/*
   * leds-netxbig.c - Driver for the 2Big and 5Big Network series LEDs
   *
   * Copyright (C) 2010 LaCie
   *
   * Author: Simon Guinot <sguinot@lacie.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/irq.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/platform_device.h>
  #include <linux/gpio.h>
  #include <linux/leds.h>
  #include <linux/platform_data/leds-kirkwood-netxbig.h>
  
  /*
   * GPIO extension bus.
   */
  
  static DEFINE_SPINLOCK(gpio_ext_lock);
  
  static void gpio_ext_set_addr(struct netxbig_gpio_ext *gpio_ext, int addr)
  {
  	int pin;
  
  	for (pin = 0; pin < gpio_ext->num_addr; pin++)
  		gpio_set_value(gpio_ext->addr[pin], (addr >> pin) & 1);
  }
  
  static void gpio_ext_set_data(struct netxbig_gpio_ext *gpio_ext, int data)
  {
  	int pin;
  
  	for (pin = 0; pin < gpio_ext->num_data; pin++)
  		gpio_set_value(gpio_ext->data[pin], (data >> pin) & 1);
  }
  
  static void gpio_ext_enable_select(struct netxbig_gpio_ext *gpio_ext)
  {
  	/* Enable select is done on the raising edge. */
  	gpio_set_value(gpio_ext->enable, 0);
  	gpio_set_value(gpio_ext->enable, 1);
  }
  
  static void gpio_ext_set_value(struct netxbig_gpio_ext *gpio_ext,
  			       int addr, int value)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&gpio_ext_lock, flags);
  	gpio_ext_set_addr(gpio_ext, addr);
  	gpio_ext_set_data(gpio_ext, value);
  	gpio_ext_enable_select(gpio_ext);
  	spin_unlock_irqrestore(&gpio_ext_lock, flags);
  }
  
  static int gpio_ext_init(struct netxbig_gpio_ext *gpio_ext)
  {
  	int err;
  	int i;
  
  	if (unlikely(!gpio_ext))
  		return -EINVAL;
  
  	/* Configure address GPIOs. */
  	for (i = 0; i < gpio_ext->num_addr; i++) {
  		err = gpio_request_one(gpio_ext->addr[i], GPIOF_OUT_INIT_LOW,
  				       "GPIO extension addr");
  		if (err)
  			goto err_free_addr;
  	}
  	/* Configure data GPIOs. */
  	for (i = 0; i < gpio_ext->num_data; i++) {
  		err = gpio_request_one(gpio_ext->data[i], GPIOF_OUT_INIT_LOW,
  				   "GPIO extension data");
  		if (err)
  			goto err_free_data;
  	}
  	/* Configure "enable select" GPIO. */
  	err = gpio_request_one(gpio_ext->enable, GPIOF_OUT_INIT_LOW,
  			       "GPIO extension enable");
  	if (err)
  		goto err_free_data;
  
  	return 0;
  
  err_free_data:
  	for (i = i - 1; i >= 0; i--)
  		gpio_free(gpio_ext->data[i]);
  	i = gpio_ext->num_addr;
  err_free_addr:
  	for (i = i - 1; i >= 0; i--)
  		gpio_free(gpio_ext->addr[i]);
  
  	return err;
  }
  
  static void gpio_ext_free(struct netxbig_gpio_ext *gpio_ext)
  {
  	int i;
  
  	gpio_free(gpio_ext->enable);
  	for (i = gpio_ext->num_addr - 1; i >= 0; i--)
  		gpio_free(gpio_ext->addr[i]);
  	for (i = gpio_ext->num_data - 1; i >= 0; i--)
  		gpio_free(gpio_ext->data[i]);
  }
  
  /*
   * Class LED driver.
   */
  
  struct netxbig_led_data {
  	struct netxbig_gpio_ext	*gpio_ext;
  	struct led_classdev	cdev;
  	int			mode_addr;
  	int			*mode_val;
  	int			bright_addr;
  	int			bright_max;
  	struct			netxbig_led_timer *timer;
  	int			num_timer;
  	enum netxbig_led_mode	mode;
  	int			sata;
  	spinlock_t		lock;
  };
  
  static int netxbig_led_get_timer_mode(enum netxbig_led_mode *mode,
  				      unsigned long delay_on,
  				      unsigned long delay_off,
  				      struct netxbig_led_timer *timer,
  				      int num_timer)
  {
  	int i;
  
  	for (i = 0; i < num_timer; i++) {
  		if (timer[i].delay_on == delay_on &&
  		    timer[i].delay_off == delay_off) {
  			*mode = timer[i].mode;
  			return 0;
  		}
  	}
  	return -EINVAL;
  }
  
  static int netxbig_led_blink_set(struct led_classdev *led_cdev,
  				 unsigned long *delay_on,
  				 unsigned long *delay_off)
  {
  	struct netxbig_led_data *led_dat =
  		container_of(led_cdev, struct netxbig_led_data, cdev);
  	enum netxbig_led_mode mode;
  	int mode_val;
  	int ret;
  
