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 | { | |
e6e3dbf9 | 40 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 41 | int brightness = bl->props.brightness; |
42 | int max = bl->props.max_brightness; | |
43 | ||
0132267d AC |
44 | if (bl->props.power != FB_BLANK_UNBLANK || |
45 | bl->props.fb_blank != FB_BLANK_UNBLANK || | |
46 | bl->props.state & BL_CORE_FBBLANK) | |
42796d37 | 47 | brightness = 0; |
48 | ||
3b73125a | 49 | if (pb->notify) |
cfc3899f | 50 | brightness = pb->notify(pb->dev, brightness); |
3b73125a | 51 | |
42796d37 | 52 | if (brightness == 0) { |
53 | pwm_config(pb->pwm, 0, pb->period); | |
54 | pwm_disable(pb->pwm); | |
55 | } else { | |
9fb978b1 AC |
56 | int duty_cycle; |
57 | ||
3e3ed6cd | 58 | if (pb->levels) { |
9fb978b1 | 59 | duty_cycle = pb->levels[brightness]; |
3e3ed6cd | 60 | max = pb->levels[max]; |
9fb978b1 AC |
61 | } else { |
62 | duty_cycle = brightness; | |
3e3ed6cd TR |
63 | } |
64 | ||
9fb978b1 AC |
65 | duty_cycle = pb->lth_brightness + |
66 | (duty_cycle * (pb->period - pb->lth_brightness) / max); | |
67 | pwm_config(pb->pwm, duty_cycle, pb->period); | |
42796d37 | 68 | pwm_enable(pb->pwm); |
69 | } | |
cc7993f6 DL |
70 | |
71 | if (pb->notify_after) | |
72 | pb->notify_after(pb->dev, brightness); | |
73 | ||
42796d37 | 74 | return 0; |
75 | } | |
76 | ||
77 | static int pwm_backlight_get_brightness(struct backlight_device *bl) | |
78 | { | |
79 | return bl->props.brightness; | |
80 | } | |
81 | ||
ef0a5e80 RM |
82 | static int pwm_backlight_check_fb(struct backlight_device *bl, |
83 | struct fb_info *info) | |
84 | { | |
e6e3dbf9 | 85 | struct pwm_bl_data *pb = bl_get_data(bl); |
ef0a5e80 RM |
86 | |
87 | return !pb->check_fb || pb->check_fb(pb->dev, info); | |
88 | } | |
89 | ||
9905a43b | 90 | static const struct backlight_ops pwm_backlight_ops = { |
42796d37 | 91 | .update_status = pwm_backlight_update_status, |
92 | .get_brightness = pwm_backlight_get_brightness, | |
ef0a5e80 | 93 | .check_fb = pwm_backlight_check_fb, |
42796d37 | 94 | }; |
95 | ||
3e3ed6cd TR |
96 | #ifdef CONFIG_OF |
97 | static int pwm_backlight_parse_dt(struct device *dev, | |
98 | struct platform_pwm_backlight_data *data) | |
99 | { | |
100 | struct device_node *node = dev->of_node; | |
101 | struct property *prop; | |
102 | int length; | |
103 | u32 value; | |
104 | int ret; | |
105 | ||
106 | if (!node) | |
107 | return -ENODEV; | |
108 | ||
109 | memset(data, 0, sizeof(*data)); | |
110 | ||
111 | /* determine the number of brightness levels */ | |
112 | prop = of_find_property(node, "brightness-levels", &length); | |
113 | if (!prop) | |
114 | return -EINVAL; | |
115 | ||
116 | data->max_brightness = length / sizeof(u32); | |
117 | ||
118 | /* read brightness levels from DT property */ | |
119 | if (data->max_brightness > 0) { | |
120 | size_t size = sizeof(*data->levels) * data->max_brightness; | |
121 | ||
122 | data->levels = devm_kzalloc(dev, size, GFP_KERNEL); | |
123 | if (!data->levels) | |
124 | return -ENOMEM; | |
125 | ||
126 | ret = of_property_read_u32_array(node, "brightness-levels", | |
127 | data->levels, | |
128 | data->max_brightness); | |
129 | if (ret < 0) | |
130 | return ret; | |
131 | ||
132 | ret = of_property_read_u32(node, "default-brightness-level", | |
133 | &value); | |
134 | if (ret < 0) | |
135 | return ret; | |
136 | ||
3e3ed6cd TR |
137 | data->dft_brightness = value; |
138 | data->max_brightness--; | |
139 | } | |
140 | ||
141 | /* | |
142 | * TODO: Most users of this driver use a number of GPIOs to control | |
143 | * backlight power. Support for specifying these needs to be | |
144 | * added. | |
145 | */ | |
146 | ||
147 | return 0; | |
148 | } | |
149 | ||
150 | static struct of_device_id pwm_backlight_of_match[] = { | |
151 | { .compatible = "pwm-backlight" }, | |
152 | { } | |
153 | }; | |
154 | ||
155 | MODULE_DEVICE_TABLE(of, pwm_backlight_of_match); | |
156 | #else | |
157 | static int pwm_backlight_parse_dt(struct device *dev, | |
158 | struct platform_pwm_backlight_data *data) | |
159 | { | |
160 | return -ENODEV; | |
161 | } | |
162 | #endif | |
163 | ||
42796d37 | 164 | static int pwm_backlight_probe(struct platform_device *pdev) |
165 | { | |
c512794c | 166 | struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev); |
3e3ed6cd TR |
167 | struct platform_pwm_backlight_data defdata; |
168 | struct backlight_properties props; | |
42796d37 | 169 | struct backlight_device *bl; |
