1 // SPDX-License-Identifier: GPL-2.0-only
25 	unsigned int		*levels;  member
33 					  int brightness);
35 					int brightness);
43 	if (pb->enabled)  in pwm_backlight_power_on()
46 	if (pb->power_supply) {  in pwm_backlight_power_on()
47 		err = regulator_enable(pb->power_supply);  in pwm_backlight_power_on()
49 			dev_err(pb->dev, "failed to enable power supply\n");  in pwm_backlight_power_on()
52 	if (pb->post_pwm_on_delay)  in pwm_backlight_power_on()
53 		msleep(pb->post_pwm_on_delay);  in pwm_backlight_power_on()
55 	gpiod_set_value_cansleep(pb->enable_gpio, 1);  in pwm_backlight_power_on()
57 	pb->enabled = true;  in pwm_backlight_power_on()
62 	if (!pb->enabled)  in pwm_backlight_power_off()
65 	gpiod_set_value_cansleep(pb->enable_gpio, 0);  in pwm_backlight_power_off()
67 	if (pb->pwm_off_delay)  in pwm_backlight_power_off()
68 		msleep(pb->pwm_off_delay);  in pwm_backlight_power_off()
70 	if (pb->power_supply)  in pwm_backlight_power_off()
71 		regulator_disable(pb->power_supply);  in pwm_backlight_power_off()
72 	pb->enabled = false;  in pwm_backlight_power_off()
75 static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness, struct pwm_state *state)  in compute_duty_cycle()  argument
77 	unsigned int lth = pb->lth_brightness;  in compute_duty_cycle()
80 	if (pb->levels)  in compute_duty_cycle()
81 		duty_cycle = pb->levels[brightness];  in compute_duty_cycle()
83 		duty_cycle = brightness;  in compute_duty_cycle()
85 	duty_cycle *= state->period - lth;  in compute_duty_cycle()
86 	do_div(duty_cycle, pb->scale);  in compute_duty_cycle()
94 	int brightness = backlight_get_brightness(bl);  in pwm_backlight_update_status()  local
97 	if (pb->notify)  in pwm_backlight_update_status()
98 		brightness = pb->notify(pb->dev, brightness);  in pwm_backlight_update_status()
100 	if (brightness > 0) {  in pwm_backlight_update_status()
101 		pwm_get_state(pb->pwm, &state);  in pwm_backlight_update_status()
102 		state.duty_cycle = compute_duty_cycle(pb, brightness, &state);  in pwm_backlight_update_status()
104 		pwm_apply_might_sleep(pb->pwm, &state);  in pwm_backlight_update_status()
110 		pwm_get_state(pb->pwm, &state);  in pwm_backlight_update_status()
120 		state.enabled = !pb->power_supply && !pb->enable_gpio;  in pwm_backlight_update_status()
121 		pwm_apply_might_sleep(pb->pwm, &state);  in pwm_backlight_update_status()
124 	if (pb->notify_after)  in pwm_backlight_update_status()
125 		pb->notify_after(pb->dev, brightness);  in pwm_backlight_update_status()
159 	 * as a fixed-point number in scale  in cie1931()
161 	 * expressed as a fixed-point number, so the above formulas  in cie1931()
170 		retval += 1ULL << (2*PWM_LUMINANCE_SHIFT - 1);  in cie1931()
178  * Create a default correction table for PWM values to create linear brightness
190 	 * Once we have 4096 levels there's little point going much higher...  in pwm_backlight_brightness_default()
194 	data->max_brightness =  in pwm_backlight_brightness_default()
197 	data->levels = devm_kcalloc(dev, data->max_brightness,  in pwm_backlight_brightness_default()
198 				    sizeof(*data->levels), GFP_KERNEL);  in pwm_backlight_brightness_default()
199 	if (!data->levels)  in pwm_backlight_brightness_default()
200 		return -ENOMEM;  in pwm_backlight_brightness_default()
203 	for (i = 0; i < data->max_brightness; i++) {  in pwm_backlight_brightness_default()
205 				 data->max_brightness) * period;  in pwm_backlight_brightness_default()
