drivers/pwm/pwm-tiecap.c - linux/kernel/git/viro/vfs - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * ECAP PWM driver
  *
  * Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/
  */

 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/pm_runtime.h>
 #include <linux/pwm.h>
 #include <linux/of.h>

 /* ECAP registers and bits definitions */
 #define CAP1			0x08
 #define CAP2			0x0C
 #define CAP3			0x10
 #define CAP4			0x14
 #define ECCTL2			0x2A
 #define ECCTL2_APWM_POL_LOW	BIT(10)
 #define ECCTL2_APWM_MODE	BIT(9)
 #define ECCTL2_SYNC_SEL_DISA	(BIT(7) | BIT(6))
 #define ECCTL2_TSCTR_FREERUN	BIT(4)

 struct ecap_context {
 	u32 cap3;
 	u32 cap4;
 	u16 ecctl2;
 };

 struct ecap_pwm_chip {
 	struct pwm_chip chip;
 	unsigned int clk_rate;
 	void __iomem *mmio_base;
 	struct ecap_context ctx;
 };

 static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
 {
 	return container_of(chip, struct ecap_pwm_chip, chip);
 }

 /*
  * period_ns = 10^9 * period_cycles / PWM_CLK_RATE
  * duty_ns   = 10^9 * duty_cycles / PWM_CLK_RATE
  */
 static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			   int duty_ns, int period_ns, int enabled)
 {
 	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
 	u32 period_cycles, duty_cycles;
 	unsigned long long c;
 	u16 value;

 	c = pc->clk_rate;
 	c = c * period_ns;
 	do_div(c, NSEC_PER_SEC);
 	period_cycles = (u32)c;

 	if (period_cycles < 1) {
 		period_cycles = 1;
 		duty_cycles = 1;
 	} else {
 		c = pc->clk_rate;
 		c = c * duty_ns;
 		do_div(c, NSEC_PER_SEC);
 		duty_cycles = (u32)c;
 	}

 	pm_runtime_get_sync(pc->chip.dev);

 	value = readw(pc->mmio_base + ECCTL2);

 	/* Configure APWM mode & disable sync option */
 	value |= ECCTL2_APWM_MODE | ECCTL2_SYNC_SEL_DISA;

 	writew(value, pc->mmio_base + ECCTL2);

 	if (!enabled) {
 		/* Update active registers if not running */
 		writel(duty_cycles, pc->mmio_base + CAP2);
 		writel(period_cycles, pc->mmio_base + CAP1);
 	} else {
 		/*
 		 * Update shadow registers to configure period and
 		 * compare values. This helps current PWM period to
 		 * complete on reconfiguring
 		 */
 		writel(duty_cycles, pc->mmio_base + CAP4);
 		writel(period_cycles, pc->mmio_base + CAP3);
 	}

 	if (!enabled) {
 		value = readw(pc->mmio_base + ECCTL2);
 		/* Disable APWM mode to put APWM output Low */
 		value &= ~ECCTL2_APWM_MODE;
 		writew(value, pc->mmio_base + ECCTL2);
 	}

 	pm_runtime_put_sync(pc->chip.dev);

 	return 0;
 }

 static int ecap_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
 				 enum pwm_polarity polarity)
 {
 	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
 	u16 value;

 	pm_runtime_get_sync(pc->chip.dev);

 	value = readw(pc->mmio_base + ECCTL2);

 	if (polarity == PWM_POLARITY_INVERSED)
 		/* Duty cycle defines LOW period of PWM */
 		value |= ECCTL2_APWM_POL_LOW;
 	else
 		/* Duty cycle defines HIGH period of PWM */
 		value &= ~ECCTL2_APWM_POL_LOW;

 	writew(value, pc->mmio_base + ECCTL2);

 	pm_runtime_put_sync(pc->chip.dev);

 	return 0;
 }

 static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
 	u16 value;

 	/* Leave clock enabled on enabling PWM */
 	pm_runtime_get_sync(pc->chip.dev);

 	/*
 	 * Enable 'Free run Time stamp counter mode' to start counter
 	 * and  'APWM mode' to enable APWM output
 	 */
 	value = readw(pc->mmio_base + ECCTL2);
 	value |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE;
 	writew(value, pc->mmio_base + ECCTL2);

 	return 0;
 }

 static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
 	u16 value;

 	/*
 	 * Disable 'Free run Time stamp counter mode' to stop counter
 	 * and 'APWM mode' to put APWM output to low
 	 */
 	value = readw(pc->mmio_base + ECCTL2);
 	value &= ~(ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE);
 	writew(value, pc->mmio_base + ECCTL2);

