1 // SPDX-License-Identifier: GPL-2.0-only
35 					  int brightness);
37 					int brightness);
47 	pwm_get_state(pb->pwm, &state);  in pwm_backlight_power_on()
48 	if (pb->enabled)  in pwm_backlight_power_on()
51 	err = regulator_enable(pb->power_supply);  in pwm_backlight_power_on()
53 		dev_err(pb->dev, "failed to enable power supply\n");  in pwm_backlight_power_on()
56 	pwm_apply_state(pb->pwm, &state);  in pwm_backlight_power_on()
58 	if (pb->post_pwm_on_delay)  in pwm_backlight_power_on()
59 		msleep(pb->post_pwm_on_delay);  in pwm_backlight_power_on()
61 	if (pb->enable_gpio)  in pwm_backlight_power_on()
62 		gpiod_set_value_cansleep(pb->enable_gpio, 1);  in pwm_backlight_power_on()
64 	pb->enabled = true;  in pwm_backlight_power_on()
71 	pwm_get_state(pb->pwm, &state);  in pwm_backlight_power_off()
72 	if (!pb->enabled)  in pwm_backlight_power_off()
75 	if (pb->enable_gpio)  in pwm_backlight_power_off()
76 		gpiod_set_value_cansleep(pb->enable_gpio, 0);  in pwm_backlight_power_off()
78 	if (pb->pwm_off_delay)  in pwm_backlight_power_off()
79 		msleep(pb->pwm_off_delay);  in pwm_backlight_power_off()
83 	pwm_apply_state(pb->pwm, &state);  in pwm_backlight_power_off()
85 	regulator_disable(pb->power_supply);  in pwm_backlight_power_off()
86 	pb->enabled = false;  in pwm_backlight_power_off()
89 static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness)  in compute_duty_cycle()  argument
91 	unsigned int lth = pb->lth_brightness;  in compute_duty_cycle()
95 	pwm_get_state(pb->pwm, &state);  in compute_duty_cycle()
97 	if (pb->levels)  in compute_duty_cycle()
98 		duty_cycle = pb->levels[brightness];  in compute_duty_cycle()
100 		duty_cycle = brightness;  in compute_duty_cycle()
102 	duty_cycle *= state.period - lth;  in compute_duty_cycle()
103 	do_div(duty_cycle, pb->scale);  in compute_duty_cycle()
111 	int brightness = backlight_get_brightness(bl);  in pwm_backlight_update_status()  local
114 	if (pb->notify)  in pwm_backlight_update_status()
115 		brightness = pb->notify(pb->dev, brightness);  in pwm_backlight_update_status()
117 	if (brightness > 0) {  in pwm_backlight_update_status()
118 		pwm_get_state(pb->pwm, &state);  in pwm_backlight_update_status()
119 		state.duty_cycle = compute_duty_cycle(pb, brightness);  in pwm_backlight_update_status()
120 		pwm_apply_state(pb->pwm, &state);  in pwm_backlight_update_status()
126 	if (pb->notify_after)  in pwm_backlight_update_status()
127 		pb->notify_after(pb->dev, brightness);  in pwm_backlight_update_status()
137 	return !pb->check_fb || pb->check_fb(pb->dev, info);  in pwm_backlight_check_fb()
170 	 * as a fixed-point number in scale  in cie1931()
172 	 * expressed as a fixed-point number, so the above formulas  in cie1931()
181 		retval += 1ULL << (2*PWM_LUMINANCE_SHIFT - 1);  in cie1931()
189  * Create a default correction table for PWM values to create linear brightness
205 	data->max_brightness =  in pwm_backlight_brightness_default()
208 	data->levels = devm_kcalloc(dev, data->max_brightness,  in pwm_backlight_brightness_default()
209 				    sizeof(*data->levels), GFP_KERNEL);  in pwm_backlight_brightness_default()
210 	if (!data->levels)  in pwm_backlight_brightness_default()
211 		return -ENOMEM;  in pwm_backlight_brightness_default()
214 	for (i = 0; i < data->max_brightness; i++) {  in pwm_backlight_brightness_default()
216 				 data->max_brightness) * period;  in pwm_backlight_brightness_default()
219 			return -EINVAL;  in pwm_backlight_brightness_default()
220 		data->levels[i] = (unsigned int)retval;  in pwm_backlight_brightness_default()
223 	data->dft_brightness = data->max_brightness / 2;  in pwm_backlight_brightness_default()
