[linux-2.6-block.git] / drivers / pwm / pwm-imx1.c

// SPDX-License-Identifier: GPL-2.0
/*
 * simple driver for PWM (Pulse Width Modulator) controller
 *
 * Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
 */

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

#define MX1_PWMC			0x00   /* PWM Control Register */
#define MX1_PWMS			0x04   /* PWM Sample Register */
#define MX1_PWMP			0x08   /* PWM Period Register */

#define MX1_PWMC_EN			BIT(4)

struct pwm_imx1_chip {
	struct clk *clk_ipg;
	struct clk *clk_per;
	void __iomem *mmio_base;
};

static inline struct pwm_imx1_chip *to_pwm_imx1_chip(struct pwm_chip *chip)
{
	return pwmchip_get_drvdata(chip);
}

static int pwm_imx1_clk_prepare_enable(struct pwm_chip *chip)
{
	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	int ret;

	ret = clk_prepare_enable(imx->clk_ipg);
	if (ret)
		return ret;

	ret = clk_prepare_enable(imx->clk_per);
	if (ret) {
		clk_disable_unprepare(imx->clk_ipg);
		return ret;
	}

	return 0;
}

static void pwm_imx1_clk_disable_unprepare(struct pwm_chip *chip)
{
	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);

	clk_disable_unprepare(imx->clk_per);
	clk_disable_unprepare(imx->clk_ipg);
}

static int pwm_imx1_config(struct pwm_chip *chip,
			   struct pwm_device *pwm, u64 duty_ns, u64 period_ns)
{
	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	u32 max, p;

	/*
	 * The PWM subsystem allows for exact frequencies. However,
	 * I cannot connect a scope on my device to the PWM line and
	 * thus cannot provide the program the PWM controller
	 * exactly. Instead, I'm relying on the fact that the
	 * Bootloader (u-boot or WinCE+haret) has programmed the PWM
	 * function group already. So I'll just modify the PWM sample
	 * register to follow the ratio of duty_ns vs. period_ns
	 * accordingly.
	 *
	 * This is good enough for programming the brightness of
	 * the LCD backlight.
	 *
	 * The real implementation would divide PERCLK[0] first by
	 * both the prescaler (/1 .. /128) and then by CLKSEL
	 * (/2 .. /16).
	 */
	max = readl(imx->mmio_base + MX1_PWMP);
	p = mul_u64_u64_div_u64(max, duty_ns, period_ns);

	writel(max - p, imx->mmio_base + MX1_PWMS);

	return 0;
}

static int pwm_imx1_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	u32 value;
	int ret;

	ret = pwm_imx1_clk_prepare_enable(chip);
	if (ret < 0)
		return ret;

	value = readl(imx->mmio_base + MX1_PWMC);
	value |= MX1_PWMC_EN;
	writel(value, imx->mmio_base + MX1_PWMC);

	return 0;
}

static void pwm_imx1_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	u32 value;

	value = readl(imx->mmio_base + MX1_PWMC);
	value &= ~MX1_PWMC_EN;
	writel(value, imx->mmio_base + MX1_PWMC);

	pwm_imx1_clk_disable_unprepare(chip);
}

static int pwm_imx1_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)
			pwm_imx1_disable(chip, pwm);

		return 0;
	}

	err = pwm_imx1_config(chip, pwm, state->duty_cycle, state->period);
	if (err)
		return err;

	if (!pwm->state.enabled)
		return pwm_imx1_enable(chip, pwm);

	return 0;
}

static const struct pwm_ops pwm_imx1_ops = {
	.apply = pwm_imx1_apply,
};

static const struct of_device_id pwm_imx1_dt_ids[] = {
	{ .compatible = "fsl,imx1-pwm", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pwm_imx1_dt_ids);

static int pwm_imx1_probe(struct platform_device *pdev)
{
	struct pwm_chip *chip;
	struct pwm_imx1_chip *imx;

	chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*imx));
	if (IS_ERR(chip))
		return PTR_ERR(chip);
	imx = to_pwm_imx1_chip(chip);

	imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
	if (IS_ERR(imx->clk_ipg))
		return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_ipg),
				     "getting ipg clock failed\n");

	imx->clk_per = devm_clk_get(&pdev->dev, "per");
	if (IS_ERR(imx->clk_per))
		return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_per),
				     "failed to get peripheral clock\n");

	chip->ops = &pwm_imx1_ops;

