drivers/pwm/pwm-tiehrpwm.c - pub/scm/linux/kernel/git/pjt/test - Git at Google

 /*
  * EHRPWM 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/pwm.h>
 #include <linux/io.h>
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/pm_runtime.h>

 /* EHRPWM registers and bits definitions */

 /* Time base module registers */
 #define TBCTL			0x00
 #define TBPRD			0x0A

 #define TBCTL_RUN_MASK		(BIT(15) | BIT(14))
 #define TBCTL_STOP_NEXT		0
 #define TBCTL_STOP_ON_CYCLE	BIT(14)
 #define TBCTL_FREE_RUN		(BIT(15) | BIT(14))
 #define TBCTL_PRDLD_MASK	BIT(3)
 #define TBCTL_PRDLD_SHDW	0
 #define TBCTL_PRDLD_IMDT	BIT(3)
 #define TBCTL_CLKDIV_MASK	(BIT(12) | BIT(11) | BIT(10) | BIT(9) | \
 				BIT(8) | BIT(7))
 #define TBCTL_CTRMODE_MASK	(BIT(1) | BIT(0))
 #define TBCTL_CTRMODE_UP	0
 #define TBCTL_CTRMODE_DOWN	BIT(0)
 #define TBCTL_CTRMODE_UPDOWN	BIT(1)
 #define TBCTL_CTRMODE_FREEZE	(BIT(1) | BIT(0))

 #define TBCTL_HSPCLKDIV_SHIFT	7
 #define TBCTL_CLKDIV_SHIFT	10

 #define CLKDIV_MAX		7
 #define HSPCLKDIV_MAX		7
 #define PERIOD_MAX		0xFFFF

 /* compare module registers */
 #define CMPA			0x12
 #define CMPB			0x14

 /* Action qualifier module registers */
 #define AQCTLA			0x16
 #define AQCTLB			0x18
 #define AQSFRC			0x1A
 #define AQCSFRC			0x1C

 #define AQCTL_CBU_MASK		(BIT(9) | BIT(8))
 #define AQCTL_CBU_FRCLOW	BIT(8)
 #define AQCTL_CBU_FRCHIGH	BIT(9)
 #define AQCTL_CBU_FRCTOGGLE	(BIT(9) | BIT(8))
 #define AQCTL_CAU_MASK		(BIT(5) | BIT(4))
 #define AQCTL_CAU_FRCLOW	BIT(4)
 #define AQCTL_CAU_FRCHIGH	BIT(5)
 #define AQCTL_CAU_FRCTOGGLE	(BIT(5) | BIT(4))
 #define AQCTL_PRD_MASK		(BIT(3) | BIT(2))
 #define AQCTL_PRD_FRCLOW	BIT(2)
 #define AQCTL_PRD_FRCHIGH	BIT(3)
 #define AQCTL_PRD_FRCTOGGLE	(BIT(3) | BIT(2))
 #define AQCTL_ZRO_MASK		(BIT(1) | BIT(0))
 #define AQCTL_ZRO_FRCLOW	BIT(0)
 #define AQCTL_ZRO_FRCHIGH	BIT(1)
 #define AQCTL_ZRO_FRCTOGGLE	(BIT(1) | BIT(0))

 #define AQSFRC_RLDCSF_MASK	(BIT(7) | BIT(6))
 #define AQSFRC_RLDCSF_ZRO	0
 #define AQSFRC_RLDCSF_PRD	BIT(6)
 #define AQSFRC_RLDCSF_ZROPRD	BIT(7)
 #define AQSFRC_RLDCSF_IMDT	(BIT(7) | BIT(6))

 #define AQCSFRC_CSFB_MASK	(BIT(3) | BIT(2))
 #define AQCSFRC_CSFB_FRCDIS	0
 #define AQCSFRC_CSFB_FRCLOW	BIT(2)
 #define AQCSFRC_CSFB_FRCHIGH	BIT(3)
 #define AQCSFRC_CSFB_DISSWFRC	(BIT(3) | BIT(2))
 #define AQCSFRC_CSFA_MASK	(BIT(1) | BIT(0))
 #define AQCSFRC_CSFA_FRCDIS	0
 #define AQCSFRC_CSFA_FRCLOW	BIT(0)
 #define AQCSFRC_CSFA_FRCHIGH	BIT(1)
 #define AQCSFRC_CSFA_DISSWFRC	(BIT(1) | BIT(0))

