pwm: add lpc32xx PWM support

LPC32XX PWM controller

Required properties:

- compatible: should be "nxp,lpc3220-pwm"

- reg: physical base address and length of the controller's registers

Examples:

pwm@0x4005C000 {

	compatible = "nxp,lpc3220-pwm";

	reg = <0x4005C000 0x8>;

};

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

	  will be called pwm-imx.

config PWM_LPC32XX

	tristate "LPC32XX PWM support"

	depends on ARCH_LPC32XX

	help

	  Generic PWM framework driver for LPC32XX. The LPC32XX SOC has two

	  PWM controllers.

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

	  will be called pwm-lpc32xx.

config PWM_MXS

	tristate "Freescale MXS PWM support"

	depends on ARCH_MXS && OF

obj-$(CONFIG_PWM)		+= core.o

obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o

obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o

obj-$(CONFIG_PWM_LPC32XX)	+= pwm-lpc32xx.o

obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o

obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o

obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o

/*

 * Copyright 2012 Alexandre Pereira da Silva <aletes.xgr@gmail.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; version 2.

 *

 */

#include <linux/clk.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/platform_device.h>

#include <linux/pwm.h>

#include <linux/slab.h>

struct lpc32xx_pwm_chip {

	struct pwm_chip chip;

	struct clk *clk;

	void __iomem *base;

};

#define PWM_ENABLE	(1 << 31)

#define PWM_RELOADV(x)	(((x) & 0xFF) << 8)

#define PWM_DUTY(x)	((x) & 0xFF)

#define to_lpc32xx_pwm_chip(_chip) \

	container_of(_chip, struct lpc32xx_pwm_chip, chip)

static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,

			      int duty_ns, int period_ns)

{

	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);

	unsigned long long c;

	int period_cycles, duty_cycles;

	c = clk_get_rate(lpc32xx->clk) / 256;

	c = c * period_ns;

	do_div(c, NSEC_PER_SEC);

	/* Handle high and low extremes */

	if (c == 0)

		c = 1;

	if (c > 255)

		c = 0; /* 0 set division by 256 */

	period_cycles = c;

	c = 256 * duty_ns;

	do_div(c, period_ns);

	duty_cycles = c;

	writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),

		lpc32xx->base + (pwm->hwpwm << 2));

	return 0;

}

static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)

{

	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);

	return clk_enable(lpc32xx->clk);

}

static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)

{

	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);

	writel(0, lpc32xx->base + (pwm->hwpwm << 2));

	clk_disable(lpc32xx->clk);

}

static const struct pwm_ops lpc32xx_pwm_ops = {

	.config = lpc32xx_pwm_config,

	.enable = lpc32xx_pwm_enable,

	.disable = lpc32xx_pwm_disable,

	.owner = THIS_MODULE,

};

static int lpc32xx_pwm_probe(struct platform_device *pdev)

{

	struct lpc32xx_pwm_chip *lpc32xx;

	struct resource *res;

	int ret;

	lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);

	if (!lpc32xx)

		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res)

		return -EINVAL;

	lpc32xx->base = devm_request_and_ioremap(&pdev->dev, res);

	if (!lpc32xx->base)

		return -EADDRNOTAVAIL;

	lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);

	if (IS_ERR(lpc32xx->clk))

		return PTR_ERR(lpc32xx->clk);

	lpc32xx->chip.dev = &pdev->dev;

	lpc32xx->chip.ops = &lpc32xx_pwm_ops;

	lpc32xx->chip.npwm = 2;

	ret = pwmchip_add(&lpc32xx->chip);

	if (ret < 0) {

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

		return ret;

	}

	platform_set_drvdata(pdev, lpc32xx);

	return 0;

}

static int __devexit lpc32xx_pwm_remove(struct platform_device *pdev)

{

	struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev);

	clk_disable(lpc32xx->clk);

	return pwmchip_remove(&lpc32xx->chip);

}

static struct of_device_id lpc32xx_pwm_dt_ids[] = {

	{ .compatible = "nxp,lpc3220-pwm", },

	{ /* sentinel */ }

};

MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);

static struct platform_driver lpc32xx_pwm_driver = {

	.driver = {

		.name = "lpc32xx-pwm",

		.of_match_table = of_match_ptr(lpc32xx_pwm_dt_ids),

	},

	.probe = lpc32xx_pwm_probe,

	.remove = __devexit_p(lpc32xx_pwm_remove),

};

module_platform_driver(lpc32xx_pwm_driver);

MODULE_ALIAS("platform:lpc32xx-pwm");

MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>");

MODULE_DESCRIPTION("LPC32XX PWM Driver");

MODULE_LICENSE("GPL v2");