Merge branch 'master' of /home/shaggy/git/linus-clean/
[linux-2.6] / drivers / video / backlight / pwm_bl.c
1 /*
2  * linux/drivers/video/backlight/pwm_bl.c
3  *
4  * simple PWM based backlight control, board code has to setup
5  * 1) pin configuration so PWM waveforms can output
6  * 2) platform_data casts to the PWM id (0/1/2/3 on PXA)
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/platform_device.h>
17 #include <linux/fb.h>
18 #include <linux/backlight.h>
19 #include <linux/err.h>
20 #include <linux/pwm.h>
21 #include <linux/pwm_backlight.h>
22
23 struct pwm_bl_data {
24         struct pwm_device       *pwm;
25         unsigned int            period;
26         int                     (*notify)(int brightness);
27 };
28
29 static int pwm_backlight_update_status(struct backlight_device *bl)
30 {
31         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
32         int brightness = bl->props.brightness;
33         int max = bl->props.max_brightness;
34
35         if (bl->props.power != FB_BLANK_UNBLANK)
36                 brightness = 0;
37
38         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
39                 brightness = 0;
40
41         if (pb->notify)
42                 brightness = pb->notify(brightness);
43
44         if (brightness == 0) {
45                 pwm_config(pb->pwm, 0, pb->period);
46                 pwm_disable(pb->pwm);
47         } else {
48                 pwm_config(pb->pwm, brightness * pb->period / max, pb->period);
49                 pwm_enable(pb->pwm);
50         }
51         return 0;
52 }
53
54 static int pwm_backlight_get_brightness(struct backlight_device *bl)
55 {
56         return bl->props.brightness;
57 }
58
59 static struct backlight_ops pwm_backlight_ops = {
60         .update_status  = pwm_backlight_update_status,
61         .get_brightness = pwm_backlight_get_brightness,
62 };
63
64 static int pwm_backlight_probe(struct platform_device *pdev)
65 {
66         struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
67         struct backlight_device *bl;
68         struct pwm_bl_data *pb;
69         int ret;
70
71         if (!data) {
72                 dev_err(&pdev->dev, "failed to find platform data\n");
73                 return -EINVAL;
74         }
75
76         if (data->init) {
77                 ret = data->init(&pdev->dev);
78                 if (ret < 0)
79                         return ret;
80         }
81
82         pb = kzalloc(sizeof(*pb), GFP_KERNEL);
83         if (!pb) {
84                 dev_err(&pdev->dev, "no memory for state\n");
85                 ret = -ENOMEM;
86                 goto err_alloc;
87         }
88
89         pb->period = data->pwm_period_ns;
90         pb->notify = data->notify;
91
92         pb->pwm = pwm_request(data->pwm_id, "backlight");
93         if (IS_ERR(pb->pwm)) {
94                 dev_err(&pdev->dev, "unable to request PWM for backlight\n");
95                 ret = PTR_ERR(pb->pwm);
96                 goto err_pwm;
97         } else
98                 dev_dbg(&pdev->dev, "got pwm for backlight\n");
99
100         bl = backlight_device_register(pdev->name, &pdev->dev,
101                         pb, &pwm_backlight_ops);
102         if (IS_ERR(bl)) {
103                 dev_err(&pdev->dev, "failed to register backlight\n");
104                 ret = PTR_ERR(bl);
105                 goto err_bl;
106         }
107
108         bl->props.max_brightness = data->max_brightness;
109         bl->props.brightness = data->dft_brightness;
110         backlight_update_status(bl);
111
112         platform_set_drvdata(pdev, bl);
113         return 0;
114
115 err_bl:
116         pwm_free(pb->pwm);
117 err_pwm:
118         kfree(pb);
119 err_alloc:
120         if (data->exit)
121                 data->exit(&pdev->dev);
122         return ret;
123 }
124
125 static int pwm_backlight_remove(struct platform_device *pdev)
126 {
127         struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
128         struct backlight_device *bl = platform_get_drvdata(pdev);
129         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
130
131         backlight_device_unregister(bl);
132         pwm_config(pb->pwm, 0, pb->period);
133         pwm_disable(pb->pwm);
134         pwm_free(pb->pwm);
135         kfree(pb);
136         if (data->exit)
137                 data->exit(&pdev->dev);
138         return 0;
139 }
140
141 #ifdef CONFIG_PM
142 static int pwm_backlight_suspend(struct platform_device *pdev,
143                                  pm_message_t state)
144 {
145         struct backlight_device *bl = platform_get_drvdata(pdev);
146         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
147
148         pwm_config(pb->pwm, 0, pb->period);
149         pwm_disable(pb->pwm);
150         return 0;
151 }
152
153 static int pwm_backlight_resume(struct platform_device *pdev)
154 {
155         struct backlight_device *bl = platform_get_drvdata(pdev);
156
157         backlight_update_status(bl);
158         return 0;
159 }
160 #else
161 #define pwm_backlight_suspend   NULL
162 #define pwm_backlight_resume    NULL
163 #endif
164
165 static struct platform_driver pwm_backlight_driver = {
166         .driver         = {
167                 .name   = "pwm-backlight",
168                 .owner  = THIS_MODULE,
169         },
170         .probe          = pwm_backlight_probe,
171         .remove         = pwm_backlight_remove,
172         .suspend        = pwm_backlight_suspend,
173         .resume         = pwm_backlight_resume,
174 };
175
176 static int __init pwm_backlight_init(void)
177 {
178         return platform_driver_register(&pwm_backlight_driver);
179 }
180 module_init(pwm_backlight_init);
181
182 static void __exit pwm_backlight_exit(void)
183 {
184         platform_driver_unregister(&pwm_backlight_driver);
185 }
186 module_exit(pwm_backlight_exit);
187
188 MODULE_DESCRIPTION("PWM based Backlight Driver");
189 MODULE_LICENSE("GPL");
190 MODULE_ALIAS("platform:pwm-backlight");
191