 #define NUM_PWM_CHANNEL		2	/* EHRPWM channels */

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

 static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
 {
 	return container_of(chip, struct ehrpwm_pwm_chip, chip);
 }

 static void ehrpwm_write(void *base, int offset, unsigned int val)
 {
 	writew(val & 0xFFFF, base + offset);
 }

 static void ehrpwm_modify(void *base, int offset,
 		unsigned short mask, unsigned short val)
 {
 	unsigned short regval;

 	regval = readw(base + offset);
 	regval &= ~mask;
 	regval |= val & mask;
 	writew(regval, base + offset);
 }

 /**
  * set_prescale_div -	Set up the prescaler divider function
  * @rqst_prescaler:	prescaler value min
  * @prescale_div:	prescaler value set
  * @tb_clk_div:		Time Base Control prescaler bits
  */
 static int set_prescale_div(unsigned long rqst_prescaler,
 		unsigned short *prescale_div, unsigned short *tb_clk_div)
 {
 	unsigned int clkdiv, hspclkdiv;

 	for (clkdiv = 0; clkdiv <= CLKDIV_MAX; clkdiv++) {
 		for (hspclkdiv = 0; hspclkdiv <= HSPCLKDIV_MAX; hspclkdiv++) {

 			/*
 			 * calculations for prescaler value :
 			 * prescale_div = HSPCLKDIVIDER * CLKDIVIDER.
 			 * HSPCLKDIVIDER =  2 ** hspclkdiv
 			 * CLKDIVIDER = (1),		if clkdiv == 0 *OR*
 			 *		(2 * clkdiv),	if clkdiv != 0
 			 *
 			 * Configure prescale_div value such that period
 			 * register value is less than 65535.
 			 */

 			*prescale_div = (1 << clkdiv) *
 					(hspclkdiv ? (hspclkdiv * 2) : 1);
 			if (*prescale_div > rqst_prescaler) {
 				*tb_clk_div = (clkdiv << TBCTL_CLKDIV_SHIFT) |
 					(hspclkdiv << TBCTL_HSPCLKDIV_SHIFT);
 				return 0;
 			}
 		}
 	}
 	return 1;
 }

 static void configure_chans(struct ehrpwm_pwm_chip *pc, int chan,
 		unsigned long duty_cycles)
 {
 	int cmp_reg, aqctl_reg;
 	unsigned short aqctl_val, aqctl_mask;

 	/*
 	 * Channels can be configured from action qualifier module.
 	 * Channel 0 configured with compare A register and for
 	 * up-counter mode.
 	 * Channel 1 configured with compare B register and for
 	 * up-counter mode.
 	 */
 	if (chan == 1) {
 		aqctl_reg = AQCTLB;
 		cmp_reg = CMPB;
 		/* Configure PWM Low from compare B value */
 		aqctl_val = AQCTL_CBU_FRCLOW;
 		aqctl_mask = AQCTL_CBU_MASK;
 	} else {
 		cmp_reg = CMPA;
 		aqctl_reg = AQCTLA;
 		/* Configure PWM Low from compare A value*/
 		aqctl_val = AQCTL_CAU_FRCLOW;
 		aqctl_mask = AQCTL_CAU_MASK;
 	}

 	/* Configure PWM High from period value and zero value */
 	aqctl_val |= AQCTL_PRD_FRCHIGH | AQCTL_ZRO_FRCHIGH;
 	aqctl_mask |= AQCTL_PRD_MASK | AQCTL_ZRO_MASK;
 	ehrpwm_modify(pc->mmio_base,  aqctl_reg, aqctl_mask, aqctl_val);

 	ehrpwm_write(pc->mmio_base,  cmp_reg, duty_cycles);
 }

 /*
  * period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE
  * duty_ns   = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE
  */
 static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		int duty_ns, int period_ns)
 {
 	struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
 	unsigned long long c;
 	unsigned long period_cycles, duty_cycles;
 	unsigned short ps_divval, tb_divval;

 	if (period_ns < 0 || duty_ns < 0 || 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;
 	}

