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; |
3e3ed6cd | 29 | unsigned int *levels; |
cfc3899f BD |
30 | int (*notify)(struct device *, |
31 | int brightness); | |
cc7993f6 DL |
32 | void (*notify_after)(struct device *, |
33 | int brightness); | |
ef0a5e80 | 34 | int (*check_fb)(struct device *, struct fb_info *); |
3e3ed6cd | 35 | void (*exit)(struct device *); |
42796d37 | 36 | }; |
37 | ||
38 | static int pwm_backlight_update_status(struct backlight_device *bl) | |
39 | { | |
40 | struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); | |
41 | int brightness = bl->props.brightness; | |
42 | int max = bl->props.max_brightness; | |
43 | ||
44 | if (bl->props.power != FB_BLANK_UNBLANK) | |
45 | brightness = 0; | |
46 | ||
47 | if (bl->props.fb_blank != FB_BLANK_UNBLANK) | |
48 | brightness = 0; | |
49 | ||
3b73125a | 50 | if (pb->notify) |
cfc3899f | 51 | brightness = pb->notify(pb->dev, brightness); |
3b73125a | 52 | |
42796d37 | 53 | if (brightness == 0) { |
54 | pwm_config(pb->pwm, 0, pb->period); | |
55 | pwm_disable(pb->pwm); | |
56 | } else { | |
9fb978b1 AC |
57 | int duty_cycle; |
58 | ||
3e3ed6cd | 59 | if (pb->levels) { |
9fb978b1 | 60 | duty_cycle = pb->levels[brightness]; |
3e3ed6cd | 61 | max = pb->levels[max]; |
9fb978b1 AC |
62 | } else { |
63 | duty_cycle = brightness; | |
3e3ed6cd TR |
64 | } |
65 | ||
9fb978b1 AC |
66 | duty_cycle = pb->lth_brightness + |
67 | (duty_cycle * (pb->period - pb->lth_brightness) / max); | |
68 | pwm_config(pb->pwm, duty_cycle, pb->period); | |
42796d37 | 69 | pwm_enable(pb->pwm); |
70 | } | |
cc7993f6 DL |
71 | |
72 | if (pb->notify_after) | |
73 | pb->notify_after(pb->dev, brightness); | |
74 | ||
42796d37 | 75 | return 0; |
76 | } | |
77 | ||
78 | static int pwm_backlight_get_brightness(struct backlight_device *bl) | |
79 | { | |
80 | return bl->props.brightness; | |
81 | } | |
82 | ||
ef0a5e80 RM |
83 | static int pwm_backlight_check_fb(struct backlight_device *bl, |
84 | struct fb_info *info) | |
85 | { | |
86 | struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); | |
87 | ||
88 | return !pb->check_fb || pb->check_fb(pb->dev, info); | |
89 | } | |
90 | ||
9905a43b | 91 | static const struct backlight_ops pwm_backlight_ops = { |
42796d37 | 92 | .update_status = pwm_backlight_update_status, |
93 | .get_brightness = pwm_backlight_get_brightness, | |
ef0a5e80 | 94 | .check_fb = pwm_backlight_check_fb, |
42796d37 | 95 | }; |
96 | ||
3e3ed6cd TR |
97 | #ifdef CONFIG_OF |
98 | static int pwm_backlight_parse_dt(struct device *dev, | |
99 | struct platform_pwm_backlight_data *data) | |
100 | { | |
101 | struct device_node *node = dev->of_node; | |
102 | struct property *prop; | |
103 | int length; | |
104 | u32 value; | |
105 | int ret; | |
106 | ||
107 | if (!node) | |
108 | return -ENODEV; | |
109 | ||
110 | memset(data, 0, sizeof(*data)); | |
111 | ||
112 | /* determine the number of brightness levels */ | |
113 | prop = of_find_property(node, "brightness-levels", &length); | |
114 | if (!prop) | |
115 | return -EINVAL; | |
116 | ||
117 | data->max_brightness = length / sizeof(u32); | |
118 | ||
119 | /* read brightness levels from DT property */ | |
120 | if (data->max_brightness > 0) { | |
121 | size_t size = sizeof(*data->levels) * data->max_brightness; | |
122 | ||
123 | data->levels = devm_kzalloc(dev, size, GFP_KERNEL); | |
124 | if (!data->levels) | |
125 | return -ENOMEM; | |
126 | ||
