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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 | ||
257462db | 13 | #include <linux/gpio/consumer.h> |
8265b2e4 | 14 | #include <linux/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; |
257462db | 35 | struct gpio_desc *enable_gpio; |
8f43e18e | 36 | unsigned int scale; |
edf387b6 | 37 | bool legacy; |
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 | 47 | { |
73d4e2b8 | 48 | int err; |
62b744a8 | 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 | ||
257462db | 57 | if (pb->enable_gpio) |
0c9501f8 | 58 | gpiod_set_value_cansleep(pb->enable_gpio, 1); |
8265b2e4 | 59 | |
62b744a8 | 60 | pwm_enable(pb->pwm); |
97c38437 | 61 | pb->enabled = true; |
62b744a8 TR |
62 | } |
63 | ||
64 | static void pwm_backlight_power_off(struct pwm_bl_data *pb) | |
65 | { | |
97c38437 TR |
66 | if (!pb->enabled) |
67 | return; | |
68 | ||
62b744a8 TR |
69 | pwm_config(pb->pwm, 0, pb->period); |
70 | pwm_disable(pb->pwm); | |
97c38437 | 71 | |
257462db | 72 | if (pb->enable_gpio) |
0c9501f8 | 73 | gpiod_set_value_cansleep(pb->enable_gpio, 0); |
8265b2e4 | 74 | |
22ceeee1 | 75 | regulator_disable(pb->power_supply); |
97c38437 | 76 | pb->enabled = false; |
62b744a8 TR |
77 | } |
78 | ||
e4bfeda9 TR |
79 | static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness) |
80 | { | |
81 | unsigned int lth = pb->lth_brightness; | |
82 | int duty_cycle; | |
83 | ||
84 | if (pb->levels) | |
85 | duty_cycle = pb->levels[brightness]; | |
86 | else | |
87 | duty_cycle = brightness; | |
88 | ||
89 | return (duty_cycle * (pb->period - lth) / pb->scale) + lth; | |
90 | } | |
91 | ||
42796d37 | 92 | static int pwm_backlight_update_status(struct backlight_device *bl) |
93 | { | |
e6e3dbf9 | 94 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 95 | int brightness = bl->props.brightness; |
e4bfeda9 | 96 | int duty_cycle; |
42796d37 | 97 | |
0132267d AC |
98 | if (bl->props.power != FB_BLANK_UNBLANK || |
99 | bl->props.fb_blank != FB_BLANK_UNBLANK || | |
100 | bl->props.state & BL_CORE_FBBLANK) | |
42796d37 | 101 | brightness = 0; |
102 | ||
3b73125a | 103 | if (pb->notify) |
cfc3899f | 104 | brightness = pb->notify(pb->dev, brightness); |
3b73125a | 105 | |
e4bfeda9 TR |
106 | if (brightness > 0) { |
107 | duty_cycle = compute_duty_cycle(pb, brightness); | |
9fb978b1 | 108 | pwm_config(pb->pwm, duty_cycle, pb->period); |
8f43e18e | 109 | pwm_backlight_power_on(pb, brightness); |
e4bfeda9 | 110 | } else |
62b744a8 | 111 | pwm_backlight_power_off(pb); |
cc7993f6 DL |
112 | |
113 | if (pb->notify_after) | |
114 | pb->notify_after(pb->dev, brightness); | |
115 | ||
42796d37 | 116 | return 0; |
117 | } | |
118 | ||
ef0a5e80 RM |
119 | static int pwm_backlight_check_fb(struct backlight_device *bl, |
120 | struct fb_info *info) | |
121 | { | |
e6e3dbf9 | 122 | struct pwm_bl_data *pb = bl_get_data(bl); |
ef0a5e80 RM |
123 | |
124 | return !pb->check_fb || pb->check_fb(pb->dev, info); | |
125 | } | |
126 | ||
9905a43b | 127 | static const struct backlight_ops pwm_backlight_ops = { |
42796d37 | 128 | .update_status = pwm_backlight_update_status, |
