Commit | Line | Data |
---|---|---|
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> | |
5a0e3ad6 | 22 | #include <linux/slab.h> |
42796d37 | 23 | |
24 | struct pwm_bl_data { | |
25 | struct pwm_device *pwm; | |
cfc3899f | 26 | struct device *dev; |
42796d37 | 27 | unsigned int period; |
fef7764f | 28 | unsigned int lth_brightness; |
cfc3899f BD |
29 | int (*notify)(struct device *, |
30 | int brightness); | |
cc7993f6 DL |
31 | void (*notify_after)(struct device *, |
32 | int brightness); | |
ef0a5e80 | 33 | int (*check_fb)(struct device *, struct fb_info *); |
42796d37 | 34 | }; |
35 | ||
36 | static int pwm_backlight_update_status(struct backlight_device *bl) | |
37 | { | |
38 | struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); | |
39 | int brightness = bl->props.brightness; | |
40 | int max = bl->props.max_brightness; | |
41 | ||
42 | if (bl->props.power != FB_BLANK_UNBLANK) | |
43 | brightness = 0; | |
44 | ||
45 | if (bl->props.fb_blank != FB_BLANK_UNBLANK) | |
46 | brightness = 0; | |
47 | ||
3b73125a | 48 | if (pb->notify) |
cfc3899f | 49 | brightness = pb->notify(pb->dev, brightness); |
3b73125a | 50 | |
42796d37 | 51 | if (brightness == 0) { |
52 | pwm_config(pb->pwm, 0, pb->period); | |
53 | pwm_disable(pb->pwm); | |
54 | } else { | |
fef7764f AM |
55 | brightness = pb->lth_brightness + |
56 | (brightness * (pb->period - pb->lth_brightness) / max); | |
57 | pwm_config(pb->pwm, brightness, pb->period); | |
42796d37 | 58 | pwm_enable(pb->pwm); |
59 | } | |
cc7993f6 DL |
60 | |
61 | if (pb->notify_after) | |
62 | pb->notify_after(pb->dev, brightness); | |
63 | ||
42796d37 | 64 | return 0; |
65 | } | |
66 | ||
67 | static int pwm_backlight_get_brightness(struct backlight_device *bl) | |
68 | { | |
69 | return bl->props.brightness; | |
70 | } | |
71 | ||
ef0a5e80 RM |
72 | static int pwm_backlight_check_fb(struct backlight_device *bl, |
73 | struct fb_info *info) | |
74 | { | |
75 | struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); | |
76 | ||
77 | return !pb->check_fb || pb->check_fb(pb->dev, info); | |
78 | } | |
79 | ||
9905a43b | 80 | static const struct backlight_ops pwm_backlight_ops = { |
42796d37 | 81 | .update_status = pwm_backlight_update_status, |
82 | .get_brightness = pwm_backlight_get_brightness, | |
ef0a5e80 | 83 | .check_fb = pwm_backlight_check_fb, |
42796d37 | 84 | }; |
85 | ||
86 | static int pwm_backlight_probe(struct platform_device *pdev) | |
87 | { | |
a19a6ee6 | 88 | struct backlight_properties props; |
42796d37 | 89 | struct platform_pwm_backlight_data *data = pdev->dev.platform_data; |
90 | struct backlight_device *bl; | |
91 | struct pwm_bl_data *pb; | |
3b73125a | 92 | int ret; |
42796d37 | 93 | |
14563a4e BD |
94 | if (!data) { |
95 | dev_err(&pdev->dev, "failed to find platform data\n"); | |
42796d37 | 96 | return -EINVAL; |
14563a4e | 97 | } |
42796d37 | 98 | |
3b73125a PZ |
99 | if (data->init) { |
100 | ret = data->init(&pdev->dev); | |
101 | if (ret < 0) | |
102 | return ret; | |
103 | } | |
104 | ||
42796d37 | 105 | pb = kzalloc(sizeof(*pb), GFP_KERNEL); |
3b73125a | 106 | if (!pb) { |
14563a4e | 107 | dev_err(&pdev->dev, "no memory for state\n"); |
3b73125a PZ |
108 | ret = -ENOMEM; |
109 | goto err_alloc; | |
110 | } | |
42796d37 | 111 | |
112 | pb->period = data->pwm_period_ns; | |
3b73125a | 113 | pb->notify = data->notify; |
cc7993f6 | 114 | pb->notify_after = data->notify_after; |
ef0a5e80 | 115 | pb->check_fb = data->check_fb; |
fef7764f AM |
116 | pb->lth_brightness = data->lth_brightness * |
117 | (data->pwm_period_ns / data->max_brightness); | |
cfc3899f | 118 | pb->dev = &pdev->dev; |
42796d37 | 119 | |
120 | pb->pwm = pwm_request(data->pwm_id, "backlight"); | |
