drivers/pwm/pwm-tiecap.c - kernel/msm-4.9 - Gitiles

 /*
  * ECAP PWM driver
  *
  * Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * 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, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #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>

 /* 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_pwm_chip {
 	struct pwm_chip	chip;
 	unsigned int	clk_rate;
 	void __iomem	*mmio_base;
 };

 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)
 {
 	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
 	unsigned long long c;
 	unsigned long period_cycles, duty_cycles;
 	unsigned int reg_val;

 	if (period_ns > NSEC_PER_SEC)
 		return -ERANGE;

 	c = pc->clk_rate;
 	c = c * period_ns;
 	do_div(c, NSEC_PER_SEC);
 	period_cycles = (unsigned long)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 = (unsigned long)c;
 	}

 	pm_runtime_get_sync(pc->chip.dev);

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

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

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

 	if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
 		/* 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 (!test_bit(PWMF_ENABLED, &pwm->flags)) {
 		reg_val = readw(pc->mmio_base + ECCTL2);
 		/* Disable APWM mode to put APWM output Low */
 		reg_val &= ~ECCTL2_APWM_MODE;
 		writew(reg_val, 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);
 	unsigned short reg_val;

 	pm_runtime_get_sync(pc->chip.dev);
 	reg_val = readw(pc->mmio_base + ECCTL2);
 	if (polarity == PWM_POLARITY_INVERSED)
 		/* Duty cycle defines LOW period of PWM */
 		reg_val |= ECCTL2_APWM_POL_LOW;
 	else
 		/* Duty cycle defines HIGH period of PWM */
 		reg_val &= ~ECCTL2_APWM_POL_LOW;

 	writew(reg_val, 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);
 	unsigned int reg_val;

 	/* 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
 	 */
 	reg_val = readw(pc->mmio_base + ECCTL2);
 	reg_val |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE;
 	writew(reg_val, 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);
 	unsigned int reg_val;

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

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

 static void ecap_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	if (test_bit(PWMF_ENABLED, &pwm->flags)) {
 		dev_warn(chip->dev, "Removing PWM device without disabling\n");
 		pm_runtime_put_sync(chip->dev);
 	}
 }

 static const struct pwm_ops ecap_pwm_ops = {
 	.free		= ecap_pwm_free,
 	.config		= ecap_pwm_config,
 	.set_polarity	= ecap_pwm_set_polarity,
 	.enable		= ecap_pwm_enable,
 	.disable	= ecap_pwm_disable,
 	.owner		= THIS_MODULE,
 };

 static int ecap_pwm_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct resource *r;
 	struct clk *clk;
 	struct ecap_pwm_chip *pc;

 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 	if (!pc) {
 		dev_err(&pdev->dev, "failed to allocate memory\n");
 		return -ENOMEM;
 	}

 	clk = devm_clk_get(&pdev->dev, "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.base = -1;
 	pc->chip.npwm = 1;

 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!r) {
 		dev_err(&pdev->dev, "no memory resource defined\n");
 		return -ENODEV;
 	}

 	pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
 	if (!pc->mmio_base)
 		return -EADDRNOTAVAIL;

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

 	pm_runtime_enable(&pdev->dev);
 	platform_set_drvdata(pdev, pc);
 	return 0;
 }

 static int ecap_pwm_remove(struct platform_device *pdev)
 {
 	struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);

 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 	return pwmchip_remove(&pc->chip);
 }

 static struct platform_driver ecap_pwm_driver = {
 	.driver = {
 		.name = "ecap",
 	},
 	.probe = ecap_pwm_probe,
 	.remove = ecap_pwm_remove,
 };

 module_platform_driver(ecap_pwm_driver);

 MODULE_DESCRIPTION("ECAP PWM driver");
 MODULE_AUTHOR("Texas Instruments");
 MODULE_LICENSE("GPL");
	/*
	* ECAP PWM driver
	*
	* Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* 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, write to the Free Software
	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#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>

	/* 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_pwm_chip {
	struct pwm_chip chip;
	unsigned int clk_rate;
	void __iomem *mmio_base;
	};

	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)
	{
	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
	unsigned long long c;
	unsigned long period_cycles, duty_cycles;
	unsigned int reg_val;

	if (period_ns > NSEC_PER_SEC)
	return -ERANGE;

	c = pc->clk_rate;
	c = c * period_ns;
	do_div(c, NSEC_PER_SEC);
	period_cycles = (unsigned long)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 = (unsigned long)c;
	}

	pm_runtime_get_sync(pc->chip.dev);

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

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

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

	if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
	/* 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 (!test_bit(PWMF_ENABLED, &pwm->flags)) {
	reg_val = readw(pc->mmio_base + ECCTL2);
	/* Disable APWM mode to put APWM output Low */
	reg_val &= ~ECCTL2_APWM_MODE;
	writew(reg_val, 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);
	unsigned short reg_val;

	pm_runtime_get_sync(pc->chip.dev);
	reg_val = readw(pc->mmio_base + ECCTL2);
	if (polarity == PWM_POLARITY_INVERSED)
	/* Duty cycle defines LOW period of PWM */
	reg_val \|= ECCTL2_APWM_POL_LOW;
	else
	/* Duty cycle defines HIGH period of PWM */
	reg_val &= ~ECCTL2_APWM_POL_LOW;

	writew(reg_val, 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);
	unsigned int reg_val;

	/* 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
	*/
	reg_val = readw(pc->mmio_base + ECCTL2);
	reg_val \|= ECCTL2_TSCTR_FREERUN \| ECCTL2_APWM_MODE;
	writew(reg_val, 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);
	unsigned int reg_val;

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

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

	static void ecap_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
	{
	if (test_bit(PWMF_ENABLED, &pwm->flags)) {
	dev_warn(chip->dev, "Removing PWM device without disabling\n");
	pm_runtime_put_sync(chip->dev);
	}
	}

	static const struct pwm_ops ecap_pwm_ops = {
	.free = ecap_pwm_free,
	.config = ecap_pwm_config,
	.set_polarity = ecap_pwm_set_polarity,
	.enable = ecap_pwm_enable,
	.disable = ecap_pwm_disable,
	.owner = THIS_MODULE,
	};

	static int ecap_pwm_probe(struct platform_device *pdev)
	{
	int ret;
	struct resource *r;
	struct clk *clk;
	struct ecap_pwm_chip *pc;

	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
	if (!pc) {
	dev_err(&pdev->dev, "failed to allocate memory\n");
	return -ENOMEM;
	}

	clk = devm_clk_get(&pdev->dev, "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.base = -1;
	pc->chip.npwm = 1;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
	dev_err(&pdev->dev, "no memory resource defined\n");
	return -ENODEV;
	}

	pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
	if (!pc->mmio_base)
	return -EADDRNOTAVAIL;

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

	pm_runtime_enable(&pdev->dev);
	platform_set_drvdata(pdev, pc);
	return 0;
	}

	static int ecap_pwm_remove(struct platform_device *pdev)
	{
	struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);

	pm_runtime_put_sync(&pdev->dev);
	pm_runtime_disable(&pdev->dev);
	return pwmchip_remove(&pc->chip);
	}

	static struct platform_driver ecap_pwm_driver = {
	.driver = {
	.name = "ecap",
	},
	.probe = ecap_pwm_probe,
	.remove = ecap_pwm_remove,
	};

	module_platform_driver(ecap_pwm_driver);

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