/*
   * 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/ctype.h>
  #include <linux/delay.h>
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/of_platform.h>
  #include <linux/fb.h>
  #include <linux/leds.h>
  #include <linux/err.h>
  #include <linux/pwm.h>
  #include <linux/leds_pwm.h>
  #include <linux/slab.h>
  #include <linux/workqueue.h>
  #include "leds.h"
  
  /* lowercase notes are an octave higher*/
  /* n means move up n octaves */
  /* Note: sharp (#) or flat (_) precedes note that it applies to */
  static unsigned base_a_g[] = {
  	36363636,	/* "A",	27.50 hz, 1250 cm */
  	32396317,	/* "B",	30.87 hz, 1110 cm */
  	61156103,	/* "C",	16.35 hz, 2100 cm */
  	54483894,	/* "D",	18.35 hz, 1870 cm */
  	48539631,	/* "E",	20.60 hz, 1670 cm */
  	45815311,	/* "F",	21.83 hz, 1580 cm */
  	40816802,	/* "G",	24.50 hz, 1400 cm */
  };
  static unsigned sharp_a_g[] = {
  	34322702,	/* "#A", "_B"	29.14 hz, 1180 cm */
  	0,		/* "B",		30.87 hz, 1110 cm */
  	57723675,	/* "#C", "_D"	17.32 hz, 1990 cm */
  	51425948,	/* "#D", "_E"	19.45 hz, 1770 cm */
  	0,		/* "E",		20.60 hz, 1670 cm */
  	43243895,	/* "#F", "_G"	23.12 hz, 1490 cm */
  	38525931,	/* "#G", "_A"	25.96 hz, 1320 cm */
  };
  static unsigned flat_a_g[] = {
  	38525931,	/* "_A"	25.96 hz, 1320 cm */
  	34322702,	/* "_B"	29.14 hz, 1180 cm */
  	0,		/* "C",	16.35 hz, 2100 cm */
  	57723675,	/* "_D" 17.32 hz, 1990 cm */
  	51425948,	/* "_E"	19.45 hz, 1770 cm */
  	0,		/* "F",	21.83 hz, 1580 cm */
  	43243895,	/* "_G"	23.12 hz, 1490 cm */
  };
  
  struct led_pwm_data {
  	struct led_classdev	cdev;
  	struct pwm_device	*pwm;
  	struct work_struct	work;
  	unsigned int		active_low;
  	unsigned int		period;
  	int			duty;
  	bool			can_sleep;
  	unsigned char		octave;
  #define NM_NORMAL 0
  #define NM_SHARP 1
  #define NM_FLAT 2
  	unsigned char		note_mode;
  };
  
  struct led_pwm_priv {
  	int num_leds;
  	struct led_pwm_data leds[0];
  };
  
  static ssize_t led_frequency_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct led_pwm_data *led_dat =
  		container_of(led_cdev, struct led_pwm_data, cdev);
  	unsigned int period =  led_dat->period;
  	unsigned int freq = period ? 1000000000 / period : 0;
  
  	return sprintf(buf, "%u
  ", freq);
  }
  
  static ssize_t led_frequency_store(struct device *dev,
  		struct device_attribute *attr, const char *buf, size_t size)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct led_pwm_data *led_dat =
  		container_of(led_cdev, struct led_pwm_data, cdev);
  	ssize_t ret = -EINVAL;
  	char *after;
  	unsigned long freq = simple_strtoul(buf, &after, 10);
  	size_t count = after - buf;
  
  	if (*after && isspace(*after))
  		count++;
  
  	if (count == size) {
  		ret = count;
  
  		led_dat->period = freq ? 1000000000 / freq : 0;
  		if (!led_cdev->brightness)
  			led_cdev->brightness = led_cdev->max_brightness >> 1;
  		led_set_brightness(led_cdev, led_cdev->brightness);
  	}
  
  	return ret;
  }
  static ssize_t led_period_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct led_pwm_data *led_dat =
  		container_of(led_cdev, struct led_pwm_data, cdev);
  	unsigned int period =  led_dat->period;
  
  	return sprintf(buf, "%u
  ", period);
  }
  
  static ssize_t led_period_store(struct device *dev,
  		struct device_attribute *attr, const char *buf, size_t size)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct led_pwm_data *led_dat =
  		container_of(led_cdev, struct led_pwm_data, cdev);
  	ssize_t ret = -EINVAL;
  	char *after;
  	unsigned long period = simple_strtoul(buf, &after, 10);
  	size_t count = after - buf;
  
  	if (*after && isspace(*after))
  		count++;
  
  	if (count == size) {
  		ret = count;
  		led_dat->period = period;
  		led_set_brightness(led_cdev, led_cdev->brightness);
  	}
  