43bda1a6 | 121 | if (IS_ERR(pb->pwm)) { |
42796d37 | 122 | dev_err(&pdev->dev, "unable to request PWM for backlight\n"); |
43bda1a6 | 123 | ret = PTR_ERR(pb->pwm); |
3b73125a | 124 | goto err_pwm; |
14563a4e BD |
125 | } else |
126 | dev_dbg(&pdev->dev, "got pwm for backlight\n"); | |
42796d37 | 127 | |
a19a6ee6 | 128 | memset(&props, 0, sizeof(struct backlight_properties)); |
bb7ca747 | 129 | props.type = BACKLIGHT_RAW; |
a19a6ee6 MG |
130 | props.max_brightness = data->max_brightness; |
131 | bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb, | |
132 | &pwm_backlight_ops, &props); | |
42796d37 | 133 | if (IS_ERR(bl)) { |
134 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
3b73125a PZ |
135 | ret = PTR_ERR(bl); |
136 | goto err_bl; | |
42796d37 | 137 | } |
138 | ||
42796d37 | 139 | bl->props.brightness = data->dft_brightness; |
140 | backlight_update_status(bl); | |
141 | ||
142 | platform_set_drvdata(pdev, bl); | |
143 | return 0; | |
3b73125a PZ |
144 | |
145 | err_bl: | |
146 | pwm_free(pb->pwm); | |
147 | err_pwm: | |
148 | kfree(pb); | |
149 | err_alloc: | |
150 | if (data->exit) | |
151 | data->exit(&pdev->dev); | |
152 | return ret; | |
42796d37 | 153 | } |
154 | ||
155 | static int pwm_backlight_remove(struct platform_device *pdev) | |
156 | { | |
3b73125a | 157 | struct platform_pwm_backlight_data *data = pdev->dev.platform_data; |
42796d37 | 158 | struct backlight_device *bl = platform_get_drvdata(pdev); |
159 | struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); | |
160 | ||
161 | backlight_device_unregister(bl); | |
162 | pwm_config(pb->pwm, 0, pb->period); | |
163 | pwm_disable(pb->pwm); | |
164 | pwm_free(pb->pwm); | |
165 | kfree(pb); | |
3b73125a PZ |
166 | if (data->exit) |
167 | data->exit(&pdev->dev); | |
42796d37 | 168 | return 0; |
169 | } | |
170 | ||
171 | #ifdef CONFIG_PM | |
172 | static int pwm_backlight_suspend(struct platform_device *pdev, | |
173 | pm_message_t state) | |
174 | { | |
175 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
176 | struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); | |
177 | ||
82e8b542 | 178 | if (pb->notify) |
cfc3899f | 179 | pb->notify(pb->dev, 0); |
42796d37 | 180 | pwm_config(pb->pwm, 0, pb->period); |
181 | pwm_disable(pb->pwm); | |
cc7993f6 DL |
182 | if (pb->notify_after) |
183 | pb->notify_after(pb->dev, 0); | |
42796d37 | 184 | return 0; |
185 | } | |
186 | ||
187 | static int pwm_backlight_resume(struct platform_device *pdev) | |
188 | { | |
189 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
190 | ||
191 | backlight_update_status(bl); | |
192 | return 0; | |
193 | } | |
194 | #else | |
195 | #define pwm_backlight_suspend NULL | |
196 | #define pwm_backlight_resume NULL | |
197 | #endif | |
198 | ||
199 | static struct platform_driver pwm_backlight_driver = { | |
200 | .driver = { | |
201 | .name = "pwm-backlight", | |
202 | .owner = THIS_MODULE, | |
203 | }, | |
204 | .probe = pwm_backlight_probe, | |
205 | .remove = pwm_backlight_remove, | |
206 | .suspend = pwm_backlight_suspend, | |
207 | .resume = pwm_backlight_resume, | |
208 | }; | |
209 | ||
210 | static int __init pwm_backlight_init(void) | |
211 | { | |
212 | return platform_driver_register(&pwm_backlight_driver); | |
213 | } | |
214 | module_init(pwm_backlight_init); | |
215 | ||
216 | static void __exit pwm_backlight_exit(void) | |
217 | { | |
218 | platform_driver_unregister(&pwm_backlight_driver); | |
219 | } | |
220 | module_exit(pwm_backlight_exit); | |
221 | ||
222 | MODULE_DESCRIPTION("PWM based Backlight Driver"); | |
223 | MODULE_LICENSE("GPL"); | |
8cd68198 BD |
224 | MODULE_ALIAS("platform:pwm-backlight"); |
225 |