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178 lines
4.0 KiB
178 lines
4.0 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* linux/drivers/leds-pwm.c |
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* |
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* simple PWM based LED control |
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* |
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* Copyright 2009 Luotao Fu @ Pengutronix ([email protected]) |
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* |
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* based on leds-gpio.c by Raphael Assenat <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/platform_device.h> |
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#include <linux/of_platform.h> |
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#include <linux/leds.h> |
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#include <linux/err.h> |
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#include <linux/pwm.h> |
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#include <linux/slab.h> |
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struct led_pwm { |
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const char *name; |
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u8 active_low; |
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unsigned int max_brightness; |
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}; |
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struct led_pwm_data { |
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struct led_classdev cdev; |
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struct pwm_device *pwm; |
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struct pwm_state pwmstate; |
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unsigned int active_low; |
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}; |
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struct led_pwm_priv { |
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int num_leds; |
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struct led_pwm_data leds[]; |
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}; |
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static int led_pwm_set(struct led_classdev *led_cdev, |
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enum led_brightness brightness) |
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{ |
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struct led_pwm_data *led_dat = |
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container_of(led_cdev, struct led_pwm_data, cdev); |
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unsigned int max = led_dat->cdev.max_brightness; |
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unsigned long long duty = led_dat->pwmstate.period; |
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duty *= brightness; |
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do_div(duty, max); |
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if (led_dat->active_low) |
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duty = led_dat->pwmstate.period - duty; |
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led_dat->pwmstate.duty_cycle = duty; |
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led_dat->pwmstate.enabled = duty > 0; |
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return pwm_apply_state(led_dat->pwm, &led_dat->pwmstate); |
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} |
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__attribute__((nonnull)) |
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static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv, |
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struct led_pwm *led, struct fwnode_handle *fwnode) |
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{ |
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struct led_pwm_data *led_data = &priv->leds[priv->num_leds]; |
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struct led_init_data init_data = { .fwnode = fwnode }; |
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int ret; |
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led_data->active_low = led->active_low; |
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led_data->cdev.name = led->name; |
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led_data->cdev.brightness = LED_OFF; |
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led_data->cdev.max_brightness = led->max_brightness; |
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led_data->cdev.flags = LED_CORE_SUSPENDRESUME; |
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led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL); |
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if (IS_ERR(led_data->pwm)) |
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return dev_err_probe(dev, PTR_ERR(led_data->pwm), |
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"unable to request PWM for %s\n", |
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led->name); |
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led_data->cdev.brightness_set_blocking = led_pwm_set; |
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pwm_init_state(led_data->pwm, &led_data->pwmstate); |
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ret = devm_led_classdev_register_ext(dev, &led_data->cdev, &init_data); |
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if (ret) { |
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dev_err(dev, "failed to register PWM led for %s: %d\n", |
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led->name, ret); |
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return ret; |
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} |
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ret = led_pwm_set(&led_data->cdev, led_data->cdev.brightness); |
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if (ret) { |
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dev_err(dev, "failed to set led PWM value for %s: %d", |
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led->name, ret); |
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return ret; |
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} |
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priv->num_leds++; |
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return 0; |
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} |
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static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv) |
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{ |
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struct fwnode_handle *fwnode; |
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struct led_pwm led; |
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int ret = 0; |
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memset(&led, 0, sizeof(led)); |
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device_for_each_child_node(dev, fwnode) { |
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ret = fwnode_property_read_string(fwnode, "label", &led.name); |
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if (ret && is_of_node(fwnode)) |
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led.name = to_of_node(fwnode)->name; |
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if (!led.name) { |
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fwnode_handle_put(fwnode); |
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return -EINVAL; |
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} |
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led.active_low = fwnode_property_read_bool(fwnode, |
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"active-low"); |
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fwnode_property_read_u32(fwnode, "max-brightness", |
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&led.max_brightness); |
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ret = led_pwm_add(dev, priv, &led, fwnode); |
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if (ret) { |
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fwnode_handle_put(fwnode); |
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break; |
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} |
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} |
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return ret; |
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} |
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static int led_pwm_probe(struct platform_device *pdev) |
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{ |
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struct led_pwm_priv *priv; |
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int ret = 0; |
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int count; |
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count = device_get_child_node_count(&pdev->dev); |
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if (!count) |
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return -EINVAL; |
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priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count), |
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GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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ret = led_pwm_create_fwnode(&pdev->dev, priv); |
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if (ret) |
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return ret; |
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platform_set_drvdata(pdev, priv); |
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return 0; |
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} |
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static const struct of_device_id of_pwm_leds_match[] = { |
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{ .compatible = "pwm-leds", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, of_pwm_leds_match); |
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static struct platform_driver led_pwm_driver = { |
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.probe = led_pwm_probe, |
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.driver = { |
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.name = "leds_pwm", |
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.of_match_table = of_pwm_leds_match, |
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}, |
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}; |
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module_platform_driver(led_pwm_driver); |
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MODULE_AUTHOR("Luotao Fu <[email protected]>"); |
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MODULE_DESCRIPTION("generic PWM LED driver"); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_ALIAS("platform:leds-pwm");
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