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

	return devm_pwmchip_add(&pdev->dev, chip);
}

static struct platform_driver pwm_imx1_driver = {
	.driver = {
		.name = "pwm-imx1",
		.of_match_table = pwm_imx1_dt_ids,
	},
	.probe = pwm_imx1_probe,
};
module_platform_driver(pwm_imx1_driver);

MODULE_DESCRIPTION("i.MX1 and i.MX21 Pulse Width Modulator driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
Commit	Line	Data
d80f8206 UKK	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* simple driver for PWM (Pulse Width Modulator) controller
	4	*
	5	* Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
	6	*/
	7
	8	#include <linux/bitfield.h>
	9	#include <linux/bitops.h>
	10	#include <linux/clk.h>
	11	#include <linux/delay.h>
	12	#include <linux/err.h>
	13	#include <linux/io.h>
	14	#include <linux/kernel.h>
	15	#include <linux/module.h>
	16	#include <linux/of.h>
d80f8206 UKK	17	#include <linux/platform_device.h>
	18	#include <linux/pwm.h>
	19	#include <linux/slab.h>
	20
	21	#define MX1_PWMC 0x00 /* PWM Control Register */
	22	#define MX1_PWMS 0x04 /* PWM Sample Register */
	23	#define MX1_PWMP 0x08 /* PWM Period Register */
	24
	25	#define MX1_PWMC_EN BIT(4)
	26
	27	struct pwm_imx1_chip {
	28	struct clk *clk_ipg;
	29	struct clk *clk_per;
	30	void __iomem *mmio_base;
d80f8206 UKK	31	};
d80f8206 UKK	32
5911fc37 UKK	33	static inline struct pwm_imx1_chip to_pwm_imx1_chip(struct pwm_chip chip)
	34	{
	35	return pwmchip_get_drvdata(chip);
	36	}
d80f8206 UKK	37
	38	static int pwm_imx1_clk_prepare_enable(struct pwm_chip *chip)
	39	{
	40	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	41	int ret;
	42
	43	ret = clk_prepare_enable(imx->clk_ipg);
	44	if (ret)
	45	return ret;
	46
	47	ret = clk_prepare_enable(imx->clk_per);
	48	if (ret) {
	49	clk_disable_unprepare(imx->clk_ipg);
	50	return ret;
	51	}
	52
	53	return 0;
	54	}
	55
	56	static void pwm_imx1_clk_disable_unprepare(struct pwm_chip *chip)
	57	{
	58	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	59
	60	clk_disable_unprepare(imx->clk_per);
	61	clk_disable_unprepare(imx->clk_ipg);
	62	}
	63
	64	static int pwm_imx1_config(struct pwm_chip *chip,
b23fd25e	65	struct pwm_device *pwm, u64 duty_ns, u64 period_ns)
d80f8206 UKK	66	{
	67	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	68	u32 max, p;
	69
	70	/*
	71	* The PWM subsystem allows for exact frequencies. However,
	72	* I cannot connect a scope on my device to the PWM line and
	73	* thus cannot provide the program the PWM controller
	74	* exactly. Instead, I'm relying on the fact that the
	75	* Bootloader (u-boot or WinCE+haret) has programmed the PWM
	76	* function group already. So I'll just modify the PWM sample
	77	* register to follow the ratio of duty_ns vs. period_ns
	78	* accordingly.
	79	*
	80	* This is good enough for programming the brightness of
	81	* the LCD backlight.
	82	*
	83	* The real implementation would divide PERCLK[0] first by
	84	* both the prescaler (/1 .. /128) and then by CLKSEL
	85	* (/2 .. /16).
	86	*/
	87	max = readl(imx->mmio_base + MX1_PWMP);
b23fd25e	88	p = mul_u64_u64_div_u64(max, duty_ns, period_ns);
d80f8206 UKK	89
	90	writel(max - p, imx->mmio_base + MX1_PWMS);
	91
