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 };
26
ab8500_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)27 static int ab8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
28 const struct pwm_state *state)
29 {
30 int ret;
31 u8 reg;
32 unsigned int higher_val, lower_val;
33
34 if (state->polarity != PWM_POLARITY_NORMAL)
35 return -EINVAL;
36
37 if (!state->enabled) {
38 ret = abx500_mask_and_set_register_interruptible(chip->dev,
39 AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
40 1 << (chip->base - 1), 0);
41
42 if (ret < 0)
43 dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
44 pwm->label, ret);
45 return ret;
46 }
47
48 /*
49 * get the first 8 bits that are be written to
50 * AB8500_PWM_OUT_CTRL1_REG[0:7]
51 */
52 lower_val = state->duty_cycle & 0x00FF;
53 /*
54 * get bits [9:10] that are to be written to
55 * AB8500_PWM_OUT_CTRL2_REG[0:1]
56 */
57 higher_val = ((state->duty_cycle & 0x0300) >> 8);
58
59 reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
60
61 ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
62 reg, (u8)lower_val);
63 if (ret < 0)
64 return ret;
65
66 ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
67 (reg + 1), (u8)higher_val);
68 if (ret < 0)
69 return ret;
70
71 ret = abx500_mask_and_set_register_interruptible(chip->dev,
72 AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
73 1 << (chip->base - 1), 1 << (chip->base - 1));
74 if (ret < 0)
75 dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
76 pwm->label, ret);
77
78 return ret;
79 }
80
81 static const struct pwm_ops ab8500_pwm_ops = {
82 .apply = ab8500_pwm_apply,
83 .owner = THIS_MODULE,
84 };
85
ab8500_pwm_probe(struct platform_device * pdev)86 static int ab8500_pwm_probe(struct platform_device *pdev)
87 {
88 struct ab8500_pwm_chip *ab8500;
89 int err;
90
91 /*
92 * Nothing to be done in probe, this is required to get the
93 * device which is required for ab8500 read and write
94 */
95 ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL);
96 if (ab8500 == NULL)
97 return -ENOMEM;
98
99 ab8500->chip.dev = &pdev->dev;
100 ab8500->chip.ops = &ab8500_pwm_ops;
101 ab8500->chip.npwm = 1;
102
103 err = pwmchip_add(&ab8500->chip);
104 if (err < 0)
105 return dev_err_probe(&pdev->dev, err, "Failed to add pwm chip\n");
106
107 dev_dbg(&pdev->dev, "pwm probe successful\n");
108 platform_set_drvdata(pdev, ab8500);
109
110 return 0;
111 }
112
ab8500_pwm_remove(struct platform_device * pdev)113 static int ab8500_pwm_remove(struct platform_device *pdev)
114 {
115 struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev);
116 int err;
117
118 err = pwmchip_remove(&ab8500->chip);
119 if (err < 0)
120 return err;
121
122 dev_dbg(&pdev->dev, "pwm driver removed\n");
123
124 return 0;
125 }
126
127 static struct platform_driver ab8500_pwm_driver = {
128 .driver = {
129 .name = "ab8500-pwm",
130 },
131 .probe = ab8500_pwm_probe,
132 .remove = ab8500_pwm_remove,
133 };
134 module_platform_driver(ab8500_pwm_driver);
135
136 MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
137 MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
138 MODULE_ALIAS("platform:ab8500-pwm");
139 MODULE_LICENSE("GPL v2");
140