224 	data->max_brightness--;  in pwm_backlight_brightness_default()
232 	struct device_node *node = dev->of_node;  in pwm_backlight_parse_dt()
243 		return -ENODEV;  in pwm_backlight_parse_dt()
248 	 * These values are optional and set as 0 by default, the out values  in pwm_backlight_parse_dt()
251 	of_property_read_u32(node, "post-pwm-on-delay-ms",  in pwm_backlight_parse_dt()
252 			     &data->post_pwm_on_delay);  in pwm_backlight_parse_dt()
253 	of_property_read_u32(node, "pwm-off-delay-ms", &data->pwm_off_delay);  in pwm_backlight_parse_dt()
256 	 * Determine the number of brightness levels, if this property is not  in pwm_backlight_parse_dt()
257 	 * set a default table of brightness levels will be used.  in pwm_backlight_parse_dt()
259 	prop = of_find_property(node, "brightness-levels", &length);  in pwm_backlight_parse_dt()
263 	data->max_brightness = length / sizeof(u32);  in pwm_backlight_parse_dt()
265 	/* read brightness levels from DT property */  in pwm_backlight_parse_dt()
266 	if (data->max_brightness > 0) {  in pwm_backlight_parse_dt()
267 		size_t size = sizeof(*data->levels) * data->max_brightness;  in pwm_backlight_parse_dt()
270 		data->levels = devm_kzalloc(dev, size, GFP_KERNEL);  in pwm_backlight_parse_dt()
271 		if (!data->levels)  in pwm_backlight_parse_dt()
272 			return -ENOMEM;  in pwm_backlight_parse_dt()
274 		ret = of_property_read_u32_array(node, "brightness-levels",  in pwm_backlight_parse_dt()
275 						 data->levels,  in pwm_backlight_parse_dt()
276 						 data->max_brightness);  in pwm_backlight_parse_dt()
280 		ret = of_property_read_u32(node, "default-brightness-level",  in pwm_backlight_parse_dt()
285 		data->dft_brightness = value;  in pwm_backlight_parse_dt()
289 		 * interpolation between each of the values of brightness levels  in pwm_backlight_parse_dt()
290 		 * and creates a new pre-computed table.  in pwm_backlight_parse_dt()
292 		of_property_read_u32(node, "num-interpolated-steps",  in pwm_backlight_parse_dt()
297 		 * brightness-levels table, otherwise we can't interpolate  in pwm_backlight_parse_dt()
301 			if (data->max_brightness < 2) {  in pwm_backlight_parse_dt()
303 				return -EINVAL;  in pwm_backlight_parse_dt()
307 			 * Recalculate the number of brightness levels, now  in pwm_backlight_parse_dt()
311 			for (i = 0; i < data->max_brightness - 1; i++) {  in pwm_backlight_parse_dt()
312 				if ((data->levels[i + 1] - data->levels[i]) /  in pwm_backlight_parse_dt()
319 			dev_dbg(dev, "new number of brightness levels: %d\n",  in pwm_backlight_parse_dt()
323 			 * Create a new table of brightness levels with all the  in pwm_backlight_parse_dt()
329 				return -ENOMEM;  in pwm_backlight_parse_dt()
333 			for (i = 0; i < data->max_brightness - 1; i++) {  in pwm_backlight_parse_dt()
334 				value = data->levels[i];  in pwm_backlight_parse_dt()
335 				n = (data->levels[i + 1] - value) / num_steps;  in pwm_backlight_parse_dt()
343 					table[levels_count] = data->levels[i];  in pwm_backlight_parse_dt()
347 			table[levels_count] = data->levels[i];  in pwm_backlight_parse_dt()
351 			 * brightness levels table and replace for the  in pwm_backlight_parse_dt()
354 			devm_kfree(dev, data->levels);  in pwm_backlight_parse_dt()
355 			data->levels = table;  in pwm_backlight_parse_dt()
359 			 * of brightness levels.  in pwm_backlight_parse_dt()
361 			data->max_brightness = num_levels;  in pwm_backlight_parse_dt()
364 		data->max_brightness--;  in pwm_backlight_parse_dt()
371 	{ .compatible = "pwm-backlight" },
380 	return -ENODEV;  in pwm_backlight_parse_dt()
388 	return -ENODEV;  in pwm_backlight_brightness_default()
394 	unsigned int nlevels = data->max_brightness + 1;  in pwm_backlight_is_linear()
