[linux-2.6-block.git] / drivers / pwm / pwm-bcm2835.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2014 Bart Tanghe <bart.tanghe@thomasmore.be>
 */

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

#define PWM_CONTROL		0x000
#define PWM_CONTROL_SHIFT(x)	((x) * 8)
#define PWM_CONTROL_MASK	0xff
#define PWM_MODE		0x80		/* set timer in PWM mode */
#define PWM_ENABLE		(1 << 0)
#define PWM_POLARITY		(1 << 4)

#define PERIOD(x)		(((x) * 0x10) + 0x10)
#define DUTY(x)			(((x) * 0x10) + 0x14)

#define MIN_PERIOD		108		/* 9.2 MHz max. PWM clock */

struct bcm2835_pwm {
	struct pwm_chip chip;
	struct device *dev;
	void __iomem *base;
	struct clk *clk;
};

static inline struct bcm2835_pwm *to_bcm2835_pwm(struct pwm_chip *chip)
{
	return container_of(chip, struct bcm2835_pwm, chip);
}

static int bcm2835_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	u32 value;

	value = readl(pc->base + PWM_CONTROL);
	value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm));
	value |= (PWM_MODE << PWM_CONTROL_SHIFT(pwm->hwpwm));
	writel(value, pc->base + PWM_CONTROL);

	return 0;
}

static void bcm2835_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	u32 value;

	value = readl(pc->base + PWM_CONTROL);
	value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm));
	writel(value, pc->base + PWM_CONTROL);
}

static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
			      int duty_ns, int period_ns)
{
	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	unsigned long rate = clk_get_rate(pc->clk);
	unsigned long scaler;

	if (!rate) {
		dev_err(pc->dev, "failed to get clock rate\n");
		return -EINVAL;
	}

	scaler = DIV_ROUND_CLOSEST(NSEC_PER_SEC, rate);

	if (period_ns <= MIN_PERIOD)
		return -EINVAL;

	writel(DIV_ROUND_CLOSEST(duty_ns, scaler),
	       pc->base + DUTY(pwm->hwpwm));
	writel(DIV_ROUND_CLOSEST(period_ns, scaler),
	       pc->base + PERIOD(pwm->hwpwm));

	return 0;
}

static int bcm2835_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	u32 value;

	value = readl(pc->base + PWM_CONTROL);
	value |= PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm);
	writel(value, pc->base + PWM_CONTROL);

	return 0;
}

static void bcm2835_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	u32 value;

	value = readl(pc->base + PWM_CONTROL);
	value &= ~(PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm));
	writel(value, pc->base + PWM_CONTROL);
}

static int bcm2835_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
				enum pwm_polarity polarity)
{
	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	u32 value;

	value = readl(pc->base + PWM_CONTROL);

	if (polarity == PWM_POLARITY_NORMAL)
		value &= ~(PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm));
	else
		value |= PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm);

	writel(value, pc->base + PWM_CONTROL);

	return 0;
}

static const struct pwm_ops bcm2835_pwm_ops = {
	.request = bcm2835_pwm_request,
	.free = bcm2835_pwm_free,
	.config = bcm2835_pwm_config,
	.enable = bcm2835_pwm_enable,
	.disable = bcm2835_pwm_disable,
	.set_polarity = bcm2835_set_polarity,
	.owner = THIS_MODULE,
};

static int bcm2835_pwm_probe(struct platform_device *pdev)
{
	struct bcm2835_pwm *pc;
	struct resource *res;
	int ret;

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

	pc->dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	pc->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(pc->base))
		return PTR_ERR(pc->base);

	pc->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(pc->clk)) {
		dev_err(&pdev->dev, "clock not found: %ld\n", PTR_ERR(pc->clk));
		return PTR_ERR(pc->clk);
	}