208 			return -EINVAL;  in pwm_backlight_brightness_default()
209 		data->levels[i] = (unsigned int)retval;  in pwm_backlight_brightness_default()
212 	data->dft_brightness = data->max_brightness / 2;  in pwm_backlight_brightness_default()
213 	data->max_brightness--;  in pwm_backlight_brightness_default()
221 	struct device_node *node = dev->of_node;  in pwm_backlight_parse_dt()
231 		return -ENODEV;  in pwm_backlight_parse_dt()
239 	of_property_read_u32(node, "post-pwm-on-delay-ms",  in pwm_backlight_parse_dt()
240 			     &data->post_pwm_on_delay);  in pwm_backlight_parse_dt()
241 	of_property_read_u32(node, "pwm-off-delay-ms", &data->pwm_off_delay);  in pwm_backlight_parse_dt()
244 	 * Determine the number of brightness levels, if this property is not  in pwm_backlight_parse_dt()
245 	 * set a default table of brightness levels will be used.  in pwm_backlight_parse_dt()
247 	prop = of_find_property(node, "brightness-levels", &length);  in pwm_backlight_parse_dt()
253 	/* read brightness levels from DT property */  in pwm_backlight_parse_dt()
255 		data->levels = devm_kcalloc(dev, num_levels,  in pwm_backlight_parse_dt()
256 					    sizeof(*data->levels), GFP_KERNEL);  in pwm_backlight_parse_dt()
257 		if (!data->levels)  in pwm_backlight_parse_dt()
258 			return -ENOMEM;  in pwm_backlight_parse_dt()
260 		ret = of_property_read_u32_array(node, "brightness-levels",  in pwm_backlight_parse_dt()
261 						 data->levels,  in pwm_backlight_parse_dt()
266 		ret = of_property_read_u32(node, "default-brightness-level",  in pwm_backlight_parse_dt()
271 		data->dft_brightness = value;  in pwm_backlight_parse_dt()
275 		 * interpolation between each of the values of brightness levels  in pwm_backlight_parse_dt()
276 		 * and creates a new pre-computed table.  in pwm_backlight_parse_dt()
278 		of_property_read_u32(node, "num-interpolated-steps",  in pwm_backlight_parse_dt()
283 		 * brightness-levels table, otherwise we can't interpolate  in pwm_backlight_parse_dt()
295 				return -EINVAL;  in pwm_backlight_parse_dt()
299 			 * Recalculate the number of brightness levels, now  in pwm_backlight_parse_dt()
301 			 * steps between two levels.  in pwm_backlight_parse_dt()
303 			num_levels = (num_input_levels - 1) * num_steps + 1;  in pwm_backlight_parse_dt()
304 			dev_dbg(dev, "new number of brightness levels: %d\n",  in pwm_backlight_parse_dt()
308 			 * Create a new table of brightness levels with all the  in pwm_backlight_parse_dt()
314 				return -ENOMEM;  in pwm_backlight_parse_dt()
320 			for (i = 0; i < num_input_levels - 1; i++) {  in pwm_backlight_parse_dt()
323 				y1 = data->levels[i];  in pwm_backlight_parse_dt()
324 				y2 = data->levels[i + 1];  in pwm_backlight_parse_dt()
325 				dy = (s64)y2 - y1;  in pwm_backlight_parse_dt()
329 						div_s64(dy * (x - x1), dx);  in pwm_backlight_parse_dt()
337 			 * brightness levels table and replace for the  in pwm_backlight_parse_dt()
340 			devm_kfree(dev, data->levels);  in pwm_backlight_parse_dt()
341 			data->levels = table;  in pwm_backlight_parse_dt()
344 		data->max_brightness = num_levels - 1;  in pwm_backlight_parse_dt()
351 	{ .compatible = "pwm-backlight" },
360 	return -ENODEV;  in pwm_backlight_parse_dt()
368 	return -ENODEV;  in pwm_backlight_brightness_default()
374 	unsigned int nlevels = data->max_brightness + 1;  in pwm_backlight_is_linear()
375 	unsigned int min_val = data->levels[0];  in pwm_backlight_is_linear()
