[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/of_device.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;
	struct pwm_chip chip;
};

#define to_pwm_imx1_chip(chip)	container_of(chip, struct pwm_imx1_chip, 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, int duty_ns, int 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 = 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 const struct pwm_ops pwm_imx1_ops = {
	.enable = pwm_imx1_enable,
	.disable = pwm_imx1_disable,
	.config = pwm_imx1_config,
	.owner = THIS_MODULE,
};

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_imx1_chip *imx;
	struct resource *r;

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

	platform_set_drvdata(pdev, imx);

	imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
	if (IS_ERR(imx->clk_ipg)) {
		dev_err(&pdev->dev, "getting ipg clock failed with %ld\n",
				PTR_ERR(imx->clk_ipg));
		return PTR_ERR(imx->clk_ipg);
	}

	imx->clk_per = devm_clk_get(&pdev->dev, "per");
	if (IS_ERR(imx->clk_per)) {
		int ret = PTR_ERR(imx->clk_per);

		if (ret != -EPROBE_DEFER)
			dev_err(&pdev->dev,
				"failed to get peripheral clock: %d\n",
				ret);

		return ret;
	}

	imx->chip.ops = &pwm_imx1_ops;
	imx->chip.dev = &pdev->dev;
	imx->chip.base = -1;
	imx->chip.npwm = 1;

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

	return pwmchip_add(&imx->chip);
}

static int pwm_imx1_remove(struct platform_device *pdev)
{
	struct pwm_imx1_chip *imx = platform_get_drvdata(pdev);

	pwm_imx1_clk_disable_unprepare(&imx->chip);

