[linux-block.git] / drivers / pwm / pwm-spear.c

/*
 * ST Microelectronics SPEAr Pulse Width Modulator driver
 *
 * Copyright (C) 2012 ST Microelectronics
 * Shiraz Hashim <shiraz.linux.kernel@gmail.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#include <linux/types.h>

#define NUM_PWM		4

/* PWM registers and bits definitions */
#define PWMCR			0x00	/* Control Register */
#define PWMCR_PWM_ENABLE	0x1
#define PWMCR_PRESCALE_SHIFT	2
#define PWMCR_MIN_PRESCALE	0x00
#define PWMCR_MAX_PRESCALE	0x3FFF

#define PWMDCR			0x04	/* Duty Cycle Register */
#define PWMDCR_MIN_DUTY		0x0001
#define PWMDCR_MAX_DUTY		0xFFFF

#define PWMPCR			0x08	/* Period Register */
#define PWMPCR_MIN_PERIOD	0x0001
#define PWMPCR_MAX_PERIOD	0xFFFF

/* Following only available on 13xx SoCs */
#define PWMMCR			0x3C	/* Master Control Register */
#define PWMMCR_PWM_ENABLE	0x1

/**
 * struct spear_pwm_chip - struct representing pwm chip
 *
 * @mmio_base: base address of pwm chip
 * @clk: pointer to clk structure of pwm chip
 * @chip: linux pwm chip representation
 */
struct spear_pwm_chip {
	void __iomem *mmio_base;
	struct clk *clk;
	struct pwm_chip chip;
};

static inline struct spear_pwm_chip *to_spear_pwm_chip(struct pwm_chip *chip)
{
	return container_of(chip, struct spear_pwm_chip, chip);
}

static inline u32 spear_pwm_readl(struct spear_pwm_chip *chip, unsigned int num,
				  unsigned long offset)
{
	return readl_relaxed(chip->mmio_base + (num << 4) + offset);
}

static inline void spear_pwm_writel(struct spear_pwm_chip *chip,
				    unsigned int num, unsigned long offset,
				    unsigned long val)
{
	writel_relaxed(val, chip->mmio_base + (num << 4) + offset);
}

static int spear_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
			    u64 duty_ns, u64 period_ns)
{
	struct spear_pwm_chip *pc = to_spear_pwm_chip(chip);
	u64 val, div, clk_rate;
	unsigned long prescale = PWMCR_MIN_PRESCALE, pv, dc;
	int ret;

	/*
	 * Find pv, dc and prescale to suit duty_ns and period_ns. This is done
	 * according to formulas described below:
	 *
	 * period_ns = 10^9 * (PRESCALE + 1) * PV / PWM_CLK_RATE
	 * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
	 *
	 * PV = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))
	 * DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))
	 */
	clk_rate = clk_get_rate(pc->clk);
	while (1) {
		div = 1000000000;
		div *= 1 + prescale;
		val = clk_rate * period_ns;
		pv = div64_u64(val, div);
		val = clk_rate * duty_ns;
		dc = div64_u64(val, div);

		/* if duty_ns and period_ns are not achievable then return */
		if (pv < PWMPCR_MIN_PERIOD || dc < PWMDCR_MIN_DUTY)
			return -EINVAL;

		/*
		 * if pv and dc have crossed their upper limit, then increase
		 * prescale and recalculate pv and dc.
		 */
		if (pv > PWMPCR_MAX_PERIOD || dc > PWMDCR_MAX_DUTY) {
			if (++prescale > PWMCR_MAX_PRESCALE)
				return -EINVAL;
			continue;
		}
		break;
	}

	/*
	 * NOTE: the clock to PWM has to be enabled first before writing to the
	 * registers.
	 */
	ret = clk_enable(pc->clk);
	if (ret)
		return ret;

	spear_pwm_writel(pc, pwm->hwpwm, PWMCR,
			prescale << PWMCR_PRESCALE_SHIFT);
	spear_pwm_writel(pc, pwm->hwpwm, PWMDCR, dc);
	spear_pwm_writel(pc, pwm->hwpwm, PWMPCR, pv);
	clk_disable(pc->clk);

	return 0;
}

static int spear_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct spear_pwm_chip *pc = to_spear_pwm_chip(chip);
	int rc = 0;
	u32 val;

	rc = clk_enable(pc->clk);
	if (rc)
		return rc;

	val = spear_pwm_readl(pc, pwm->hwpwm, PWMCR);
	val |= PWMCR_PWM_ENABLE;
	spear_pwm_writel(pc, pwm->hwpwm, PWMCR, val);

	return 0;
}

static void spear_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct spear_pwm_chip *pc = to_spear_pwm_chip(chip);
	u32 val;