 	/* Configure clock prescaler to support Low frequency PWM wave */
 	if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval,
 				&tb_divval)) {
 		dev_err(chip->dev, "Unsupported values\n");
 		return -EINVAL;
 	}

 	pm_runtime_get_sync(chip->dev);

 	/* Update clock prescaler values */
 	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CLKDIV_MASK, tb_divval);

 	/* Update period & duty cycle with presacler division */
 	period_cycles = period_cycles / ps_divval;
 	duty_cycles = duty_cycles / ps_divval;

 	/* Configure shadow loading on Period register */
 	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_PRDLD_MASK, TBCTL_PRDLD_SHDW);

 	ehrpwm_write(pc->mmio_base, TBPRD, period_cycles);

 	/* Configure ehrpwm counter for up-count mode */
 	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CTRMODE_MASK,
 			TBCTL_CTRMODE_UP);

 	/* Configure the channel for duty cycle */
 	configure_chans(pc, pwm->hwpwm, duty_cycles);
 	pm_runtime_put_sync(chip->dev);
 	return 0;
 }

 static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
 	unsigned short aqcsfrc_val, aqcsfrc_mask;

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

 	/* Disabling Action Qualifier on PWM output */
 	if (pwm->hwpwm) {
 		aqcsfrc_val = AQCSFRC_CSFB_FRCDIS;
 		aqcsfrc_mask = AQCSFRC_CSFB_MASK;
 	} else {
 		aqcsfrc_val = AQCSFRC_CSFA_FRCDIS;
 		aqcsfrc_mask = AQCSFRC_CSFA_MASK;
 	}

 	/* Changes to shadow mode */
 	ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
 			AQSFRC_RLDCSF_ZRO);

 	ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);

 	/* Enable time counter for free_run */
 	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_FREE_RUN);
 	return 0;
 }

 static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
 	unsigned short aqcsfrc_val, aqcsfrc_mask;

 	/* Action Qualifier puts PWM output low forcefully */
 	if (pwm->hwpwm) {
 		aqcsfrc_val = AQCSFRC_CSFB_FRCLOW;
 		aqcsfrc_mask = AQCSFRC_CSFB_MASK;
 	} else {
 		aqcsfrc_val = AQCSFRC_CSFA_FRCLOW;
 		aqcsfrc_mask = AQCSFRC_CSFA_MASK;
 	}

 	/*
 	 * Changes to immediate action on Action Qualifier. This puts
 	 * Action Qualifier control on PWM output from next TBCLK
 	 */
 	ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
 			AQSFRC_RLDCSF_IMDT);

 	ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);

 	/* Stop Time base counter */
 	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_STOP_NEXT);

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

 static void ehrpwm_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 ehrpwm_pwm_ops = {
 	.free		= ehrpwm_pwm_free,
 	.config		= ehrpwm_pwm_config,
 	.enable		= ehrpwm_pwm_enable,
 	.disable	= ehrpwm_pwm_disable,
 	.owner		= THIS_MODULE,
 };

 static int __devinit ehrpwm_pwm_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct resource *r;
 	struct clk *clk;
 	struct ehrpwm_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 = &ehrpwm_pwm_ops;
 	pc->chip.base = -1;
 	pc->chip.npwm = NUM_PWM_CHANNEL;

 	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) {
 		dev_err(&pdev->dev, "failed to ioremap() registers\n");
 		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 __devexit ehrpwm_pwm_remove(struct platform_device *pdev)
 {
 	struct ehrpwm_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 ehrpwm_pwm_driver = {
 	.driver = {
 		.name = "ehrpwm",
 	},
 	.probe = ehrpwm_pwm_probe,
 	.remove = __devexit_p(ehrpwm_pwm_remove),
 };

 module_platform_driver(ehrpwm_pwm_driver);

