tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Cirrus Logic CLPS711X PWM driver
4 * Author: Alexander Shiyan <shc_work@mail.ru>
5 */
6
7#include <linux/clk.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
14struct clps711x_chip {
15 struct pwm_chip chip;
16 void __iomem *pmpcon;
17 struct clk *clk;
18 spinlock_t lock;
19};
20
21static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
22{
23 return container_of(chip, struct clps711x_chip, chip);
24}
25
26static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
27{
28 struct clps711x_chip *priv = to_clps711x_chip(chip);
29 unsigned int freq = clk_get_rate(priv->clk);
30
31 if (!freq)
32 return -EINVAL;
33
34 /* Store constant period value */
35 pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
36
37 return 0;
38}
39
40static int clps711x_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
41 const struct pwm_state *state)
42{
43 struct clps711x_chip *priv = to_clps711x_chip(chip);
44 /* PWM0 - bits 4..7, PWM1 - bits 8..11 */
45 u32 shift = (pwm->hwpwm + 1) * 4;
46 unsigned long flags;
47 u32 pmpcon, val;
48
49 if (state->polarity != PWM_POLARITY_NORMAL)
50 return -EINVAL;
51
52 if (state->period != pwm->args.period)
53 return -EINVAL;
54
55 if (state->enabled)
56 val = mul_u64_u64_div_u64(state->duty_cycle, 0xf, state->period);
57 else
58 val = 0;
59
60 spin_lock_irqsave(&priv->lock, flags);
61
62 pmpcon = readl(priv->pmpcon);
63 pmpcon &= ~(0xf << shift);
64 pmpcon |= val << shift;
65 writel(pmpcon, priv->pmpcon);
66
67 spin_unlock_irqrestore(&priv->lock, flags);
68
69 return 0;
70}
71
72static const struct pwm_ops clps711x_pwm_ops = {
73 .request = clps711x_pwm_request,
74 .apply = clps711x_pwm_apply,
75};
76
77static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip,
78 const struct of_phandle_args *args)
79{
80 if (args->args[0] >= chip->npwm)
81 return ERR_PTR(-EINVAL);
82
83 return pwm_request_from_chip(chip, args->args[0], NULL);
84}
85
86static int clps711x_pwm_probe(struct platform_device *pdev)
87{
88 struct clps711x_chip *priv;
89
90 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
91 if (!priv)
92 return -ENOMEM;
93
94 priv->pmpcon = devm_platform_ioremap_resource(pdev, 0);
95 if (IS_ERR(priv->pmpcon))
96 return PTR_ERR(priv->pmpcon);
97
98 priv->clk = devm_clk_get(&pdev->dev, NULL);
99 if (IS_ERR(priv->clk))
100 return PTR_ERR(priv->clk);
101
102 priv->chip.ops = &clps711x_pwm_ops;
103 priv->chip.dev = &pdev->dev;
104 priv->chip.npwm = 2;
105 priv->chip.of_xlate = clps711x_pwm_xlate;
106 priv->chip.of_pwm_n_cells = 1;
107
108 spin_lock_init(&priv->lock);
109
110 return devm_pwmchip_add(&pdev->dev, &priv->chip);
111}
112
113static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
114 { .compatible = "cirrus,ep7209-pwm", },
115 { }
116};
117MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
118
119static struct platform_driver clps711x_pwm_driver = {
120 .driver = {
121 .name = "clps711x-pwm",
122 .of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
123 },
124 .probe = clps711x_pwm_probe,
125};
126module_platform_driver(clps711x_pwm_driver);
127
128MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
129MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
130MODULE_LICENSE("GPL");