ef0a5e80 | 129 | .check_fb = pwm_backlight_check_fb, |
42796d37 | 130 | }; |
131 | ||
3e3ed6cd TR |
132 | #ifdef CONFIG_OF |
133 | static int pwm_backlight_parse_dt(struct device *dev, | |
134 | struct platform_pwm_backlight_data *data) | |
135 | { | |
136 | struct device_node *node = dev->of_node; | |
137 | struct property *prop; | |
138 | int length; | |
139 | u32 value; | |
140 | int ret; | |
141 | ||
142 | if (!node) | |
143 | return -ENODEV; | |
144 | ||
145 | memset(data, 0, sizeof(*data)); | |
146 | ||
147 | /* determine the number of brightness levels */ | |
148 | prop = of_find_property(node, "brightness-levels", &length); | |
149 | if (!prop) | |
150 | return -EINVAL; | |
151 | ||
152 | data->max_brightness = length / sizeof(u32); | |
153 | ||
154 | /* read brightness levels from DT property */ | |
155 | if (data->max_brightness > 0) { | |
156 | size_t size = sizeof(*data->levels) * data->max_brightness; | |
157 | ||
158 | data->levels = devm_kzalloc(dev, size, GFP_KERNEL); | |
159 | if (!data->levels) | |
160 | return -ENOMEM; | |
161 | ||
162 | ret = of_property_read_u32_array(node, "brightness-levels", | |
163 | data->levels, | |
164 | data->max_brightness); | |
165 | if (ret < 0) | |
166 | return ret; | |
167 | ||
168 | ret = of_property_read_u32(node, "default-brightness-level", | |
169 | &value); | |
170 | if (ret < 0) | |
171 | return ret; | |
172 | ||
3e3ed6cd TR |
173 | data->dft_brightness = value; |
174 | data->max_brightness--; | |
175 | } | |
176 | ||
937222c4 | 177 | data->enable_gpio = -EINVAL; |
3e3ed6cd TR |
178 | return 0; |
179 | } | |
180 | ||
181 | static struct of_device_id pwm_backlight_of_match[] = { | |
182 | { .compatible = "pwm-backlight" }, | |
183 | { } | |
184 | }; | |
185 | ||
186 | MODULE_DEVICE_TABLE(of, pwm_backlight_of_match); | |
187 | #else | |
188 | static int pwm_backlight_parse_dt(struct device *dev, | |
189 | struct platform_pwm_backlight_data *data) | |
190 | { | |
191 | return -ENODEV; | |
192 | } | |
193 | #endif | |
194 | ||
7613c922 PU |
195 | static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb) |
196 | { | |
197 | struct device_node *node = pb->dev->of_node; | |
198 | ||
199 | /* Not booted with device tree or no phandle link to the node */ | |
200 | if (!node || !node->phandle) | |
201 | return FB_BLANK_UNBLANK; | |
202 | ||
203 | /* | |
204 | * If the driver is probed from the device tree and there is a | |
205 | * phandle link pointing to the backlight node, it is safe to | |
206 | * assume that another driver will enable the backlight at the | |
207 | * appropriate time. Therefore, if it is disabled, keep it so. | |
208 | */ | |
209 | ||
210 | /* if the enable GPIO is disabled, do not enable the backlight */ | |
211 | if (pb->enable_gpio && gpiod_get_value(pb->enable_gpio) == 0) | |
212 | return FB_BLANK_POWERDOWN; | |
213 | ||
214 | /* The regulator is disabled, do not enable the backlight */ | |
215 | if (!regulator_is_enabled(pb->power_supply)) | |
216 | return FB_BLANK_POWERDOWN; | |
217 | ||
d1b81294 PU |
218 | /* The PWM is disabled, keep it like this */ |
219 | if (!pwm_is_enabled(pb->pwm)) | |
