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Commit daa5abc4 authored by Yendapally Reddy Dhananjaya Reddy's avatar Yendapally Reddy Dhananjaya Reddy Committed by Thierry Reding
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pwm: Add support for Broadcom iProc PWM controller 



Add support for the PWM controller present in Broadcom's iProc family of
SoCs. It has been tested on the  Northstar+ bcm958625HR board.

Signed-off-by: default avatarYendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
[thierry.reding@gmail.com: bunch of coding style fixes, cleanups]
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent f734f6dd

drivers/pwm/Kconfig

+10 −0
Original line number Original line Diff line number Diff line
@@ -74,6 +74,16 @@ config PWM_ATMEL_TCB 
	  To compile this driver as a module, choose M here: the module

	  To compile this driver as a module, choose M here: the module

	  will be called pwm-atmel-tcb.

	  will be called pwm-atmel-tcb.





config PWM_BCM_IPROC

	tristate "iProc PWM support"

	depends on ARCH_BCM_IPROC

	help

	  Generic PWM framework driver for Broadcom iProc PWM block. This

	  block is used in Broadcom iProc SoC's.



	  To compile this driver as a module, choose M here: the module

	  will be called pwm-bcm-iproc.



config PWM_BCM_KONA

config PWM_BCM_KONA

	tristate "Kona PWM support"

	tristate "Kona PWM support"

	depends on ARCH_BCM_MOBILE

	depends on ARCH_BCM_MOBILE

drivers/pwm/Makefile

+1 −0
Original line number Original line Diff line number Diff line
@@ -4,6 +4,7 @@ obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o 
obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o

obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o

obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)	+= pwm-atmel-hlcdc.o

obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)	+= pwm-atmel-hlcdc.o

obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o

obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o

obj-$(CONFIG_PWM_BCM_IPROC)	+= pwm-bcm-iproc.o

obj-$(CONFIG_PWM_BCM_KONA)	+= pwm-bcm-kona.o

obj-$(CONFIG_PWM_BCM_KONA)	+= pwm-bcm-kona.o

obj-$(CONFIG_PWM_BCM2835)	+= pwm-bcm2835.o

obj-$(CONFIG_PWM_BCM2835)	+= pwm-bcm2835.o

obj-$(CONFIG_PWM_BERLIN)	+= pwm-berlin.o

obj-$(CONFIG_PWM_BERLIN)	+= pwm-berlin.o

drivers/pwm/pwm-bcm-iproc.c

0 → 100644
+277 −0
Original line number Original line Diff line number Diff line 
/*

 * Copyright (C) 2016 Broadcom

 *

 * 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 version 2.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/math64.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/pwm.h>



#define IPROC_PWM_CTRL_OFFSET			0x00

#define IPROC_PWM_CTRL_TYPE_SHIFT(ch)		(15 + (ch))

#define IPROC_PWM_CTRL_POLARITY_SHIFT(ch)	(8 + (ch))

#define IPROC_PWM_CTRL_EN_SHIFT(ch)		(ch)



#define IPROC_PWM_PERIOD_OFFSET(ch)		(0x04 + ((ch) << 3))

#define IPROC_PWM_PERIOD_MIN			0x02

#define IPROC_PWM_PERIOD_MAX			0xffff



#define IPROC_PWM_DUTY_CYCLE_OFFSET(ch)		(0x08 + ((ch) << 3))

#define IPROC_PWM_DUTY_CYCLE_MIN		0x00

#define IPROC_PWM_DUTY_CYCLE_MAX		0xffff



#define IPROC_PWM_PRESCALE_OFFSET		0x24

#define IPROC_PWM_PRESCALE_BITS			0x06

#define IPROC_PWM_PRESCALE_SHIFT(ch)		((3 - (ch)) * \

						 IPROC_PWM_PRESCALE_BITS)

#define IPROC_PWM_PRESCALE_MASK(ch)		(IPROC_PWM_PRESCALE_MAX << \

						 IPROC_PWM_PRESCALE_SHIFT(ch))

#define IPROC_PWM_PRESCALE_MIN			0x00

#define IPROC_PWM_PRESCALE_MAX			0x3f



struct iproc_pwmc {

	struct pwm_chip chip;

	void __iomem *base;

	struct clk *clk;

};



static inline struct iproc_pwmc *to_iproc_pwmc(struct pwm_chip *chip)

{

	return container_of(chip, struct iproc_pwmc, chip);

}



static void iproc_pwmc_enable(struct iproc_pwmc *ip, unsigned int channel)

{

	u32 value;



	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);

	value |= 1 << IPROC_PWM_CTRL_EN_SHIFT(channel);

	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);



	/* must be a 400 ns delay between clearing and setting enable bit */

	ndelay(400);

}



static void iproc_pwmc_disable(struct iproc_pwmc *ip, unsigned int channel)

{

	u32 value;



	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);

	value &= ~(1 << IPROC_PWM_CTRL_EN_SHIFT(channel));

	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);



	/* must be a 400 ns delay between clearing and setting enable bit */

	ndelay(400);

}



static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,

				 struct pwm_state *state)

{

	struct iproc_pwmc *ip = to_iproc_pwmc(chip);

	u64 tmp, multi, rate;

	u32 value, prescale;



	rate = clk_get_rate(ip->clk);



