/*
   *  Nano River Technologies viperboard GPIO lib driver
   *
   *  (C) 2012 by Lemonage GmbH
   *  Author: Lars Poeschel <poeschel@lemonage.de>
   *  All rights reserved.
   *
   *  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.
   *
   */
  
  #include <linux/kernel.h>
  #include <linux/errno.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/types.h>
  #include <linux/mutex.h>
  #include <linux/platform_device.h>
  
  #include <linux/usb.h>
  #include <linux/gpio.h>
  
  #include <linux/mfd/viperboard.h>
  
  #define VPRBRD_GPIOA_CLK_1MHZ		0
  #define VPRBRD_GPIOA_CLK_100KHZ		1
  #define VPRBRD_GPIOA_CLK_10KHZ		2
  #define VPRBRD_GPIOA_CLK_1KHZ		3
  #define VPRBRD_GPIOA_CLK_100HZ		4
  #define VPRBRD_GPIOA_CLK_10HZ		5
  
  #define VPRBRD_GPIOA_FREQ_DEFAULT	1000
  
  #define VPRBRD_GPIOA_CMD_CONT		0x00
  #define VPRBRD_GPIOA_CMD_PULSE		0x01
  #define VPRBRD_GPIOA_CMD_PWM		0x02
  #define VPRBRD_GPIOA_CMD_SETOUT		0x03
  #define VPRBRD_GPIOA_CMD_SETIN		0x04
  #define VPRBRD_GPIOA_CMD_SETINT		0x05
  #define VPRBRD_GPIOA_CMD_GETIN		0x06
  
  #define VPRBRD_GPIOB_CMD_SETDIR		0x00
  #define VPRBRD_GPIOB_CMD_SETVAL		0x01
  
  struct vprbrd_gpioa_msg {
  	u8 cmd;
  	u8 clk;
  	u8 offset;
  	u8 t1;
  	u8 t2;
  	u8 invert;
  	u8 pwmlevel;
  	u8 outval;
  	u8 risefall;
  	u8 answer;
  	u8 __fill;
  } __packed;
  
  struct vprbrd_gpiob_msg {
  	u8 cmd;
  	u16 val;
  	u16 mask;
  } __packed;
  
  struct vprbrd_gpio {
  	struct gpio_chip gpioa; /* gpio a related things */
  	u32 gpioa_out;
  	u32 gpioa_val;
  	struct gpio_chip gpiob; /* gpio b related things */
  	u32 gpiob_out;
  	u32 gpiob_val;
  	struct vprbrd *vb;
  };
  
  /* gpioa sampling clock module parameter */
  static unsigned char gpioa_clk;
  static unsigned int gpioa_freq = VPRBRD_GPIOA_FREQ_DEFAULT;
  module_param(gpioa_freq, uint, 0);
  MODULE_PARM_DESC(gpioa_freq,
  	"gpio-a sampling freq in Hz (default is 1000Hz) valid values: 10, 100, 1000, 10000, 100000, 1000000");
  
  /* ----- begin of gipo a chip -------------------------------------------- */
  
  static int vprbrd_gpioa_get(struct gpio_chip *chip,
  		unsigned offset)
  {
  	int ret, answer, error = 0;
  	struct vprbrd_gpio *gpio =
  			container_of(chip, struct vprbrd_gpio, gpioa);
  	struct vprbrd *vb = gpio->vb;
  	struct vprbrd_gpioa_msg *gamsg = (struct vprbrd_gpioa_msg *)vb->buf;
  
  	/* if io is set to output, just return the saved value */
  	if (gpio->gpioa_out & (1 << offset))
  		return gpio->gpioa_val & (1 << offset);
  
  	mutex_lock(&vb->lock);
  
  	gamsg->cmd = VPRBRD_GPIOA_CMD_GETIN;
  	gamsg->clk = 0x00;
  	gamsg->offset = offset;
  	gamsg->t1 = 0x00;
  	gamsg->t2 = 0x00;
  	gamsg->invert = 0x00;
  	gamsg->pwmlevel = 0x00;
  	gamsg->outval = 0x00;
  	gamsg->risefall = 0x00;
  	gamsg->answer = 0x00;
  	gamsg->__fill = 0x00;
  
  	ret = usb_control_msg(vb->usb_dev, usb_sndctrlpipe(vb->usb_dev, 0),
  		VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_OUT, 0x0000,
  		0x0000, gamsg, sizeof(struct vprbrd_gpioa_msg),
  		VPRBRD_USB_TIMEOUT_MS);
  	if (ret != sizeof(struct vprbrd_gpioa_msg))
  		error = -EREMOTEIO;
  
