[go: nahoru, domu]
1/*
2 * Cirrus Logic CLPS711X PWM driver
3 *
4 * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
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 as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 */
11
12#include <linux/clk.h>
13#include <linux/io.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/platform_device.h>
17#include <linux/pwm.h>
18
19struct clps711x_chip {
20	struct pwm_chip chip;
21	void __iomem *pmpcon;
22	struct clk *clk;
23	spinlock_t lock;
24};
25
26static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
27{
28	return container_of(chip, struct clps711x_chip, chip);
29}
30
31static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
32{
33	/* PWM0 - bits 4..7, PWM1 - bits 8..11 */
34	u32 shift = (n + 1) * 4;
35	unsigned long flags;
36	u32 tmp;
37
38	spin_lock_irqsave(&priv->lock, flags);
39
40	tmp = readl(priv->pmpcon);
41	tmp &= ~(0xf << shift);
42	tmp |= v << shift;
43	writel(tmp, priv->pmpcon);
44
45	spin_unlock_irqrestore(&priv->lock, flags);
46}
47
48static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
49{
50	/* Duty cycle 0..15 max */
51	return DIV_ROUND_CLOSEST(v * 0xf, pwm_get_period(pwm));
52}
53
54static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
55{
56	struct clps711x_chip *priv = to_clps711x_chip(chip);
57	unsigned int freq = clk_get_rate(priv->clk);
58
59	if (!freq)
60		return -EINVAL;
61
62	/* Store constant period value */
63	pwm_set_period(pwm, DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq));
64
65	return 0;
66}
67
68static int clps711x_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
69			       int duty_ns, int period_ns)
70{
71	struct clps711x_chip *priv = to_clps711x_chip(chip);
72	unsigned int duty;
73
74	if (period_ns != pwm_get_period(pwm))
75		return -EINVAL;
76
77	duty = clps711x_get_duty(pwm, duty_ns);
78	clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
79
80	return 0;
81}
82
83static int clps711x_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
84{
85	struct clps711x_chip *priv = to_clps711x_chip(chip);
86	unsigned int duty;
87
88	duty = clps711x_get_duty(pwm, pwm_get_duty_cycle(pwm));
89	clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
90
91	return 0;
92}
93
94static void clps711x_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
95{
96	struct clps711x_chip *priv = to_clps711x_chip(chip);
97
98	clps711x_pwm_update_val(priv, pwm->hwpwm, 0);
99}
100
101static const struct pwm_ops clps711x_pwm_ops = {
102	.request = clps711x_pwm_request,
103	.config = clps711x_pwm_config,
104	.enable = clps711x_pwm_enable,
105	.disable = clps711x_pwm_disable,
106	.owner = THIS_MODULE,
107};
108
109static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip,
110					     const struct of_phandle_args *args)
111{
112	if (args->args[0] >= chip->npwm)
113		return ERR_PTR(-EINVAL);
114
115	return pwm_request_from_chip(chip, args->args[0], NULL);
116}
117
118static int clps711x_pwm_probe(struct platform_device *pdev)
119{
120	struct clps711x_chip *priv;
121	struct resource *res;
122
123	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
124	if (!priv)
125		return -ENOMEM;
126
127	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
128	priv->pmpcon = devm_ioremap_resource(&pdev->dev, res);
129	if (IS_ERR(priv->pmpcon))
130		return PTR_ERR(priv->pmpcon);
131
132	priv->clk = devm_clk_get(&pdev->dev, NULL);
133	if (IS_ERR(priv->clk))
134		return PTR_ERR(priv->clk);
135
136	priv->chip.ops = &clps711x_pwm_ops;
137	priv->chip.dev = &pdev->dev;
138	priv->chip.base = -1;
139	priv->chip.npwm = 2;
140	priv->chip.of_xlate = clps711x_pwm_xlate;
141	priv->chip.of_pwm_n_cells = 1;
142
143	spin_lock_init(&priv->lock);
144
145	platform_set_drvdata(pdev, priv);
146
147	return pwmchip_add(&priv->chip);
148}
149
150static int clps711x_pwm_remove(struct platform_device *pdev)
151{
152	struct clps711x_chip *priv = platform_get_drvdata(pdev);
153
154	return pwmchip_remove(&priv->chip);
155}
156
157static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
158	{ .compatible = "cirrus,clps711x-pwm", },
159	{ }
160};
161MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
162
163static struct platform_driver clps711x_pwm_driver = {
164	.driver = {
165		.name = "clps711x-pwm",
166		.owner = THIS_MODULE,
167		.of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
168	},
169	.probe = clps711x_pwm_probe,
170	.remove = clps711x_pwm_remove,
171};
172module_platform_driver(clps711x_pwm_driver);
173
174MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
175MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
176MODULE_LICENSE("GPL");
177