GNU Linux-libre 4.9.328-gnu1
[releases.git] / drivers / pwm / pwm-clps711x.c
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
19 struct clps711x_chip {
20         struct pwm_chip chip;
21         void __iomem *pmpcon;
22         struct clk *clk;
23         spinlock_t lock;
24 };
25
26 static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
27 {
28         return container_of(chip, struct clps711x_chip, chip);
29 }
30
31 static 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
48 static 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->args.period);
52 }
53
54 static 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->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
64
65         return 0;
66 }
67
68 static 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->args.period)
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
83 static 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
94 static 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
101 static 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
109 static 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
118 static 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
150 static 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
157 static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
158         { .compatible = "cirrus,ep7209-pwm", },
159         { }
160 };
161 MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
162
163 static struct platform_driver clps711x_pwm_driver = {
164         .driver = {
165                 .name = "clps711x-pwm",
166                 .of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
167         },
168         .probe = clps711x_pwm_probe,
169         .remove = clps711x_pwm_remove,
170 };
171 module_platform_driver(clps711x_pwm_driver);
172
173 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
174 MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
175 MODULE_LICENSE("GPL");