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 | ||
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 AC |
57 | if (pb->enable_gpio) |
58 | gpiod_set_value(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 AC |
72 | if (pb->enable_gpio) |
73 | gpiod_set_value(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 | ||
42796d37 | 195 | static int pwm_backlight_probe(struct platform_device *pdev) |
196 | { | |
c512794c | 197 | struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev); |
3e3ed6cd TR |
198 | struct platform_pwm_backlight_data defdata; |
199 | struct backlight_properties props; | |
42796d37 | 200 | struct backlight_device *bl; |
87770780 | 201 | struct device_node *node = pdev->dev.of_node; |
42796d37 | 202 | struct pwm_bl_data *pb; |
3698d7e7 | 203 | int initial_blank = FB_BLANK_UNBLANK; |
6cb9644d | 204 | struct pwm_args pargs; |
3b73125a | 205 | int ret; |
42796d37 | 206 | |
14563a4e | 207 | if (!data) { |
3e3ed6cd TR |
208 | ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); |
209 | if (ret < 0) { | |
210 | dev_err(&pdev->dev, "failed to find platform data\n"); | |
211 | return ret; | |
212 | } | |
213 | ||
214 | data = &defdata; | |
14563a4e | 215 | } |
42796d37 | 216 | |
3b73125a PZ |
217 | if (data->init) { |
218 | ret = data->init(&pdev->dev); | |
219 | if (ret < 0) | |
220 | return ret; | |
221 | } | |
222 | ||
ce969228 | 223 | pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); |
3b73125a PZ |
224 | if (!pb) { |
225 | ret = -ENOMEM; | |
226 | goto err_alloc; | |
227 | } | |
42796d37 | 228 | |
3e3ed6cd | 229 | if (data->levels) { |
8f43e18e MD |
230 | unsigned int i; |
231 | ||
232 | for (i = 0; i <= data->max_brightness; i++) | |
233 | if (data->levels[i] > pb->scale) | |
234 | pb->scale = data->levels[i]; | |
235 | ||
3e3ed6cd TR |
236 | pb->levels = data->levels; |
237 | } else | |
8f43e18e | 238 | pb->scale = data->max_brightness; |
3e3ed6cd | 239 | |
3b73125a | 240 | pb->notify = data->notify; |
cc7993f6 | 241 | pb->notify_after = data->notify_after; |
ef0a5e80 | 242 | pb->check_fb = data->check_fb; |
3e3ed6cd | 243 | pb->exit = data->exit; |
cfc3899f | 244 | pb->dev = &pdev->dev; |
97c38437 | 245 | pb->enabled = false; |
42796d37 | 246 | |
cdaefcce | 247 | pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", |
3698d7e7 | 248 | GPIOD_ASIS); |
257462db AC |
249 | if (IS_ERR(pb->enable_gpio)) { |
250 | ret = PTR_ERR(pb->enable_gpio); | |
ff9c5422 | 251 | goto err_alloc; |
257462db | 252 | } |
8265b2e4 | 253 | |
257462db AC |
254 | /* |
255 | * Compatibility fallback for drivers still using the integer GPIO | |
256 | * platform data. Must go away soon. | |
257 | */ | |
258 | if (!pb->enable_gpio && gpio_is_valid(data->enable_gpio)) { | |
259 | ret = devm_gpio_request_one(&pdev->dev, data->enable_gpio, | |
260 | GPIOF_OUT_INIT_HIGH, "enable"); | |
8265b2e4 TR |
261 | if (ret < 0) { |
262 | dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n", | |
257462db | 263 | data->enable_gpio, ret); |
8265b2e4 TR |
264 | goto err_alloc; |
265 | } | |
257462db AC |
266 | |
267 | pb->enable_gpio = gpio_to_desc(data->enable_gpio); | |
8265b2e4 TR |
268 | } |
269 | ||
3698d7e7 PZ |
270 | if (pb->enable_gpio) { |
