xfs: remove incorrect assert in xfs_vm_writepage
[pandora-kernel.git] / 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 being correctly configured
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 #include <linux/slab.h>
23
24 struct pwm_bl_data {
25         struct pwm_device       *pwm;
26         struct device           *dev;
27         unsigned int            period;
28         int                     (*notify)(struct device *,
29                                           int brightness);
30 };
31
32 static int pwm_backlight_update_status(struct backlight_device *bl)
33 {
34         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
35         int brightness = bl->props.brightness;
36         int max = bl->props.max_brightness;
37
38         if (bl->props.power != FB_BLANK_UNBLANK)
39                 brightness = 0;
40
41         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
42                 brightness = 0;
43
44         if (pb->notify)
45                 brightness = pb->notify(pb->dev, brightness);
46
47         if (brightness == 0) {
48                 pwm_config(pb->pwm, 0, pb->period);
49                 pwm_disable(pb->pwm);
50         } else {
51                 pwm_config(pb->pwm, brightness * pb->period / max, pb->period);
52                 pwm_enable(pb->pwm);
53         }
54         return 0;
55 }
56
57 static int pwm_backlight_get_brightness(struct backlight_device *bl)
58 {
59         return bl->props.brightness;
60 }
61
62 static const struct backlight_ops pwm_backlight_ops = {
63         .update_status  = pwm_backlight_update_status,
64         .get_brightness = pwm_backlight_get_brightness,
65 };
66
67 static int pwm_backlight_probe(struct platform_device *pdev)
68 {
69         struct backlight_properties props;
70         struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
71         struct backlight_device *bl;
72         struct pwm_bl_data *pb;
73         int ret;
74
75         if (!data) {
76                 dev_err(&pdev->dev, "failed to find platform data\n");
77                 return -EINVAL;
78         }
79
80         if (data->init) {
81                 ret = data->init(&pdev->dev);
82                 if (ret < 0)
83                         return ret;
84         }
85
86         pb = kzalloc(sizeof(*pb), GFP_KERNEL);
87         if (!pb) {
88                 dev_err(&pdev->dev, "no memory for state\n");
89                 ret = -ENOMEM;
90                 goto err_alloc;
91         }
92
93         pb->period = data->pwm_period_ns;
94         pb->notify = data->notify;
95         pb->dev = &pdev->dev;
96
97         pb->pwm = pwm_request(data->pwm_id, "backlight");
98         if (IS_ERR(pb->pwm)) {
99                 dev_err(&pdev->dev, "unable to request PWM for backlight\n");
100                 ret = PTR_ERR(pb->pwm);
101                 goto err_pwm;
102         } else
103                 dev_dbg(&pdev->dev, "got pwm for backlight\n");
104
105         memset(&props, 0, sizeof(struct backlight_properties));
106         props.max_brightness = data->max_brightness;
107         bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
108                                        &pwm_backlight_ops, &props);
109         if (IS_ERR(bl)) {
110                 dev_err(&pdev->dev, "failed to register backlight\n");
111                 ret = PTR_ERR(bl);
112                 goto err_bl;
113         }
114
115         bl->props.brightness = data->dft_brightness;
116         backlight_update_status(bl);
117
118         platform_set_drvdata(pdev, bl);
119         return 0;
120
121 err_bl:
122         pwm_free(pb->pwm);
123 err_pwm:
124         kfree(pb);
125 err_alloc:
126         if (data->exit)
127                 data->exit(&pdev->dev);
128         return ret;
129 }
130
131 static int pwm_backlight_remove(struct platform_device *pdev)
132 {
133         struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
134         struct backlight_device *bl = platform_get_drvdata(pdev);
135         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
136
137         backlight_device_unregister(bl);
138         pwm_config(pb->pwm, 0, pb->period);
139         pwm_disable(pb->pwm);
140         pwm_free(pb->pwm);
141         kfree(pb);
142         if (data->exit)
143                 data->exit(&pdev->dev);
144         return 0;
145 }
146
147 #ifdef CONFIG_PM
148 static int pwm_backlight_suspend(struct platform_device *pdev,
149                                  pm_message_t state)
150 {
151         struct backlight_device *bl = platform_get_drvdata(pdev);
152         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
153
154         if (pb->notify)
155                 pb->notify(pb->dev, 0);
156         pwm_config(pb->pwm, 0, pb->period);
157         pwm_disable(pb->pwm);
158         return 0;
159 }
160
161 static int pwm_backlight_resume(struct platform_device *pdev)
162 {
163         struct backlight_device *bl = platform_get_drvdata(pdev);
164
165         backlight_update_status(bl);
166         return 0;
167 }
168 #else
169 #define pwm_backlight_suspend   NULL
170 #define pwm_backlight_resume    NULL
171 #endif
172
173 static struct platform_driver pwm_backlight_driver = {
174         .driver         = {
175                 .name   = "pwm-backlight",
176                 .owner  = THIS_MODULE,
177         },
178         .probe          = pwm_backlight_probe,
179         .remove         = pwm_backlight_remove,
180         .suspend        = pwm_backlight_suspend,
181         .resume         = pwm_backlight_resume,
182 };
183
184 static int __init pwm_backlight_init(void)
185 {
186         return platform_driver_register(&pwm_backlight_driver);
187 }
188 module_init(pwm_backlight_init);
189
190 static void __exit pwm_backlight_exit(void)
191 {
192         platform_driver_unregister(&pwm_backlight_driver);
193 }
194 module_exit(pwm_backlight_exit);
195
196 MODULE_DESCRIPTION("PWM based Backlight Driver");
197 MODULE_LICENSE("GPL");
198 MODULE_ALIAS("platform:pwm-backlight");
199