127 | ret = of_property_read_u32_array(node, "brightness-levels", | |
128 | data->levels, | |
129 | data->max_brightness); | |
130 | if (ret < 0) | |
131 | return ret; | |
132 | ||
133 | ret = of_property_read_u32(node, "default-brightness-level", | |
134 | &value); | |
135 | if (ret < 0) | |
136 | return ret; | |
137 | ||
138 | if (value >= data->max_brightness) { | |
139 | dev_warn(dev, "invalid default brightness level: %u, using %u\n", | |
140 | value, data->max_brightness - 1); | |
141 | value = data->max_brightness - 1; | |
142 | } | |
143 | ||
144 | data->dft_brightness = value; | |
145 | data->max_brightness--; | |
146 | } | |
147 | ||
148 | /* | |
149 | * TODO: Most users of this driver use a number of GPIOs to control | |
150 | * backlight power. Support for specifying these needs to be | |
151 | * added. | |
152 | */ | |
153 | ||
154 | return 0; | |
155 | } | |
156 | ||
157 | static struct of_device_id pwm_backlight_of_match[] = { | |
158 | { .compatible = "pwm-backlight" }, | |
159 | { } | |
160 | }; | |
161 | ||
162 | MODULE_DEVICE_TABLE(of, pwm_backlight_of_match); | |
163 | #else | |
164 | static int pwm_backlight_parse_dt(struct device *dev, | |
165 | struct platform_pwm_backlight_data *data) | |
166 | { | |
167 | return -ENODEV; | |
168 | } | |
169 | #endif | |
170 | ||
42796d37 | 171 | static int pwm_backlight_probe(struct platform_device *pdev) |
172 | { | |
173 | struct platform_pwm_backlight_data *data = pdev->dev.platform_data; | |
3e3ed6cd TR |
174 | struct platform_pwm_backlight_data defdata; |
175 | struct backlight_properties props; | |
42796d37 | 176 | struct backlight_device *bl; |
177 | struct pwm_bl_data *pb; | |
3e3ed6cd | 178 | unsigned int max; |
3b73125a | 179 | int ret; |
42796d37 | 180 | |
14563a4e | 181 | if (!data) { |
3e3ed6cd TR |
182 | ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); |
183 | if (ret < 0) { | |
184 | dev_err(&pdev->dev, "failed to find platform data\n"); | |
185 | return ret; | |
186 | } | |
187 | ||
188 | data = &defdata; | |
14563a4e | 189 | } |
42796d37 | 190 | |
3b73125a PZ |
191 | if (data->init) { |
192 | ret = data->init(&pdev->dev); | |
193 | if (ret < 0) | |
194 | return ret; | |
195 | } | |
196 | ||
ce969228 | 197 | pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); |
3b73125a | 198 | if (!pb) { |
14563a4e | 199 | dev_err(&pdev->dev, "no memory for state\n"); |
3b73125a PZ |
200 | ret = -ENOMEM; |
201 | goto err_alloc; | |
202 | } | |
42796d37 | 203 | |
3e3ed6cd TR |
204 | if (data->levels) { |
205 | max = data->levels[data->max_brightness]; | |
206 | pb->levels = data->levels; | |
207 | } else | |
208 | max = data->max_brightness; | |
209 | ||
3b73125a | 210 | pb->notify = data->notify; |
cc7993f6 | 211 | pb->notify_after = data->notify_after; |
ef0a5e80 | 212 | pb->check_fb = data->check_fb; |
3e3ed6cd | 213 | pb->exit = data->exit; |
cfc3899f | 214 | pb->dev = &pdev->dev; |
42796d37 | 215 | |
60ce7028 | 216 | pb->pwm = devm_pwm_get(&pdev->dev, NULL); |
43bda1a6 | 217 | if (IS_ERR(pb->pwm)) { |
3e3ed6cd TR |
218 | dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); |
219 | ||
220 | pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); | |
221 | if (IS_ERR(pb->pwm)) { | |
222 | dev_err(&pdev->dev, "unable to request legacy PWM\n"); | |
223 | ret = PTR_ERR(pb->pwm); | |
224 | goto err_alloc; | |
225 | } | |
226 | } | |
227 | ||
228 | dev_dbg(&pdev->dev, "got pwm for backlight\n"); | |
229 | ||
230 | /* | |