 	/* Disable clock on PWM disable */
 	pm_runtime_put_sync(pc->chip.dev);
 }

 static int ecap_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			  const struct pwm_state *state)
 {
 	int err;
 	int enabled = pwm->state.enabled;

 	if (state->polarity != pwm->state.polarity) {

 		if (enabled) {
 			ecap_pwm_disable(chip, pwm);
 			enabled = false;
 		}

 		err = ecap_pwm_set_polarity(chip, pwm, state->polarity);
 		if (err)
 			return err;
 	}

 	if (!state->enabled) {
 		if (enabled)
 			ecap_pwm_disable(chip, pwm);
 		return 0;
 	}

 	if (state->period > NSEC_PER_SEC)
 		return -ERANGE;

 	err = ecap_pwm_config(chip, pwm, state->duty_cycle,
 			      state->period, enabled);
 	if (err)
 		return err;

 	if (!enabled)
 		return ecap_pwm_enable(chip, pwm);

 	return 0;
 }

 static const struct pwm_ops ecap_pwm_ops = {
 	.apply = ecap_pwm_apply,
 };

 static const struct of_device_id ecap_of_match[] = {
 	{ .compatible	= "ti,am3352-ecap" },
 	{ .compatible	= "ti,am33xx-ecap" },
 	{},
 };
 MODULE_DEVICE_TABLE(of, ecap_of_match);

 static int ecap_pwm_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct ecap_pwm_chip *pc;
 	struct clk *clk;
 	int ret;

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

 	clk = devm_clk_get(&pdev->dev, "fck");
 	if (IS_ERR(clk)) {
 		if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
 			dev_warn(&pdev->dev, "Binding is obsolete.\n");
 			clk = devm_clk_get(pdev->dev.parent, "fck");
 		}
 	}

 	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "failed to get clock\n");
 		return PTR_ERR(clk);
 	}

 	pc->clk_rate = clk_get_rate(clk);
 	if (!pc->clk_rate) {
 		dev_err(&pdev->dev, "failed to get clock rate\n");
 		return -EINVAL;
 	}

 	pc->chip.dev = &pdev->dev;
 	pc->chip.ops = &ecap_pwm_ops;
 	pc->chip.npwm = 1;

 	pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(pc->mmio_base))
 		return PTR_ERR(pc->mmio_base);

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

 	platform_set_drvdata(pdev, pc);
 	pm_runtime_enable(&pdev->dev);

 	return 0;
 }

 static void ecap_pwm_remove(struct platform_device *pdev)
 {
 	pm_runtime_disable(&pdev->dev);
 }

 #ifdef CONFIG_PM_SLEEP
 static void ecap_pwm_save_context(struct ecap_pwm_chip *pc)
 {
 	pm_runtime_get_sync(pc->chip.dev);
 	pc->ctx.ecctl2 = readw(pc->mmio_base + ECCTL2);
 	pc->ctx.cap4 = readl(pc->mmio_base + CAP4);
 	pc->ctx.cap3 = readl(pc->mmio_base + CAP3);
 	pm_runtime_put_sync(pc->chip.dev);
 }

 static void ecap_pwm_restore_context(struct ecap_pwm_chip *pc)
 {
 	writel(pc->ctx.cap3, pc->mmio_base + CAP3);
 	writel(pc->ctx.cap4, pc->mmio_base + CAP4);
 	writew(pc->ctx.ecctl2, pc->mmio_base + ECCTL2);
 }

 static int ecap_pwm_suspend(struct device *dev)
 {
 	struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
 	struct pwm_device *pwm = pc->chip.pwms;

 	ecap_pwm_save_context(pc);

 	/* Disable explicitly if PWM is running */
 	if (pwm_is_enabled(pwm))
 		pm_runtime_put_sync(dev);

 	return 0;
 }

 static int ecap_pwm_resume(struct device *dev)
 {
 	struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
 	struct pwm_device *pwm = pc->chip.pwms;

 	/* Enable explicitly if PWM was running */
 	if (pwm_is_enabled(pwm))
 		pm_runtime_get_sync(dev);

 	ecap_pwm_restore_context(pc);
 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(ecap_pwm_pm_ops, ecap_pwm_suspend, ecap_pwm_resume);

 static struct platform_driver ecap_pwm_driver = {
 	.driver = {
 		.name = "ecap",
 		.of_match_table = ecap_of_match,
 		.pm = &ecap_pwm_pm_ops,
 	},
 	.probe = ecap_pwm_probe,
 	.remove_new = ecap_pwm_remove,
 };
 module_platform_driver(ecap_pwm_driver);

 MODULE_DESCRIPTION("ECAP PWM driver");
 MODULE_AUTHOR("Texas Instruments");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* ECAP PWM driver
	*
	* Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/
	*/