  	ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
  		VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_IN, 0x0000,
  		0x0000, gamsg, sizeof(struct vprbrd_gpioa_msg),
  		VPRBRD_USB_TIMEOUT_MS);
  	answer = gamsg->answer & 0x01;
  
  	mutex_unlock(&vb->lock);
  
  	if (ret != sizeof(struct vprbrd_gpioa_msg))
  		error = -EREMOTEIO;
  
  	if (error)
  		return error;
  
  	return answer;
  }
  
  static void vprbrd_gpioa_set(struct gpio_chip *chip,
  		unsigned offset, int value)
  {
  	int ret;
  	struct vprbrd_gpio *gpio =
  			container_of(chip, struct vprbrd_gpio, gpioa);
  	struct vprbrd *vb = gpio->vb;
  	struct vprbrd_gpioa_msg *gamsg = (struct vprbrd_gpioa_msg *)vb->buf;
  
  	if (gpio->gpioa_out & (1 << offset)) {
  		if (value)
  			gpio->gpioa_val |= (1 << offset);
  		else
  			gpio->gpioa_val &= ~(1 << offset);
  
  		mutex_lock(&vb->lock);
  
  		gamsg->cmd = VPRBRD_GPIOA_CMD_SETOUT;
  		gamsg->clk = 0x00;
  		gamsg->offset = offset;
  		gamsg->t1 = 0x00;
  		gamsg->t2 = 0x00;
  		gamsg->invert = 0x00;
  		gamsg->pwmlevel = 0x00;
  		gamsg->outval = value;
  		gamsg->risefall = 0x00;
  		gamsg->answer = 0x00;
  		gamsg->__fill = 0x00;
  
  		ret = usb_control_msg(vb->usb_dev,
  			usb_sndctrlpipe(vb->usb_dev, 0),
  			VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_OUT,
  			0x0000,	0x0000, gamsg,
  			sizeof(struct vprbrd_gpioa_msg), VPRBRD_USB_TIMEOUT_MS);
  
  		mutex_unlock(&vb->lock);
  
  		if (ret != sizeof(struct vprbrd_gpioa_msg))
  			dev_err(chip->dev, "usb error setting pin value
  ");
  	}
  }
  
  static int vprbrd_gpioa_direction_input(struct gpio_chip *chip,
  			unsigned offset)
  {
  	int ret;
  	struct vprbrd_gpio *gpio =
  			container_of(chip, struct vprbrd_gpio, gpioa);
  	struct vprbrd *vb = gpio->vb;
  	struct vprbrd_gpioa_msg *gamsg = (struct vprbrd_gpioa_msg *)vb->buf;
  
  	gpio->gpioa_out &= ~(1 << offset);
  
  	mutex_lock(&vb->lock);
  
  	gamsg->cmd = VPRBRD_GPIOA_CMD_SETIN;
  	gamsg->clk = gpioa_clk;
  	gamsg->offset = offset;
  	gamsg->t1 = 0x00;
  	gamsg->t2 = 0x00;
  	gamsg->invert = 0x00;
  	gamsg->pwmlevel = 0x00;
  	gamsg->outval = 0x00;
  	gamsg->risefall = 0x00;
  	gamsg->answer = 0x00;
  	gamsg->__fill = 0x00;
  
  	ret = usb_control_msg(vb->usb_dev, usb_sndctrlpipe(vb->usb_dev, 0),
  		VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_OUT, 0x0000,
  		0x0000, gamsg, sizeof(struct vprbrd_gpioa_msg),
  		VPRBRD_USB_TIMEOUT_MS);
  
