text: /*
   * LED driver for WM831x status LEDs
   *
   * Copyright(C) 2009 Wolfson Microelectronics PLC.
   *
   * 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/kernel.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <linux/leds.h>
  #include <linux/err.h>
  #include <linux/mfd/wm831x/core.h>
  #include <linux/mfd/wm831x/pdata.h>
  #include <linux/mfd/wm831x/status.h>
  #include <linux/module.h>
  
  
  struct wm831x_status {
  	struct led_classdev cdev;
  	struct wm831x *wm831x;
  	struct work_struct work;
  	struct mutex mutex;
  
  	spinlock_t value_lock;
  	int reg;     /* Control register */
  	int reg_val; /* Control register value */
  
  	int blink;
  	int blink_time;
  	int blink_cyc;
  	int src;
  	enum led_brightness brightness;
  };
  
  #define to_wm831x_status(led_cdev) \
  	container_of(led_cdev, struct wm831x_status, cdev)
  
  static void wm831x_status_work(struct work_struct *work)
  {
  	struct wm831x_status *led = container_of(work, struct wm831x_status,
  						 work);
  	unsigned long flags;
  
  	mutex_lock(&led->mutex);
  
  	led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
  			  WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
  
  	spin_lock_irqsave(&led->value_lock, flags);
  
  	led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
  	if (led->blink) {
  		led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
  		led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
  		led->reg_val |= led->blink_cyc;
  	} else {
  		if (led->brightness != LED_OFF)
  			led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
  	}
  
  	spin_unlock_irqrestore(&led->value_lock, flags);
  
  	wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
  
  	mutex_unlock(&led->mutex);
  }
  
  static void wm831x_status_set(struct led_classdev *led_cdev,
  			   enum led_brightness value)
  {
  	struct wm831x_status *led = to_wm831x_status(led_cdev);
  	unsigned long flags;
  
  	spin_lock_irqsave(&led->value_lock, flags);
  	led->brightness = value;
  	if (value == LED_OFF)
  		led->blink = 0;
  	schedule_work(&led->work);
  	spin_unlock_irqrestore(&led->value_lock, flags);
  }
  
  static int wm831x_status_blink_set(struct led_classdev *led_cdev,
  				   unsigned long *delay_on,
  				   unsigned long *delay_off)
  {
  	struct wm831x_status *led = to_wm831x_status(led_cdev);
  	unsigned long flags;
  	int ret = 0;
  
  	/* Pick some defaults if we've not been given times */
  	if (*delay_on == 0 && *delay_off == 0) {
  		*delay_on = 250;
  		*delay_off = 250;
  	}
  
  	spin_lock_irqsave(&led->value_lock, flags);
  
  	/* We only have a limited selection of settings, see if we can
  	 * support the configuration we're being given */
  	switch (*delay_on) {
  	case 1000:
  		led->blink_time = 0;
  		break;
  	case 250:
  		led->blink_time = 1;
  		break;
  	case 125:
  		led->blink_time = 2;
  		break;
  	case 62:
  	case 63:
  		/* Actually 62.5ms */
  		led->blink_time = 3;
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	}
  
  	if (ret == 0) {
  		switch (*delay_off / *delay_on) {
  		case 1:
  			led->blink_cyc = 0;
  			break;
  		case 3:
  			led->blink_cyc = 1;
  			break;
  		case 4:
  			led->blink_cyc = 2;
  			break;
  		case 8:
  			led->blink_cyc = 3;
  			break;
  		default:
  			ret = -EINVAL;
  			break;
  		}
  	}
  
  	if (ret == 0)
  		led->blink = 1;
  	else
  		led->blink = 0;
  
  	/* Always update; if we fail turn off blinking since we expect
  	 * a software fallback. */
  	schedule_work(&led->work);
  
  	spin_unlock_irqrestore(&led->value_lock, flags);
  
  	return ret;
  }
  
  static const char * const led_src_texts[] = {
  	"otp",
  	"power",
  	"charger",
  	"soft",
  };
  
  static ssize_t wm831x_status_src_show(struct device *dev,
  				      struct device_attribute *attr, char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct wm831x_status *led = to_wm831x_status(led_cdev);
  	int i;
  	ssize_t ret = 0;
  
  	mutex_lock(&led->mutex);
  
  	for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
  		if (i == led->src)
  			ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
  		else
  			ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
  