376 	unsigned int max_val = data->levels[nlevels - 1];  in pwm_backlight_is_linear()
379 	 * as (max_val - min_val) == nlevels the error at max_val is less  in pwm_backlight_is_linear()
382 	unsigned int slope = (128 * (max_val - min_val)) / nlevels;  in pwm_backlight_is_linear()
383 	unsigned int margin = (max_val - min_val) / 20; /* 5% */  in pwm_backlight_is_linear()
388 		unsigned int delta = abs(linear_value - data->levels[i]);  in pwm_backlight_is_linear()
399 	struct device_node *node = pb->dev->of_node;  in pwm_backlight_initial_power_state()
406 	if (pb->enable_gpio && gpiod_get_value_cansleep(pb->enable_gpio) == 0)  in pwm_backlight_initial_power_state()
409 	if (pb->power_supply && !regulator_is_enabled(pb->power_supply))  in pwm_backlight_initial_power_state()
412 	if (!pwm_is_enabled(pb->pwm))  in pwm_backlight_initial_power_state()
419 	gpiod_direction_output(pb->enable_gpio, active);  in pwm_backlight_initial_power_state()
422 	 * Do not change pb->enabled here! pb->enabled essentially  in pwm_backlight_initial_power_state()
428 	if (!node || !node->phandle)  in pwm_backlight_initial_power_state()
442 	struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev);  in pwm_backlight_probe()
452 		ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);  in pwm_backlight_probe()
454 			return dev_err_probe(&pdev->dev, ret,  in pwm_backlight_probe()
460 	if (data->init) {  in pwm_backlight_probe()
461 		ret = data->init(&pdev->dev);  in pwm_backlight_probe()
466 	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);  in pwm_backlight_probe()
468 		ret = -ENOMEM;  in pwm_backlight_probe()
472 	pb->notify = data->notify;  in pwm_backlight_probe()
473 	pb->notify_after = data->notify_after;  in pwm_backlight_probe()
474 	pb->exit = data->exit;  in pwm_backlight_probe()
475 	pb->dev = &pdev->dev;  in pwm_backlight_probe()
476 	pb->enabled = false;  in pwm_backlight_probe()
477 	pb->post_pwm_on_delay = data->post_pwm_on_delay;  in pwm_backlight_probe()
478 	pb->pwm_off_delay = data->pwm_off_delay;  in pwm_backlight_probe()
480 	pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",  in pwm_backlight_probe()
482 	if (IS_ERR(pb->enable_gpio)) {  in pwm_backlight_probe()
483 		ret = dev_err_probe(&pdev->dev, PTR_ERR(pb->enable_gpio),  in pwm_backlight_probe()
488 	pb->power_supply = devm_regulator_get_optional(&pdev->dev, "power");  in pwm_backlight_probe()
489 	if (IS_ERR(pb->power_supply)) {  in pwm_backlight_probe()
490 		ret = PTR_ERR(pb->power_supply);  in pwm_backlight_probe()
491 		if (ret == -ENODEV) {  in pwm_backlight_probe()
492 			pb->power_supply = NULL;  in pwm_backlight_probe()
494 			dev_err_probe(&pdev->dev, ret,  in pwm_backlight_probe()
500 	pb->pwm = devm_pwm_get(&pdev->dev, NULL);  in pwm_backlight_probe()
501 	if (IS_ERR(pb->pwm)) {  in pwm_backlight_probe()
502 		ret = dev_err_probe(&pdev->dev, PTR_ERR(pb->pwm),  in pwm_backlight_probe()
507 	dev_dbg(&pdev->dev, "got pwm for backlight\n");  in pwm_backlight_probe()
510 	pwm_init_state(pb->pwm, &state);  in pwm_backlight_probe()
514 	 * period, parsed from the DT, in the PWM device. For the non-DT case,  in pwm_backlight_probe()
518 	if (!state.period && (data->pwm_period_ns > 0))  in pwm_backlight_probe()
519 		state.period = data->pwm_period_ns;  in pwm_backlight_probe()
521 	ret = pwm_apply_might_sleep(pb->pwm, &state);  in pwm_backlight_probe()
523 		dev_err_probe(&pdev->dev, ret,  in pwm_backlight_probe()
530 	if (data->levels) {  in pwm_backlight_probe()