271 | /* | |
272 | * If the driver is probed from the device tree and there is a | |
273 | * phandle link pointing to the backlight node, it is safe to | |
274 | * assume that another driver will enable the backlight at the | |
275 | * appropriate time. Therefore, if it is disabled, keep it so. | |
276 | */ | |
87770780 | 277 | if (node && node->phandle && |
3698d7e7 PZ |
278 | gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT && |
279 | gpiod_get_value(pb->enable_gpio) == 0) | |
280 | initial_blank = FB_BLANK_POWERDOWN; | |
281 | else | |
282 | gpiod_direction_output(pb->enable_gpio, 1); | |
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); | |
257462db | 288 | goto err_alloc; |
22ceeee1 | 289 | } |
42796d37 | 290 | |
87770780 | 291 | if (node && node->phandle && !regulator_is_enabled(pb->power_supply)) |
3698d7e7 PZ |
292 | initial_blank = FB_BLANK_POWERDOWN; |
293 | ||
60ce7028 | 294 | pb->pwm = devm_pwm_get(&pdev->dev, NULL); |
87770780 | 295 | if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) { |
3e3ed6cd | 296 | dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); |
edf387b6 | 297 | pb->legacy = true; |
3e3ed6cd | 298 | pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); |
dc881123 VZ |
299 | } |
300 | ||
301 | if (IS_ERR(pb->pwm)) { | |
302 | ret = PTR_ERR(pb->pwm); | |
303 | if (ret != -EPROBE_DEFER) | |
304 | dev_err(&pdev->dev, "unable to request PWM\n"); | |
305 | goto err_alloc; | |
3e3ed6cd TR |
306 | } |
307 | ||
308 | dev_dbg(&pdev->dev, "got pwm for backlight\n"); | |
309 | ||
6cb9644d BB |
310 | /* |
311 | * FIXME: pwm_apply_args() should be removed when switching to | |
312 | * the atomic PWM API. | |
313 | */ | |
314 | pwm_apply_args(pb->pwm); | |
315 | ||
3e3ed6cd TR |
316 | /* |
317 | * The DT case will set the pwm_period_ns field to 0 and store the | |
318 | * period, parsed from the DT, in the PWM device. For the non-DT case, | |
16fc3352 AB |
319 | * set the period from platform data if it has not already been set |
320 | * via the PWM lookup table. | |
3e3ed6cd | 321 | */ |
6cb9644d BB |
322 | pwm_get_args(pb->pwm, &pargs); |
323 | pb->period = pargs.period; | |
7f044b09 | 324 | if (!pb->period && (data->pwm_period_ns > 0)) |
16fc3352 | 325 | pb->period = data->pwm_period_ns; |
3e3ed6cd | 326 | |
8f43e18e | 327 | pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale); |
42796d37 | 328 | |
a19a6ee6 | 329 | memset(&props, 0, sizeof(struct backlight_properties)); |
bb7ca747 | 330 | props.type = BACKLIGHT_RAW; |
a19a6ee6 MG |
331 | props.max_brightness = data->max_brightness; |
332 | bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb, | |
333 | &pwm_backlight_ops, &props); | |
42796d37 | 334 | if (IS_ERR(bl)) { |
335 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
3b73125a | 336 | ret = PTR_ERR(bl); |
60d613d6 VZ |
337 | if (pb->legacy) |
338 | pwm_free(pb->pwm); | |
257462db | 339 | goto err_alloc; |
42796d37 | 340 | } |
341 | ||
83cfd726 PU |
342 | if (data->dft_brightness > data->max_brightness) { |
343 | dev_warn(&pdev->dev, | |
344 | "invalid default brightness level: %u, using %u\n", | |
345 | data->dft_brightness, data->max_brightness); | |
346 | data->dft_brightness = data->max_brightness; | |
