[deliverable/linux.git] / drivers / pwm / pwm-pxa.c

/*
 * drivers/pwm/pwm-pxa.c
 *
 * simple driver for PWM (Pulse Width Modulator) controller
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 2008-02-13	initial version
 * 		eric miao <eric.miao@marvell.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pwm.h>

#include <asm/div64.h>

#define HAS_SECONDARY_PWM	0x10

static const struct platform_device_id pwm_id_table[] = {
	/*   PWM    has_secondary_pwm? */
	{ "pxa25x-pwm", 0 },
	{ "pxa27x-pwm", HAS_SECONDARY_PWM },
	{ "pxa168-pwm", 0 },
	{ "pxa910-pwm", 0 },
	{ },
};
MODULE_DEVICE_TABLE(platform, pwm_id_table);

/* PWM registers and bits definitions */
#define PWMCR		(0x00)
#define PWMDCR		(0x04)
#define PWMPCR		(0x08)

#define PWMCR_SD	(1 << 6)
#define PWMDCR_FD	(1 << 10)

struct pxa_pwm_chip {
	struct pwm_chip	chip;
	struct device	*dev;

	struct clk	*clk;
	void __iomem	*mmio_base;
};

static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
{
	return container_of(chip, struct pxa_pwm_chip, chip);
}

/*
 * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
 * duty_ns   = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
 */
static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
			  int duty_ns, int period_ns)
{
	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
	unsigned long long c;
	unsigned long period_cycles, prescale, pv, dc;
	unsigned long offset;
	int rc;

	offset = pwm->hwpwm ? 0x10 : 0;

	c = clk_get_rate(pc->clk);
	c = c * period_ns;
	do_div(c, 1000000000);
	period_cycles = c;

	if (period_cycles < 1)
		period_cycles = 1;
	prescale = (period_cycles - 1) / 1024;
	pv = period_cycles / (prescale + 1) - 1;

	if (prescale > 63)
		return -EINVAL;

	if (duty_ns == period_ns)
		dc = PWMDCR_FD;
	else
		dc = (pv + 1) * duty_ns / period_ns;

	/* NOTE: the clock to PWM has to be enabled first
	 * before writing to the registers
	 */
	rc = clk_prepare_enable(pc->clk);
	if (rc < 0)
		return rc;

	writel(prescale, pc->mmio_base + offset + PWMCR);
	writel(dc, pc->mmio_base + offset + PWMDCR);
	writel(pv, pc->mmio_base + offset + PWMPCR);

	clk_disable_unprepare(pc->clk);
	return 0;
}

static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);

	return clk_prepare_enable(pc->clk);
}

static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);

	clk_disable_unprepare(pc->clk);
}

static struct pwm_ops pxa_pwm_ops = {
	.config = pxa_pwm_config,
	.enable = pxa_pwm_enable,
	.disable = pxa_pwm_disable,
	.owner = THIS_MODULE,
};

static int pwm_probe(struct platform_device *pdev)
{
	const struct platform_device_id *id = platform_get_device_id(pdev);
	struct pxa_pwm_chip *pwm;
	struct resource *r;
	int ret = 0;

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

	pwm->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(pwm->clk))
		return PTR_ERR(pwm->clk);

	pwm->chip.dev = &pdev->dev;
	pwm->chip.ops = &pxa_pwm_ops;
	pwm->chip.base = -1;
	pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
	if (IS_ERR(pwm->mmio_base))
		return PTR_ERR(pwm->mmio_base);

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

	platform_set_drvdata(pdev, pwm);
	return 0;
}

static int pwm_remove(struct platform_device *pdev)
{
	struct pxa_pwm_chip *chip;

	chip = platform_get_drvdata(pdev);
	if (chip == NULL)
		return -ENODEV;

	return pwmchip_remove(&chip->chip);
}

static struct platform_driver pwm_driver = {
	.driver		= {
		.name	= "pxa25x-pwm",
		.owner	= THIS_MODULE,
	},
	.probe		= pwm_probe,
	.remove		= pwm_remove,
	.id_table	= pwm_id_table,
};

module_platform_driver(pwm_driver);