	val = spear_pwm_readl(pc, pwm->hwpwm, PWMCR);
	val &= ~PWMCR_PWM_ENABLE;
	spear_pwm_writel(pc, pwm->hwpwm, PWMCR, val);

	clk_disable(pc->clk);
}

static int spear_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
			   const struct pwm_state *state)
{
	int err;

	if (state->polarity != PWM_POLARITY_NORMAL)
		return -EINVAL;

	if (!state->enabled) {
		if (pwm->state.enabled)
			spear_pwm_disable(chip, pwm);
		return 0;
	}

	err = spear_pwm_config(chip, pwm, state->duty_cycle, state->period);
	if (err)
		return err;

	if (!pwm->state.enabled)
		return spear_pwm_enable(chip, pwm);

	return 0;
}

static const struct pwm_ops spear_pwm_ops = {
	.apply = spear_pwm_apply,
	.owner = THIS_MODULE,
};

static int spear_pwm_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct spear_pwm_chip *pc;
	int ret;
	u32 val;

	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
	if (!pc)
		return -ENOMEM;

	pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(pc->mmio_base))
		return PTR_ERR(pc->mmio_base);

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

	platform_set_drvdata(pdev, pc);

	pc->chip.dev = &pdev->dev;
	pc->chip.ops = &spear_pwm_ops;
	pc->chip.npwm = NUM_PWM;

	ret = clk_prepare(pc->clk);
	if (ret)
		return ret;

	if (of_device_is_compatible(np, "st,spear1340-pwm")) {
		ret = clk_enable(pc->clk);
		if (ret) {
			clk_unprepare(pc->clk);
			return ret;
		}
		/*
		 * Following enables PWM chip, channels would still be
		 * enabled individually through their control register
		 */
		val = readl_relaxed(pc->mmio_base + PWMMCR);
		val |= PWMMCR_PWM_ENABLE;
		writel_relaxed(val, pc->mmio_base + PWMMCR);

		clk_disable(pc->clk);
	}

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

	return ret;
}

static int spear_pwm_remove(struct platform_device *pdev)
{
	struct spear_pwm_chip *pc = platform_get_drvdata(pdev);

	pwmchip_remove(&pc->chip);

	/* clk was prepared in probe, hence unprepare it here */
	clk_unprepare(pc->clk);

	return 0;
}

static const struct of_device_id spear_pwm_of_match[] = {
	{ .compatible = "st,spear320-pwm" },
	{ .compatible = "st,spear1340-pwm" },
	{ }
};

MODULE_DEVICE_TABLE(of, spear_pwm_of_match);

static struct platform_driver spear_pwm_driver = {
	.driver = {
		.name = "spear-pwm",
		.of_match_table = spear_pwm_of_match,
	},
	.probe = spear_pwm_probe,
	.remove = spear_pwm_remove,
};

