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 | ||
8265b2e4 TR |
13 | #include <linux/gpio.h> |
14 | #include <linux/of_gpio.h> | |
42796d37 | 15 | #include <linux/module.h> |
16 | #include <linux/kernel.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/fb.h> | |
20 | #include <linux/backlight.h> | |
21 | #include <linux/err.h> | |
22 | #include <linux/pwm.h> | |
23 | #include <linux/pwm_backlight.h> | |
22ceeee1 | 24 | #include <linux/regulator/consumer.h> |
5a0e3ad6 | 25 | #include <linux/slab.h> |
42796d37 | 26 | |
27 | struct pwm_bl_data { | |
28 | struct pwm_device *pwm; | |
cfc3899f | 29 | struct device *dev; |
42796d37 | 30 | unsigned int period; |
fef7764f | 31 | unsigned int lth_brightness; |
3e3ed6cd | 32 | unsigned int *levels; |
97c38437 | 33 | bool enabled; |
22ceeee1 | 34 | struct regulator *power_supply; |
8265b2e4 TR |
35 | int enable_gpio; |
36 | unsigned long enable_gpio_flags; | |
8f43e18e | 37 | unsigned int scale; |
cfc3899f BD |
38 | int (*notify)(struct device *, |
39 | int brightness); | |
cc7993f6 DL |
40 | void (*notify_after)(struct device *, |
41 | int brightness); | |
ef0a5e80 | 42 | int (*check_fb)(struct device *, struct fb_info *); |
3e3ed6cd | 43 | void (*exit)(struct device *); |
42796d37 | 44 | }; |
45 | ||
8f43e18e | 46 | static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) |
62b744a8 TR |
47 | { |
48 | int duty_cycle, err; | |
49 | ||
97c38437 TR |
50 | if (pb->enabled) |
51 | return; | |
52 | ||
22ceeee1 TR |
53 | err = regulator_enable(pb->power_supply); |
54 | if (err < 0) | |
55 | dev_err(pb->dev, "failed to enable power supply\n"); | |
56 | ||
8265b2e4 TR |
57 | if (gpio_is_valid(pb->enable_gpio)) { |
58 | if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW) | |
59 | gpio_set_value(pb->enable_gpio, 0); | |
60 | else | |
61 | gpio_set_value(pb->enable_gpio, 1); | |
62 | } | |
63 | ||
62b744a8 | 64 | pwm_enable(pb->pwm); |
97c38437 | 65 | pb->enabled = true; |
62b744a8 TR |
66 | } |
67 | ||
68 | static void pwm_backlight_power_off(struct pwm_bl_data *pb) | |
69 | { | |
97c38437 TR |
70 | if (!pb->enabled) |
71 | return; | |
72 | ||
62b744a8 TR |
73 | pwm_config(pb->pwm, 0, pb->period); |
74 | pwm_disable(pb->pwm); | |
97c38437 | 75 | |
8265b2e4 TR |
76 | if (gpio_is_valid(pb->enable_gpio)) { |
77 | if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW) | |
78 | gpio_set_value(pb->enable_gpio, 1); | |
79 | else | |
80 | gpio_set_value(pb->enable_gpio, 0); | |
81 | } | |
82 | ||
22ceeee1 | 83 | regulator_disable(pb->power_supply); |
97c38437 | 84 | pb->enabled = false; |
62b744a8 TR |
85 | } |
86 | ||
e4bfeda9 TR |
87 | static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness) |
88 | { | |
89 | unsigned int lth = pb->lth_brightness; | |
90 | int duty_cycle; | |
91 | ||
92 | if (pb->levels) | |
93 | duty_cycle = pb->levels[brightness]; | |
94 | else | |
95 | duty_cycle = brightness; | |
96 | ||
97 | return (duty_cycle * (pb->period - lth) / pb->scale) + lth; | |
98 | } | |
99 | ||
42796d37 | 100 | static int pwm_backlight_update_status(struct backlight_device *bl) |
101 | { | |
e6e3dbf9 | 102 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 103 | int brightness = bl->props.brightness; |
e4bfeda9 | 104 | int duty_cycle; |
42796d37 | 105 | |
0132267d AC |
106 | if (bl->props.power != FB_BLANK_UNBLANK || |
107 | bl->props.fb_blank != FB_BLANK_UNBLANK || | |
108 | bl->props.state & BL_CORE_FBBLANK) | |
42796d37 | 109 | brightness = 0; |
110 | ||
3b73125a | 111 | if (pb->notify) |
