/*
 *  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 = gpiochip_get_data(chip);
	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 = gpiochip_get_data(chip);
	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->parent, "usb error setting pin value\n");
	}
}

static int vprbrd_gpioa_direction_input(struct gpio_chip *chip,
			unsigned offset)
{
	int ret;
	struct vprbrd_gpio *gpio = gpiochip_get_data(chip);
	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 = gpiochip_get_data(chip);
	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 = gpiochip_get_data(chip);
	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 = gpiochip_get_data(chip);
	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->parent, "usb error setting pin value\n");
	}
}

static int vprbrd_gpiob_direction_input(struct gpio_chip *chip,
			unsigned offset)
{
	int ret;
	struct vprbrd_gpio *gpio = gpiochip_get_data(chip);
	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->parent, "usb error setting pin to input\n");

	return ret;
}

static int vprbrd_gpiob_direction_output(struct gpio_chip *chip,
			unsigned offset, int value)
{
	int ret;
	struct vprbrd_gpio *gpio = gpiochip_get_data(chip);
	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->parent, "usb error setting pin to output\n");

	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.parent = &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 = devm_gpiochip_add_data(&pdev->dev, &vb_gpio->gpioa, vb_gpio);
	if (ret < 0) {
		dev_err(vb_gpio->gpioa.parent, "could not add gpio a");
		return ret;
	}

	/* registering gpio b */
	vb_gpio->gpiob.label = "viperboard gpio b";
	vb_gpio->gpiob.parent = &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 = devm_gpiochip_add_data(&pdev->dev, &vb_gpio->gpiob, vb_gpio);
	if (ret < 0) {
		dev_err(vb_gpio->gpiob.parent, "could not add gpio b");
		return ret;
	}

	platform_set_drvdata(pdev, vb_gpio);

	return ret;
}

static struct platform_driver vprbrd_gpio_driver = {
	.driver.name	= "viperboard-gpio",
	.probe		= vprbrd_gpio_probe,
};

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)\n", 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");