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f0f05b1c AM |
1 | /* |
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> | |
f0f05b1c | 11 | #include <linux/mfd/abx500.h> |
ee66e653 | 12 | #include <linux/mfd/abx500/ab8500.h> |
eb12a679 | 13 | #include <linux/module.h> |
f0f05b1c AM |
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 | ||
27 | struct pwm_device { | |
28 | struct device *dev; | |
29 | struct list_head node; | |
30 | const char *label; | |
31 | unsigned int pwm_id; | |
32 | }; | |
33 | ||
34 | static LIST_HEAD(pwm_list); | |
35 | ||
36 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) | |
37 | { | |
38 | int ret = 0; | |
39 | unsigned int higher_val, lower_val; | |
40 | u8 reg; | |
41 | ||
42 | /* | |
43 | * get the first 8 bits that are be written to | |
44 | * AB8500_PWM_OUT_CTRL1_REG[0:7] | |
45 | */ | |
46 | lower_val = duty_ns & 0x00FF; | |
47 | /* | |
48 | * get bits [9:10] that are to be written to | |
49 | * AB8500_PWM_OUT_CTRL2_REG[0:1] | |
50 | */ | |
51 | higher_val = ((duty_ns & 0x0300) >> 8); | |
52 | ||
53 | reg = AB8500_PWM_OUT_CTRL1_REG + ((pwm->pwm_id - 1) * 2); | |
54 | ||
55 | ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC, | |
56 | reg, (u8)lower_val); | |
57 | if (ret < 0) | |
58 | return ret; | |
59 | ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC, | |
60 | (reg + 1), (u8)higher_val); | |
61 | ||
62 | return ret; | |
63 | } | |
64 | EXPORT_SYMBOL(pwm_config); | |
65 | ||
66 | int pwm_enable(struct pwm_device *pwm) | |
67 | { | |
68 | int ret; | |
69 | ||
70 | ret = abx500_mask_and_set_register_interruptible(pwm->dev, | |
71 | AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, | |
72 | 1 << (pwm->pwm_id-1), ENABLE_PWM); | |
73 | if (ret < 0) | |
74 | dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n", | |
75 | pwm->label, ret); | |
76 | return ret; | |
77 | } | |
78 | EXPORT_SYMBOL(pwm_enable); | |
79 | ||
80 | void pwm_disable(struct pwm_device *pwm) | |
81 | { | |
82 | int ret; | |
83 | ||
84 | ret = abx500_mask_and_set_register_interruptible(pwm->dev, | |
85 | AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, | |
86 | 1 << (pwm->pwm_id-1), DISABLE_PWM); | |
87 | if (ret < 0) | |
88 | dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n", | |
89 | pwm->label, ret); | |
90 | return; | |
91 | } | |
92 | EXPORT_SYMBOL(pwm_disable); | |
93 | ||
94 | struct pwm_device *pwm_request(int pwm_id, const char *label) | |
95 | { | |
96 | struct pwm_device *pwm; | |
97 | ||
98 | list_for_each_entry(pwm, &pwm_list, node) { | |
99 | if (pwm->pwm_id == pwm_id) { | |
100 | pwm->label = label; | |
101 | pwm->pwm_id = pwm_id; | |
102 | return pwm; | |
103 | } | |
104 | } | |
105 | ||
106 | return ERR_PTR(-ENOENT); | |
107 | } | |
108 | EXPORT_SYMBOL(pwm_request); | |
109 | ||
110 | void pwm_free(struct pwm_device *pwm) | |
111 | { | |
112 | pwm_disable(pwm); | |
113 | } | |
114 | EXPORT_SYMBOL(pwm_free); | |
115 | ||
116 | static int __devinit ab8500_pwm_probe(struct platform_device *pdev) | |
117 | { | |
118 | struct pwm_device *pwm; | |
119 | /* | |
120 | * Nothing to be done in probe, this is required to get the | |
121 | * device which is required for ab8500 read and write | |
122 | */ | |
123 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
124 | if (pwm == NULL) { | |
125 | dev_err(&pdev->dev, "failed to allocate memory\n"); | |
126 | return -ENOMEM; | |
127 | } | |
128 | pwm->dev = &pdev->dev; | |
129 | pwm->pwm_id = pdev->id; | |
130 | list_add_tail(&pwm->node, &pwm_list); | |
131 | platform_set_drvdata(pdev, pwm); | |
132 | dev_dbg(pwm->dev, "pwm probe successful\n"); | |
133 | return 0; | |
134 | } | |
135 | ||
136 | static int __devexit ab8500_pwm_remove(struct platform_device *pdev) | |
137 | { | |
138 | struct pwm_device *pwm = platform_get_drvdata(pdev); | |
139 | list_del(&pwm->node); | |
140 | dev_dbg(&pdev->dev, "pwm driver removed\n"); | |
141 | kfree(pwm); | |
142 | return 0; | |
143 | } | |
144 | ||
145 | static struct platform_driver ab8500_pwm_driver = { | |
146 | .driver = { | |
147 | .name = "ab8500-pwm", | |
148 | .owner = THIS_MODULE, | |
149 | }, | |
150 | .probe = ab8500_pwm_probe, | |
151 | .remove = __devexit_p(ab8500_pwm_remove), | |
152 | }; | |
153 | ||
154 | static int __init ab8500_pwm_init(void) | |
155 | { | |
156 | return platform_driver_register(&ab8500_pwm_driver); | |
157 | } | |
158 | ||
159 | static void __exit ab8500_pwm_exit(void) | |
160 | { | |
161 | platform_driver_unregister(&ab8500_pwm_driver); | |
162 | } | |
163 | ||
164 | subsys_initcall(ab8500_pwm_init); | |
165 | module_exit(ab8500_pwm_exit); | |
166 | MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>"); | |
167 | MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver"); | |
37b7bf67 | 168 | MODULE_ALIAS("platform:ab8500-pwm"); |
f0f05b1c | 169 | MODULE_LICENSE("GPL v2"); |