module_platform_driver(spear_pwm_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Shiraz Hashim <shiraz.linux.kernel@gmail.com>");
MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.com>");
MODULE_ALIAS("platform:spear-pwm");
Commit	Line	Data
ce20364b SH	1	/*
	2	* ST Microelectronics SPEAr Pulse Width Modulator driver
	3	*
	4	* Copyright (C) 2012 ST Microelectronics
9cc23682	5	* Shiraz Hashim <shiraz.linux.kernel@gmail.com>
ce20364b SH	6	*
	7	* This file is licensed under the terms of the GNU General Public
	8	* License version 2. This program is licensed "as is" without any
	9	* warranty of any kind, whether express or implied.
	10	*/
	11
	12	#include <linux/clk.h>
	13	#include <linux/err.h>
	14	#include <linux/io.h>
	15	#include <linux/ioport.h>
	16	#include <linux/kernel.h>
	17	#include <linux/math64.h>
	18	#include <linux/module.h>
	19	#include <linux/of.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/pwm.h>
	22	#include <linux/slab.h>
	23	#include <linux/types.h>
	24
	25	#define NUM_PWM 4
	26
	27	/* PWM registers and bits definitions */
	28	#define PWMCR 0x00 /* Control Register */
	29	#define PWMCR_PWM_ENABLE 0x1
	30	#define PWMCR_PRESCALE_SHIFT 2
	31	#define PWMCR_MIN_PRESCALE 0x00
	32	#define PWMCR_MAX_PRESCALE 0x3FFF
	33
	34	#define PWMDCR 0x04 /* Duty Cycle Register */
	35	#define PWMDCR_MIN_DUTY 0x0001
	36	#define PWMDCR_MAX_DUTY 0xFFFF
	37
	38	#define PWMPCR 0x08 /* Period Register */
	39	#define PWMPCR_MIN_PERIOD 0x0001
	40	#define PWMPCR_MAX_PERIOD 0xFFFF
	41
	42	/* Following only available on 13xx SoCs */
	43	#define PWMMCR 0x3C /* Master Control Register */
	44	#define PWMMCR_PWM_ENABLE 0x1
	45
	46	/**
	47	* struct spear_pwm_chip - struct representing pwm chip
	48	*
	49	* @mmio_base: base address of pwm chip
	50	* @clk: pointer to clk structure of pwm chip
	51	* @chip: linux pwm chip representation
ce20364b SH	52	*/
	53	struct spear_pwm_chip {
	54	void __iomem *mmio_base;
	55	struct clk *clk;
	56	struct pwm_chip chip;
ce20364b SH	57	};
	58
	59	static inline struct spear_pwm_chip to_spear_pwm_chip(struct pwm_chip chip)
	60	{
	61	return container_of(chip, struct spear_pwm_chip, chip);
	62	}
	63
	64	static inline u32 spear_pwm_readl(struct spear_pwm_chip *chip, unsigned int num,
	65	unsigned long offset)
	66	{
	67	return readl_relaxed(chip->mmio_base + (num << 4) + offset);
	68	}
	69
	70	static inline void spear_pwm_writel(struct spear_pwm_chip *chip,
	71	unsigned int num, unsigned long offset,
	72	unsigned long val)
	73	{
	74	writel_relaxed(val, chip->mmio_base + (num << 4) + offset);
	75	}
	76
c9371360	77	static int spear_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
98761ce4	78	u64 duty_ns, u64 period_ns)
ce20364b SH	79	{
	80	struct spear_pwm_chip *pc = to_spear_pwm_chip(chip);
	81	u64 val, div, clk_rate;
	82	unsigned long prescale = PWMCR_MIN_PRESCALE, pv, dc;
	83	int ret;
	84
	85	/*
	86	* Find pv, dc and prescale to suit duty_ns and period_ns. This is done
	87	* according to formulas described below:
	88	*
	89	* period_ns = 10^9 * (PRESCALE + 1) * PV / PWM_CLK_RATE
	90	* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
	91	*
	92	* PV = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))
	93	* DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))
	94	*/
	95	clk_rate = clk_get_rate(pc->clk);
	96	while (1) {
	97	div = 1000000000;
	98	div *= 1 + prescale;
	99	val = clk_rate * period_ns;
	100	pv = div64_u64(val, div);
	101	val = clk_rate * duty_ns;
	102	dc = div64_u64(val, div);
	103
	104	/* if duty_ns and period_ns are not achievable then return */
	105	if (pv < PWMPCR_MIN_PERIOD \|\| dc < PWMDCR_MIN_DUTY)
	106	return -EINVAL;
	107
	108	/*
	109	* if pv and dc have crossed their upper limit, then increase
	110	* prescale and recalculate pv and dc.
	111	*/
	112	if (pv > PWMPCR_MAX_PERIOD \|\| dc > PWMDCR_MAX_DUTY) {
	113	if (++prescale > PWMCR_MAX_PRESCALE)
	114	return -EINVAL;
	115	continue;
	116	}
	117	break;
	118	}
	119
	120	/*
	121	* NOTE: the clock to PWM has to be enabled first before writing to the
	122	* registers.
	123	*/
	124	ret = clk_enable(pc->clk);
	125	if (ret)
	126	return ret;
	127
	128	spear_pwm_writel(pc, pwm->hwpwm, PWMCR,
	129	prescale << PWMCR_PRESCALE_SHIFT);
	130	spear_pwm_writel(pc, pwm->hwpwm, PWMDCR, dc);
	131	spear_pwm_writel(pc, pwm->hwpwm, PWMPCR, pv);