220 | return FB_BLANK_POWERDOWN; | |
221 | ||
7613c922 PU |
222 | return FB_BLANK_UNBLANK; |
223 | } | |
224 | ||
42796d37 | 225 | static int pwm_backlight_probe(struct platform_device *pdev) |
226 | { | |
c512794c | 227 | struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev); |
3e3ed6cd TR |
228 | struct platform_pwm_backlight_data defdata; |
229 | struct backlight_properties props; | |
42796d37 | 230 | struct backlight_device *bl; |
87770780 | 231 | struct device_node *node = pdev->dev.of_node; |
42796d37 | 232 | struct pwm_bl_data *pb; |
6cb9644d | 233 | struct pwm_args pargs; |
3b73125a | 234 | int ret; |
42796d37 | 235 | |
14563a4e | 236 | if (!data) { |
3e3ed6cd TR |
237 | ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); |
238 | if (ret < 0) { | |
239 | dev_err(&pdev->dev, "failed to find platform data\n"); | |
240 | return ret; | |
241 | } | |
242 | ||
243 | data = &defdata; | |
14563a4e | 244 | } |
42796d37 | 245 | |
3b73125a PZ |
246 | if (data->init) { |
247 | ret = data->init(&pdev->dev); | |
248 | if (ret < 0) | |
249 | return ret; | |
250 | } | |
251 | ||
ce969228 | 252 | pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); |
3b73125a PZ |
253 | if (!pb) { |
254 | ret = -ENOMEM; | |
255 | goto err_alloc; | |
256 | } | |
42796d37 | 257 | |
3e3ed6cd | 258 | if (data->levels) { |
8f43e18e MD |
259 | unsigned int i; |
260 | ||
261 | for (i = 0; i <= data->max_brightness; i++) | |
262 | if (data->levels[i] > pb->scale) | |
263 | pb->scale = data->levels[i]; | |
264 | ||
3e3ed6cd TR |
265 | pb->levels = data->levels; |
266 | } else | |
8f43e18e | 267 | pb->scale = data->max_brightness; |
3e3ed6cd | 268 | |
3b73125a | 269 | pb->notify = data->notify; |
cc7993f6 | 270 | pb->notify_after = data->notify_after; |
ef0a5e80 | 271 | pb->check_fb = data->check_fb; |
3e3ed6cd | 272 | pb->exit = data->exit; |
cfc3899f | 273 | pb->dev = &pdev->dev; |
97c38437 | 274 | pb->enabled = false; |
42796d37 | 275 | |
cdaefcce | 276 | pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", |
3698d7e7 | 277 | GPIOD_ASIS); |
257462db AC |
278 | if (IS_ERR(pb->enable_gpio)) { |
279 | ret = PTR_ERR(pb->enable_gpio); | |
ff9c5422 | 280 | goto err_alloc; |
257462db | 281 | } |
8265b2e4 | 282 | |
257462db AC |
283 | /* |
284 | * Compatibility fallback for drivers still using the integer GPIO | |
285 | * platform data. Must go away soon. | |
286 | */ | |
287 | if (!pb->enable_gpio && gpio_is_valid(data->enable_gpio)) { | |
288 | ret = devm_gpio_request_one(&pdev->dev, data->enable_gpio, | |
289 | GPIOF_OUT_INIT_HIGH, "enable"); | |
8265b2e4 TR |
290 | if (ret < 0) { |
291 | dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n", | |
257462db | 292 | data->enable_gpio, ret); |
8265b2e4 TR |
293 | goto err_alloc; |
294 | } | |
257462db AC |
295 | |
296 | pb->enable_gpio = gpio_to_desc(data->enable_gpio); | |
8265b2e4 TR |
297 | } |
298 | ||
7613c922 | 299 | /* |
892c7788 GU |
300 | * If the GPIO is not known to be already configured as output, that |
301 | * is, if gpiod_get_direction returns either GPIOF_DIR_IN or -EINVAL, | |
302 | * change the direction to output and set the GPIO as active. | |