  	/* Look for a LED mode with the requested timer frequency. */
  	ret = netxbig_led_get_timer_mode(&mode, *delay_on, *delay_off,
  					 led_dat->timer, led_dat->num_timer);
  	if (ret < 0)
  		return ret;
  
  	mode_val = led_dat->mode_val[mode];
  	if (mode_val == NETXBIG_LED_INVALID_MODE)
  		return -EINVAL;
  
  	spin_lock_irq(&led_dat->lock);
  
  	gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
  	led_dat->mode = mode;
  
  	spin_unlock_irq(&led_dat->lock);
  
  	return 0;
  }
  
  static void netxbig_led_set(struct led_classdev *led_cdev,
  			    enum led_brightness value)
  {
  	struct netxbig_led_data *led_dat =
  		container_of(led_cdev, struct netxbig_led_data, cdev);
  	enum netxbig_led_mode mode;
  	int mode_val, bright_val;
  	int set_brightness = 1;
  	unsigned long flags;
  
  	spin_lock_irqsave(&led_dat->lock, flags);
  
  	if (value == LED_OFF) {
  		mode = NETXBIG_LED_OFF;
  		set_brightness = 0;
  	} else {
  		if (led_dat->sata)
  			mode = NETXBIG_LED_SATA;
  		else if (led_dat->mode == NETXBIG_LED_OFF)
  			mode = NETXBIG_LED_ON;
  		else /* Keep 'timer' mode. */
  			mode = led_dat->mode;
  	}
  	mode_val = led_dat->mode_val[mode];
  
  	gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
  	led_dat->mode = mode;
  	/*
  	 * Note that the brightness register is shared between all the
  	 * SATA LEDs. So, change the brightness setting for a single
  	 * SATA LED will affect all the others.
  	 */
  	if (set_brightness) {
  		bright_val = DIV_ROUND_UP(value * led_dat->bright_max,
  					  LED_FULL);
  		gpio_ext_set_value(led_dat->gpio_ext,
  				   led_dat->bright_addr, bright_val);
  	}
  
  	spin_unlock_irqrestore(&led_dat->lock, flags);
  }
  
  static ssize_t netxbig_led_sata_store(struct device *dev,
  				      struct device_attribute *attr,
  				      const char *buff, size_t count)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct netxbig_led_data *led_dat =
  		container_of(led_cdev, struct netxbig_led_data, cdev);
  	unsigned long enable;
  	enum netxbig_led_mode mode;
  	int mode_val;
  	int ret;
  
  	ret = kstrtoul(buff, 10, &enable);
  	if (ret < 0)
  		return ret;
  
  	enable = !!enable;
  
  	spin_lock_irq(&led_dat->lock);
  
  	if (led_dat->sata == enable) {
  		ret = count;
  		goto exit_unlock;
  	}
  
  	if (led_dat->mode != NETXBIG_LED_ON &&
  	    led_dat->mode != NETXBIG_LED_SATA)
  		mode = led_dat->mode; /* Keep modes 'off' and 'timer'. */
  	else if (enable)
  		mode = NETXBIG_LED_SATA;
  	else
  		mode = NETXBIG_LED_ON;
  
  	mode_val = led_dat->mode_val[mode];
  	if (mode_val == NETXBIG_LED_INVALID_MODE) {
  		ret = -EINVAL;
  		goto exit_unlock;
  	}
  
  	gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
  	led_dat->mode = mode;
  	led_dat->sata = enable;
  
  	ret = count;
  
  exit_unlock:
  	spin_unlock_irq(&led_dat->lock);
  
  	return ret;
  }
  
  static ssize_t netxbig_led_sata_show(struct device *dev,
  				     struct device_attribute *attr, char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct netxbig_led_data *led_dat =
  		container_of(led_cdev, struct netxbig_led_data, cdev);
  
