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