1 // SPDX-License-Identifier: GPL-2.0-only
3  * linux/drivers/leds-pwm.c
5  * simple PWM based LED control
9  * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
16 #include <linux/leds.h>
18 #include <linux/pwm.h>
30 	struct pwm_device	*pwm;  member
37 	struct led_pwm_data leds[];  member
45 	unsigned int max = led_dat->cdev.max_brightness;  in led_pwm_set()
46 	unsigned long long duty = led_dat->pwmstate.period;  in led_pwm_set()
51 	if (led_dat->active_low)  in led_pwm_set()
52 		duty = led_dat->pwmstate.period - duty;  in led_pwm_set()
54 	led_dat->pwmstate.duty_cycle = duty;  in led_pwm_set()
56 	 * Disabling a PWM doesn't guarantee that it emits the inactive level.  in led_pwm_set()
57 	 * So keep it on. Only for suspending the PWM should be disabled because  in led_pwm_set()
61 	led_dat->pwmstate.enabled = !(led_cdev->flags & LED_SUSPENDED);  in led_pwm_set()
62 	return pwm_apply_might_sleep(led_dat->pwm, &led_dat->pwmstate);  in led_pwm_set()
71 	ret = fwnode_property_read_u32(fwnode, "default-brightness",  in led_pwm_default_brightness_get()
83 	struct led_pwm_data *led_data = &priv->leds[priv->num_leds];  in led_pwm_add()
87 	led_data->active_low = led->active_low;  in led_pwm_add()
88 	led_data->cdev.name = led->name;  in led_pwm_add()
89 	led_data->cdev.brightness = LED_OFF;  in led_pwm_add()
90 	led_data->cdev.max_brightness = led->max_brightness;  in led_pwm_add()
91 	led_data->cdev.flags = LED_CORE_SUSPENDRESUME;  in led_pwm_add()
93 	led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);  in led_pwm_add()
94 	if (IS_ERR(led_data->pwm))  in led_pwm_add()
95 		return dev_err_probe(dev, PTR_ERR(led_data->pwm),  in led_pwm_add()
96 				     "unable to request PWM for %s\n",  in led_pwm_add()
97 				     led->name);  in led_pwm_add()
99 	led_data->cdev.brightness_set_blocking = led_pwm_set;  in led_pwm_add()
101 	/* init PWM state */  in led_pwm_add()
102 	switch (led->default_state) {  in led_pwm_add()
104 		pwm_get_state(led_data->pwm, &led_data->pwmstate);  in led_pwm_add()
105 		if (led_data->pwmstate.period)  in led_pwm_add()
107 		led->default_state = LEDS_DEFSTATE_OFF;  in led_pwm_add()
110 			led->name);  in led_pwm_add()
113 		pwm_init_state(led_data->pwm, &led_data->pwmstate);  in led_pwm_add()
118 	switch (led->default_state) {  in led_pwm_add()
120 		led_data->cdev.brightness =  in led_pwm_add()
121 			led_pwm_default_brightness_get(fwnode, led->max_brightness);  in led_pwm_add()
127 		brightness = led->max_brightness;  in led_pwm_add()
128 		brightness *= led_data->pwmstate.duty_cycle;  in led_pwm_add()
129 		do_div(brightness, led_data->pwmstate.period);  in led_pwm_add()
130 		led_data->cdev.brightness = brightness;  in led_pwm_add()
135 	ret = devm_led_classdev_register_ext(dev, &led_data->cdev, &init_data);  in led_pwm_add()
137 		dev_err(dev, "failed to register PWM led for %s: %d\n",  in led_pwm_add()
138 			led->name, ret);  in led_pwm_add()
142 	if (led->default_state != LEDS_DEFSTATE_KEEP) {  in led_pwm_add()
143 		ret = led_pwm_set(&led_data->cdev, led_data->cdev.brightness);  in led_pwm_add()
145 			dev_err(dev, "failed to set led PWM value for %s: %d",  in led_pwm_add()
146 				led->name, ret);  in led_pwm_add()
151 	priv->num_leds++;  in led_pwm_add()
165 			led.name = to_of_node(fwnode)->name;  in led_pwm_create_fwnode()
168 			return -EINVAL;  in led_pwm_create_fwnode()
171 							   "active-low");  in led_pwm_create_fwnode()
172 		fwnode_property_read_u32(fwnode, "max-brightness",  in led_pwm_create_fwnode()
191 	count = device_get_child_node_count(&pdev->dev);  in led_pwm_probe()
194 		return -EINVAL;  in led_pwm_probe()
196 	priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),  in led_pwm_probe()
199 		return -ENOMEM;  in led_pwm_probe()
201 	ret = led_pwm_create_fwnode(&pdev->dev, priv);  in led_pwm_probe()
212 	{ .compatible = "pwm-leds", },
228 MODULE_DESCRIPTION("generic PWM LED driver");
230 MODULE_ALIAS("platform:leds-pwm");