  	return ret;
  }
  
  static ssize_t led_note_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct led_pwm_data *led_dat =
  		container_of(led_cdev, struct led_pwm_data, cdev);
  	unsigned int period =  led_dat->period;
  	unsigned i;
  	int octave = 0;
  	unsigned best = 0;
  	unsigned best_err = 0xffffffff;
  	char note_mode = 0;
  
  	if (period == 0)
  		return sprintf(buf, "
  ");
  
  	while (period < base_a_g[2]) {
  		octave++;
  		period <<= 1;
  	}
  	while (period > base_a_g[2]) {
  		octave--;
  		period >>= 1;
  	}
  	for (i = 0; i < 7; i++) {
  		unsigned err = (base_a_g[i] > period) ? (base_a_g[i] - period) :
  			(period - base_a_g[i]);
  		if (best_err > err) {
  			best = i;
  			best_err = err;
  			note_mode = 0;
  		}
  		err = (sharp_a_g[i] > period) ? (sharp_a_g[i] - period) :
  			(period - sharp_a_g[i]);
  		if (best_err > err) {
  			best = i;
  			best_err = err;
  			note_mode = '#';
  		}
  	}
  	return sprintf(buf, "%u%s%c
  ", octave, &note_mode, 'A' + best);
  }
  
  static ssize_t led_note_store(struct device *dev,
  		struct device_attribute *attr, const char *buf, size_t size)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct led_pwm_data *led_dat =
  		container_of(led_cdev, struct led_pwm_data, cdev);
  	size_t count = 0;
  	while (count < size) {
  		char octave = led_dat->octave;
  		char note_mode = led_dat->note_mode;
  		char c = *buf++;
  		int period = -1;
  		count++;
  		if (c == ' ') {
  			period = 0;
  		} else if (c == '_') {
  			note_mode = NM_FLAT;
  		} else if (c == '#') {
  			note_mode = NM_SHARP;
  		} else if ((c >= '0') && (c <= '9')) {
  			octave = c - '0';
  			led_dat->octave = octave;
  		} else {
  			if ((c >= 'a') && (c <= 'g')) {
  				octave++;
  				c -= 'a' - 'A';
  			}
  			if ((c >= 'A') && (c <= 'G')) {
  				c -= 'A';
  				if (note_mode == NM_NORMAL)
  					period = base_a_g[(int)c];
  				else if (note_mode == NM_SHARP)
  					period = sharp_a_g[(int)c];
  				else if (note_mode == NM_FLAT)
  					period = flat_a_g[(int)c];
  			}
  		}
  		led_dat->note_mode = note_mode;
  		if (period >= 0) {
  			period >>= octave;
  			led_dat->period = period;
  			if (!led_cdev->brightness)
  				led_cdev->brightness = led_cdev->max_brightness
  							>> 1;
  			led_set_brightness(led_cdev, led_cdev->brightness);
  			led_dat->note_mode = NM_NORMAL;
  			if (count < size)
  				msleep(period ? 1000 : 100);
  		}
  	}
  	return count;
  }
  
  static DEVICE_ATTR(note, 0644, led_note_show, led_note_store);
  static DEVICE_ATTR(frequency, 0644, led_frequency_show, led_frequency_store);
  static DEVICE_ATTR(period, 0644, led_period_show, led_period_store);
  
  static void __led_pwm_set(struct led_pwm_data *led_dat)
  {
  	int new_duty = led_dat->duty;
  
  	pwm_config(led_dat->pwm, new_duty, led_dat->period);
  
  	if (new_duty == 0)
  		pwm_disable(led_dat->pwm);
  	else
  		pwm_enable(led_dat->pwm);
  }
  
  static void led_pwm_work(struct work_struct *work)
  {
  	struct led_pwm_data *led_dat =
  		container_of(work, struct led_pwm_data, work);
  
  	__led_pwm_set(led_dat);
  }
  
  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->cdev.max_brightness;
  	unsigned long long duty =  led_dat->period;
  
  	duty *= brightness;
  	do_div(duty, max);
  	led_dat->duty = duty;
  
  	if (led_dat->can_sleep)
  		schedule_work(&led_dat->work);
  	else
  		__led_pwm_set(led_dat);
  }
  
  static inline size_t sizeof_pwm_leds_priv(int num_leds)
  {
  	return sizeof(struct led_pwm_priv) +
  		      (sizeof(struct led_pwm_data) * num_leds);
  }
  
  static void led_pwm_cleanup(struct led_pwm_priv *priv)
  {
  	while (priv->num_leds--) {
  		struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
  
  		device_remove_file(led_dat->cdev.dev, &dev_attr_note);
  		device_remove_file(led_dat->cdev.dev, &dev_attr_frequency);
  		device_remove_file(led_dat->cdev.dev, &dev_attr_period);
  		led_classdev_unregister(&led_dat->cdev);
  		if (priv->leds[priv->num_leds].can_sleep)
  			cancel_work_sync(&priv->leds[priv->num_leds].work);
  	}
  }
  