7613c922 PU |
303 | * Do not force the GPIO to active when it was already output as it |
304 | * could cause backlight flickering or we would enable the backlight too | |
305 | * early. Leave the decision of the initial backlight state for later. | |
306 | */ | |
307 | if (pb->enable_gpio && | |
892c7788 | 308 | gpiod_get_direction(pb->enable_gpio) != GPIOF_DIR_OUT) |
7613c922 | 309 | gpiod_direction_output(pb->enable_gpio, 1); |
3698d7e7 | 310 | |
22ceeee1 TR |
311 | pb->power_supply = devm_regulator_get(&pdev->dev, "power"); |
312 | if (IS_ERR(pb->power_supply)) { | |
313 | ret = PTR_ERR(pb->power_supply); | |
257462db | 314 | goto err_alloc; |
22ceeee1 | 315 | } |
42796d37 | 316 | |
60ce7028 | 317 | pb->pwm = devm_pwm_get(&pdev->dev, NULL); |
87770780 | 318 | if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) { |
3e3ed6cd | 319 | dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); |
edf387b6 | 320 | pb->legacy = true; |
3e3ed6cd | 321 | pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); |
dc881123 VZ |
322 | } |
323 | ||
324 | if (IS_ERR(pb->pwm)) { | |
325 | ret = PTR_ERR(pb->pwm); | |
326 | if (ret != -EPROBE_DEFER) | |
327 | dev_err(&pdev->dev, "unable to request PWM\n"); | |
328 | goto err_alloc; | |
3e3ed6cd TR |
329 | } |
330 | ||
331 | dev_dbg(&pdev->dev, "got pwm for backlight\n"); | |
332 | ||
6cb9644d BB |
333 | /* |
334 | * FIXME: pwm_apply_args() should be removed when switching to | |
335 | * the atomic PWM API. | |
336 | */ | |
337 | pwm_apply_args(pb->pwm); | |
338 | ||
3e3ed6cd TR |
339 | /* |
340 | * The DT case will set the pwm_period_ns field to 0 and store the | |
341 | * period, parsed from the DT, in the PWM device. For the non-DT case, | |
16fc3352 AB |
342 | * set the period from platform data if it has not already been set |
343 | * via the PWM lookup table. | |
3e3ed6cd | 344 | */ |
6cb9644d BB |
345 | pwm_get_args(pb->pwm, &pargs); |
346 | pb->period = pargs.period; | |
7f044b09 | 347 | if (!pb->period && (data->pwm_period_ns > 0)) |
16fc3352 | 348 | pb->period = data->pwm_period_ns; |
3e3ed6cd | 349 | |
8f43e18e | 350 | pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale); |
42796d37 | 351 | |
a19a6ee6 | 352 | memset(&props, 0, sizeof(struct backlight_properties)); |
bb7ca747 | 353 | props.type = BACKLIGHT_RAW; |
a19a6ee6 MG |
354 | props.max_brightness = data->max_brightness; |
355 | bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb, | |
356 | &pwm_backlight_ops, &props); | |
42796d37 | 357 | if (IS_ERR(bl)) { |
358 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
3b73125a | 359 | ret = PTR_ERR(bl); |
60d613d6 VZ |
360 | if (pb->legacy) |
361 | pwm_free(pb->pwm); | |
257462db | 362 | goto err_alloc; |
42796d37 | 363 | } |
364 | ||
83cfd726 PU |
365 | if (data->dft_brightness > data->max_brightness) { |
366 | dev_warn(&pdev->dev, | |
367 | "invalid default brightness level: %u, using %u\n", | |
368 | data->dft_brightness, data->max_brightness); | |
369 | data->dft_brightness = data->max_brightness; | |
370 | } | |
371 | ||
42796d37 | 372 | bl->props.brightness = data->dft_brightness; |