cfc3899f | 112 | brightness = pb->notify(pb->dev, brightness); |
3b73125a | 113 | |
e4bfeda9 TR |
114 | if (brightness > 0) { |
115 | duty_cycle = compute_duty_cycle(pb, brightness); | |
116 | pwm_config(pb->pwm, duty_cycle, pb->period); | |
8f43e18e | 117 | pwm_backlight_power_on(pb, brightness); |
e4bfeda9 | 118 | } else |
62b744a8 | 119 | pwm_backlight_power_off(pb); |
cc7993f6 DL |
120 | |
121 | if (pb->notify_after) | |
122 | pb->notify_after(pb->dev, brightness); | |
123 | ||
42796d37 | 124 | return 0; |
125 | } | |
126 | ||
127 | static int pwm_backlight_get_brightness(struct backlight_device *bl) | |
128 | { | |
129 | return bl->props.brightness; | |
130 | } | |
131 | ||
ef0a5e80 RM |
132 | static int pwm_backlight_check_fb(struct backlight_device *bl, |
133 | struct fb_info *info) | |
134 | { | |
e6e3dbf9 | 135 | struct pwm_bl_data *pb = bl_get_data(bl); |
ef0a5e80 RM |
136 | |
137 | return !pb->check_fb || pb->check_fb(pb->dev, info); | |
138 | } | |
139 | ||
9905a43b | 140 | static const struct backlight_ops pwm_backlight_ops = { |
42796d37 | 141 | .update_status = pwm_backlight_update_status, |
142 | .get_brightness = pwm_backlight_get_brightness, | |
ef0a5e80 | 143 | .check_fb = pwm_backlight_check_fb, |
42796d37 | 144 | }; |
145 | ||
3e3ed6cd TR |
146 | #ifdef CONFIG_OF |
147 | static int pwm_backlight_parse_dt(struct device *dev, | |
148 | struct platform_pwm_backlight_data *data) | |
149 | { | |
150 | struct device_node *node = dev->of_node; | |
8265b2e4 | 151 | enum of_gpio_flags flags; |
3e3ed6cd TR |
152 | struct property *prop; |
153 | int length; | |
154 | u32 value; | |
155 | int ret; | |
156 | ||
157 | if (!node) | |
158 | return -ENODEV; | |
159 | ||
160 | memset(data, 0, sizeof(*data)); | |
161 | ||
162 | /* determine the number of brightness levels */ | |
163 | prop = of_find_property(node, "brightness-levels", &length); | |
164 | if (!prop) | |
165 | return -EINVAL; | |
166 | ||
167 | data->max_brightness = length / sizeof(u32); | |
168 | ||
169 | /* read brightness levels from DT property */ | |
170 | if (data->max_brightness > 0) { | |
171 | size_t size = sizeof(*data->levels) * data->max_brightness; | |
172 | ||
173 | data->levels = devm_kzalloc(dev, size, GFP_KERNEL); | |
174 | if (!data->levels) | |
175 | return -ENOMEM; | |
176 | ||
177 | ret = of_property_read_u32_array(node, "brightness-levels", | |
178 | data->levels, | |
179 | data->max_brightness); | |
180 | if (ret < 0) | |
181 | return ret; | |
182 | ||
183 | ret = of_property_read_u32(node, "default-brightness-level", | |
184 | &value); | |
185 | if (ret < 0) | |
186 | return ret; | |
187 | ||
3e3ed6cd TR |
188 | data->dft_brightness = value; |
189 | data->max_brightness--; | |
190 | } | |
191 | ||
8265b2e4 TR |
192 | data->enable_gpio = of_get_named_gpio_flags(node, "enable-gpios", 0, |
193 | &flags); | |
194 | if (data->enable_gpio == -EPROBE_DEFER) | |
195 | return -EPROBE_DEFER; | |
196 | ||
197 | if (gpio_is_valid(data->enable_gpio) && (flags & OF_GPIO_ACTIVE_LOW)) | |
198 | data->enable_gpio_flags |= PWM_BACKLIGHT_GPIO_ACTIVE_LOW; | |
3e3ed6cd TR |
199 | |
200 | return 0; | |
201 | } | |
202 | ||
203 | static struct of_device_id pwm_backlight_of_match[] = { | |
204 | { .compatible = "pwm-backlight" }, | |
205 | { } | |
206 | }; | |
207 | ||
208 | MODULE_DEVICE_TABLE(of, pwm_backlight_of_match); | |
209 | #else | |
210 | static int pwm_backlight_parse_dt(struct device *dev, | |
211 | struct platform_pwm_backlight_data *data) | |
212 | { | |
213 | return -ENODEV; | |
214 | } | |
215 | #endif | |
216 | ||