MODULE_LICENSE("GPL v2");
Commit	Line	Data
	1	/*
	2	* drivers/pwm/pwm-pxa.c
	3	*
	4	* simple driver for PWM (Pulse Width Modulator) controller
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* 2008-02-13 initial version
	11	* eric miao <eric.miao@marvell.com>
	12	*/
	13
	14	#include <linux/module.h>
	15	#include <linux/kernel.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/slab.h>
	18	#include <linux/err.h>
	19	#include <linux/clk.h>
	20	#include <linux/io.h>
	21	#include <linux/pwm.h>
	22
	23	#include <asm/div64.h>
	24
	25	#define HAS_SECONDARY_PWM 0x10
	26
	27	static const struct platform_device_id pwm_id_table[] = {
	28	/* PWM has_secondary_pwm? */
	29	{ "pxa25x-pwm", 0 },
	30	{ "pxa27x-pwm", HAS_SECONDARY_PWM },
	31	{ "pxa168-pwm", 0 },
	32	{ "pxa910-pwm", 0 },
	33	{ },
	34	};
	35	MODULE_DEVICE_TABLE(platform, pwm_id_table);
	36
	37	/* PWM registers and bits definitions */
	38	#define PWMCR (0x00)
	39	#define PWMDCR (0x04)
	40	#define PWMPCR (0x08)
	41
	42	#define PWMCR_SD (1 << 6)
	43	#define PWMDCR_FD (1 << 10)
	44
	45	struct pxa_pwm_chip {
	46	struct pwm_chip chip;
	47	struct device *dev;
	48
	49	struct clk *clk;
	50	void __iomem *mmio_base;
	51	};
	52
	53	static inline struct pxa_pwm_chip to_pxa_pwm_chip(struct pwm_chip chip)
	54	{
	55	return container_of(chip, struct pxa_pwm_chip, chip);
	56	}
	57
	58	/*
	59	* period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
	60	* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
	61	*/
	62	static int pxa_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	63	int duty_ns, int period_ns)
	64	{
	65	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
	66	unsigned long long c;
	67	unsigned long period_cycles, prescale, pv, dc;
	68	unsigned long offset;
	69	int rc;
	70
	71	offset = pwm->hwpwm ? 0x10 : 0;
	72
	73	c = clk_get_rate(pc->clk);
	74	c = c * period_ns;
	75	do_div(c, 1000000000);
	76	period_cycles = c;
	77
	78	if (period_cycles < 1)
	79	period_cycles = 1;
	80	prescale = (period_cycles - 1) / 1024;
	81	pv = period_cycles / (prescale + 1) - 1;
	82
	83	if (prescale > 63)
	84	return -EINVAL;
	85
	86	if (duty_ns == period_ns)
	87	dc = PWMDCR_FD;
	88	else
	89	dc = (pv + 1) * duty_ns / period_ns;
	90
	91	/* NOTE: the clock to PWM has to be enabled first
	92	* before writing to the registers
	93	*/
	94	rc = clk_prepare_enable(pc->clk);
	95	if (rc < 0)
	96	return rc;
	97
	98	writel(prescale, pc->mmio_base + offset + PWMCR);
	99	writel(dc, pc->mmio_base + offset + PWMDCR);
	100	writel(pv, pc->mmio_base + offset + PWMPCR);
	101
	102	clk_disable_unprepare(pc->clk);
	103	return 0;
	104	}
	105
	106	static int pxa_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	107	{
	108	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
	109
	110	return clk_prepare_enable(pc->clk);
	111	}
	112
	113	static void pxa_pwm_disable(struct pwm_chip chip, struct pwm_device pwm)
	114	{
	115	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
	116
	117	clk_disable_unprepare(pc->clk);
	118	}
	119
	120	static struct pwm_ops pxa_pwm_ops = {
	121	.config = pxa_pwm_config,
	122	.enable = pxa_pwm_enable,
	123	.disable = pxa_pwm_disable,
	124	.owner = THIS_MODULE,
	125	};
	126
	127	static int pwm_probe(struct platform_device *pdev)
	128	{
	129	const struct platform_device_id *id = platform_get_device_id(pdev);
	130	struct pxa_pwm_chip *pwm;
	131	struct resource *r;
	132	int ret = 0;
	133
	134	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
	135	if (pwm == NULL) {
	136	dev_err(&pdev->dev, "failed to allocate memory\n");
	137	return -ENOMEM;
	138	}
	139
	140	pwm->clk = devm_clk_get(&pdev->dev, NULL);
	141	if (IS_ERR(pwm->clk))
	142	return PTR_ERR(pwm->clk);
	143
	144	pwm->chip.dev = &pdev->dev;
	145	pwm->chip.ops = &pxa_pwm_ops;
	146	pwm->chip.base = -1;
	147	pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
	148
	149	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	150	pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
	151	if (IS_ERR(pwm->mmio_base))
	152	return PTR_ERR(pwm->mmio_base);
	153
	154	ret = pwmchip_add(&pwm->chip);
	155	if (ret < 0) {
	156	dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
	157	return ret;
	158	}
	159
	160	platform_set_drvdata(pdev, pwm);
	161	return 0;
	162	}
	163
	164	static int pwm_remove(struct platform_device *pdev)
	165	{
	166	struct pxa_pwm_chip *chip;
	167
	168	chip = platform_get_drvdata(pdev);
	169	if (chip == NULL)
	170	return -ENODEV;
	171
	172	return pwmchip_remove(&chip->chip);
	173	}
	174
	175	static struct platform_driver pwm_driver = {
	176	.driver = {
	177	.name = "pxa25x-pwm",
	178	.owner = THIS_MODULE,
	179	},
	180	.probe = pwm_probe,
	181	.remove = pwm_remove,
	182	.id_table = pwm_id_table,
	183	};
	184
	185	module_platform_driver(pwm_driver);
	186
	187	MODULE_LICENSE("GPL v2");