531 		pb->levels = data->levels;  in pwm_backlight_probe()
534 		 * For the DT case, only when brightness levels is defined  in pwm_backlight_probe()
535 		 * data->levels is filled. For the non-DT case, data->levels  in pwm_backlight_probe()
538 		for (i = 0; i <= data->max_brightness; i++)  in pwm_backlight_probe()
539 			if (data->levels[i] > pb->scale)  in pwm_backlight_probe()
540 				pb->scale = data->levels[i];  in pwm_backlight_probe()
546 	} else if (!data->max_brightness) {  in pwm_backlight_probe()
548 		 * If no brightness levels are provided and max_brightness is  in pwm_backlight_probe()
549 		 * not set, use the default brightness table. For the DT case,  in pwm_backlight_probe()
550 		 * max_brightness is set to 0 when brightness levels is not  in pwm_backlight_probe()
551 		 * specified. For the non-DT case, max_brightness is usually  in pwm_backlight_probe()
556 		pwm_get_state(pb->pwm, &state);  in pwm_backlight_probe()
558 		ret = pwm_backlight_brightness_default(&pdev->dev, data,  in pwm_backlight_probe()
561 			dev_err_probe(&pdev->dev, ret,  in pwm_backlight_probe()
562 				      "failed to setup default brightness table\n");  in pwm_backlight_probe()
566 		for (i = 0; i <= data->max_brightness; i++) {  in pwm_backlight_probe()
567 			if (data->levels[i] > pb->scale)  in pwm_backlight_probe()
568 				pb->scale = data->levels[i];  in pwm_backlight_probe()
570 			pb->levels = data->levels;  in pwm_backlight_probe()
576 		 * That only happens for the non-DT case, where platform data  in pwm_backlight_probe()
579 		pb->scale = data->max_brightness;  in pwm_backlight_probe()
582 	pb->lth_brightness = data->lth_brightness * (div_u64(state.period,  in pwm_backlight_probe()
583 				pb->scale));  in pwm_backlight_probe()
586 	props.max_brightness = data->max_brightness;  in pwm_backlight_probe()
587 	bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,  in pwm_backlight_probe()
590 		ret = dev_err_probe(&pdev->dev, PTR_ERR(bl),  in pwm_backlight_probe()
595 	if (data->dft_brightness > data->max_brightness) {  in pwm_backlight_probe()
596 		dev_warn(&pdev->dev,  in pwm_backlight_probe()
597 			 "invalid default brightness level: %u, using %u\n",  in pwm_backlight_probe()
598 			 data->dft_brightness, data->max_brightness);  in pwm_backlight_probe()
599 		data->dft_brightness = data->max_brightness;  in pwm_backlight_probe()
602 	bl->props.brightness = data->dft_brightness;  in pwm_backlight_probe()
603 	bl->props.power = pwm_backlight_initial_power_state(pb);  in pwm_backlight_probe()
610 	if (data->exit)  in pwm_backlight_probe()
611 		data->exit(&pdev->dev);  in pwm_backlight_probe()
623 	pwm_get_state(pb->pwm, &state);  in pwm_backlight_remove()
626 	pwm_apply_might_sleep(pb->pwm, &state);  in pwm_backlight_remove()
628 	if (pb->exit)  in pwm_backlight_remove()
629 		pb->exit(&pdev->dev);  in pwm_backlight_remove()
639 	pwm_get_state(pb->pwm, &state);  in pwm_backlight_shutdown()
642 	pwm_apply_might_sleep(pb->pwm, &state);  in pwm_backlight_shutdown()
652 	if (pb->notify)  in pwm_backlight_suspend()
653 		pb->notify(pb->dev, 0);  in pwm_backlight_suspend()
663 	pwm_get_state(pb->pwm, &state);  in pwm_backlight_suspend()
666 	pwm_apply_might_sleep(pb->pwm, &state);  in pwm_backlight_suspend()
668 	if (pb->notify_after)  in pwm_backlight_suspend()
669 		pb->notify_after(pb->dev, 0);  in pwm_backlight_suspend()
695 		.name		= "pwm-backlight",
708 MODULE_ALIAS("platform:pwm-backlight");