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Thierry Reding6173f8f2012-08-31 11:46:24 +02001/*
2 * Copyright (C) ST-Ericsson SA 2010
3 *
4 * Author: Arun R Murthy <arun.murthy@stericsson.com>
5 * License terms: GNU General Public License (GPL) version 2
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/* backlight driver constants */
24#define ENABLE_PWM 1
25#define DISABLE_PWM 0
26
27struct ab8500_pwm_chip {
28 struct pwm_chip chip;
29};
30
31static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
32 int duty_ns, int period_ns)
33{
34 int ret = 0;
35 unsigned int higher_val, lower_val;
36 u8 reg;
37
38 /*
39 * get the first 8 bits that are be written to
40 * AB8500_PWM_OUT_CTRL1_REG[0:7]
41 */
42 lower_val = duty_ns & 0x00FF;
43 /*
44 * get bits [9:10] that are to be written to
45 * AB8500_PWM_OUT_CTRL2_REG[0:1]
46 */
47 higher_val = ((duty_ns & 0x0300) >> 8);
48
49 reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
50
51 ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
52 reg, (u8)lower_val);
53 if (ret < 0)
54 return ret;
55 ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
56 (reg + 1), (u8)higher_val);
57
58 return ret;
59}
60
61static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
62{
63 int ret;
64
65 ret = abx500_mask_and_set_register_interruptible(chip->dev,
66 AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
67 1 << (chip->base - 1), ENABLE_PWM);
68 if (ret < 0)
69 dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
70 pwm->label, ret);
71 return ret;
72}
73
74static void ab8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
75{
76 int ret;
77
78 ret = abx500_mask_and_set_register_interruptible(chip->dev,
79 AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
80 1 << (chip->base - 1), DISABLE_PWM);
81 if (ret < 0)
82 dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
83 pwm->label, ret);
84 return;
85}
86
87static const struct pwm_ops ab8500_pwm_ops = {
88 .config = ab8500_pwm_config,
89 .enable = ab8500_pwm_enable,
90 .disable = ab8500_pwm_disable,
91};
92
93static int __devinit ab8500_pwm_probe(struct platform_device *pdev)
94{
95 struct ab8500_pwm_chip *ab8500;
96 int err;
97
98 /*
99 * Nothing to be done in probe, this is required to get the
100 * device which is required for ab8500 read and write
101 */
102 ab8500 = kzalloc(sizeof(*ab8500), GFP_KERNEL);
103 if (ab8500 == NULL) {
104 dev_err(&pdev->dev, "failed to allocate memory\n");
105 return -ENOMEM;
106 }
107
108 ab8500->chip.dev = &pdev->dev;
109 ab8500->chip.ops = &ab8500_pwm_ops;
110 ab8500->chip.base = pdev->id;
111 ab8500->chip.npwm = 1;
112
113 err = pwmchip_add(&ab8500->chip);
114 if (err < 0) {
115 kfree(ab8500);
116 return err;
117 }
118
119 dev_dbg(&pdev->dev, "pwm probe successful\n");
120 platform_set_drvdata(pdev, ab8500);
121
122 return 0;
123}
124
125static int __devexit ab8500_pwm_remove(struct platform_device *pdev)
126{
127 struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev);
128 int err;
129
130 err = pwmchip_remove(&ab8500->chip);
131 if (err < 0)
132 return err;
133
134 dev_dbg(&pdev->dev, "pwm driver removed\n");
135 kfree(ab8500);
136
137 return 0;
138}
139
140static struct platform_driver ab8500_pwm_driver = {
141 .driver = {
142 .name = "ab8500-pwm",
143 .owner = THIS_MODULE,
144 },
145 .probe = ab8500_pwm_probe,
146 .remove = __devexit_p(ab8500_pwm_remove),
147};
148module_platform_driver(ab8500_pwm_driver);
149
150MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
151MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
152MODULE_ALIAS("platform:ab8500-pwm");
153MODULE_LICENSE("GPL v2");