  	mutex_unlock(&vb->lock);
  
  	if (ret != sizeof(struct vprbrd_gpioa_msg))
  		return -EREMOTEIO;
  
  	return 0;
  }
  
  static int vprbrd_gpioa_direction_output(struct gpio_chip *chip,
  			unsigned offset, int value)
  {
  	int ret;
  	struct vprbrd_gpio *gpio =
  			container_of(chip, struct vprbrd_gpio, gpioa);
  	struct vprbrd *vb = gpio->vb;
  	struct vprbrd_gpioa_msg *gamsg = (struct vprbrd_gpioa_msg *)vb->buf;
  
  	gpio->gpioa_out |= (1 << offset);
  	if (value)
  		gpio->gpioa_val |= (1 << offset);
  	else
  		gpio->gpioa_val &= ~(1 << offset);
  
  	mutex_lock(&vb->lock);
  
  	gamsg->cmd = VPRBRD_GPIOA_CMD_SETOUT;
  	gamsg->clk = 0x00;
  	gamsg->offset = offset;
  	gamsg->t1 = 0x00;
  	gamsg->t2 = 0x00;
  	gamsg->invert = 0x00;
  	gamsg->pwmlevel = 0x00;
  	gamsg->outval = value;
  	gamsg->risefall = 0x00;
  	gamsg->answer = 0x00;
  	gamsg->__fill = 0x00;
  
  	ret = usb_control_msg(vb->usb_dev, usb_sndctrlpipe(vb->usb_dev, 0),
  		VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_OUT, 0x0000,
  		0x0000, gamsg, sizeof(struct vprbrd_gpioa_msg),
  		VPRBRD_USB_TIMEOUT_MS);
  
  	mutex_unlock(&vb->lock);
  
  	if (ret != sizeof(struct vprbrd_gpioa_msg))
  		return -EREMOTEIO;
  
  	return 0;
  }
  
  /* ----- end of gpio a chip ---------------------------------------------- */
  
  /* ----- begin of gipo b chip -------------------------------------------- */
  
  static int vprbrd_gpiob_setdir(struct vprbrd *vb, unsigned offset,
  	unsigned dir)
  {
  	struct vprbrd_gpiob_msg *gbmsg = (struct vprbrd_gpiob_msg *)vb->buf;
  	int ret;
  
  	gbmsg->cmd = VPRBRD_GPIOB_CMD_SETDIR;
  	gbmsg->val = cpu_to_be16(dir << offset);
  	gbmsg->mask = cpu_to_be16(0x0001 << offset);
  
  	ret = usb_control_msg(vb->usb_dev, usb_sndctrlpipe(vb->usb_dev, 0),
  		VPRBRD_USB_REQUEST_GPIOB, VPRBRD_USB_TYPE_OUT, 0x0000,
  		0x0000, gbmsg, sizeof(struct vprbrd_gpiob_msg),
  		VPRBRD_USB_TIMEOUT_MS);
  
  	if (ret != sizeof(struct vprbrd_gpiob_msg))
  		return -EREMOTEIO;
  
  	return 0;
  }
  
  static int vprbrd_gpiob_get(struct gpio_chip *chip,
  		unsigned offset)
  {
  	int ret;
  	u16 val;
  	struct vprbrd_gpio *gpio =
  			container_of(chip, struct vprbrd_gpio, gpiob);
  	struct vprbrd *vb = gpio->vb;
  	struct vprbrd_gpiob_msg *gbmsg = (struct vprbrd_gpiob_msg *)vb->buf;
  
  	/* if io is set to output, just return the saved value */
  	if (gpio->gpiob_out & (1 << offset))
  		return gpio->gpiob_val & (1 << offset);
  
  	mutex_lock(&vb->lock);
  
  	ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
  		VPRBRD_USB_REQUEST_GPIOB, VPRBRD_USB_TYPE_IN, 0x0000,
  		0x0000, gbmsg,	sizeof(struct vprbrd_gpiob_msg),
  		VPRBRD_USB_TIMEOUT_MS);
  	val = gbmsg->val;
  
  	mutex_unlock(&vb->lock);
  
  	if (ret != sizeof(struct vprbrd_gpiob_msg))
  		return ret;
  