 MODULE_DESCRIPTION("EHRPWM PWM driver");
 MODULE_AUTHOR("Texas Instruments");
 MODULE_LICENSE("GPL");
	/*
	* EHRPWM 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/pwm.h>
	#include <linux/io.h>
	#include <linux/err.h>
	#include <linux/clk.h>
	#include <linux/pm_runtime.h>

	/* EHRPWM registers and bits definitions */

	/* Time base module registers */
	#define TBCTL 0x00
	#define TBPRD 0x0A

	#define TBCTL_RUN_MASK (BIT(15) \| BIT(14))
	#define TBCTL_STOP_NEXT 0
	#define TBCTL_STOP_ON_CYCLE BIT(14)
	#define TBCTL_FREE_RUN (BIT(15) \| BIT(14))
	#define TBCTL_PRDLD_MASK BIT(3)
	#define TBCTL_PRDLD_SHDW 0
	#define TBCTL_PRDLD_IMDT BIT(3)
	#define TBCTL_CLKDIV_MASK (BIT(12) \| BIT(11) \| BIT(10) \| BIT(9) \| \
	BIT(8) \| BIT(7))
	#define TBCTL_CTRMODE_MASK (BIT(1) \| BIT(0))
	#define TBCTL_CTRMODE_UP 0
	#define TBCTL_CTRMODE_DOWN BIT(0)
	#define TBCTL_CTRMODE_UPDOWN BIT(1)
	#define TBCTL_CTRMODE_FREEZE (BIT(1) \| BIT(0))

	#define TBCTL_HSPCLKDIV_SHIFT 7
	#define TBCTL_CLKDIV_SHIFT 10

	#define CLKDIV_MAX 7
	#define HSPCLKDIV_MAX 7
	#define PERIOD_MAX 0xFFFF

	/* compare module registers */
	#define CMPA 0x12
	#define CMPB 0x14

	/* Action qualifier module registers */
	#define AQCTLA 0x16
	#define AQCTLB 0x18
	#define AQSFRC 0x1A
	#define AQCSFRC 0x1C

	#define AQCTL_CBU_MASK (BIT(9) \| BIT(8))
	#define AQCTL_CBU_FRCLOW BIT(8)
	#define AQCTL_CBU_FRCHIGH BIT(9)
	#define AQCTL_CBU_FRCTOGGLE (BIT(9) \| BIT(8))
	#define AQCTL_CAU_MASK (BIT(5) \| BIT(4))
	#define AQCTL_CAU_FRCLOW BIT(4)
	#define AQCTL_CAU_FRCHIGH BIT(5)
	#define AQCTL_CAU_FRCTOGGLE (BIT(5) \| BIT(4))
	#define AQCTL_PRD_MASK (BIT(3) \| BIT(2))
	#define AQCTL_PRD_FRCLOW BIT(2)
	#define AQCTL_PRD_FRCHIGH BIT(3)
	#define AQCTL_PRD_FRCTOGGLE (BIT(3) \| BIT(2))
	#define AQCTL_ZRO_MASK (BIT(1) \| BIT(0))
	#define AQCTL_ZRO_FRCLOW BIT(0)
	#define AQCTL_ZRO_FRCHIGH BIT(1)
	#define AQCTL_ZRO_FRCTOGGLE (BIT(1) \| BIT(0))

	#define AQSFRC_RLDCSF_MASK (BIT(7) \| BIT(6))
	#define AQSFRC_RLDCSF_ZRO 0
	#define AQSFRC_RLDCSF_PRD BIT(6)
	#define AQSFRC_RLDCSF_ZROPRD BIT(7)
	#define AQSFRC_RLDCSF_IMDT (BIT(7) \| BIT(6))