395 	unsigned int min_val = data->levels[0];  in pwm_backlight_is_linear()
396 	unsigned int max_val = data->levels[nlevels - 1];  in pwm_backlight_is_linear()
399 	 * as (max_val - min_val) == nlevels the error at max_val is less  in pwm_backlight_is_linear()
402 	unsigned int slope = (128 * (max_val - min_val)) / nlevels;  in pwm_backlight_is_linear()
403 	unsigned int margin = (max_val - min_val) / 20; /* 5% */  in pwm_backlight_is_linear()
408 		unsigned int delta = abs(linear_value - data->levels[i]);  in pwm_backlight_is_linear()
419 	struct device_node *node = pb->dev->of_node;  in pwm_backlight_initial_power_state()
422 	if (!node || !node->phandle)  in pwm_backlight_initial_power_state()
433 	if (pb->enable_gpio && gpiod_get_value_cansleep(pb->enable_gpio) == 0)  in pwm_backlight_initial_power_state()
437 	if (!regulator_is_enabled(pb->power_supply))  in pwm_backlight_initial_power_state()
441 	if (!pwm_is_enabled(pb->pwm))  in pwm_backlight_initial_power_state()
449 	struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev);  in pwm_backlight_probe()
453 	struct device_node *node = pdev->dev.of_node;  in pwm_backlight_probe()
460 		ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);  in pwm_backlight_probe()
462 			dev_err(&pdev->dev, "failed to find platform data\n");  in pwm_backlight_probe()
469 	if (data->init) {  in pwm_backlight_probe()
470 		ret = data->init(&pdev->dev);  in pwm_backlight_probe()
475 	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);  in pwm_backlight_probe()
477 		ret = -ENOMEM;  in pwm_backlight_probe()
481 	pb->notify = data->notify;  in pwm_backlight_probe()
482 	pb->notify_after = data->notify_after;  in pwm_backlight_probe()
483 	pb->check_fb = data->check_fb;  in pwm_backlight_probe()
484 	pb->exit = data->exit;  in pwm_backlight_probe()
485 	pb->dev = &pdev->dev;  in pwm_backlight_probe()
486 	pb->enabled = false;  in pwm_backlight_probe()
487 	pb->post_pwm_on_delay = data->post_pwm_on_delay;  in pwm_backlight_probe()
488 	pb->pwm_off_delay = data->pwm_off_delay;  in pwm_backlight_probe()
490 	pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",  in pwm_backlight_probe()
492 	if (IS_ERR(pb->enable_gpio)) {  in pwm_backlight_probe()
493 		ret = PTR_ERR(pb->enable_gpio);  in pwm_backlight_probe()
499 	 * is, if gpiod_get_direction returns either 1 or -EINVAL, change the  in pwm_backlight_probe()
505 	if (pb->enable_gpio &&  in pwm_backlight_probe()
506 	    gpiod_get_direction(pb->enable_gpio) != 0)  in pwm_backlight_probe()
507 		gpiod_direction_output(pb->enable_gpio, 1);  in pwm_backlight_probe()
509 	pb->power_supply = devm_regulator_get(&pdev->dev, "power");  in pwm_backlight_probe()
510 	if (IS_ERR(pb->power_supply)) {  in pwm_backlight_probe()
511 		ret = PTR_ERR(pb->power_supply);  in pwm_backlight_probe()
515 	pb->pwm = devm_pwm_get(&pdev->dev, NULL);  in pwm_backlight_probe()
516 	if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) {  in pwm_backlight_probe()
517 		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");  in pwm_backlight_probe()
518 		pb->legacy = true;  in pwm_backlight_probe()
519 		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");  in pwm_backlight_probe()
522 	if (IS_ERR(pb->pwm)) {  in pwm_backlight_probe()
523 		ret = PTR_ERR(pb->pwm);  in pwm_backlight_probe()
524 		if (ret != -EPROBE_DEFER)  in pwm_backlight_probe()
525 			dev_err(&pdev->dev, "unable to request PWM\n");  in pwm_backlight_probe()
529 	dev_dbg(&pdev->dev, "got pwm for backlight\n");  in pwm_backlight_probe()
532 	pwm_init_state(pb->pwm, &state);  in pwm_backlight_probe()