  	/* cache the read values */
  	gpio->gpiob_val = be16_to_cpu(val);
  
  	return (gpio->gpiob_val >> offset) & 0x1;
  }
  
  static void vprbrd_gpiob_set(struct gpio_chip *chip,
  		unsigned offset, int value)
  {
  	int ret;
  	struct vprbrd_gpio *gpio =
  			container_of(chip, struct vprbrd_gpio, gpiob);
  	struct vprbrd *vb = gpio->vb;
  	struct vprbrd_gpiob_msg *gbmsg = (struct vprbrd_gpiob_msg *)vb->buf;
  
  	if (gpio->gpiob_out & (1 << offset)) {
  		if (value)
  			gpio->gpiob_val |= (1 << offset);
  		else
  			gpio->gpiob_val &= ~(1 << offset);
  
  		mutex_lock(&vb->lock);
  
  		gbmsg->cmd = VPRBRD_GPIOB_CMD_SETVAL;
  		gbmsg->val = cpu_to_be16(value << offset);
  		gbmsg->mask = cpu_to_be16(0x0001 << offset);
  
  		ret = usb_control_msg(vb->usb_dev,
  			usb_sndctrlpipe(vb->usb_dev, 0),
  			VPRBRD_USB_REQUEST_GPIOB, VPRBRD_USB_TYPE_OUT,
  			0x0000,	0x0000, gbmsg,
  			sizeof(struct vprbrd_gpiob_msg), VPRBRD_USB_TIMEOUT_MS);
  
  		mutex_unlock(&vb->lock);
  
  		if (ret != sizeof(struct vprbrd_gpiob_msg))
  			dev_err(chip->dev, "usb error setting pin value
  ");
  	}
  }
  
  static int vprbrd_gpiob_direction_input(struct gpio_chip *chip,
  			unsigned offset)
  {
  	int ret;
  	struct vprbrd_gpio *gpio =
  			container_of(chip, struct vprbrd_gpio, gpiob);
  	struct vprbrd *vb = gpio->vb;
  
  	gpio->gpiob_out &= ~(1 << offset);
  
  	mutex_lock(&vb->lock);
  
  	ret = vprbrd_gpiob_setdir(vb, offset, 0);
  
  	mutex_unlock(&vb->lock);
  
  	if (ret)
  		dev_err(chip->dev, "usb error setting pin to input
  ");
  
  	return ret;
  }
  
  static int vprbrd_gpiob_direction_output(struct gpio_chip *chip,
  			unsigned offset, int value)
  {
  	int ret;
  	struct vprbrd_gpio *gpio =
  			container_of(chip, struct vprbrd_gpio, gpiob);
  	struct vprbrd *vb = gpio->vb;
  
  	gpio->gpiob_out |= (1 << offset);
  
  	mutex_lock(&vb->lock);
  
  	ret = vprbrd_gpiob_setdir(vb, offset, 1);
  	if (ret)
  		dev_err(chip->dev, "usb error setting pin to output
  ");
  
  	mutex_unlock(&vb->lock);
  
  	vprbrd_gpiob_set(chip, offset, value);
  
  	return ret;
  }
  
  /* ----- end of gpio b chip ---------------------------------------------- */
  
  static int vprbrd_gpio_probe(struct platform_device *pdev)
  {
  	struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
  	struct vprbrd_gpio *vb_gpio;
  	int ret;
  
  	vb_gpio = devm_kzalloc(&pdev->dev, sizeof(*vb_gpio), GFP_KERNEL);
  	if (vb_gpio == NULL)
  		return -ENOMEM;
  