  static int led_pwm_create_of(struct platform_device *pdev,
  			     struct led_pwm_priv *priv)
  {
  	struct device_node *child;
  	int ret;
  
  	for_each_child_of_node(pdev->dev.of_node, child) {
  		struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
  		led_dat->cdev.name = of_get_property(child, "label",
  						     NULL) ? : child->name;
  
  		led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
  		if (IS_ERR(led_dat->pwm)) {
  			dev_err(&pdev->dev, "unable to request PWM for %s
  ",
  				led_dat->cdev.name);
  			ret = PTR_ERR(led_dat->pwm);
  			goto err;
  		}
  		/* Get the period from PWM core when n*/
  		led_dat->period = pwm_get_period(led_dat->pwm);
  
  		led_dat->cdev.default_trigger = of_get_property(child,
  						"linux,default-trigger", NULL);
  		of_property_read_u32(child, "max-brightness",
  				     &led_dat->cdev.max_brightness);
  
  		led_dat->cdev.brightness_set = led_pwm_set;
  		led_dat->cdev.brightness = LED_OFF;
  		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
  		led_dat->octave = 4;
  		led_dat->period = led_dat->pwm->period;
  
  		led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
  		if (led_dat->can_sleep)
  			INIT_WORK(&led_dat->work, led_pwm_work);
  
  		ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
  		if (ret < 0) {
  			dev_err(&pdev->dev, "failed to register for %s
  ",
  				led_dat->cdev.name);
  			of_node_put(child);
  			goto err;
  		}
  
  		/* register the attributes */
  		ret = device_create_file(led_dat->cdev.dev,
  					 &dev_attr_frequency);
  		if (ret)
  			goto err;
  		ret = device_create_file(led_dat->cdev.dev, &dev_attr_period);
  		if (ret)
  			goto err;
  		ret = device_create_file(led_dat->cdev.dev, &dev_attr_note);
  		if (ret)
  			goto err;
  		priv->num_leds++;
  	}
  
  	return 0;
  err:
  	led_pwm_cleanup(priv);
  
  	return ret;
  }
  
  static int led_pwm_probe(struct platform_device *pdev)
  {
  	struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
  	struct led_pwm_priv *priv;
  	int count, i;
  	int ret = 0;
  
  	if (pdata)
  		count = pdata->num_leds;
  	else
  		count = of_get_child_count(pdev->dev.of_node);
  
  	if (!count)
  		return -EINVAL;
  
  	priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
  			    GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	if (pdata) {
  		for (i = 0; i < count; i++) {
  			struct led_pwm *cur_led = &pdata->leds[i];
  			struct led_pwm_data *led_dat = &priv->leds[i];
  
  			led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
  			if (IS_ERR(led_dat->pwm)) {
  				ret = PTR_ERR(led_dat->pwm);
  				dev_err(&pdev->dev,
  					"unable to request PWM for %s
  ",
  					cur_led->name);
  				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->period = cur_led->pwm_period_ns;
  			led_dat->cdev.brightness_set = led_pwm_set;
  			led_dat->cdev.brightness = LED_OFF;
  			led_dat->cdev.max_brightness = cur_led->max_brightness;
  			led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
  
  			led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
  			if (led_dat->can_sleep)
  				INIT_WORK(&led_dat->work, led_pwm_work);
  
  			ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
  			if (ret < 0)
  				goto err;
  		}
  		priv->num_leds = count;
  	} else {
  		ret = led_pwm_create_of(pdev, priv);
  		if (ret)
  			return ret;
  	}
  
  	platform_set_drvdata(pdev, priv);
  
  	return 0;
  
  err:
  	priv->num_leds = i;
  	led_pwm_cleanup(priv);
  
  	return ret;
  }
  
  static int led_pwm_remove(struct platform_device *pdev)
  {
  	struct led_pwm_priv *priv = platform_get_drvdata(pdev);
  
  	led_pwm_cleanup(priv);
  
  	return 0;
  }
  
  static const struct of_device_id of_pwm_leds_match[] = {
  	{ .compatible = "pwm-leds", },
  	{},
  };
  MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
  
  static struct platform_driver led_pwm_driver = {
  	.probe		= led_pwm_probe,
  	.remove		= led_pwm_remove,
  	.driver		= {
  		.name	= "leds_pwm",
  		.owner	= THIS_MODULE,
  		.of_match_table = of_pwm_leds_match,
  	},
  };
  
  module_platform_driver(led_pwm_driver);
  
  MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
  MODULE_DESCRIPTION("PWM LED driver for PXA");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:leds-pwm");