1 // SPDX-License-Identifier: GPL-2.0-only
25 		 "pwm bl quiescent when reboot quiescent [default=false]");
40 					  int brightness);
42 					int brightness);
52 	pwm_get_state(pb->pwm, &state);  in pwm_backlight_power_on()
53 	if (pb->enabled)  in pwm_backlight_power_on()
56 	err = regulator_enable(pb->power_supply);  in pwm_backlight_power_on()
58 		dev_err(pb->dev, "failed to enable power supply\n");  in pwm_backlight_power_on()
61 	pwm_apply_state(pb->pwm, &state);  in pwm_backlight_power_on()
63 	if (pb->post_pwm_on_delay)  in pwm_backlight_power_on()
64 		msleep(pb->post_pwm_on_delay);  in pwm_backlight_power_on()
66 	if (pb->enable_gpio)  in pwm_backlight_power_on()
67 		gpiod_set_value_cansleep(pb->enable_gpio, 1);  in pwm_backlight_power_on()
69 	pb->enabled = true;  in pwm_backlight_power_on()
76 	pwm_get_state(pb->pwm, &state);  in pwm_backlight_power_off()
77 	if (!pb->enabled)  in pwm_backlight_power_off()
80 	if (pb->enable_gpio)  in pwm_backlight_power_off()
81 		gpiod_set_value_cansleep(pb->enable_gpio, 0);  in pwm_backlight_power_off()
83 	if (pb->pwm_off_delay)  in pwm_backlight_power_off()
84 		msleep(pb->pwm_off_delay);  in pwm_backlight_power_off()
88 	pwm_apply_state(pb->pwm, &state);  in pwm_backlight_power_off()
90 	regulator_disable(pb->power_supply);  in pwm_backlight_power_off()
91 	pb->enabled = false;  in pwm_backlight_power_off()
94 static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness)  in compute_duty_cycle()  argument
96 	unsigned int lth = pb->lth_brightness;  in compute_duty_cycle()
100 	pwm_get_state(pb->pwm, &state);  in compute_duty_cycle()
102 	if (pb->levels)  in compute_duty_cycle()
103 		duty_cycle = pb->levels[brightness];  in compute_duty_cycle()
105 		duty_cycle = brightness;  in compute_duty_cycle()
107 	duty_cycle *= state.period - lth;  in compute_duty_cycle()
108 	do_div(duty_cycle, pb->scale);  in compute_duty_cycle()
116 	int brightness = backlight_get_brightness(bl);  in pwm_backlight_update_status()  local
119 	if (pb->notify)  in pwm_backlight_update_status()
120 		brightness = pb->notify(pb->dev, brightness);  in pwm_backlight_update_status()
122 	if (brightness > 0) {  in pwm_backlight_update_status()
123 		pwm_get_state(pb->pwm, &state);  in pwm_backlight_update_status()
124 		state.duty_cycle = compute_duty_cycle(pb, brightness);  in pwm_backlight_update_status()
125 		pwm_apply_state(pb->pwm, &state);  in pwm_backlight_update_status()
131 	if (pb->notify_after)  in pwm_backlight_update_status()
132 		pb->notify_after(pb->dev, brightness);  in pwm_backlight_update_status()
142 	return !pb->check_fb || pb->check_fb(pb->dev, info);  in pwm_backlight_check_fb()
175 	 * as a fixed-point number in scale  in cie1931()
177 	 * expressed as a fixed-point number, so the above formulas  in cie1931()
186 		retval += 1ULL << (2*PWM_LUMINANCE_SHIFT - 1);  in cie1931()
194  * Create a default correction table for PWM values to create linear brightness
210 	data->max_brightness =  in pwm_backlight_brightness_default()
213 	data->levels = devm_kcalloc(dev, data->max_brightness,  in pwm_backlight_brightness_default()
214 				    sizeof(*data->levels), GFP_KERNEL);  in pwm_backlight_brightness_default()
215 	if (!data->levels)  in pwm_backlight_brightness_default()
216 		return -ENOMEM;  in pwm_backlight_brightness_default()
219 	for (i = 0; i < data->max_brightness; i++) {  in pwm_backlight_brightness_default()
221 				 data->max_brightness) * period;  in pwm_backlight_brightness_default()
224 			return -EINVAL;  in pwm_backlight_brightness_default()
225 		data->levels[i] = (unsigned int)retval;  in pwm_backlight_brightness_default()
228 	data->dft_brightness = data->max_brightness / 2;  in pwm_backlight_brightness_default()
