text: /*
   * Backlight driver for Marvell Semiconductor 88PM8606
   *
   * Copyright (C) 2009 Marvell International Ltd.
   *	Haojian Zhuang <haojian.zhuang@marvell.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/init.h>
  #include <linux/kernel.h>
  #include <linux/of.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <linux/fb.h>
  #include <linux/i2c.h>
  #include <linux/backlight.h>
  #include <linux/mfd/88pm860x.h>
  #include <linux/module.h>
  
  #define MAX_BRIGHTNESS		(0xFF)
  #define MIN_BRIGHTNESS		(0)
  
  #define CURRENT_BITMASK		(0x1F << 1)
  
  struct pm860x_backlight_data {
  	struct pm860x_chip *chip;
  	struct i2c_client *i2c;
  	int	current_brightness;
  	int	port;
  	int	pwm;
  	int	iset;
  	int	reg_duty_cycle;
  	int	reg_always_on;
  	int	reg_current;
  };
  
  static int backlight_power_set(struct pm860x_chip *chip, int port,
  		int on)
  {
  	int ret = -EINVAL;
  
  	switch (port) {
  	case 0:
  		ret = on ? pm8606_osc_enable(chip, WLED1_DUTY) :
  			pm8606_osc_disable(chip, WLED1_DUTY);
  		break;
  	case 1:
  		ret = on ? pm8606_osc_enable(chip, WLED2_DUTY) :
  			pm8606_osc_disable(chip, WLED2_DUTY);
  		break;
  	case 2:
  		ret = on ? pm8606_osc_enable(chip, WLED3_DUTY) :
  			pm8606_osc_disable(chip, WLED3_DUTY);
  		break;
  	}
  	return ret;
  }
  
  static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
  {
  	struct pm860x_backlight_data *data = bl_get_data(bl);
  	struct pm860x_chip *chip = data->chip;
  	unsigned char value;
  	int ret;
  
  	if (brightness > MAX_BRIGHTNESS)
  		value = MAX_BRIGHTNESS;
  	else
  		value = brightness;
  
  	if (brightness)
  		backlight_power_set(chip, data->port, 1);
  
  	ret = pm860x_reg_write(data->i2c, data->reg_duty_cycle, value);
  	if (ret < 0)
  		goto out;
  
  	if ((data->current_brightness == 0) && brightness) {
  		if (data->iset) {
  			ret = pm860x_set_bits(data->i2c, data->reg_current,
  					      CURRENT_BITMASK, data->iset);
  			if (ret < 0)
  				goto out;
  		}
  		if (data->pwm) {
  			ret = pm860x_set_bits(data->i2c, PM8606_PWM,
  					      PM8606_PWM_FREQ_MASK, data->pwm);
  			if (ret < 0)
  				goto out;
  		}
  		if (brightness == MAX_BRIGHTNESS) {
  			/* set WLED_ON bit as 100% */
  			ret = pm860x_set_bits(data->i2c, data->reg_always_on,
  					      PM8606_WLED_ON, PM8606_WLED_ON);
  		}
  	} else {
  		if (brightness == MAX_BRIGHTNESS) {
  			/* set WLED_ON bit as 100% */
  			ret = pm860x_set_bits(data->i2c, data->reg_always_on,
  					      PM8606_WLED_ON, PM8606_WLED_ON);
  		} else {
  			/* clear WLED_ON bit since it's not 100% */
  			ret = pm860x_set_bits(data->i2c, data->reg_always_on,
  					      PM8606_WLED_ON, 0);
  		}
  	}
  	if (ret < 0)
  		goto out;
  
  	if (brightness == 0)
  		backlight_power_set(chip, data->port, 0);
  
  	dev_dbg(chip->dev, "set brightness %d\n", value);
  	data->current_brightness = value;
  	return 0;
  out:
  	dev_dbg(chip->dev, "set brightness %d failure with return "
  		"value:%d\n", value, ret);
  	return ret;
  }
  
  static int pm860x_backlight_update_status(struct backlight_device *bl)
  {
  	int brightness = bl->props.brightness;
  
  	if (bl->props.power != FB_BLANK_UNBLANK)
  		brightness = 0;
  
  	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
  		brightness = 0;
  
  	if (bl->props.state & BL_CORE_SUSPENDED)
  		brightness = 0;
  
  	return pm860x_backlight_set(bl, brightness);
  }
  
  static int pm860x_backlight_get_brightness(struct backlight_device *bl)
  {
  	struct pm860x_backlight_data *data = bl_get_data(bl);
  	struct pm860x_chip *chip = data->chip;
  	int ret;
  
  	ret = pm860x_reg_read(data->i2c, data->reg_duty_cycle);
  	if (ret < 0)
  		goto out;
  	data->current_brightness = ret;
  	dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
  	return data->current_brightness;
  out:
  	return -EINVAL;
  }
  
  static const struct backlight_ops pm860x_backlight_ops = {
  	.options	= BL_CORE_SUSPENDRESUME,
  	.update_status	= pm860x_backlight_update_status,
  	.get_brightness	= pm860x_backlight_get_brightness,
  };
  
