readl(priv->base + offset);

	buff = u32_replace_bits(buff, val, mask);
	writel(buff, priv->base + offset);
	}

	static void keembay_pwm_enable(struct keembay_pwm *priv, int ch)
	{
	keembay_pwm_update_bits(priv, KMB_PWM_EN_BIT, 1,
	KMB_PWM_LEADIN_OFFSET(ch));
	}

	static void keembay_pwm_disable(struct keembay_pwm *priv, int ch)
	{
	keembay_pwm_update_bits(priv, KMB_PWM_EN_BIT, 0,
	KMB_PWM_LEADIN_OFFSET(ch));
	}

	static void keembay_pwm_get_state(struct pwm_chip chip, struct pwm_device pwm,
	struct pwm_state *state)
	{
	struct keembay_pwm *priv = to_keembay_pwm_dev(chip);
	unsigned long long high, low;
	unsigned long clk_rate;
	u32 highlow;

	clk_rate = clk_get_rate(priv->clk);

	/* Read channel enabled status */
	highlow = readl(priv->base + KMB_PWM_LEADIN_OFFSET(pwm->hwpwm));
	if (highlow & KMB_PWM_EN_BIT)
	state->enabled = true;
	else
	state->enabled = false;

	/* Read period and duty cycle */
	highlow = readl(priv->base + KMB_PWM_HIGHLOW_OFFSET(pwm->hwpwm));
	low = FIELD_GET(KMB_PWM_LOW_MASK, highlow) * NSEC_PER_SEC;
	high = FIELD_GET(KMB_PWM_HIGH_MASK, highlow) * NSEC_PER_SEC;
	state->duty_cycle = DIV_ROUND_UP_ULL(high, clk_rate);
	state->period = DIV_ROUND_UP_ULL(high + low, clk_rate);
	state->polarity = PWM_POLARITY_NORMAL;
	}

	static int keembay_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	const struct pwm_state *state)
	{
	struct keembay_pwm *priv = to_keembay_pwm_dev(chip);
	struct pwm_state current_state;
	unsigned long long div;
	unsigned long clk_rate;
	u32 pwm_count = 0;
	u16 high, low;

	if (state->polarity != PWM_POLARITY_NORMAL)
	return -EINVAL;

	/*
	* Configure the pwm repeat count as infinite at (15:0) and leadin
	* low time as 0 at (30:16), which is in terms of clock cycles.
	*/
	keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0,
	KMB_PWM_LEADIN_OFFSET(pwm->hwpwm));

	keembay_pwm_get_state(chip, pwm, &current_state);

	if (!state->enabled) {
	if (current_state.enabled)
	keembay_pwm_disable(priv, pwm->hwpwm);
	return 0;
	}

	/*
	* The upper 16 bits and lower 16 bits of the KMB_PWM_HIGHLOW_OFFSET
	* register contain the high time and low time of waveform accordingly.
	* All the values are in terms of clock cycles.
	*/

	clk_rate = clk_get_rate(priv->clk);
	div = clk_rate * state->duty_cycle;
	div = DIV_ROUND_DOWN_ULL(div, NSEC_PER_SEC);
	if (div > KMB_PWM_COUNT_MAX)
	return -ERANGE;

	high = div;
	div = clk_rate * state->period;
	div = DIV_ROUND_DOWN_ULL(div, NSEC_PER_SEC);
	div = div - high;
	if (div > KMB_PWM_COUNT_MAX)
	return -ERANGE;

	low = div;

	pwm_count = FIELD_PREP(KMB_PWM_HIGH_MASK, high) \|
	FIELD_PREP(KMB_PWM_LOW_MASK, low);

	writel(pwm_count, priv->base + KMB_PWM_HIGHLOW_OFFSET(pwm->hwpwm));

	if (state->enabled && !current_state.enabled)
	keembay_pwm_enable(priv, pwm->hwpwm);

	return 0;
	}

	static const struct pwm_ops keembay_pwm_ops = {
	.owner = THIS_MODULE,
	.apply = keembay_pwm_apply,
	.get_state = keembay_pwm_get_state,
	};

	static int keembay_pwm_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct keembay_pwm *priv;
	int ret;

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

	priv->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(priv->clk))
	return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to get clock\n");

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

	ret = keembay_clk_enable(dev, priv->clk);
	if (ret)
	return ret;

	priv->chip.dev = dev;
	priv->chip.ops = &keembay_pwm_ops;
	priv->chip.npwm = KMB_TOTAL_PWM_CHANNELS;

	ret = pwmchip_add(&priv->chip);
	if (ret)
	return dev_err_probe(dev, ret, "Failed to add PWM chip\n");

	platform_set_drvdata(pdev, priv);

	return 0;
	}

	static int keembay_pwm_remove(struct platform_device *pdev)
	{
	struct keembay_pwm *priv = platform_get_drvdata(pdev);

	return pwmchip_remove(&priv->chip);
	}

	static const struct of_device_id keembay_pwm_of_match[] = {
	{ .compatible = "intel,keembay-pwm" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, keembay_pwm_of_match);

	static struct platform_driver keembay_pwm_driver = {
	.probe = keembay_pwm_probe,
	.remove = keembay_pwm_remove,
	.driver = {
	.name = "pwm-keembay",
	.of_match_table = keembay_pwm_of_match,
	},
	};
	module_platform_driver(keembay_pwm_driver);

	MODULE_ALIAS("platform:pwm-keembay");
	MODULE_DESCRIPTION("Intel Keem Bay PWM driver");
	MODULE_LICENSE("GPL v2");