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

	pc->chip.dev = &pdev->dev;
	pc->chip.ops = &bcm2835_pwm_ops;
	pc->chip.npwm = 2;
	pc->chip.of_xlate = of_pwm_xlate_with_flags;
	pc->chip.of_pwm_n_cells = 3;

	platform_set_drvdata(pdev, pc);

	ret = pwmchip_add(&pc->chip);
	if (ret < 0)
		goto add_fail;

	return 0;

add_fail:
	clk_disable_unprepare(pc->clk);
	return ret;
}

static int bcm2835_pwm_remove(struct platform_device *pdev)
{
	struct bcm2835_pwm *pc = platform_get_drvdata(pdev);

	clk_disable_unprepare(pc->clk);

	return pwmchip_remove(&pc->chip);
}

static const struct of_device_id bcm2835_pwm_of_match[] = {
	{ .compatible = "brcm,bcm2835-pwm", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, bcm2835_pwm_of_match);

static struct platform_driver bcm2835_pwm_driver = {
	.driver = {
		.name = "bcm2835-pwm",
		.of_match_table = bcm2835_pwm_of_match,
	},
	.probe = bcm2835_pwm_probe,
	.remove = bcm2835_pwm_remove,
};
module_platform_driver(bcm2835_pwm_driver);

MODULE_AUTHOR("Bart Tanghe <bart.tanghe@thomasmore.be>");
MODULE_DESCRIPTION("Broadcom BCM2835 PWM driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
e747cbe2	1	// SPDX-License-Identifier: GPL-2.0
e5a06dc5 BT	2	/*
e5a06dc5 BT	3	* Copyright 2014 Bart Tanghe <bart.tanghe@thomasmore.be>
e5a06dc5 BT	4	*/
	5
	6	#include <linux/clk.h>
	7	#include <linux/err.h>
	8	#include <linux/io.h>
	9	#include <linux/module.h>
	10	#include <linux/of.h>
	11	#include <linux/platform_device.h>
	12	#include <linux/pwm.h>
	13
	14	#define PWM_CONTROL 0x000
	15	#define PWM_CONTROL_SHIFT(x) ((x) * 8)
	16	#define PWM_CONTROL_MASK 0xff
	17	#define PWM_MODE 0x80 /* set timer in PWM mode */
	18	#define PWM_ENABLE (1 << 0)
	19	#define PWM_POLARITY (1 << 4)
	20
	21	#define PERIOD(x) (((x) * 0x10) + 0x10)
	22	#define DUTY(x) (((x) * 0x10) + 0x14)
	23
	24	#define MIN_PERIOD 108 /* 9.2 MHz max. PWM clock */
	25
	26	struct bcm2835_pwm {
	27	struct pwm_chip chip;
	28	struct device *dev;
e5a06dc5 BT	29	void __iomem *base;
	30	struct clk *clk;
	31	};
	32
	33	static inline struct bcm2835_pwm to_bcm2835_pwm(struct pwm_chip chip)
	34	{
	35	return container_of(chip, struct bcm2835_pwm, chip);
	36	}
	37
	38	static int bcm2835_pwm_request(struct pwm_chip chip, struct pwm_device pwm)
	39	{
	40	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	41	u32 value;
	42
	43	value = readl(pc->base + PWM_CONTROL);
	44	value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm));
	45	value \|= (PWM_MODE << PWM_CONTROL_SHIFT(pwm->hwpwm));
	46	writel(value, pc->base + PWM_CONTROL);
	47
	48	return 0;
	49	}
	50
	51	static void bcm2835_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
	52	{
	53	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	54	u32 value;
	55
	56	value = readl(pc->base + PWM_CONTROL);
	57	value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm));
	58	writel(value, pc->base + PWM_CONTROL);
	59	}
	60
	61	static int bcm2835_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	62	int duty_ns, int period_ns)
	63	{
	64	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
fd13c144 SW	65	unsigned long rate = clk_get_rate(pc->clk);
	66	unsigned long scaler;
	67
	68	if (!rate) {
	69	dev_err(pc->dev, "failed to get clock rate\n");
	70	return -EINVAL;
	71	}
	72
11fc4edc	73	scaler = DIV_ROUND_CLOSEST(NSEC_PER_SEC, rate);
e5a06dc5	74
4537e52a	75	if (period_ns <= MIN_PERIOD)
e5a06dc5	76	return -EINVAL;
e5a06dc5	77
11fc4edc SY	78	writel(DIV_ROUND_CLOSEST(duty_ns, scaler),
	79	pc->base + DUTY(pwm->hwpwm));
	80	writel(DIV_ROUND_CLOSEST(period_ns, scaler),
	81	pc->base + PERIOD(pwm->hwpwm));
e5a06dc5 BT	82