231 | * The DT case will set the pwm_period_ns field to 0 and store the | |
232 | * period, parsed from the DT, in the PWM device. For the non-DT case, | |
233 | * set the period from platform data. | |
234 | */ | |
235 | if (data->pwm_period_ns > 0) | |
236 | pwm_set_period(pb->pwm, data->pwm_period_ns); | |
237 | ||
238 | pb->period = pwm_get_period(pb->pwm); | |
239 | pb->lth_brightness = data->lth_brightness * (pb->period / max); | |
42796d37 | 240 | |
a19a6ee6 | 241 | memset(&props, 0, sizeof(struct backlight_properties)); |
bb7ca747 | 242 | props.type = BACKLIGHT_RAW; |
a19a6ee6 MG |
243 | props.max_brightness = data->max_brightness; |
244 | bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb, | |
245 | &pwm_backlight_ops, &props); | |
42796d37 | 246 | if (IS_ERR(bl)) { |
247 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
3b73125a | 248 | ret = PTR_ERR(bl); |
60ce7028 | 249 | goto err_alloc; |
42796d37 | 250 | } |
251 | ||
42796d37 | 252 | bl->props.brightness = data->dft_brightness; |
253 | backlight_update_status(bl); | |
254 | ||
255 | platform_set_drvdata(pdev, bl); | |
256 | return 0; | |
3b73125a | 257 | |
3b73125a PZ |
258 | err_alloc: |
259 | if (data->exit) | |
260 | data->exit(&pdev->dev); | |
261 | return ret; | |
42796d37 | 262 | } |
263 | ||
264 | static int pwm_backlight_remove(struct platform_device *pdev) | |
265 | { | |
266 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
267 | struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); | |
268 | ||
269 | backlight_device_unregister(bl); | |
270 | pwm_config(pb->pwm, 0, pb->period); | |
271 | pwm_disable(pb->pwm); | |
3e3ed6cd TR |
272 | if (pb->exit) |
273 | pb->exit(&pdev->dev); | |
42796d37 | 274 | return 0; |
275 | } | |
276 | ||
277 | #ifdef CONFIG_PM | |
e2c17bc6 | 278 | static int pwm_backlight_suspend(struct device *dev) |
42796d37 | 279 | { |
e2c17bc6 | 280 | struct backlight_device *bl = dev_get_drvdata(dev); |
42796d37 | 281 | struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); |
282 | ||
82e8b542 | 283 | if (pb->notify) |
cfc3899f | 284 | pb->notify(pb->dev, 0); |
42796d37 | 285 | pwm_config(pb->pwm, 0, pb->period); |
286 | pwm_disable(pb->pwm); | |
cc7993f6 DL |
287 | if (pb->notify_after) |
288 | pb->notify_after(pb->dev, 0); | |
42796d37 | 289 | return 0; |
290 | } | |
291 | ||
e2c17bc6 | 292 | static int pwm_backlight_resume(struct device *dev) |
42796d37 | 293 | { |
e2c17bc6 | 294 | struct backlight_device *bl = dev_get_drvdata(dev); |
42796d37 | 295 | |
296 | backlight_update_status(bl); | |
297 | return 0; | |
298 | } | |
e2c17bc6 MB |
299 | |
300 | static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend, | |
301 | pwm_backlight_resume); | |
302 | ||
42796d37 | 303 | #endif |
304 | ||
305 | static struct platform_driver pwm_backlight_driver = { | |
306 | .driver = { | |
3e3ed6cd TR |
307 | .name = "pwm-backlight", |
308 | .owner = THIS_MODULE, | |
e2c17bc6 | 309 | #ifdef CONFIG_PM |
3e3ed6cd | 310 | .pm = &pwm_backlight_pm_ops, |
e2c17bc6 | 311 | #endif |
3e3ed6cd | 312 | .of_match_table = of_match_ptr(pwm_backlight_of_match), |
42796d37 | 313 | }, |
314 | .probe = pwm_backlight_probe, | |
315 | .remove = pwm_backlight_remove, | |
42796d37 | 316 | }; |
317 | ||
81178e02 | 318 | module_platform_driver(pwm_backlight_driver); |
42796d37 | 319 | |
320 | MODULE_DESCRIPTION("PWM based Backlight Driver"); | |
321 | MODULE_LICENSE("GPL"); | |
8cd68198 BD |
322 | MODULE_ALIAS("platform:pwm-backlight"); |
323 |