	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/io.h>
	#include <linux/err.h>
	#include <linux/clk.h>
	#include <linux/pm_runtime.h>
	#include <linux/pwm.h>
	#include <linux/of.h>

	/* ECAP registers and bits definitions */
	#define CAP1 0x08
	#define CAP2 0x0C
	#define CAP3 0x10
	#define CAP4 0x14
	#define ECCTL2 0x2A
	#define ECCTL2_APWM_POL_LOW BIT(10)
	#define ECCTL2_APWM_MODE BIT(9)
	#define ECCTL2_SYNC_SEL_DISA (BIT(7) \| BIT(6))
	#define ECCTL2_TSCTR_FREERUN BIT(4)

	struct ecap_context {
	u32 cap3;
	u32 cap4;
	u16 ecctl2;
	};

	struct ecap_pwm_chip {
	struct pwm_chip chip;
	unsigned int clk_rate;
	void __iomem *mmio_base;
	struct ecap_context ctx;
	};

	static inline struct ecap_pwm_chip to_ecap_pwm_chip(struct pwm_chip chip)
	{
	return container_of(chip, struct ecap_pwm_chip, chip);
	}

	/*
	* period_ns = 10^9 * period_cycles / PWM_CLK_RATE
	* duty_ns = 10^9 * duty_cycles / PWM_CLK_RATE
	*/
	static int ecap_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	int duty_ns, int period_ns, int enabled)
	{
	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
	u32 period_cycles, duty_cycles;
	unsigned long long c;
	u16 value;

	c = pc->clk_rate;
	c = c * period_ns;
	do_div(c, NSEC_PER_SEC);
	period_cycles = (u32)c;

	if (period_cycles < 1) {
	period_cycles = 1;
	duty_cycles = 1;
	} else {
	c = pc->clk_rate;
	c = c * duty_ns;
	do_div(c, NSEC_PER_SEC);
	duty_cycles = (u32)c;
	}

	pm_runtime_get_sync(pc->chip.dev);

	value = readw(pc->mmio_base + ECCTL2);

	/* Configure APWM mode & disable sync option */
	value \|= ECCTL2_APWM_MODE \| ECCTL2_SYNC_SEL_DISA;

	writew(value, pc->mmio_base + ECCTL2);

	if (!enabled) {
	/* Update active registers if not running */
	writel(duty_cycles, pc->mmio_base + CAP2);
	writel(period_cycles, pc->mmio_base + CAP1);
	} else {
	/*
	* Update shadow registers to configure period and
	* compare values. This helps current PWM period to
	* complete on reconfiguring
	*/
	writel(duty_cycles, pc->mmio_base + CAP4);
	writel(period_cycles, pc->mmio_base + CAP3);
	}

	if (!enabled) {
	value = readw(pc->mmio_base + ECCTL2);
	/* Disable APWM mode to put APWM output Low */
	value &= ~ECCTL2_APWM_MODE;
	writew(value, pc->mmio_base + ECCTL2);
	}

	pm_runtime_put_sync(pc->chip.dev);

	return 0;
	}

	static int ecap_pwm_set_polarity(struct pwm_chip chip, struct pwm_device pwm,
	enum pwm_polarity polarity)
	{
	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
	u16 value;

	pm_runtime_get_sync(pc->chip.dev);

	value = readw(pc->mmio_base + ECCTL2);

	if (polarity == PWM_POLARITY_INVERSED)
	/* Duty cycle defines LOW period of PWM */
	value \|= ECCTL2_APWM_POL_LOW;
	else
	/* Duty cycle defines HIGH period of PWM */
	value &= ~ECCTL2_APWM_POL_LOW;

	writew(value, pc->mmio_base + ECCTL2);

	pm_runtime_put_sync(pc->chip.dev);

	return 0;
	}

	static int ecap_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
	u16 value;

	/* Leave clock enabled on enabling PWM */
	pm_runtime_get_sync(pc->chip.dev);

	/*
	* Enable 'Free run Time stamp counter mode' to start counter
	* and 'APWM mode' to enable APWM output
	*/
	value = readw(pc->mmio_base + ECCTL2);
	value \|= ECCTL2_TSCTR_FREERUN \| ECCTL2_APWM_MODE;
	writew(value, pc->mmio_base + ECCTL2);

	return 0;
	}

	static void ecap_pwm_disable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
	u16 value;

	/*
	* Disable 'Free run Time stamp counter mode' to stop counter
	* and 'APWM mode' to put APWM output to low
	*/
	value = readw(pc->mmio_base + ECCTL2);
	value &= ~(ECCTL2_TSCTR_FREERUN \| ECCTL2_APWM_MODE);
	writew(value, pc->mmio_base + ECCTL2);