42796d37 | 217 | static int pwm_backlight_probe(struct platform_device *pdev) |
218 | { | |
219 | struct platform_pwm_backlight_data *data = pdev->dev.platform_data; | |
3e3ed6cd TR |
220 | struct platform_pwm_backlight_data defdata; |
221 | struct backlight_properties props; | |
42796d37 | 222 | struct backlight_device *bl; |
223 | struct pwm_bl_data *pb; | |
3b73125a | 224 | int ret; |
42796d37 | 225 | |
14563a4e | 226 | if (!data) { |
3e3ed6cd TR |
227 | ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); |
228 | if (ret < 0) { | |
229 | dev_err(&pdev->dev, "failed to find platform data\n"); | |
230 | return ret; | |
231 | } | |
232 | ||
233 | data = &defdata; | |
14563a4e | 234 | } |
42796d37 | 235 | |
3b73125a PZ |
236 | if (data->init) { |
237 | ret = data->init(&pdev->dev); | |
238 | if (ret < 0) | |
239 | return ret; | |
240 | } | |
241 | ||
ce969228 | 242 | pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); |
3b73125a | 243 | if (!pb) { |
14563a4e | 244 | dev_err(&pdev->dev, "no memory for state\n"); |
3b73125a PZ |
245 | ret = -ENOMEM; |
246 | goto err_alloc; | |
247 | } | |
42796d37 | 248 | |
3e3ed6cd | 249 | if (data->levels) { |
8f43e18e MD |
250 | unsigned int i; |
251 | ||
252 | for (i = 0; i <= data->max_brightness; i++) | |
253 | if (data->levels[i] > pb->scale) | |
254 | pb->scale = data->levels[i]; | |
255 | ||
3e3ed6cd TR |
256 | pb->levels = data->levels; |
257 | } else | |
8f43e18e | 258 | pb->scale = data->max_brightness; |
3e3ed6cd | 259 | |
8265b2e4 TR |
260 | pb->enable_gpio = data->enable_gpio; |
261 | pb->enable_gpio_flags = data->enable_gpio_flags; | |
3b73125a | 262 | pb->notify = data->notify; |
cc7993f6 | 263 | pb->notify_after = data->notify_after; |
ef0a5e80 | 264 | pb->check_fb = data->check_fb; |
3e3ed6cd | 265 | pb->exit = data->exit; |
cfc3899f | 266 | pb->dev = &pdev->dev; |
97c38437 | 267 | pb->enabled = false; |
42796d37 | 268 | |
8265b2e4 TR |
269 | if (gpio_is_valid(pb->enable_gpio)) { |
270 | unsigned long flags; | |
271 | ||
272 | if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW) | |
273 | flags = GPIOF_OUT_INIT_HIGH; | |
274 | else | |
275 | flags = GPIOF_OUT_INIT_LOW; | |
276 | ||
277 | ret = gpio_request_one(pb->enable_gpio, flags, "enable"); | |
278 | if (ret < 0) { | |
279 | dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n", | |
280 | pb->enable_gpio, ret); | |
281 | goto err_alloc; | |
282 | } | |
283 | } | |
284 | ||
22ceeee1 TR |
285 | pb->power_supply = devm_regulator_get(&pdev->dev, "power"); |
286 | if (IS_ERR(pb->power_supply)) { | |
287 | ret = PTR_ERR(pb->power_supply); | |
288 | goto err_gpio; | |
289 | } | |
290 | ||
60ce7028 | 291 | pb->pwm = devm_pwm_get(&pdev->dev, NULL); |
43bda1a6 | 292 | if (IS_ERR(pb->pwm)) { |
3e3ed6cd TR |
293 | dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); |
294 | ||
295 | pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); | |
296 | if (IS_ERR(pb->pwm)) { | |
297 | dev_err(&pdev->dev, "unable to request legacy PWM\n"); | |
298 | ret = PTR_ERR(pb->pwm); | |
8265b2e4 | 299 | goto err_gpio; |
3e3ed6cd TR |
300 | } |
301 | } | |
302 | ||
303 | dev_dbg(&pdev->dev, "got pwm for backlight\n"); | |
304 | ||
305 | /* | |
306 | * The DT case will set the pwm_period_ns field to 0 and store the | |
307 | * period, parsed from the DT, in the PWM device. For the non-DT case, | |
308 | * set the period from platform data. | |
309 | */ | |
310 | if (data->pwm_period_ns > 0) | |
311 | pwm_set_period(pb->pwm, data->pwm_period_ns); | |
312 | ||
313 | pb->period = pwm_get_period(pb->pwm); | |