	83	return 0;
	84	}
	85
	86	static int bcm2835_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	87	{
	88	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	89	u32 value;
	90
	91	value = readl(pc->base + PWM_CONTROL);
	92	value \|= PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm);
	93	writel(value, pc->base + PWM_CONTROL);
	94
	95	return 0;
	96	}
	97
	98	static void bcm2835_pwm_disable(struct pwm_chip chip, struct pwm_device pwm)
	99	{
	100	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	101	u32 value;
	102
	103	value = readl(pc->base + PWM_CONTROL);
	104	value &= ~(PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm));
	105	writel(value, pc->base + PWM_CONTROL);
	106	}
	107
	108	static int bcm2835_set_polarity(struct pwm_chip chip, struct pwm_device pwm,
	109	enum pwm_polarity polarity)
	110	{
	111	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
	112	u32 value;
	113
	114	value = readl(pc->base + PWM_CONTROL);
	115
	116	if (polarity == PWM_POLARITY_NORMAL)
	117	value &= ~(PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm));
	118	else
	119	value \|= PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm);
	120
	121	writel(value, pc->base + PWM_CONTROL);
	122
	123	return 0;
	124	}
	125
	126	static const struct pwm_ops bcm2835_pwm_ops = {
	127	.request = bcm2835_pwm_request,
	128	.free = bcm2835_pwm_free,
	129	.config = bcm2835_pwm_config,
	130	.enable = bcm2835_pwm_enable,
	131	.disable = bcm2835_pwm_disable,
	132	.set_polarity = bcm2835_set_polarity,
	133	.owner = THIS_MODULE,
	134	};
	135
	136	static int bcm2835_pwm_probe(struct platform_device *pdev)
	137	{
	138	struct bcm2835_pwm *pc;
	139	struct resource *res;
	140	int ret;
	141
	142	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
	143	if (!pc)
	144	return -ENOMEM;
	145
146	pc->dev = &pdev->dev;
147
148	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
149	pc->base = devm_ioremap_resource(&pdev->dev, res);
150	if (IS_ERR(pc->base))
151	return PTR_ERR(pc->base);
152
153	pc->clk = devm_clk_get(&pdev->dev, NULL);
154	if (IS_ERR(pc->clk)) {
155	dev_err(&pdev->dev, "clock not found: %ld\n", PTR_ERR(pc->clk));
156	return PTR_ERR(pc->clk);
157	}
158
159	ret = clk_prepare_enable(pc->clk);
160	if (ret)
161	return ret;
162
e5a06dc5 BT	163	pc->chip.dev = &pdev->dev;
	164	pc->chip.ops = &bcm2835_pwm_ops;
	165	pc->chip.npwm = 2;
8a88b2a2 SW	166	pc->chip.of_xlate = of_pwm_xlate_with_flags;
8a88b2a2 SW	167	pc->chip.of_pwm_n_cells = 3;
e5a06dc5 BT	168
	169	platform_set_drvdata(pdev, pc);
	170
	171	ret = pwmchip_add(&pc->chip);
	172	if (ret < 0)
	173	goto add_fail;
	174
	175	return 0;
	176
	177	add_fail:
	178	clk_disable_unprepare(pc->clk);
	179	return ret;
	180	}
	181
	182	static int bcm2835_pwm_remove(struct platform_device *pdev)
	183	{
	184	struct bcm2835_pwm *pc = platform_get_drvdata(pdev);
	185
	186	clk_disable_unprepare(pc->clk);
	187
	188	return pwmchip_remove(&pc->chip);
	189	}
	190
	191	static const struct of_device_id bcm2835_pwm_of_match[] = {
	192	{ .compatible = "brcm,bcm2835-pwm", },
	193	{ /* sentinel */ }
	194	};
	195	MODULE_DEVICE_TABLE(of, bcm2835_pwm_of_match);
	196
	197	static struct platform_driver bcm2835_pwm_driver = {
	198	.driver = {
	199	.name = "bcm2835-pwm",
	200	.of_match_table = bcm2835_pwm_of_match,
	201	},
	202	.probe = bcm2835_pwm_probe,
	203	.remove = bcm2835_pwm_remove,
	204	};
	205	module_platform_driver(bcm2835_pwm_driver);
	206
6ef7d1c4	207	MODULE_AUTHOR("Bart Tanghe <bart.tanghe@thomasmore.be>");
e5a06dc5 BT	208	MODULE_DESCRIPTION("Broadcom BCM2835 PWM driver");
e5a06dc5 BT	209	MODULE_LICENSE("GPL v2");