  #ifdef CONFIG_OF
  static int pm860x_backlight_dt_init(struct platform_device *pdev,
  				    struct pm860x_backlight_data *data,
  				    char *name)
  {
  	struct device_node *nproot = pdev->dev.parent->of_node, *np;
  	int iset = 0;
  	if (!nproot)
  		return -ENODEV;
  	nproot = of_find_node_by_name(nproot, "backlights");
  	if (!nproot) {
  		dev_err(&pdev->dev, "failed to find backlights node\n");
  		return -ENODEV;
  	}
  	for_each_child_of_node(nproot, np) {
  		if (!of_node_cmp(np->name, name)) {
  			of_property_read_u32(np, "marvell,88pm860x-iset",
  					     &iset);
  			data->iset = PM8606_WLED_CURRENT(iset);
  			of_property_read_u32(np, "marvell,88pm860x-pwm",
  					     &data->pwm);
  			break;
  		}
  	}
  	return 0;
  }
  #else
  #define pm860x_backlight_dt_init(x, y, z)	(-1)
  #endif
  
  static int pm860x_backlight_probe(struct platform_device *pdev)
  {
  	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
  	struct pm860x_backlight_pdata *pdata = pdev->dev.platform_data;
  	struct pm860x_backlight_data *data;
  	struct backlight_device *bl;
  	struct resource *res;
  	struct backlight_properties props;
  	char name[MFD_NAME_SIZE];
  	int ret = 0;
  
  	data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data),
  			    GFP_KERNEL);
  	if (data == NULL)
  		return -ENOMEM;
  	res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle");
  	if (!res) {
  		dev_err(&pdev->dev, "No REG resource for duty cycle\n");
  		ret = -ENXIO;
  		goto out;
  	}
  	data->reg_duty_cycle = res->start;
  	res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on");
  	if (!res) {
  		dev_err(&pdev->dev, "No REG resorce for always on\n");
  		ret = -ENXIO;
  		goto out;
  	}
  	data->reg_always_on = res->start;
  	res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current");
  	if (!res) {
  		dev_err(&pdev->dev, "No REG resource for current\n");
  		ret = -ENXIO;
  		goto out;
  	}
  	data->reg_current = res->start;
  
  	memset(name, 0, MFD_NAME_SIZE);
  	sprintf(name, "backlight-%d", pdev->id);
  	data->port = pdev->id;
  	data->chip = chip;
  	data->i2c = (chip->id == CHIP_PM8606) ? chip->client	\
  			: chip->companion;
  	data->current_brightness = MAX_BRIGHTNESS;
  	if (pm860x_backlight_dt_init(pdev, data, name)) {
  		if (pdata) {
  			data->pwm = pdata->pwm;
  			data->iset = pdata->iset;
  		}
  	}
  
  	memset(&props, 0, sizeof(struct backlight_properties));
  	props.type = BACKLIGHT_RAW;
  	props.max_brightness = MAX_BRIGHTNESS;
  	bl = backlight_device_register(name, &pdev->dev, data,
  					&pm860x_backlight_ops, &props);
  	if (IS_ERR(bl)) {
  		dev_err(&pdev->dev, "failed to register backlight\n");
  		return PTR_ERR(bl);
  	}
  	bl->props.brightness = MAX_BRIGHTNESS;
  
  	platform_set_drvdata(pdev, bl);
  
  	/* read current backlight */
  	ret = pm860x_backlight_get_brightness(bl);
  	if (ret < 0)
  		goto out_brt;
  
  	backlight_update_status(bl);
  	return 0;
  out_brt:
  	backlight_device_unregister(bl);
  out:
  	devm_kfree(&pdev->dev, data);
  	return ret;
  }
  
  static int pm860x_backlight_remove(struct platform_device *pdev)
  {
  	struct backlight_device *bl = platform_get_drvdata(pdev);
  
  	backlight_device_unregister(bl);
  	return 0;
  }
  
  static struct platform_driver pm860x_backlight_driver = {
  	.driver		= {
  		.name	= "88pm860x-backlight",
  		.owner	= THIS_MODULE,
  	},
  	.probe		= pm860x_backlight_probe,
  	.remove		= pm860x_backlight_remove,
  };
  
  module_platform_driver(pm860x_backlight_driver);
  
  MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
  MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:88pm860x-backlight");
  