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