  	vb_gpio->vb = vb;
  	/* registering gpio a */
  	vb_gpio->gpioa.label = "viperboard gpio a";
  	vb_gpio->gpioa.dev = &pdev->dev;
  	vb_gpio->gpioa.owner = THIS_MODULE;
  	vb_gpio->gpioa.base = -1;
  	vb_gpio->gpioa.ngpio = 16;
  	vb_gpio->gpioa.can_sleep = true;
  	vb_gpio->gpioa.set = vprbrd_gpioa_set;
  	vb_gpio->gpioa.get = vprbrd_gpioa_get;
  	vb_gpio->gpioa.direction_input = vprbrd_gpioa_direction_input;
  	vb_gpio->gpioa.direction_output = vprbrd_gpioa_direction_output;
  	ret = gpiochip_add(&vb_gpio->gpioa);
  	if (ret < 0) {
  		dev_err(vb_gpio->gpioa.dev, "could not add gpio a");
  		goto err_gpioa;
  	}
  
  	/* registering gpio b */
  	vb_gpio->gpiob.label = "viperboard gpio b";
  	vb_gpio->gpiob.dev = &pdev->dev;
  	vb_gpio->gpiob.owner = THIS_MODULE;
  	vb_gpio->gpiob.base = -1;
  	vb_gpio->gpiob.ngpio = 16;
  	vb_gpio->gpiob.can_sleep = true;
  	vb_gpio->gpiob.set = vprbrd_gpiob_set;
  	vb_gpio->gpiob.get = vprbrd_gpiob_get;
  	vb_gpio->gpiob.direction_input = vprbrd_gpiob_direction_input;
  	vb_gpio->gpiob.direction_output = vprbrd_gpiob_direction_output;
  	ret = gpiochip_add(&vb_gpio->gpiob);
  	if (ret < 0) {
  		dev_err(vb_gpio->gpiob.dev, "could not add gpio b");
  		goto err_gpiob;
  	}
  
  	platform_set_drvdata(pdev, vb_gpio);
  
  	return ret;
  
  err_gpiob:
  	if (gpiochip_remove(&vb_gpio->gpioa))
  		dev_err(&pdev->dev, "%s gpiochip_remove failed
  ", __func__);
  
  err_gpioa:
  	return ret;
  }
  
  static int vprbrd_gpio_remove(struct platform_device *pdev)
  {
  	struct vprbrd_gpio *vb_gpio = platform_get_drvdata(pdev);
  	int ret;
  
  	ret = gpiochip_remove(&vb_gpio->gpiob);
  	if (ret == 0)
  		ret = gpiochip_remove(&vb_gpio->gpioa);
  
  	return ret;
  }
  
  static struct platform_driver vprbrd_gpio_driver = {
  	.driver.name	= "viperboard-gpio",
  	.driver.owner	= THIS_MODULE,
  	.probe		= vprbrd_gpio_probe,
  	.remove		= vprbrd_gpio_remove,
  };
  
  static int __init vprbrd_gpio_init(void)
  {
  	switch (gpioa_freq) {
  	case 1000000:
  		gpioa_clk = VPRBRD_GPIOA_CLK_1MHZ;
  		break;
  	case 100000:
  		gpioa_clk = VPRBRD_GPIOA_CLK_100KHZ;
  		break;
  	case 10000:
  		gpioa_clk = VPRBRD_GPIOA_CLK_10KHZ;
  		break;
  	case 1000:
  		gpioa_clk = VPRBRD_GPIOA_CLK_1KHZ;
  		break;
  	case 100:
  		gpioa_clk = VPRBRD_GPIOA_CLK_100HZ;
  		break;
  	case 10:
  		gpioa_clk = VPRBRD_GPIOA_CLK_10HZ;
  		break;
  	default:
  		pr_warn("invalid gpioa_freq (%d)
  ", gpioa_freq);
  		gpioa_clk = VPRBRD_GPIOA_CLK_1KHZ;
  	}
  
  	return platform_driver_register(&vprbrd_gpio_driver);
  }
  subsys_initcall(vprbrd_gpio_init);
  
  static void __exit vprbrd_gpio_exit(void)
  {
  	platform_driver_unregister(&vprbrd_gpio_driver);
  }
  module_exit(vprbrd_gpio_exit);
  
  MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
  MODULE_DESCRIPTION("GPIO driver for Nano River Techs Viperboard");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:viperboard-gpio");