diff options
Diffstat (limited to 'drivers/leds/leds-pwm.c')
| -rw-r--r-- | drivers/leds/leds-pwm.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c new file mode 100644 index 000000000000..cdfdc8714e10 --- /dev/null +++ b/drivers/leds/leds-pwm.c @@ -0,0 +1,153 @@ +/* + * linux/drivers/leds-pwm.c + * + * simple PWM based LED control + * + * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de) + * + * based on leds-gpio.c by Raphael Assenat <raph@8d.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/fb.h> +#include <linux/leds.h> +#include <linux/err.h> +#include <linux/pwm.h> +#include <linux/leds_pwm.h> + +struct led_pwm_data { + struct led_classdev cdev; + struct pwm_device *pwm; + unsigned int active_low; + unsigned int period; + unsigned int max_brightness; +}; + +static void led_pwm_set(struct led_classdev *led_cdev, + enum led_brightness brightness) +{ + struct led_pwm_data *led_dat = + container_of(led_cdev, struct led_pwm_data, cdev); + unsigned int max = led_dat->max_brightness; + unsigned int period = led_dat->period; + + if (brightness == 0) { + pwm_config(led_dat->pwm, 0, period); + pwm_disable(led_dat->pwm); + } else { + pwm_config(led_dat->pwm, brightness * period / max, period); + pwm_enable(led_dat->pwm); + } +} + +static int led_pwm_probe(struct platform_device *pdev) +{ + struct led_pwm_platform_data *pdata = pdev->dev.platform_data; + struct led_pwm *cur_led; + struct led_pwm_data *leds_data, *led_dat; + int i, ret = 0; + + if (!pdata) + return -EBUSY; + + leds_data = kzalloc(sizeof(struct led_pwm_data) * pdata->num_leds, + GFP_KERNEL); + if (!leds_data) + return -ENOMEM; + + for (i = 0; i < pdata->num_leds; i++) { + cur_led = &pdata->leds[i]; + led_dat = &leds_data[i]; + + led_dat->pwm = pwm_request(cur_led->pwm_id, + cur_led->name); + if (IS_ERR(led_dat->pwm)) { + dev_err(&pdev->dev, "unable to request PWM %d\n", + cur_led->pwm_id); + goto err; + } + + led_dat->cdev.name = cur_led->name; + led_dat->cdev.default_trigger = cur_led->default_trigger; + led_dat->active_low = cur_led->active_low; + led_dat->max_brightness = cur_led->max_brightness; + led_dat->period = cur_led->pwm_period_ns; + led_dat->cdev.brightness_set = led_pwm_set; + led_dat->cdev.brightness = LED_OFF; + led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; + + ret = led_classdev_register(&pdev->dev, &led_dat->cdev); + if (ret < 0) { + pwm_free(led_dat->pwm); + goto err; + } + } + + platform_set_drvdata(pdev, leds_data); + + return 0; + +err: + if (i > 0) { + for (i = i - 1; i >= 0; i--) { + led_classdev_unregister(&leds_data[i].cdev); + pwm_free(leds_data[i].pwm); + } + } + + kfree(leds_data); + + return ret; +} + +static int __devexit led_pwm_remove(struct platform_device *pdev) +{ + int i; + struct led_pwm_platform_data *pdata = pdev->dev.platform_data; + struct led_pwm_data *leds_data; + + leds_data = platform_get_drvdata(pdev); + + for (i = 0; i < pdata->num_leds; i++) { + led_classdev_unregister(&leds_data[i].cdev); + pwm_free(leds_data[i].pwm); + } + + kfree(leds_data); + + return 0; +} + +static struct platform_driver led_pwm_driver = { + .probe = led_pwm_probe, + .remove = __devexit_p(led_pwm_remove), + .driver = { + .name = "leds_pwm", + .owner = THIS_MODULE, + }, +}; + +static int __init led_pwm_init(void) +{ + return platform_driver_register(&led_pwm_driver); +} + +static void __exit led_pwm_exit(void) +{ + platform_driver_unregister(&led_pwm_driver); +} + +module_init(led_pwm_init); +module_exit(led_pwm_exit); + +MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>"); +MODULE_DESCRIPTION("PWM LED driver for PXA"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:leds-pwm"); |