347 | } | |
348 | ||
42796d37 | 349 | bl->props.brightness = data->dft_brightness; |
3698d7e7 | 350 | bl->props.power = initial_blank; |
42796d37 | 351 | backlight_update_status(bl); |
352 | ||
353 | platform_set_drvdata(pdev, bl); | |
354 | return 0; | |
3b73125a | 355 | |
3b73125a PZ |
356 | err_alloc: |
357 | if (data->exit) | |
358 | data->exit(&pdev->dev); | |
359 | return ret; | |
42796d37 | 360 | } |
361 | ||
362 | static int pwm_backlight_remove(struct platform_device *pdev) | |
363 | { | |
364 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
e6e3dbf9 | 365 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 366 | |
367 | backlight_device_unregister(bl); | |
62b744a8 | 368 | pwm_backlight_power_off(pb); |
668e63c6 | 369 | |
3e3ed6cd TR |
370 | if (pb->exit) |
371 | pb->exit(&pdev->dev); | |
edf387b6 VZ |
372 | if (pb->legacy) |
373 | pwm_free(pb->pwm); | |
668e63c6 | 374 | |
42796d37 | 375 | return 0; |
376 | } | |
377 | ||
5f33b896 TR |
378 | static void pwm_backlight_shutdown(struct platform_device *pdev) |
379 | { | |
380 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
381 | struct pwm_bl_data *pb = bl_get_data(bl); | |
382 | ||
383 | pwm_backlight_power_off(pb); | |
384 | } | |
385 | ||
c791126b | 386 | #ifdef CONFIG_PM_SLEEP |
e2c17bc6 | 387 | static int pwm_backlight_suspend(struct device *dev) |
42796d37 | 388 | { |
e2c17bc6 | 389 | struct backlight_device *bl = dev_get_drvdata(dev); |
e6e3dbf9 | 390 | struct pwm_bl_data *pb = bl_get_data(bl); |
42796d37 | 391 | |
82e8b542 | 392 | if (pb->notify) |
cfc3899f | 393 | pb->notify(pb->dev, 0); |
668e63c6 | 394 | |
62b744a8 | 395 | pwm_backlight_power_off(pb); |
668e63c6 | 396 | |
cc7993f6 DL |
397 | if (pb->notify_after) |
398 | pb->notify_after(pb->dev, 0); | |
668e63c6 | 399 | |
42796d37 | 400 | return 0; |
401 | } | |
402 | ||
e2c17bc6 | 403 | static int pwm_backlight_resume(struct device *dev) |
42796d37 | 404 | { |
e2c17bc6 | 405 | struct backlight_device *bl = dev_get_drvdata(dev); |
42796d37 | 406 | |
407 | backlight_update_status(bl); | |
668e63c6 | 408 | |
42796d37 | 409 | return 0; |
410 | } | |
c791126b | 411 | #endif |
e2c17bc6 | 412 | |
1dea1fd0 HL |
413 | static const struct dev_pm_ops pwm_backlight_pm_ops = { |
414 | #ifdef CONFIG_PM_SLEEP | |
415 | .suspend = pwm_backlight_suspend, | |
416 | .resume = pwm_backlight_resume, | |
417 | .poweroff = pwm_backlight_suspend, | |
418 | .restore = pwm_backlight_resume, | |
419 | #endif | |
420 | }; | |
e2c17bc6 | 421 | |
42796d37 | 422 | static struct platform_driver pwm_backlight_driver = { |
423 | .driver = { | |
3e3ed6cd | 424 | .name = "pwm-backlight", |
3e3ed6cd | 425 | .pm = &pwm_backlight_pm_ops, |
3e3ed6cd | 426 | .of_match_table = of_match_ptr(pwm_backlight_of_match), |
42796d37 | 427 | }, |
428 | .probe = pwm_backlight_probe, | |
429 | .remove = pwm_backlight_remove, | |
5f33b896 | 430 | .shutdown = pwm_backlight_shutdown, |
42796d37 | 431 | }; |
432 | ||
81178e02 | 433 | module_platform_driver(pwm_backlight_driver); |
42796d37 | 434 | |
435 | MODULE_DESCRIPTION("PWM based Backlight Driver"); | |
436 | MODULE_LICENSE("GPL"); | |
8cd68198 | 437 | MODULE_ALIAS("platform:pwm-backlight"); |