/*
 * Simple synchronous userspace interface to SPI devices
 *
 * Copyright (C) 2006 SWAPP
 *	Andrea Paterniani <a.paterniani@swapp-eng.it>
 * Copyright (C) 2007 David Brownell (simplification, cleanup)
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */
/*
 * Modified by ST Microelectronics.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/ioctl.h>
#include <linux/fs.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/compat.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/acpi.h>
#include <linux/pinctrl/consumer.h>

#include <linux/spi/spi.h>
#include <linux/spi/spidev.h>

#include <linux/gpio.h>
#include <linux/of_gpio.h>

#include <linux/uaccess.h>

#define ST21NFCD_MTK 1
// #define WITH_SPI_CLK_MNGT 1

#ifdef ST21NFCD_MTK
#include <linux/platform_data/spi-mt65xx.h>
#endif // ST21NFCD_MTK

#include "../st21nfc-i2c/st21nfc.h"
#include <soc/oppo/oppo_nfc.h>


/*
 * This supports access to SPI devices using normal userspace I/O calls.
 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
 * and often mask message boundaries, full SPI support requires full duplex
 * transfers.  There are several kinds of internal message boundaries to
 * handle chipselect management and other protocol options.
 *
 * SPI has a character major number assigned.  We allocate minor numbers
 * dynamically using a bitmask.  You must use hotplug tools, such as udev
 * (or mdev with busybox) to create and destroy the /dev/st54spi device
 * nodes, since there is no fixed association of minor numbers with any
 * particular SPI bus or device.
 */
//#define SPIDEV_MAJOR            0    /* dynamic */
static int spidev_major;
#define N_SPI_MINORS 1 /* ... up to 256 */

static DECLARE_BITMAP(minors, N_SPI_MINORS);

#define ST54SPI_IOC_RD_POWER _IOR(SPI_IOC_MAGIC, 99, __u32)
#define ST54SPI_IOC_WR_POWER _IOW(SPI_IOC_MAGIC, 99, __u32)

/* Bit masks for spi_device.mode management.  Note that incorrect
 * settings for some settings can cause *lots* of trouble for other
 * devices on a shared bus:
 *
 *  - CS_HIGH ... this device will be active when it shouldn't be
 *  - 3WIRE ... when active, it won't behave as it should
 *  - NO_CS ... there will be no explicit message boundaries; this
 *    is completely incompatible with the shared bus model
 *  - READY ... transfers may proceed when they shouldn't.
 *
 * REVISIT should changing those flags be privileged?
 */
#define SPI_MODE_MASK                \
    (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH |    \
    SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP |    \
    SPI_NO_CS | SPI_READY | SPI_TX_DUAL |    \
    SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)

struct st54spi_data {
    dev_t devt;
    spinlock_t spi_lock;
    struct spi_device *spi;
    struct spi_device *spi_reset;
    struct list_head device_entry;

    /* TX/RX buffers are NULL unless this device is open (users > 0) */
    struct mutex buf_lock;
    unsigned int users;
    u8 *tx_buffer;
    u8 *rx_buffer;
    u32 speed_hz;

    /* GPIO for SE_POWER_REQ / SE_nRESET */
    int power_or_nreset_gpio_mode;
    int power_or_nreset_gpio;
    int nfcc_needs_poweron;
    int sehal_needs_poweron;
    int se_is_poweron;
    struct pinctrl *pctrl;
    struct pinctrl_state *pctrl_mode_spi, *pctrl_mode_idle;
};

#define POWER_MODE_NONE -1
#define POWER_MODE_ST54H 0
#define POWER_MODE_ST54J 1

static LIST_HEAD(device_list);
static DEFINE_MUTEX(device_list_lock);

static unsigned int bufsiz = 4096;
module_param(bufsiz, uint, 0444);
MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");

static bool debug_enabled = true;
#define VERBOSE 1

/*-------------------------------------------------------------------------*/

static ssize_t st54spi_sync(
    struct st54spi_data *st54spi, struct spi_message *message)
{
    DECLARE_COMPLETION_ONSTACK(done);
    int status;
    struct spi_device *spi;

    spin_lock_irq(&st54spi->spi_lock);
    spi = st54spi->spi;
    spin_unlock_irq(&st54spi->spi_lock);

    if (spi == NULL)
        status = -ESHUTDOWN;
    else
        status = spi_sync(spi, message);