	92	return 0;
	93	}
	94
	95	static int pwm_imx1_enable(struct pwm_chip chip, struct pwm_device pwm)
	96	{
	97	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	98	u32 value;
	99	int ret;
	100
	101	ret = pwm_imx1_clk_prepare_enable(chip);
	102	if (ret < 0)
	103	return ret;
	104
	105	value = readl(imx->mmio_base + MX1_PWMC);
	106	value \|= MX1_PWMC_EN;
	107	writel(value, imx->mmio_base + MX1_PWMC);
	108
	109	return 0;
	110	}
	111
	112	static void pwm_imx1_disable(struct pwm_chip chip, struct pwm_device pwm)
	113	{
	114	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	115	u32 value;
	116
	117	value = readl(imx->mmio_base + MX1_PWMC);
	118	value &= ~MX1_PWMC_EN;
	119	writel(value, imx->mmio_base + MX1_PWMC);
	120
	121	pwm_imx1_clk_disable_unprepare(chip);
	122	}
	123
b23fd25e UKK	124	static int pwm_imx1_apply(struct pwm_chip chip, struct pwm_device pwm,
	125	const struct pwm_state *state)
	126	{
	127	int err;
	128
	129	if (state->polarity != PWM_POLARITY_NORMAL)
	130	return -EINVAL;
	131
	132	if (!state->enabled) {
	133	if (pwm->state.enabled)
	134	pwm_imx1_disable(chip, pwm);
	135
	136	return 0;
	137	}
	138
	139	err = pwm_imx1_config(chip, pwm, state->duty_cycle, state->period);
	140	if (err)
	141	return err;
	142
	143	if (!pwm->state.enabled)
	144	return pwm_imx1_enable(chip, pwm);
	145
	146	return 0;
	147	}
	148
d80f8206	149	static const struct pwm_ops pwm_imx1_ops = {
b23fd25e	150	.apply = pwm_imx1_apply,
d80f8206 UKK	151	};
	152
	153	static const struct of_device_id pwm_imx1_dt_ids[] = {
	154	{ .compatible = "fsl,imx1-pwm", },
	155	{ /* sentinel */ }
	156	};
	157	MODULE_DEVICE_TABLE(of, pwm_imx1_dt_ids);
	158
	159	static int pwm_imx1_probe(struct platform_device *pdev)
	160	{
5911fc37	161	struct pwm_chip *chip;
d80f8206	162	struct pwm_imx1_chip *imx;
d80f8206	163
5911fc37 UKK	164	chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*imx));
	165	if (IS_ERR(chip))
	166	return PTR_ERR(chip);
	167	imx = to_pwm_imx1_chip(chip);
d80f8206	168
d80f8206	169	imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
f1332e92 AH	170	if (IS_ERR(imx->clk_ipg))
	171	return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_ipg),
	172	"getting ipg clock failed\n");
d80f8206 UKK	173
d80f8206 UKK	174	imx->clk_per = devm_clk_get(&pdev->dev, "per");
f1332e92 AH	175	if (IS_ERR(imx->clk_per))
	176	return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_per),
	177	"failed to get peripheral clock\n");
d80f8206	178
5911fc37	179	chip->ops = &pwm_imx1_ops;
d80f8206	180
860b1ca0	181	imx->mmio_base = devm_platform_ioremap_resource(pdev, 0);
d80f8206 UKK	182	if (IS_ERR(imx->mmio_base))
	183	return PTR_ERR(imx->mmio_base);
	184
5911fc37	185	return devm_pwmchip_add(&pdev->dev, chip);
d80f8206 UKK	186	}
	187
	188	static struct platform_driver pwm_imx1_driver = {
	189	.driver = {
	190	.name = "pwm-imx1",
	191	.of_match_table = pwm_imx1_dt_ids,
	192	},
	193	.probe = pwm_imx1_probe,
d80f8206 UKK	194	};
	195	module_platform_driver(pwm_imx1_driver);
	196
2c69747c	197	MODULE_DESCRIPTION("i.MX1 and i.MX21 Pulse Width Modulator driver");
d80f8206 UKK	198	MODULE_LICENSE("GPL v2");
d80f8206 UKK	199	MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");