	return pwmchip_remove(&imx->chip);
}

static struct platform_driver pwm_imx1_driver = {
	.driver = {
		.name = "pwm-imx1",
		.of_match_table = pwm_imx1_dt_ids,
	},
	.probe = pwm_imx1_probe,
	.remove = pwm_imx1_remove,
};
module_platform_driver(pwm_imx1_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>
	17	#include <linux/of_device.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/pwm.h>
	20	#include <linux/slab.h>
	21
	22	#define MX1_PWMC 0x00 /* PWM Control Register */
	23	#define MX1_PWMS 0x04 /* PWM Sample Register */
	24	#define MX1_PWMP 0x08 /* PWM Period Register */
	25
	26	#define MX1_PWMC_EN BIT(4)
	27
	28	struct pwm_imx1_chip {
	29	struct clk *clk_ipg;
	30	struct clk *clk_per;
	31	void __iomem *mmio_base;
	32	struct pwm_chip chip;
	33	};
	34
	35	#define to_pwm_imx1_chip(chip) container_of(chip, struct pwm_imx1_chip, chip)
	36
	37	static int pwm_imx1_clk_prepare_enable(struct pwm_chip *chip)
	38	{
	39	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	40	int ret;
	41
	42	ret = clk_prepare_enable(imx->clk_ipg);
	43	if (ret)
	44	return ret;
	45
	46	ret = clk_prepare_enable(imx->clk_per);
	47	if (ret) {
	48	clk_disable_unprepare(imx->clk_ipg);
	49	return ret;
	50	}
	51
	52	return 0;
	53	}
	54
	55	static void pwm_imx1_clk_disable_unprepare(struct pwm_chip *chip)
	56	{
	57	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
	58
	59	clk_disable_unprepare(imx->clk_per);
	60	clk_disable_unprepare(imx->clk_ipg);
	61	}
	62
	63	static int pwm_imx1_config(struct pwm_chip *chip,
	64	struct pwm_device *pwm, int duty_ns, int period_ns)
65	{
66	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
67	u32 max, p;
68
69	/*
70	* The PWM subsystem allows for exact frequencies. However,
71	* I cannot connect a scope on my device to the PWM line and
72	* thus cannot provide the program the PWM controller
73	* exactly. Instead, I'm relying on the fact that the
74	* Bootloader (u-boot or WinCE+haret) has programmed the PWM
75	* function group already. So I'll just modify the PWM sample
76	* register to follow the ratio of duty_ns vs. period_ns
77	* accordingly.
78	*
79	* This is good enough for programming the brightness of
80	* the LCD backlight.
81	*
82	* The real implementation would divide PERCLK[0] first by
83	* both the prescaler (/1 .. /128) and then by CLKSEL
84	* (/2 .. /16).
85	*/
86	max = readl(imx->mmio_base + MX1_PWMP);
87	p = max * duty_ns / period_ns;
88
89	writel(max - p, imx->mmio_base + MX1_PWMS);
90
91	return 0;
92	}
93
94	static int pwm_imx1_enable(struct pwm_chip chip, struct pwm_device pwm)
95	{
96	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
97	u32 value;
98	int ret;
99
100	ret = pwm_imx1_clk_prepare_enable(chip);
101	if (ret < 0)
102	return ret;
103
104	value = readl(imx->mmio_base + MX1_PWMC);
105	value \|= MX1_PWMC_EN;
106	writel(value, imx->mmio_base + MX1_PWMC);
107
108	return 0;
109	}
110
111	static void pwm_imx1_disable(struct pwm_chip chip, struct pwm_device pwm)
112	{
113	struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
114	u32 value;
115
116	value = readl(imx->mmio_base + MX1_PWMC);
117	value &= ~MX1_PWMC_EN;
118	writel(value, imx->mmio_base + MX1_PWMC);
119
120	pwm_imx1_clk_disable_unprepare(chip);
121	}
122
123	static const struct pwm_ops pwm_imx1_ops = {
124	.enable = pwm_imx1_enable,
125	.disable = pwm_imx1_disable,
126	.config = pwm_imx1_config,
127	.owner = THIS_MODULE,
128	};
129
130	static const struct of_device_id pwm_imx1_dt_ids[] = {
131	{ .compatible = "fsl,imx1-pwm", },
132	{ /* sentinel */ }
133	};
134	MODULE_DEVICE_TABLE(of, pwm_imx1_dt_ids);
135
136	static int pwm_imx1_probe(struct platform_device *pdev)
137	{
138	struct pwm_imx1_chip *imx;
139	struct resource *r;
140
141	imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
142	if (!imx)
143	return -ENOMEM;
144
145	platform_set_drvdata(pdev, imx);
146
147	imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
148	if (IS_ERR(imx->clk_ipg)) {
149	dev_err(&pdev->dev, "getting ipg clock failed with %ld\n",
150	PTR_ERR(imx->clk_ipg));
151	return PTR_ERR(imx->clk_ipg);
152	}
153
154	imx->clk_per = devm_clk_get(&pdev->dev, "per");
155	if (IS_ERR(imx->clk_per)) {
156	int ret = PTR_ERR(imx->clk_per);
157
158	if (ret != -EPROBE_DEFER)
159	dev_err(&pdev->dev,
160	"failed to get peripheral clock: %d\n",
161	ret);
162
163	return ret;
164	}
165
166	imx->chip.ops = &pwm_imx1_ops;
167	imx->chip.dev = &pdev->dev;
168	imx->chip.base = -1;
169	imx->chip.npwm = 1;
170
171	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
172	imx->mmio_base = devm_ioremap_resource(&pdev->dev, r);
173	if (IS_ERR(imx->mmio_base))
174	return PTR_ERR(imx->mmio_base);
175
176	return pwmchip_add(&imx->chip);
177	}
178
179	static int pwm_imx1_remove(struct platform_device *pdev)
180	{
181	struct pwm_imx1_chip *imx = platform_get_drvdata(pdev);
182
183	pwm_imx1_clk_disable_unprepare(&imx->chip);
184
185	return pwmchip_remove(&imx->chip);
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,
194	.remove = pwm_imx1_remove,
195	};
196	module_platform_driver(pwm_imx1_driver);
197
198	MODULE_LICENSE("GPL v2");
199	MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");