7613c922 | 373 | bl->props.power = pwm_backlight_initial_power_state(pb); |
42796d37 | 374 | backlight_update_status(bl); |
375 | ||
376 | platform_set_drvdata(pdev, bl); | |
377 | return 0; | |
3b73125a | 378 | |
3b73125a PZ |
379 | err_alloc: |
380 | if (data->exit) | |
381 | data->exit(&pdev->dev); | |
382 | return ret; | |
42796d37 | 383 | } |
384 | ||
385 | static int pwm_backlight_remove(struct platform_device *pdev) | |
386 | { | |
387 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
e6e3dbf9 | 388 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 389 | |
390 | backlight_device_unregister(bl); | |
62b744a8 | 391 | pwm_backlight_power_off(pb); |
668e63c6 | 392 | |
3e3ed6cd TR |
393 | if (pb->exit) |
394 | pb->exit(&pdev->dev); | |
edf387b6 VZ |
395 | if (pb->legacy) |
396 | pwm_free(pb->pwm); | |
668e63c6 | 397 | |
42796d37 | 398 | return 0; |
399 | } | |
400 | ||
5f33b896 TR |
401 | static void pwm_backlight_shutdown(struct platform_device *pdev) |
402 | { | |
403 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
404 | struct pwm_bl_data *pb = bl_get_data(bl); | |
405 | ||
406 | pwm_backlight_power_off(pb); | |
407 | } | |
408 | ||
c791126b | 409 | #ifdef CONFIG_PM_SLEEP |
e2c17bc6 | 410 | static int pwm_backlight_suspend(struct device *dev) |
42796d37 | 411 | { |
e2c17bc6 | 412 | struct backlight_device *bl = dev_get_drvdata(dev); |
e6e3dbf9 | 413 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 414 | |
82e8b542 | 415 | if (pb->notify) |
cfc3899f | 416 | pb->notify(pb->dev, 0); |
668e63c6 | 417 | |
62b744a8 | 418 | pwm_backlight_power_off(pb); |
668e63c6 | 419 | |
cc7993f6 DL |
420 | if (pb->notify_after) |
421 | pb->notify_after(pb->dev, 0); | |
668e63c6 | 422 | |
42796d37 | 423 | return 0; |
424 | } | |
425 | ||
e2c17bc6 | 426 | static int pwm_backlight_resume(struct device *dev) |
42796d37 | 427 | { |
e2c17bc6 | 428 | struct backlight_device *bl = dev_get_drvdata(dev); |
42796d37 | 429 | |
430 | backlight_update_status(bl); | |
668e63c6 | 431 | |
42796d37 | 432 | return 0; |
433 | } | |
c791126b | 434 | #endif |
e2c17bc6 | 435 | |
1dea1fd0 HL |
436 | static const struct dev_pm_ops pwm_backlight_pm_ops = { |
437 | #ifdef CONFIG_PM_SLEEP | |
438 | .suspend = pwm_backlight_suspend, | |
439 | .resume = pwm_backlight_resume, | |
440 | .poweroff = pwm_backlight_suspend, | |
441 | .restore = pwm_backlight_resume, | |
442 | #endif | |
443 | }; | |
e2c17bc6 | 444 | |
42796d37 | 445 | static struct platform_driver pwm_backlight_driver = { |
446 | .driver = { | |
3e3ed6cd | 447 | .name = "pwm-backlight", |
3e3ed6cd | 448 | .pm = &pwm_backlight_pm_ops, |
3e3ed6cd | 449 | .of_match_table = of_match_ptr(pwm_backlight_of_match), |
42796d37 | 450 | }, |
451 | .probe = pwm_backlight_probe, | |
452 | .remove = pwm_backlight_remove, | |
5f33b896 | 453 | .shutdown = pwm_backlight_shutdown, |
42796d37 | 454 | }; |
455 | ||
81178e02 | 456 | module_platform_driver(pwm_backlight_driver); |
42796d37 | 457 | |
458 | MODULE_DESCRIPTION("PWM based Backlight Driver"); | |
459 | MODULE_LICENSE("GPL"); | |
8cd68198 | 460 | MODULE_ALIAS("platform:pwm-backlight"); |