229 	data->max_brightness--;  in pwm_backlight_brightness_default()
237 	struct device_node *node = dev->of_node;  in pwm_backlight_parse_dt()
248 		return -ENODEV;  in pwm_backlight_parse_dt()
253 	 * These values are optional and set as 0 by default, the out values  in pwm_backlight_parse_dt()
256 	of_property_read_u32(node, "post-pwm-on-delay-ms",  in pwm_backlight_parse_dt()
257 			     &data->post_pwm_on_delay);  in pwm_backlight_parse_dt()
258 	of_property_read_u32(node, "pwm-off-delay-ms", &data->pwm_off_delay);  in pwm_backlight_parse_dt()
261 	 * Determine the number of brightness levels, if this property is not  in pwm_backlight_parse_dt()
262 	 * set a default table of brightness levels will be used.  in pwm_backlight_parse_dt()
264 	prop = of_find_property(node, "brightness-levels", &length);  in pwm_backlight_parse_dt()
268 	data->max_brightness = length / sizeof(u32);  in pwm_backlight_parse_dt()
270 	/* read brightness levels from DT property */  in pwm_backlight_parse_dt()
271 	if (data->max_brightness > 0) {  in pwm_backlight_parse_dt()
272 		size_t size = sizeof(*data->levels) * data->max_brightness;  in pwm_backlight_parse_dt()
275 		data->levels = devm_kzalloc(dev, size, GFP_KERNEL);  in pwm_backlight_parse_dt()
276 		if (!data->levels)  in pwm_backlight_parse_dt()
277 			return -ENOMEM;  in pwm_backlight_parse_dt()
279 		ret = of_property_read_u32_array(node, "brightness-levels",  in pwm_backlight_parse_dt()
280 						 data->levels,  in pwm_backlight_parse_dt()
281 						 data->max_brightness);  in pwm_backlight_parse_dt()
285 		ret = of_property_read_u32(node, "default-brightness-level",  in pwm_backlight_parse_dt()
290 		data->dft_brightness = value;  in pwm_backlight_parse_dt()
294 		 * interpolation between each of the values of brightness levels  in pwm_backlight_parse_dt()
295 		 * and creates a new pre-computed table.  in pwm_backlight_parse_dt()
297 		of_property_read_u32(node, "num-interpolated-steps",  in pwm_backlight_parse_dt()
302 		 * brightness-levels table, otherwise we can't interpolate  in pwm_backlight_parse_dt()
306 			if (data->max_brightness < 2) {  in pwm_backlight_parse_dt()
308 				return -EINVAL;  in pwm_backlight_parse_dt()
312 			 * Recalculate the number of brightness levels, now  in pwm_backlight_parse_dt()
316 			for (i = 0; i < data->max_brightness - 1; i++) {  in pwm_backlight_parse_dt()
317 				if ((data->levels[i + 1] - data->levels[i]) /  in pwm_backlight_parse_dt()
324 			dev_dbg(dev, "new number of brightness levels: %d\n",  in pwm_backlight_parse_dt()
328 			 * Create a new table of brightness levels with all the  in pwm_backlight_parse_dt()
334 				return -ENOMEM;  in pwm_backlight_parse_dt()
338 			for (i = 0; i < data->max_brightness - 1; i++) {  in pwm_backlight_parse_dt()
339 				value = data->levels[i];  in pwm_backlight_parse_dt()
340 				n = (data->levels[i + 1] - value) / num_steps;  in pwm_backlight_parse_dt()
348 					table[levels_count] = data->levels[i];  in pwm_backlight_parse_dt()
352 			table[levels_count] = data->levels[i];  in pwm_backlight_parse_dt()
356 			 * brightness levels table and replace for the  in pwm_backlight_parse_dt()
359 			devm_kfree(dev, data->levels);  in pwm_backlight_parse_dt()
360 			data->levels = table;  in pwm_backlight_parse_dt()
364 			 * of brightness levels.  in pwm_backlight_parse_dt()
366 			data->max_brightness = num_levels;  in pwm_backlight_parse_dt()
369 		data->max_brightness--;  in pwm_backlight_parse_dt()
376 	{ .compatible = "pwm-backlight" },
385 	return -ENODEV;  in pwm_backlight_parse_dt()
393 	return -ENODEV;  in pwm_backlight_brightness_default()
399 	unsigned int nlevels = data->max_brightness + 1;  in pwm_backlight_is_linear()
