1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) ST-Ericsson SA 2010
4  *
5  * Author: Arun R Murthy <arun.murthy@stericsson.com>
6  */
7 #include <linux/err.h>
8 #include <linux/platform_device.h>
9 #include <linux/slab.h>
10 #include <linux/pwm.h>
11 #include <linux/mfd/abx500.h>
12 #include <linux/mfd/abx500/ab8500.h>
13 #include <linux/module.h>
14 
15 /*
16  * PWM Out generators
17  * Bank: 0x10
18  */
19 #define AB8500_PWM_OUT_CTRL1_REG	0x60
20 #define AB8500_PWM_OUT_CTRL2_REG	0x61
21 #define AB8500_PWM_OUT_CTRL7_REG	0x66
22 
23 struct ab8500_pwm_chip {
24 	struct pwm_chip chip;
25 	unsigned int hwid;
26 };
27 
ab8500_pwm_from_chip(struct pwm_chip * chip)28 static struct ab8500_pwm_chip *ab8500_pwm_from_chip(struct pwm_chip *chip)
29 {
30 	return container_of(chip, struct ab8500_pwm_chip, chip);
31 }
32 
ab8500_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)33 static int ab8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
34 			    const struct pwm_state *state)
35 {
36 	int ret;
37 	u8 reg;
38 	unsigned int higher_val, lower_val;
39 	struct ab8500_pwm_chip *ab8500 = ab8500_pwm_from_chip(chip);
40 
41 	if (state->polarity != PWM_POLARITY_NORMAL)
42 		return -EINVAL;
43 
44 	if (!state->enabled) {
45 		ret = abx500_mask_and_set_register_interruptible(chip->dev,
46 					AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
47 					1 << ab8500->hwid, 0);
48 
49 		if (ret < 0)
50 			dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
51 								pwm->label, ret);
52 		return ret;
53 	}
54 
55 	/*
56 	 * get the first 8 bits that are be written to
57 	 * AB8500_PWM_OUT_CTRL1_REG[0:7]
58 	 */
59 	lower_val = state->duty_cycle & 0x00FF;
60 	/*
61 	 * get bits [9:10] that are to be written to
62 	 * AB8500_PWM_OUT_CTRL2_REG[0:1]
63 	 */
64 	higher_val = ((state->duty_cycle & 0x0300) >> 8);
65 
66 	reg = AB8500_PWM_OUT_CTRL1_REG + (ab8500->hwid * 2);
67 
68 	ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
69 			reg, (u8)lower_val);
70 	if (ret < 0)
71 		return ret;
72 
73 	ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
74 			(reg + 1), (u8)higher_val);
75 	if (ret < 0)
76 		return ret;
77 
78 	ret = abx500_mask_and_set_register_interruptible(chip->dev,
79 				AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
80 				1 << ab8500->hwid, 1 << ab8500->hwid);
81 	if (ret < 0)
82 		dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
83 							pwm->label, ret);
84 
85 	return ret;
86 }
87 
88 static const struct pwm_ops ab8500_pwm_ops = {
89 	.apply = ab8500_pwm_apply,
90 	.owner = THIS_MODULE,
91 };
92 
ab8500_pwm_probe(struct platform_device * pdev)93 static int ab8500_pwm_probe(struct platform_device *pdev)
94 {
95 	struct ab8500_pwm_chip *ab8500;
96 	int err;
97 
98 	if (pdev->id < 1 || pdev->id > 31)
99 		return dev_err_probe(&pdev->dev, EINVAL, "Invalid device id %d\n", pdev->id);
100 
101 	/*
102 	 * Nothing to be done in probe, this is required to get the
103 	 * device which is required for ab8500 read and write
104 	 */
105 	ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL);
106 	if (ab8500 == NULL)
107 		return -ENOMEM;
108 
109 	ab8500->chip.dev = &pdev->dev;
110 	ab8500->chip.ops = &ab8500_pwm_ops;
111 	ab8500->chip.npwm = 1;
112 	ab8500->hwid = pdev->id - 1;
113 
114 	err = devm_pwmchip_add(&pdev->dev, &ab8500->chip);
115 	if (err < 0)
116 		return dev_err_probe(&pdev->dev, err, "Failed to add pwm chip\n");
117 
118 	dev_dbg(&pdev->dev, "pwm probe successful\n");
119 
120 	return 0;
121 }
122 
123 static struct platform_driver ab8500_pwm_driver = {
124 	.driver = {
125 		.name = "ab8500-pwm",
126 	},
127 	.probe = ab8500_pwm_probe,
128 };
129 module_platform_driver(ab8500_pwm_driver);
130 
131 MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
132 MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
133 MODULE_ALIAS("platform:ab8500-pwm");
134 MODULE_LICENSE("GPL v2");
135