drivers: make tegra-throughput driver always post fps
[linux-2.6.git] / drivers / misc / ab8500-pwm.c
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>
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
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");
168 MODULE_ALIAS("platform:ab8500-pwm");
169 MODULE_LICENSE("GPL v2");