400 	unsigned int min_val = data->levels[0];  in pwm_backlight_is_linear()
401 	unsigned int max_val = data->levels[nlevels - 1];  in pwm_backlight_is_linear()
404 	 * as (max_val - min_val) == nlevels the error at max_val is less  in pwm_backlight_is_linear()
407 	unsigned int slope = (128 * (max_val - min_val)) / nlevels;  in pwm_backlight_is_linear()
408 	unsigned int margin = (max_val - min_val) / 20; /* 5% */  in pwm_backlight_is_linear()
413 		unsigned int delta = abs(linear_value - data->levels[i]);  in pwm_backlight_is_linear()
424 	struct device_node *node = pb->dev->of_node;  in pwm_backlight_initial_power_state()
431 	if (pb->enable_gpio && gpiod_get_value_cansleep(pb->enable_gpio) == 0)  in pwm_backlight_initial_power_state()
434 	if (!regulator_is_enabled(pb->power_supply))  in pwm_backlight_initial_power_state()
437 	if (!pwm_is_enabled(pb->pwm))  in pwm_backlight_initial_power_state()
444 	if (pb->enable_gpio)  in pwm_backlight_initial_power_state()
445 		gpiod_direction_output(pb->enable_gpio, active);  in pwm_backlight_initial_power_state()
448 	 * Do not change pb->enabled here! pb->enabled essentially  in pwm_backlight_initial_power_state()
454 	if (!node || !node->phandle)  in pwm_backlight_initial_power_state()
468 	struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev);  in pwm_backlight_probe()
472 	struct device_node *node = pdev->dev.of_node;  in pwm_backlight_probe()
479 		ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);  in pwm_backlight_probe()
481 			dev_err(&pdev->dev, "failed to find platform data\n");  in pwm_backlight_probe()
488 	if (data->init) {  in pwm_backlight_probe()
489 		ret = data->init(&pdev->dev);  in pwm_backlight_probe()
494 	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);  in pwm_backlight_probe()
496 		ret = -ENOMEM;  in pwm_backlight_probe()
500 	pb->notify = data->notify;  in pwm_backlight_probe()
501 	pb->notify_after = data->notify_after;  in pwm_backlight_probe()
502 	pb->check_fb = data->check_fb;  in pwm_backlight_probe()
503 	pb->exit = data->exit;  in pwm_backlight_probe()
504 	pb->dev = &pdev->dev;  in pwm_backlight_probe()
505 	pb->enabled = false;  in pwm_backlight_probe()
506 	pb->post_pwm_on_delay = data->post_pwm_on_delay;  in pwm_backlight_probe()
507 	pb->pwm_off_delay = data->pwm_off_delay;  in pwm_backlight_probe()
509 	pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",  in pwm_backlight_probe()
511 	if (IS_ERR(pb->enable_gpio)) {  in pwm_backlight_probe()
512 		ret = PTR_ERR(pb->enable_gpio);  in pwm_backlight_probe()
516 	pb->power_supply = devm_regulator_get(&pdev->dev, "power");  in pwm_backlight_probe()
517 	if (IS_ERR(pb->power_supply)) {  in pwm_backlight_probe()
518 		ret = PTR_ERR(pb->power_supply);  in pwm_backlight_probe()
522 	pb->pwm = devm_pwm_get(&pdev->dev, NULL);  in pwm_backlight_probe()
523 	if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) {  in pwm_backlight_probe()
524 		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");  in pwm_backlight_probe()
525 		pb->legacy = true;  in pwm_backlight_probe()
526 		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");  in pwm_backlight_probe()
529 	if (IS_ERR(pb->pwm)) {  in pwm_backlight_probe()
530 		ret = PTR_ERR(pb->pwm);  in pwm_backlight_probe()
531 		if (ret != -EPROBE_DEFER)  in pwm_backlight_probe()
532 			dev_err(&pdev->dev, "unable to request PWM\n");  in pwm_backlight_probe()
536 	dev_dbg(&pdev->dev, "got pwm for backlight\n");  in pwm_backlight_probe()
539 	pwm_init_state(pb->pwm, &state);  in pwm_backlight_probe()
543 	 * period, parsed from the DT, in the PWM device. For the non-DT case,  in pwm_backlight_probe()
547 	if (!state.period && (data->pwm_period_ns > 0))  in pwm_backlight_probe()