	#define AQCSFRC_CSFB_MASK (BIT(3) \| BIT(2))
	#define AQCSFRC_CSFB_FRCDIS 0
	#define AQCSFRC_CSFB_FRCLOW BIT(2)
	#define AQCSFRC_CSFB_FRCHIGH BIT(3)
	#define AQCSFRC_CSFB_DISSWFRC (BIT(3) \| BIT(2))
	#define AQCSFRC_CSFA_MASK (BIT(1) \| BIT(0))
	#define AQCSFRC_CSFA_FRCDIS 0
	#define AQCSFRC_CSFA_FRCLOW BIT(0)
	#define AQCSFRC_CSFA_FRCHIGH BIT(1)
	#define AQCSFRC_CSFA_DISSWFRC (BIT(1) \| BIT(0))

	#define NUM_PWM_CHANNEL 2 /* EHRPWM channels */

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

	static inline struct ehrpwm_pwm_chip to_ehrpwm_pwm_chip(struct pwm_chip chip)
	{
	return container_of(chip, struct ehrpwm_pwm_chip, chip);
	}

	static void ehrpwm_write(void *base, int offset, unsigned int val)
	{
	writew(val & 0xFFFF, base + offset);
	}

	static void ehrpwm_modify(void *base, int offset,
	unsigned short mask, unsigned short val)
	{
	unsigned short regval;

	regval = readw(base + offset);
	regval &= ~mask;
	regval \|= val & mask;
	writew(regval, base + offset);
	}

	/**
	* set_prescale_div - Set up the prescaler divider function
	* @rqst_prescaler: prescaler value min
	* @prescale_div: prescaler value set
	* @tb_clk_div: Time Base Control prescaler bits
	*/
	static int set_prescale_div(unsigned long rqst_prescaler,
	unsigned short prescale_div, unsigned short tb_clk_div)
	{
	unsigned int clkdiv, hspclkdiv;

	for (clkdiv = 0; clkdiv <= CLKDIV_MAX; clkdiv++) {
	for (hspclkdiv = 0; hspclkdiv <= HSPCLKDIV_MAX; hspclkdiv++) {

	/*
	* calculations for prescaler value :
	* prescale_div = HSPCLKDIVIDER * CLKDIVIDER.
	* HSPCLKDIVIDER = 2 ** hspclkdiv
	* CLKDIVIDER = (1), if clkdiv == 0 OR
	* (2 * clkdiv), if clkdiv != 0
	*
	* Configure prescale_div value such that period
	* register value is less than 65535.
	*/

	prescale_div = (1 << clkdiv)
	(hspclkdiv ? (hspclkdiv * 2) : 1);
	if (*prescale_div > rqst_prescaler) {
	*tb_clk_div = (clkdiv << TBCTL_CLKDIV_SHIFT) \|
	(hspclkdiv << TBCTL_HSPCLKDIV_SHIFT);
	return 0;
	}
	}
	}
	return 1;
	}

	static void configure_chans(struct ehrpwm_pwm_chip *pc, int chan,
	unsigned long duty_cycles)
	{
	int cmp_reg, aqctl_reg;
	unsigned short aqctl_val, aqctl_mask;

	/*
	* Channels can be configured from action qualifier module.
	* Channel 0 configured with compare A register and for
	* up-counter mode.
	* Channel 1 configured with compare B register and for
	* up-counter mode.
	*/
	if (chan == 1) {
	aqctl_reg = AQCTLB;
	cmp_reg = CMPB;
	/* Configure PWM Low from compare B value */
	aqctl_val = AQCTL_CBU_FRCLOW;
	aqctl_mask = AQCTL_CBU_MASK;
	} else {
	cmp_reg = CMPA;
	aqctl_reg = AQCTLA;
	/* Configure PWM Low from compare A value*/
	aqctl_val = AQCTL_CAU_FRCLOW;
	aqctl_mask = AQCTL_CAU_MASK;
	}

	/* Configure PWM High from period value and zero value */
	aqctl_val \|= AQCTL_PRD_FRCHIGH \| AQCTL_ZRO_FRCHIGH;
	aqctl_mask \|= AQCTL_PRD_MASK \| AQCTL_ZRO_MASK;
	ehrpwm_modify(pc->mmio_base, aqctl_reg, aqctl_mask, aqctl_val);

	ehrpwm_write(pc->mmio_base, cmp_reg, duty_cycles);
	}

	/*
	* period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE
	* duty_ns = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE
	*/
	static int ehrpwm_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	int duty_ns, int period_ns)
	{
	struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
	unsigned long long c;
	unsigned long period_cycles, duty_cycles;
	unsigned short ps_divval, tb_divval;

	if (period_ns < 0 \|\| duty_ns < 0 \|\| 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;
	}

