Commit | Line | Data |
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42796d37 | 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 | |
b8cdd877 | 6 | * 2) platform_data being correctly configured |
42796d37 | 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; | |
3b73125a | 26 | int (*notify)(int brightness); |
42796d37 | 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 | ||
3b73125a PZ |
41 | if (pb->notify) |
42 | brightness = pb->notify(brightness); | |
43 | ||
42796d37 | 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; | |
3b73125a | 69 | int ret; |
42796d37 | 70 | |
14563a4e BD |
71 | if (!data) { |
72 | dev_err(&pdev->dev, "failed to find platform data\n"); | |
42796d37 | 73 | return -EINVAL; |
14563a4e | 74 | } |
42796d37 | 75 | |
3b73125a PZ |
76 | if (data->init) { |
77 | ret = data->init(&pdev->dev); | |
78 | if (ret < 0) | |
79 | return ret; | |
80 | } | |
81 | ||
42796d37 | 82 | pb = kzalloc(sizeof(*pb), GFP_KERNEL); |
3b73125a | 83 | if (!pb) { |
14563a4e | 84 | dev_err(&pdev->dev, "no memory for state\n"); |
3b73125a PZ |
85 | ret = -ENOMEM; |
86 | goto err_alloc; | |
87 | } | |
42796d37 | 88 | |
89 | pb->period = data->pwm_period_ns; | |
3b73125a | 90 | pb->notify = data->notify; |
42796d37 | 91 | |
92 | pb->pwm = pwm_request(data->pwm_id, "backlight"); | |
43bda1a6 | 93 | if (IS_ERR(pb->pwm)) { |
42796d37 | 94 | dev_err(&pdev->dev, "unable to request PWM for backlight\n"); |
43bda1a6 | 95 | ret = PTR_ERR(pb->pwm); |
3b73125a | 96 | goto err_pwm; |
14563a4e BD |
97 | } else |
98 | dev_dbg(&pdev->dev, "got pwm for backlight\n"); | |
42796d37 | 99 | |
b8cdd877 | 100 | bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, |
42796d37 | 101 | pb, &pwm_backlight_ops); |
102 | if (IS_ERR(bl)) { | |
103 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
3b73125a PZ |
104 | ret = PTR_ERR(bl); |
105 | goto err_bl; | |
42796d37 | 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; | |
3b73125a PZ |
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; | |
42796d37 | 123 | } |
124 | ||
125 | static int pwm_backlight_remove(struct platform_device *pdev) | |
126 | { | |
3b73125a | 127 | struct platform_pwm_backlight_data *data = pdev->dev.platform_data; |
42796d37 | 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); | |
3b73125a PZ |
136 | if (data->exit) |
137 | data->exit(&pdev->dev); | |
42796d37 | 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 | ||
82e8b542 MZ |
148 | if (pb->notify) |
149 | pb->notify(0); | |
42796d37 | 150 | pwm_config(pb->pwm, 0, pb->period); |
151 | pwm_disable(pb->pwm); | |
152 | return 0; | |
153 | } | |
154 | ||
155 | static int pwm_backlight_resume(struct platform_device *pdev) | |
156 | { | |
157 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
158 | ||
159 | backlight_update_status(bl); | |
160 | return 0; | |
161 | } | |
162 | #else | |
163 | #define pwm_backlight_suspend NULL | |
164 | #define pwm_backlight_resume NULL | |
165 | #endif | |
166 | ||
167 | static struct platform_driver pwm_backlight_driver = { | |
168 | .driver = { | |
169 | .name = "pwm-backlight", | |
170 | .owner = THIS_MODULE, | |
171 | }, | |
172 | .probe = pwm_backlight_probe, | |
173 | .remove = pwm_backlight_remove, | |
174 | .suspend = pwm_backlight_suspend, | |
175 | .resume = pwm_backlight_resume, | |
176 | }; | |
177 | ||
178 | static int __init pwm_backlight_init(void) | |
179 | { | |
180 | return platform_driver_register(&pwm_backlight_driver); | |
181 | } | |
182 | module_init(pwm_backlight_init); | |
183 | ||
184 | static void __exit pwm_backlight_exit(void) | |
185 | { | |
186 | platform_driver_unregister(&pwm_backlight_driver); | |
187 | } | |
188 | module_exit(pwm_backlight_exit); | |
189 | ||
190 | MODULE_DESCRIPTION("PWM based Backlight Driver"); | |
191 | MODULE_LICENSE("GPL"); | |
8cd68198 BD |
192 | MODULE_ALIAS("platform:pwm-backlight"); |
193 |