548 		state.period = data->pwm_period_ns;  in pwm_backlight_probe()
550 	ret = pwm_apply_state(pb->pwm, &state);  in pwm_backlight_probe()
552 		dev_err(&pdev->dev, "failed to apply initial PWM state: %d\n",  in pwm_backlight_probe()
559 	if (data->levels) {  in pwm_backlight_probe()
560 		pb->levels = data->levels;  in pwm_backlight_probe()
563 		 * For the DT case, only when brightness levels is defined  in pwm_backlight_probe()
564 		 * data->levels is filled. For the non-DT case, data->levels  in pwm_backlight_probe()
567 		for (i = 0; i <= data->max_brightness; i++)  in pwm_backlight_probe()
568 			if (data->levels[i] > pb->scale)  in pwm_backlight_probe()
569 				pb->scale = data->levels[i];  in pwm_backlight_probe()
575 	} else if (!data->max_brightness) {  in pwm_backlight_probe()
577 		 * If no brightness levels are provided and max_brightness is  in pwm_backlight_probe()
578 		 * not set, use the default brightness table. For the DT case,  in pwm_backlight_probe()
579 		 * max_brightness is set to 0 when brightness levels is not  in pwm_backlight_probe()
580 		 * specified. For the non-DT case, max_brightness is usually  in pwm_backlight_probe()
585 		pwm_get_state(pb->pwm, &state);  in pwm_backlight_probe()
587 		ret = pwm_backlight_brightness_default(&pdev->dev, data,  in pwm_backlight_probe()
590 			dev_err(&pdev->dev,  in pwm_backlight_probe()
591 				"failed to setup default brightness table\n");  in pwm_backlight_probe()
595 		for (i = 0; i <= data->max_brightness; i++) {  in pwm_backlight_probe()
596 			if (data->levels[i] > pb->scale)  in pwm_backlight_probe()
597 				pb->scale = data->levels[i];  in pwm_backlight_probe()
599 			pb->levels = data->levels;  in pwm_backlight_probe()
605 		 * That only happens for the non-DT case, where platform data  in pwm_backlight_probe()
608 		pb->scale = data->max_brightness;  in pwm_backlight_probe()
611 	pwm_adjust_config(pb->pwm);  in pwm_backlight_probe()
613 	pb->lth_brightness = data->lth_brightness * (div_u64(state.period,  in pwm_backlight_probe()
614 				pb->scale));  in pwm_backlight_probe()
617 	props.max_brightness = data->max_brightness;  in pwm_backlight_probe()
618 	bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,  in pwm_backlight_probe()
621 		dev_err(&pdev->dev, "failed to register backlight\n");  in pwm_backlight_probe()
623 		if (pb->legacy)  in pwm_backlight_probe()
624 			pwm_free(pb->pwm);  in pwm_backlight_probe()
628 	if (data->dft_brightness > data->max_brightness) {  in pwm_backlight_probe()
629 		dev_warn(&pdev->dev,  in pwm_backlight_probe()
630 			 "invalid default brightness level: %u, using %u\n",  in pwm_backlight_probe()
631 			 data->dft_brightness, data->max_brightness);  in pwm_backlight_probe()
632 		data->dft_brightness = data->max_brightness;  in pwm_backlight_probe()
635 	/* set brightness 0, when boot quiescent */  in pwm_backlight_probe()
637 		bl->props.brightness = 0;  in pwm_backlight_probe()
639 		bl->props.brightness = data->dft_brightness;  in pwm_backlight_probe()
641 	bl->props.power = pwm_backlight_initial_power_state(pb);  in pwm_backlight_probe()
648 	if (data->exit)  in pwm_backlight_probe()
649 		data->exit(&pdev->dev);  in pwm_backlight_probe()
661 	if (pb->exit)  in pwm_backlight_remove()
662 		pb->exit(&pdev->dev);  in pwm_backlight_remove()
663 	if (pb->legacy)  in pwm_backlight_remove()
664 		pwm_free(pb->pwm);  in pwm_backlight_remove()
683 	if (pb->notify)  in pwm_backlight_suspend()
684 		pb->notify(pb->dev, 0);  in pwm_backlight_suspend()
688 	if (pb->notify_after)  in pwm_backlight_suspend()
689 		pb->notify_after(pb->dev, 0);  in pwm_backlight_suspend()
715 		.name		= "pwm-backlight",
728 MODULE_ALIAS("platform:pwm-backlight");