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 	struct pwm_chip chip;
16 	void __iomem *pmpcon;
17 	struct clk *clk;
18 	spinlock_t lock;
19 };
20 
to_clps711x_chip(struct pwm_chip * chip)21 static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
22 {
23 	return container_of(chip, struct clps711x_chip, chip);
24 }
25 
clps711x_pwm_update_val(struct clps711x_chip * priv,u32 n,u32 v)26 static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
27 {
28 	/* PWM0 - bits 4..7, PWM1 - bits 8..11 */
29 	u32 shift = (n + 1) * 4;
30 	unsigned long flags;
31 	u32 tmp;
32 
33 	spin_lock_irqsave(&priv->lock, flags);
34 
35 	tmp = readl(priv->pmpcon);
36 	tmp &= ~(0xf << shift);
37 	tmp |= v << shift;
38 	writel(tmp, priv->pmpcon);
39 
40 	spin_unlock_irqrestore(&priv->lock, flags);
41 }
42 
clps711x_get_duty(struct pwm_device * pwm,unsigned int v)43 static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
44 {
45 	/* Duty cycle 0..15 max */
46 	return DIV64_U64_ROUND_CLOSEST(v * 0xf, pwm->args.period);
47 }
48 
clps711x_pwm_request(struct pwm_chip * chip,struct pwm_device * pwm)49 static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
50 {
51 	struct clps711x_chip *priv = to_clps711x_chip(chip);
52 	unsigned int freq = clk_get_rate(priv->clk);
53 
54 	if (!freq)
55 		return -EINVAL;
56 
57 	/* Store constant period value */
58 	pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
59 
60 	return 0;
61 }
62 
clps711x_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)63 static int clps711x_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
64 			       int duty_ns, int period_ns)
65 {
66 	struct clps711x_chip *priv = to_clps711x_chip(chip);
67 	unsigned int duty;
68 
69 	if (period_ns != pwm->args.period)
70 		return -EINVAL;
71 
72 	duty = clps711x_get_duty(pwm, duty_ns);
73 	clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
74 
75 	return 0;
76 }
77 
clps711x_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)78 static int clps711x_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
79 {
80 	struct clps711x_chip *priv = to_clps711x_chip(chip);
81 	unsigned int duty;
82 
83 	duty = clps711x_get_duty(pwm, pwm_get_duty_cycle(pwm));
84 	clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
85 
86 	return 0;
87 }
88 
clps711x_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)89 static void clps711x_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
90 {
91 	struct clps711x_chip *priv = to_clps711x_chip(chip);
92 
93 	clps711x_pwm_update_val(priv, pwm->hwpwm, 0);
94 }
95 
96 static const struct pwm_ops clps711x_pwm_ops = {
97 	.request = clps711x_pwm_request,
98 	.config = clps711x_pwm_config,
99 	.enable = clps711x_pwm_enable,
100 	.disable = clps711x_pwm_disable,
101 	.owner = THIS_MODULE,
102 };
103 
clps711x_pwm_xlate(struct pwm_chip * chip,const struct of_phandle_args * args)104 static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip,
105 					     const struct of_phandle_args *args)
106 {
107 	if (args->args[0] >= chip->npwm)
108 		return ERR_PTR(-EINVAL);
109 
110 	return pwm_request_from_chip(chip, args->args[0], NULL);
111 }
112 
clps711x_pwm_probe(struct platform_device * pdev)113 static int clps711x_pwm_probe(struct platform_device *pdev)
114 {
115 	struct clps711x_chip *priv;
116 
117 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
118 	if (!priv)
119 		return -ENOMEM;
120 
121 	priv->pmpcon = devm_platform_ioremap_resource(pdev, 0);
122 	if (IS_ERR(priv->pmpcon))
123 		return PTR_ERR(priv->pmpcon);
124 
125 	priv->clk = devm_clk_get(&pdev->dev, NULL);
126 	if (IS_ERR(priv->clk))
127 		return PTR_ERR(priv->clk);
128 
129 	priv->chip.ops = &clps711x_pwm_ops;
130 	priv->chip.dev = &pdev->dev;
131 	priv->chip.npwm = 2;
132 	priv->chip.of_xlate = clps711x_pwm_xlate;
133 	priv->chip.of_pwm_n_cells = 1;
134 
135 	spin_lock_init(&priv->lock);
136 
137 	return devm_pwmchip_add(&pdev->dev, &priv->chip);
138 }
139 
140 static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
141 	{ .compatible = "cirrus,ep7209-pwm", },
142 	{ }
143 };
144 MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
145 
146 static struct platform_driver clps711x_pwm_driver = {
147 	.driver = {
148 		.name = "clps711x-pwm",
149 		.of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
150 	},
151 	.probe = clps711x_pwm_probe,
152 };
153 module_platform_driver(clps711x_pwm_driver);
154 
155 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
156 MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
157 MODULE_LICENSE("GPL");
158