	/* Disable clock on PWM disable */
	pm_runtime_put_sync(pc->chip.dev);
	}

	static int ecap_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	const struct pwm_state *state)
	{
	int err;
	int enabled = pwm->state.enabled;

	if (state->polarity != pwm->state.polarity) {

	if (enabled) {
	ecap_pwm_disable(chip, pwm);
	enabled = false;
	}

	err = ecap_pwm_set_polarity(chip, pwm, state->polarity);
	if (err)
	return err;
	}

	if (!state->enabled) {
	if (enabled)
	ecap_pwm_disable(chip, pwm);
	return 0;
	}

	if (state->period > NSEC_PER_SEC)
	return -ERANGE;

	err = ecap_pwm_config(chip, pwm, state->duty_cycle,
	state->period, enabled);
	if (err)
	return err;

	if (!enabled)
	return ecap_pwm_enable(chip, pwm);

	return 0;
	}

	static const struct pwm_ops ecap_pwm_ops = {
	.apply = ecap_pwm_apply,
	};

	static const struct of_device_id ecap_of_match[] = {
	{ .compatible = "ti,am3352-ecap" },
	{ .compatible = "ti,am33xx-ecap" },
	{},
	};
	MODULE_DEVICE_TABLE(of, ecap_of_match);

	static int ecap_pwm_probe(struct platform_device *pdev)
	{
	struct device_node *np = pdev->dev.of_node;
	struct ecap_pwm_chip *pc;
	struct clk *clk;
	int ret;

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

	clk = devm_clk_get(&pdev->dev, "fck");
	if (IS_ERR(clk)) {
	if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
	dev_warn(&pdev->dev, "Binding is obsolete.\n");
	clk = devm_clk_get(pdev->dev.parent, "fck");
	}
	}

	if (IS_ERR(clk)) {
	dev_err(&pdev->dev, "failed to get clock\n");
	return PTR_ERR(clk);
	}

	pc->clk_rate = clk_get_rate(clk);
	if (!pc->clk_rate) {
	dev_err(&pdev->dev, "failed to get clock rate\n");
	return -EINVAL;
	}

	pc->chip.dev = &pdev->dev;
	pc->chip.ops = &ecap_pwm_ops;
	pc->chip.npwm = 1;

	pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(pc->mmio_base))
	return PTR_ERR(pc->mmio_base);

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

	platform_set_drvdata(pdev, pc);
	pm_runtime_enable(&pdev->dev);

	return 0;
	}

	static void ecap_pwm_remove(struct platform_device *pdev)
	{
	pm_runtime_disable(&pdev->dev);
	}

	#ifdef CONFIG_PM_SLEEP
	static void ecap_pwm_save_context(struct ecap_pwm_chip *pc)
	{
	pm_runtime_get_sync(pc->chip.dev);
	pc->ctx.ecctl2 = readw(pc->mmio_base + ECCTL2);
	pc->ctx.cap4 = readl(pc->mmio_base + CAP4);
	pc->ctx.cap3 = readl(pc->mmio_base + CAP3);
	pm_runtime_put_sync(pc->chip.dev);
	}

	static void ecap_pwm_restore_context(struct ecap_pwm_chip *pc)
	{
	writel(pc->ctx.cap3, pc->mmio_base + CAP3);
	writel(pc->ctx.cap4, pc->mmio_base + CAP4);
	writew(pc->ctx.ecctl2, pc->mmio_base + ECCTL2);
	}

	static int ecap_pwm_suspend(struct device *dev)
	{
	struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
	struct pwm_device *pwm = pc->chip.pwms;

	ecap_pwm_save_context(pc);

	/* Disable explicitly if PWM is running */
	if (pwm_is_enabled(pwm))
	pm_runtime_put_sync(dev);

	return 0;
	}

	static int ecap_pwm_resume(struct device *dev)
	{
	struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
	struct pwm_device *pwm = pc->chip.pwms;

	/* Enable explicitly if PWM was running */
	if (pwm_is_enabled(pwm))
	pm_runtime_get_sync(dev);

	ecap_pwm_restore_context(pc);
	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(ecap_pwm_pm_ops, ecap_pwm_suspend, ecap_pwm_resume);

	static struct platform_driver ecap_pwm_driver = {
	.driver = {
	.name = "ecap",
	.of_match_table = ecap_of_match,
	.pm = &ecap_pwm_pm_ops,
	},
	.probe = ecap_pwm_probe,
	.remove_new = ecap_pwm_remove,
	};
	module_platform_driver(ecap_pwm_driver);

	MODULE_DESCRIPTION("ECAP PWM driver");
	MODULE_AUTHOR("Texas Instruments");
	MODULE_LICENSE("GPL");