	/* Configure clock prescaler to support Low frequency PWM wave */
	if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval,
	&tb_divval)) {
	dev_err(chip->dev, "Unsupported values\n");
	return -EINVAL;
	}

	pm_runtime_get_sync(chip->dev);

	/* Update clock prescaler values */
	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CLKDIV_MASK, tb_divval);

	/* Update period & duty cycle with presacler division */
	period_cycles = period_cycles / ps_divval;
	duty_cycles = duty_cycles / ps_divval;

	/* Configure shadow loading on Period register */
	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_PRDLD_MASK, TBCTL_PRDLD_SHDW);

	ehrpwm_write(pc->mmio_base, TBPRD, period_cycles);

	/* Configure ehrpwm counter for up-count mode */
	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CTRMODE_MASK,
	TBCTL_CTRMODE_UP);

	/* Configure the channel for duty cycle */
	configure_chans(pc, pwm->hwpwm, duty_cycles);
	pm_runtime_put_sync(chip->dev);
	return 0;
	}

	static int ehrpwm_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
	unsigned short aqcsfrc_val, aqcsfrc_mask;

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

	/* Disabling Action Qualifier on PWM output */
	if (pwm->hwpwm) {
	aqcsfrc_val = AQCSFRC_CSFB_FRCDIS;
	aqcsfrc_mask = AQCSFRC_CSFB_MASK;
	} else {
	aqcsfrc_val = AQCSFRC_CSFA_FRCDIS;
	aqcsfrc_mask = AQCSFRC_CSFA_MASK;
	}

	/* Changes to shadow mode */
	ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
	AQSFRC_RLDCSF_ZRO);

	ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);

	/* Enable time counter for free_run */
	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_FREE_RUN);
	return 0;
	}

	static void ehrpwm_pwm_disable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
	unsigned short aqcsfrc_val, aqcsfrc_mask;

	/* Action Qualifier puts PWM output low forcefully */
	if (pwm->hwpwm) {
	aqcsfrc_val = AQCSFRC_CSFB_FRCLOW;
	aqcsfrc_mask = AQCSFRC_CSFB_MASK;
	} else {
	aqcsfrc_val = AQCSFRC_CSFA_FRCLOW;
	aqcsfrc_mask = AQCSFRC_CSFA_MASK;
	}

	/*
	* Changes to immediate action on Action Qualifier. This puts
	* Action Qualifier control on PWM output from next TBCLK
	*/
	ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
	AQSFRC_RLDCSF_IMDT);

	ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);

	/* Stop Time base counter */
	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_STOP_NEXT);

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

	static void ehrpwm_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 ehrpwm_pwm_ops = {
	.free = ehrpwm_pwm_free,
	.config = ehrpwm_pwm_config,
	.enable = ehrpwm_pwm_enable,
	.disable = ehrpwm_pwm_disable,
	.owner = THIS_MODULE,
	};

	static int __devinit ehrpwm_pwm_probe(struct platform_device *pdev)
	{
	int ret;
	struct resource *r;
	struct clk *clk;
	struct ehrpwm_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 = &ehrpwm_pwm_ops;
	pc->chip.base = -1;
	pc->chip.npwm = NUM_PWM_CHANNEL;

	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) {
	dev_err(&pdev->dev, "failed to ioremap() registers\n");
	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 __devexit ehrpwm_pwm_remove(struct platform_device *pdev)
	{
	struct ehrpwm_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 ehrpwm_pwm_driver = {
	.driver = {
	.name = "ehrpwm",
	},
	.probe = ehrpwm_pwm_probe,
	.remove = __devexit_p(ehrpwm_pwm_remove),
	};

	module_platform_driver(ehrpwm_pwm_driver);

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