// SPDX-License-Identifier: GPL-2.0+
/*
 *  Nano River Technologies viperboard GPIO lib driver
 *
 *  (C) 2012 by Lemonage GmbH
 *  Author: Lars Poeschel <poeschel@lemonage.de>
 *  All rights reserved.
 */

#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/driver.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 int 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 int vprbrd_gpioa_set(struct gpio_chip *chip, unsigned int offset,
                            int value)
{
        int ret = 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 (!(gpio->gpioa_out & (1 << offset)))
                return 0;

        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");
                return -EREMOTEIO;
        }

        return 0;
}

static int vprbrd_gpioa_direction_input(struct gpio_chip *chip,
                        unsigned int 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 int 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 int offset,
        unsigned int 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 int 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 int vprbrd_gpiob_set(struct gpio_chip *chip, unsigned int 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)))
                return 0;

        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");
                return -EREMOTEIO;
        }

        return 0;
}

static int vprbrd_gpiob_direction_input(struct gpio_chip *chip,
                        unsigned int 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 int 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);
        mutex_unlock(&vb->lock);
        if (ret) {
                dev_err(chip->parent, "usb error setting pin to output\n");
                return ret;
        }

        return vprbrd_gpiob_set(chip, offset, value);
}

/* ----- 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)
                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;

        return devm_gpiochip_add_data(&pdev->dev, &vb_gpio->gpiob, vb_gpio);
}

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");