170 | struct pwm_bl_data *pb; | |
3e3ed6cd | 171 | unsigned int max; |
3b73125a | 172 | int ret; |
42796d37 | 173 | |
14563a4e | 174 | if (!data) { |
3e3ed6cd TR |
175 | ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); |
176 | if (ret < 0) { | |
177 | dev_err(&pdev->dev, "failed to find platform data\n"); | |
178 | return ret; | |
179 | } | |
180 | ||
181 | data = &defdata; | |
14563a4e | 182 | } |
42796d37 | 183 | |
3b73125a PZ |
184 | if (data->init) { |
185 | ret = data->init(&pdev->dev); | |
186 | if (ret < 0) | |
187 | return ret; | |
188 | } | |
189 | ||
ce969228 | 190 | pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); |
3b73125a | 191 | if (!pb) { |
14563a4e | 192 | dev_err(&pdev->dev, "no memory for state\n"); |
3b73125a PZ |
193 | ret = -ENOMEM; |
194 | goto err_alloc; | |
195 | } | |
42796d37 | 196 | |
3e3ed6cd TR |
197 | if (data->levels) { |
198 | max = data->levels[data->max_brightness]; | |
199 | pb->levels = data->levels; | |
200 | } else | |
201 | max = data->max_brightness; | |
202 | ||
3b73125a | 203 | pb->notify = data->notify; |
cc7993f6 | 204 | pb->notify_after = data->notify_after; |
ef0a5e80 | 205 | pb->check_fb = data->check_fb; |
3e3ed6cd | 206 | pb->exit = data->exit; |
cfc3899f | 207 | pb->dev = &pdev->dev; |
42796d37 | 208 | |
60ce7028 | 209 | pb->pwm = devm_pwm_get(&pdev->dev, NULL); |
43bda1a6 | 210 | if (IS_ERR(pb->pwm)) { |
3e3ed6cd TR |
211 | dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); |
212 | ||
213 | pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); | |
214 | if (IS_ERR(pb->pwm)) { | |
215 | dev_err(&pdev->dev, "unable to request legacy PWM\n"); | |
216 | ret = PTR_ERR(pb->pwm); | |
217 | goto err_alloc; | |
218 | } | |
219 | } | |
220 | ||
221 | dev_dbg(&pdev->dev, "got pwm for backlight\n"); | |
222 | ||
223 | /* | |
224 | * The DT case will set the pwm_period_ns field to 0 and store the | |
225 | * period, parsed from the DT, in the PWM device. For the non-DT case, | |
226 | * set the period from platform data. | |
227 | */ | |
228 | if (data->pwm_period_ns > 0) | |
229 | pwm_set_period(pb->pwm, data->pwm_period_ns); | |
230 | ||
231 | pb->period = pwm_get_period(pb->pwm); | |
232 | pb->lth_brightness = data->lth_brightness * (pb->period / max); | |
42796d37 | 233 | |
a19a6ee6 | 234 | memset(&props, 0, sizeof(struct backlight_properties)); |
bb7ca747 | 235 | props.type = BACKLIGHT_RAW; |
a19a6ee6 MG |
236 | props.max_brightness = data->max_brightness; |
237 | bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb, | |
238 | &pwm_backlight_ops, &props); | |
42796d37 | 239 | if (IS_ERR(bl)) { |
240 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
3b73125a | 241 | ret = PTR_ERR(bl); |
60ce7028 | 242 | goto err_alloc; |
42796d37 | 243 | } |
244 | ||
83cfd726 PU |
245 | if (data->dft_brightness > data->max_brightness) { |
246 | dev_warn(&pdev->dev, | |
247 | "invalid default brightness level: %u, using %u\n", | |
248 | data->dft_brightness, data->max_brightness); | |
249 | data->dft_brightness = data->max_brightness; | |
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); | |
e6e3dbf9 | 267 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 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 | ||
c791126b | 277 | #ifdef CONFIG_PM_SLEEP |
e2c17bc6 | 278 | static int pwm_backlight_suspend(struct device *dev) |
42796d37 | 279 | { |
e2c17bc6 | 280 | struct backlight_device *bl = dev_get_drvdata(dev); |
e6e3dbf9 | 281 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 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 | } | |
c791126b | 299 | #endif |
e2c17bc6 MB |
300 | |
301 | static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend, | |
302 | pwm_backlight_resume); | |
303 | ||
42796d37 | 304 | static struct platform_driver pwm_backlight_driver = { |
305 | .driver = { | |
3e3ed6cd TR |
306 | .name = "pwm-backlight", |
307 | .owner = THIS_MODULE, | |
3e3ed6cd | 308 | .pm = &pwm_backlight_pm_ops, |
3e3ed6cd | 309 | .of_match_table = of_match_ptr(pwm_backlight_of_match), |
42796d37 | 310 | }, |
311 | .probe = pwm_backlight_probe, | |
312 | .remove = pwm_backlight_remove, | |
42796d37 | 313 | }; |
314 | ||
81178e02 | 315 | module_platform_driver(pwm_backlight_driver); |
42796d37 | 316 | |
317 | MODULE_DESCRIPTION("PWM based Backlight Driver"); | |
318 | MODULE_LICENSE("GPL"); | |
8cd68198 BD |
319 | MODULE_ALIAS("platform:pwm-backlight"); |
320 |