	132	clk_disable(pc->clk);
	133
	134	return 0;
	135	}
	136
	137	static int spear_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	138	{
	139	struct spear_pwm_chip *pc = to_spear_pwm_chip(chip);
	140	int rc = 0;
	141	u32 val;
	142
143	rc = clk_enable(pc->clk);
563861cd	144	if (rc)
ce20364b SH	145	return rc;
	146
	147	val = spear_pwm_readl(pc, pwm->hwpwm, PWMCR);
	148	val \|= PWMCR_PWM_ENABLE;
	149	spear_pwm_writel(pc, pwm->hwpwm, PWMCR, val);
	150
	151	return 0;
	152	}
	153
	154	static void spear_pwm_disable(struct pwm_chip chip, struct pwm_device pwm)
	155	{
	156	struct spear_pwm_chip *pc = to_spear_pwm_chip(chip);
	157	u32 val;
	158
	159	val = spear_pwm_readl(pc, pwm->hwpwm, PWMCR);
	160	val &= ~PWMCR_PWM_ENABLE;
	161	spear_pwm_writel(pc, pwm->hwpwm, PWMCR, val);
	162
	163	clk_disable(pc->clk);
	164	}
	165
98761ce4 UKK	166	static int spear_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	167	const struct pwm_state *state)
	168	{
	169	int err;
	170
	171	if (state->polarity != PWM_POLARITY_NORMAL)
	172	return -EINVAL;
	173
	174	if (!state->enabled) {
	175	if (pwm->state.enabled)
	176	spear_pwm_disable(chip, pwm);
	177	return 0;
	178	}
	179
fe8255f8 UKK	180	err = spear_pwm_config(chip, pwm, state->duty_cycle, state->period);
	181	if (err)
	182	return err;
98761ce4 UKK	183
	184	if (!pwm->state.enabled)
	185	return spear_pwm_enable(chip, pwm);
	186
	187	return 0;
	188	}
	189
ce20364b	190	static const struct pwm_ops spear_pwm_ops = {
98761ce4	191	.apply = spear_pwm_apply,
ce20364b SH	192	.owner = THIS_MODULE,
	193	};
	194
	195	static int spear_pwm_probe(struct platform_device *pdev)
	196	{
	197	struct device_node *np = pdev->dev.of_node;
	198	struct spear_pwm_chip *pc;
ce20364b SH	199	int ret;
	200	u32 val;
	201
ce20364b	202	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
9321fe9d	203	if (!pc)
ce20364b	204	return -ENOMEM;
ce20364b	205
21af4356	206	pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
6d4294d1 TR	207	if (IS_ERR(pc->mmio_base))
6d4294d1 TR	208	return PTR_ERR(pc->mmio_base);
ce20364b SH	209
	210	pc->clk = devm_clk_get(&pdev->dev, NULL);
	211	if (IS_ERR(pc->clk))
	212	return PTR_ERR(pc->clk);
	213
ce20364b SH	214	platform_set_drvdata(pdev, pc);
	215
	216	pc->chip.dev = &pdev->dev;
	217	pc->chip.ops = &spear_pwm_ops;
ce20364b SH	218	pc->chip.npwm = NUM_PWM;
	219
	220	ret = clk_prepare(pc->clk);
563861cd	221	if (ret)
ce20364b SH	222	return ret;
	223
	224	if (of_device_is_compatible(np, "st,spear1340-pwm")) {
	225	ret = clk_enable(pc->clk);
563861cd	226	if (ret) {
ce20364b SH	227	clk_unprepare(pc->clk);
	228	return ret;
	229	}
	230	/*
	231	* Following enables PWM chip, channels would still be
	232	* enabled individually through their control register
	233	*/
	234	val = readl_relaxed(pc->mmio_base + PWMMCR);
	235	val \|= PWMMCR_PWM_ENABLE;
	236	writel_relaxed(val, pc->mmio_base + PWMMCR);
	237
	238	clk_disable(pc->clk);
	239	}
	240
	241	ret = pwmchip_add(&pc->chip);
5b1e8e06	242	if (ret < 0) {
ce20364b SH	243	clk_unprepare(pc->clk);
	244	dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
	245	}
	246
	247	return ret;
	248	}
	249
	250	static int spear_pwm_remove(struct platform_device *pdev)
	251	{
	252	struct spear_pwm_chip *pc = platform_get_drvdata(pdev);
ce20364b	253
da0dea89 UKK	254	pwmchip_remove(&pc->chip);
da0dea89 UKK	255
ce20364b SH	256	/* clk was prepared in probe, hence unprepare it here */
ce20364b SH	257	clk_unprepare(pc->clk);
da0dea89 UKK	258
da0dea89 UKK	259	return 0;
ce20364b SH	260	}
ce20364b SH	261
f1a8870a	262	static const struct of_device_id spear_pwm_of_match[] = {
ce20364b SH	263	{ .compatible = "st,spear320-pwm" },
	264	{ .compatible = "st,spear1340-pwm" },
	265	{ }
	266	};
	267
	268	MODULE_DEVICE_TABLE(of, spear_pwm_of_match);
	269
	270	static struct platform_driver spear_pwm_driver = {
	271	.driver = {
	272	.name = "spear-pwm",
	273	.of_match_table = spear_pwm_of_match,
	274	},
	275	.probe = spear_pwm_probe,
	276	.remove = spear_pwm_remove,
	277	};
	278
	279	module_platform_driver(spear_pwm_driver);
	280
	281	MODULE_LICENSE("GPL");
9cc23682	282	MODULE_AUTHOR("Shiraz Hashim <shiraz.linux.kernel@gmail.com>");
ce20364b SH	283	MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.com>");
ce20364b SH	284	MODULE_ALIAS("platform:spear-pwm");