  	mutex_unlock(&led->mutex);
  
  	ret += sprintf(&buf[ret], "\n");
  
  	return ret;
  }
  
  static ssize_t wm831x_status_src_store(struct device *dev,
  				       struct device_attribute *attr,
  				       const char *buf, size_t size)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct wm831x_status *led = to_wm831x_status(led_cdev);
  	char name[20];
  	int i;
  	size_t len;
  
  	name[sizeof(name) - 1] = '\0';
  	strncpy(name, buf, sizeof(name) - 1);
  	len = strlen(name);
  
  	if (len && name[len - 1] == '\n')
  		name[len - 1] = '\0';
  
  	for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
  		if (!strcmp(name, led_src_texts[i])) {
  			mutex_lock(&led->mutex);
  
  			led->src = i;
  			schedule_work(&led->work);
  
  			mutex_unlock(&led->mutex);
  		}
  	}
  
  	return size;
  }
  
  static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
  
  static int wm831x_status_probe(struct platform_device *pdev)
  {
  	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
  	struct wm831x_pdata *chip_pdata;
  	struct wm831x_status_pdata pdata;
  	struct wm831x_status *drvdata;
  	struct resource *res;
  	int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
  	int ret;
  
  	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
  	if (res == NULL) {
  		dev_err(&pdev->dev, "No register resource\n");
  		ret = -EINVAL;
  		goto err;
  	}
  
  	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
  			       GFP_KERNEL);
  	if (!drvdata)
  		return -ENOMEM;
  	dev_set_drvdata(&pdev->dev, drvdata);
  
  	drvdata->wm831x = wm831x;
  	drvdata->reg = res->start;
  
  	if (wm831x->dev->platform_data)
  		chip_pdata = wm831x->dev->platform_data;
  	else
  		chip_pdata = NULL;
  
  	memset(&pdata, 0, sizeof(pdata));
  	if (chip_pdata && chip_pdata->status[id])
  		memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
  	else
  		pdata.name = dev_name(&pdev->dev);
  
  	mutex_init(&drvdata->mutex);
  	INIT_WORK(&drvdata->work, wm831x_status_work);
  	spin_lock_init(&drvdata->value_lock);
  
  	/* We cache the configuration register and read startup values
  	 * from it. */
  	drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
  
  	if (drvdata->reg_val & WM831X_LED_MODE_MASK)
  		drvdata->brightness = LED_FULL;
  	else
  		drvdata->brightness = LED_OFF;
  
  	/* Set a default source if configured, otherwise leave the
  	 * current hardware setting.
  	 */
  	if (pdata.default_src == WM831X_STATUS_PRESERVE) {
  		drvdata->src = drvdata->reg_val;
  		drvdata->src &= WM831X_LED_SRC_MASK;
  		drvdata->src >>= WM831X_LED_SRC_SHIFT;
  	} else {
  		drvdata->src = pdata.default_src - 1;
  	}
  
  	drvdata->cdev.name = pdata.name;
  	drvdata->cdev.default_trigger = pdata.default_trigger;
  	drvdata->cdev.brightness_set = wm831x_status_set;
  	drvdata->cdev.blink_set = wm831x_status_blink_set;
  
  	ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
  		goto err_led;
  	}
  
  	ret = device_create_file(drvdata->cdev.dev, &dev_attr_src);
  	if (ret != 0)
  		dev_err(&pdev->dev,
  			"No source control for LED: %d\n", ret);
  
  	return 0;
  
  err_led:
  	led_classdev_unregister(&drvdata->cdev);
  err:
  	return ret;
  }
  
  static int wm831x_status_remove(struct platform_device *pdev)
  {
  	struct wm831x_status *drvdata = platform_get_drvdata(pdev);
  
  	device_remove_file(drvdata->cdev.dev, &dev_attr_src);
  	led_classdev_unregister(&drvdata->cdev);
  
  	return 0;
  }
  
  static struct platform_driver wm831x_status_driver = {
  	.driver = {
  		   .name = "wm831x-status",
  		   .owner = THIS_MODULE,
  		   },
  	.probe = wm831x_status_probe,
  	.remove = wm831x_status_remove,
  };
  
  module_platform_driver(wm831x_status_driver);
  
  MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
  MODULE_DESCRIPTION("WM831x status LED driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:wm831x-status");
  