536 	 * period, parsed from the DT, in the PWM device. For the non-DT case,  in pwm_backlight_probe()
540 	if (!state.period && (data->pwm_period_ns > 0))  in pwm_backlight_probe()
541 		state.period = data->pwm_period_ns;  in pwm_backlight_probe()
543 	ret = pwm_apply_state(pb->pwm, &state);  in pwm_backlight_probe()
545 		dev_err(&pdev->dev, "failed to apply initial PWM state: %d\n",  in pwm_backlight_probe()
552 	if (data->levels) {  in pwm_backlight_probe()
553 		pb->levels = data->levels;  in pwm_backlight_probe()
556 		 * For the DT case, only when brightness levels is defined  in pwm_backlight_probe()
557 		 * data->levels is filled. For the non-DT case, data->levels  in pwm_backlight_probe()
560 		for (i = 0; i <= data->max_brightness; i++)  in pwm_backlight_probe()
561 			if (data->levels[i] > pb->scale)  in pwm_backlight_probe()
562 				pb->scale = data->levels[i];  in pwm_backlight_probe()
568 	} else if (!data->max_brightness) {  in pwm_backlight_probe()
570 		 * If no brightness levels are provided and max_brightness is  in pwm_backlight_probe()
571 		 * not set, use the default brightness table. For the DT case,  in pwm_backlight_probe()
572 		 * max_brightness is set to 0 when brightness levels is not  in pwm_backlight_probe()
573 		 * specified. For the non-DT case, max_brightness is usually  in pwm_backlight_probe()
578 		pwm_get_state(pb->pwm, &state);  in pwm_backlight_probe()
580 		ret = pwm_backlight_brightness_default(&pdev->dev, data,  in pwm_backlight_probe()
583 			dev_err(&pdev->dev,  in pwm_backlight_probe()
584 				"failed to setup default brightness table\n");  in pwm_backlight_probe()
588 		for (i = 0; i <= data->max_brightness; i++) {  in pwm_backlight_probe()
589 			if (data->levels[i] > pb->scale)  in pwm_backlight_probe()
590 				pb->scale = data->levels[i];  in pwm_backlight_probe()
592 			pb->levels = data->levels;  in pwm_backlight_probe()
598 		 * That only happens for the non-DT case, where platform data  in pwm_backlight_probe()
601 		pb->scale = data->max_brightness;  in pwm_backlight_probe()
604 	pb->lth_brightness = data->lth_brightness * (div_u64(state.period,  in pwm_backlight_probe()
605 				pb->scale));  in pwm_backlight_probe()
608 	props.max_brightness = data->max_brightness;  in pwm_backlight_probe()
609 	bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,  in pwm_backlight_probe()
612 		dev_err(&pdev->dev, "failed to register backlight\n");  in pwm_backlight_probe()
614 		if (pb->legacy)  in pwm_backlight_probe()
615 			pwm_free(pb->pwm);  in pwm_backlight_probe()
619 	if (data->dft_brightness > data->max_brightness) {  in pwm_backlight_probe()
620 		dev_warn(&pdev->dev,  in pwm_backlight_probe()
621 			 "invalid default brightness level: %u, using %u\n",  in pwm_backlight_probe()
622 			 data->dft_brightness, data->max_brightness);  in pwm_backlight_probe()
623 		data->dft_brightness = data->max_brightness;  in pwm_backlight_probe()
626 	bl->props.brightness = data->dft_brightness;  in pwm_backlight_probe()
627 	bl->props.power = pwm_backlight_initial_power_state(pb);  in pwm_backlight_probe()
634 	if (data->exit)  in pwm_backlight_probe()
635 		data->exit(&pdev->dev);  in pwm_backlight_probe()
647 	if (pb->exit)  in pwm_backlight_remove()
648 		pb->exit(&pdev->dev);  in pwm_backlight_remove()
649 	if (pb->legacy)  in pwm_backlight_remove()
650 		pwm_free(pb->pwm);  in pwm_backlight_remove()
669 	if (pb->notify)  in pwm_backlight_suspend()
670 		pb->notify(pb->dev, 0);  in pwm_backlight_suspend()
674 	if (pb->notify_after)  in pwm_backlight_suspend()
675 		pb->notify_after(pb->dev, 0);  in pwm_backlight_suspend()
701 		.name		= "pwm-backlight",
714 MODULE_ALIAS("platform:pwm-backlight");