	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);



	if (value & BIT(IPROC_PWM_CTRL_EN_SHIFT(pwm->hwpwm)))

		state->enabled = true;

	else

		state->enabled = false;



	if (value & BIT(IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm)))

		state->polarity = PWM_POLARITY_NORMAL;

	else

		state->polarity = PWM_POLARITY_INVERSED;



	value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);

	prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);

	prescale &= IPROC_PWM_PRESCALE_MAX;



	multi = NSEC_PER_SEC * (prescale + 1);



	value = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));

	tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;

	state->period = div64_u64(tmp, rate);



	value = readl(ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));

	tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;

	state->duty_cycle = div64_u64(tmp, rate);

}



static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,

			    struct pwm_state *state)

{

	unsigned long prescale = IPROC_PWM_PRESCALE_MIN;

	struct iproc_pwmc *ip = to_iproc_pwmc(chip);

	u32 value, period, duty;

	u64 rate;



	rate = clk_get_rate(ip->clk);



	/*

	 * Find period count, duty count and prescale to suit duty_cycle and

	 * period. This is done according to formulas described below:

	 *

	 * period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE

	 * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE

	 *

	 * PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))

	 * DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))

	 */

	while (1) {

		u64 value, div;



		div = NSEC_PER_SEC * (prescale + 1);

		value = rate * state->period;

		period = div64_u64(value, div);

		value = rate * state->duty_cycle;

		duty = div64_u64(value, div);



		if (period < IPROC_PWM_PERIOD_MIN ||

		    duty < IPROC_PWM_DUTY_CYCLE_MIN)

			return -EINVAL;



		if (period <= IPROC_PWM_PERIOD_MAX &&

		     duty <= IPROC_PWM_DUTY_CYCLE_MAX)

			break;



		/* Otherwise, increase prescale and recalculate counts */

		if (++prescale > IPROC_PWM_PRESCALE_MAX)

			return -EINVAL;

	}



	iproc_pwmc_disable(ip, pwm->hwpwm);



	/* Set prescale */

	value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);

	value &= ~IPROC_PWM_PRESCALE_MASK(pwm->hwpwm);

	value |= prescale << IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);

	writel(value, ip->base + IPROC_PWM_PRESCALE_OFFSET);



	/* set period and duty cycle */

	writel(period, ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));

	writel(duty, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));



	/* set polarity */

	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);



	if (state->polarity == PWM_POLARITY_NORMAL)

		value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm);

	else

		value &= ~(1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm));



	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);



	if (state->enabled)

		iproc_pwmc_enable(ip, pwm->hwpwm);



	return 0;

}



static const struct pwm_ops iproc_pwm_ops = {

	.apply = iproc_pwmc_apply,

	.get_state = iproc_pwmc_get_state,

};



static int iproc_pwmc_probe(struct platform_device *pdev)

{

	struct iproc_pwmc *ip;

	struct resource *res;

	unsigned int i;

	u32 value;

	int ret;



	ip = devm_kzalloc(&pdev->dev, sizeof(*ip), GFP_KERNEL);

	if (!ip)

		return -ENOMEM;



	platform_set_drvdata(pdev, ip);



	ip->chip.dev = &pdev->dev;

	ip->chip.ops = &iproc_pwm_ops;

	ip->chip.base = -1;

	ip->chip.npwm = 4;

	ip->chip.of_xlate = of_pwm_xlate_with_flags;

	ip->chip.of_pwm_n_cells = 3;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	ip->base = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(ip->base))

		return PTR_ERR(ip->base);



	ip->clk = devm_clk_get(&pdev->dev, NULL);

	if (IS_ERR(ip->clk)) {

		dev_err(&pdev->dev, "failed to get clock: %ld\n",

			PTR_ERR(ip->clk));

		return PTR_ERR(ip->clk);

	}



	ret = clk_prepare_enable(ip->clk);

	if (ret < 0) {

		dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);

		return ret;

	}



	/* Set full drive and normal polarity for all channels */

	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);



	for (i = 0; i < ip->chip.npwm; i++) {

		value &= ~(1 << IPROC_PWM_CTRL_TYPE_SHIFT(i));

		value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(i);

	}



	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);



	ret = pwmchip_add(&ip->chip);

	if (ret < 0) {

		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);

		clk_disable_unprepare(ip->clk);

	}



	return ret;

}



static int iproc_pwmc_remove(struct platform_device *pdev)

{

	struct iproc_pwmc *ip = platform_get_drvdata(pdev);



	clk_disable_unprepare(ip->clk);



	return pwmchip_remove(&ip->chip);

}



static const struct of_device_id bcm_iproc_pwmc_dt[] = {

	{ .compatible = "brcm,iproc-pwm" },

	{ },

};

MODULE_DEVICE_TABLE(of, bcm_iproc_pwmc_dt);



static struct platform_driver iproc_pwmc_driver = {

	.driver = {

		.name = "bcm-iproc-pwm",

		.of_match_table = bcm_iproc_pwmc_dt,

	},

	.probe = iproc_pwmc_probe,

	.remove = iproc_pwmc_remove,

};

module_platform_driver(iproc_pwmc_driver);



MODULE_AUTHOR("Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>");

MODULE_DESCRIPTION("Broadcom iProc PWM driver");

MODULE_LICENSE("GPL v2");