8f43e18e | 314 | pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale); |
42796d37 | 315 | |
a19a6ee6 | 316 | memset(&props, 0, sizeof(struct backlight_properties)); |
bb7ca747 | 317 | props.type = BACKLIGHT_RAW; |
a19a6ee6 MG |
318 | props.max_brightness = data->max_brightness; |
319 | bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb, | |
320 | &pwm_backlight_ops, &props); | |
42796d37 | 321 | if (IS_ERR(bl)) { |
322 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
3b73125a | 323 | ret = PTR_ERR(bl); |
8265b2e4 | 324 | goto err_gpio; |
42796d37 | 325 | } |
326 | ||
83cfd726 PU |
327 | if (data->dft_brightness > data->max_brightness) { |
328 | dev_warn(&pdev->dev, | |
329 | "invalid default brightness level: %u, using %u\n", | |
330 | data->dft_brightness, data->max_brightness); | |
331 | data->dft_brightness = data->max_brightness; | |
332 | } | |
333 | ||
42796d37 | 334 | bl->props.brightness = data->dft_brightness; |
335 | backlight_update_status(bl); | |
336 | ||
337 | platform_set_drvdata(pdev, bl); | |
338 | return 0; | |
3b73125a | 339 | |
8265b2e4 TR |
340 | err_gpio: |
341 | if (gpio_is_valid(pb->enable_gpio)) | |
342 | gpio_free(pb->enable_gpio); | |
3b73125a PZ |
343 | err_alloc: |
344 | if (data->exit) | |
345 | data->exit(&pdev->dev); | |
346 | return ret; | |
42796d37 | 347 | } |
348 | ||
349 | static int pwm_backlight_remove(struct platform_device *pdev) | |
350 | { | |
351 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
e6e3dbf9 | 352 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 353 | |
354 | backlight_device_unregister(bl); | |
62b744a8 | 355 | pwm_backlight_power_off(pb); |
668e63c6 | 356 | |
3e3ed6cd TR |
357 | if (pb->exit) |
358 | pb->exit(&pdev->dev); | |
668e63c6 | 359 | |
42796d37 | 360 | return 0; |
361 | } | |
362 | ||
c791126b | 363 | #ifdef CONFIG_PM_SLEEP |
e2c17bc6 | 364 | static int pwm_backlight_suspend(struct device *dev) |
42796d37 | 365 | { |
e2c17bc6 | 366 | struct backlight_device *bl = dev_get_drvdata(dev); |
e6e3dbf9 | 367 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 368 | |
82e8b542 | 369 | if (pb->notify) |
cfc3899f | 370 | pb->notify(pb->dev, 0); |
668e63c6 | 371 | |
62b744a8 | 372 | pwm_backlight_power_off(pb); |
668e63c6 | 373 | |
cc7993f6 DL |
374 | if (pb->notify_after) |
375 | pb->notify_after(pb->dev, 0); | |
668e63c6 | 376 | |
42796d37 | 377 | return 0; |
378 | } | |
379 | ||
e2c17bc6 | 380 | static int pwm_backlight_resume(struct device *dev) |
42796d37 | 381 | { |
e2c17bc6 | 382 | struct backlight_device *bl = dev_get_drvdata(dev); |
42796d37 | 383 | |
384 | backlight_update_status(bl); | |
668e63c6 | 385 | |
42796d37 | 386 | return 0; |
387 | } | |
c791126b | 388 | #endif |
e2c17bc6 MB |
389 | |
390 | static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend, | |
391 | pwm_backlight_resume); | |
392 | ||
42796d37 | 393 | static struct platform_driver pwm_backlight_driver = { |
394 | .driver = { | |
3e3ed6cd TR |
395 | .name = "pwm-backlight", |
396 | .owner = THIS_MODULE, | |
3e3ed6cd | 397 | .pm = &pwm_backlight_pm_ops, |
3e3ed6cd | 398 | .of_match_table = of_match_ptr(pwm_backlight_of_match), |
42796d37 | 399 | }, |
400 | .probe = pwm_backlight_probe, | |
401 | .remove = pwm_backlight_remove, | |
42796d37 | 402 | }; |
403 | ||
81178e02 | 404 | module_platform_driver(pwm_backlight_driver); |
42796d37 | 405 | |
406 | MODULE_DESCRIPTION("PWM based Backlight Driver"); | |
407 | MODULE_LICENSE("GPL"); | |
8cd68198 | 408 | MODULE_ALIAS("platform:pwm-backlight"); |