  	return sprintf(buf, "%d
  ", led_dat->sata);
  }
  
  static DEVICE_ATTR(sata, 0644, netxbig_led_sata_show, netxbig_led_sata_store);
  
  static void delete_netxbig_led(struct netxbig_led_data *led_dat)
  {
  	if (led_dat->mode_val[NETXBIG_LED_SATA] != NETXBIG_LED_INVALID_MODE)
  		device_remove_file(led_dat->cdev.dev, &dev_attr_sata);
  	led_classdev_unregister(&led_dat->cdev);
  }
  
  static int
  create_netxbig_led(struct platform_device *pdev,
  		   struct netxbig_led_data *led_dat,
  		   const struct netxbig_led *template)
  {
  	struct netxbig_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
  	int ret;
  
  	spin_lock_init(&led_dat->lock);
  	led_dat->gpio_ext = pdata->gpio_ext;
  	led_dat->cdev.name = template->name;
  	led_dat->cdev.default_trigger = template->default_trigger;
  	led_dat->cdev.blink_set = netxbig_led_blink_set;
  	led_dat->cdev.brightness_set = netxbig_led_set;
  	/*
  	 * Because the GPIO extension bus don't allow to read registers
  	 * value, there is no way to probe the LED initial state.
  	 * So, the initial sysfs LED value for the "brightness" and "sata"
  	 * attributes are inconsistent.
  	 *
  	 * Note that the initial LED state can't be reconfigured.
  	 * The reason is that the LED behaviour must stay uniform during
  	 * the whole boot process (bootloader+linux).
  	 */
  	led_dat->sata = 0;
  	led_dat->cdev.brightness = LED_OFF;
  	led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
  	led_dat->mode_addr = template->mode_addr;
  	led_dat->mode_val = template->mode_val;
  	led_dat->bright_addr = template->bright_addr;
  	led_dat->bright_max = (1 << pdata->gpio_ext->num_data) - 1;
  	led_dat->timer = pdata->timer;
  	led_dat->num_timer = pdata->num_timer;
  
  	ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
  	if (ret < 0)
  		return ret;
  
  	/*
  	 * If available, expose the SATA activity blink capability through
  	 * a "sata" sysfs attribute.
  	 */
  	if (led_dat->mode_val[NETXBIG_LED_SATA] != NETXBIG_LED_INVALID_MODE) {
  		ret = device_create_file(led_dat->cdev.dev, &dev_attr_sata);
  		if (ret)
  			led_classdev_unregister(&led_dat->cdev);
  	}
  
  	return ret;
  }
  
  static int netxbig_led_probe(struct platform_device *pdev)
  {
  	struct netxbig_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
  	struct netxbig_led_data *leds_data;
  	int i;
  	int ret;
  
  	if (!pdata)
  		return -EINVAL;
  
  	leds_data = devm_kzalloc(&pdev->dev,
  		sizeof(struct netxbig_led_data) * pdata->num_leds, GFP_KERNEL);
  	if (!leds_data)
  		return -ENOMEM;
  
  	ret = gpio_ext_init(pdata->gpio_ext);
  	if (ret < 0)
  		return ret;
  
  	for (i = 0; i < pdata->num_leds; i++) {
  		ret = create_netxbig_led(pdev, &leds_data[i], &pdata->leds[i]);
  		if (ret < 0)
  			goto err_free_leds;
  	}
  
  	platform_set_drvdata(pdev, leds_data);
  
  	return 0;
  
  err_free_leds:
  	for (i = i - 1; i >= 0; i--)
  		delete_netxbig_led(&leds_data[i]);
  
  	gpio_ext_free(pdata->gpio_ext);
  	return ret;
  }
  
  static int netxbig_led_remove(struct platform_device *pdev)
  {
  	struct netxbig_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
  	struct netxbig_led_data *leds_data;
  	int i;
  
  	leds_data = platform_get_drvdata(pdev);
  
  	for (i = 0; i < pdata->num_leds; i++)
  		delete_netxbig_led(&leds_data[i]);
  
  	gpio_ext_free(pdata->gpio_ext);
  
  	return 0;
  }
  
  static struct platform_driver netxbig_led_driver = {
  	.probe		= netxbig_led_probe,
  	.remove		= netxbig_led_remove,
  	.driver		= {
  		.name	= "leds-netxbig",
  		.owner	= THIS_MODULE,
  	},
  };
  
  module_platform_driver(netxbig_led_driver);
  
  MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
  MODULE_DESCRIPTION("LED driver for LaCie xBig Network boards");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:leds-netxbig");