    if (status == 0)
        status = message->actual_length;

    return status;
}

static inline ssize_t st54spi_sync_write(
    struct st54spi_data *st54spi, size_t len)
{
    struct spi_transfer t = {
        .tx_buf = st54spi->tx_buffer,
        .len = len,
        .speed_hz = st54spi->speed_hz,
    };
    struct spi_message m;

    spi_message_init(&m);
    spi_message_add_tail(&t, &m);
    return st54spi_sync(st54spi, &m);
}

static inline ssize_t st54spi_sync_read(
    struct st54spi_data *st54spi, size_t len)
{
    struct spi_transfer t = {
        .rx_buf = st54spi->rx_buffer,
        .len = len,
        .speed_hz = st54spi->speed_hz,
    };
    struct spi_message m;

    spi_message_init(&m);
    spi_message_add_tail(&t, &m);
    return st54spi_sync(st54spi, &m);
}

/*-------------------------------------------------------------------------*/

/* Read-only message with current device setup */
static ssize_t st54spi_read(
    struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
    struct st54spi_data *st54spi;
    ssize_t status = 0;

    /* chipselect only toggles at start or end of operation */
    if (count > bufsiz)
        return -EMSGSIZE;

    st54spi = filp->private_data;

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi Read: %d bytes\n", count);

    mutex_lock(&st54spi->buf_lock);
    status = st54spi_sync_read(st54spi, count);
    if (status > 0) {
        unsigned long missing;

        missing = copy_to_user(buf, st54spi->rx_buffer, status);
        if (missing == status)
            status = -EFAULT;
        else
            status = status - missing;
    }
    mutex_unlock(&st54spi->buf_lock);

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi Read: status: %d\n", status);

    return status;
}

/* Write-only message with current device setup */
static ssize_t st54spi_write(
    struct file *filp, const char __user *buf, size_t count, loff_t *f_pos)
{
    struct st54spi_data *st54spi;
    ssize_t status = 0;
    unsigned long missing;

    /* chipselect only toggles at start or end of operation */
    if (count > bufsiz)
        return -EMSGSIZE;

    st54spi = filp->private_data;

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi Write: %d bytes\n", count);

    mutex_lock(&st54spi->buf_lock);
    missing = copy_from_user(st54spi->tx_buffer, buf, count);
    if (missing == 0)
        status = st54spi_sync_write(st54spi, count);
    else
        status = -EFAULT;
    mutex_unlock(&st54spi->buf_lock);

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi Write: status: %d\n", status);

    return status;
}

static int st54spi_message(
    struct st54spi_data *st54spi,
    struct spi_ioc_transfer *u_xfers,
    unsigned int n_xfers)
{
    struct spi_message msg;
    struct spi_transfer *k_xfers;
    struct spi_transfer *k_tmp;
    struct spi_ioc_transfer *u_tmp;
    unsigned int n, total, tx_total, rx_total;
    u8 *tx_buf, *rx_buf;
    int status = -EFAULT;

    spi_message_init(&msg);
    k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
    if (k_xfers == NULL)
        return -ENOMEM;

    /* Construct spi_message, copying any tx data to bounce buffer.
     * We walk the array of user-provided transfers, using each one
     * to initialize a kernel version of the same transfer.
     */
    tx_buf = st54spi->tx_buffer;
    rx_buf = st54spi->rx_buffer;
    total = 0;
    tx_total = 0;
    rx_total = 0;
    for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
        n; n--, k_tmp++, u_tmp++) {
        k_tmp->len = u_tmp->len;

        total += k_tmp->len;
        /* Since the function returns the total length of transfers
         * on success, restrict the total to positive int values to
         * avoid the return value looking like an error.  Also check
         * each transfer length to avoid arithmetic overflow.
         */
        if (total > INT_MAX || k_tmp->len > INT_MAX) {
            status = -EMSGSIZE;
            goto done;
        }

        if (u_tmp->rx_buf) {
            /* this transfer needs space in RX bounce buffer */
            rx_total += k_tmp->len;
            if (rx_total > bufsiz) {
                status = -EMSGSIZE;
                goto done;
            }
            k_tmp->rx_buf = rx_buf;
            if (!access_ok(VERIFY_WRITE,
                (u8 __user *)(uintptr_t)u_tmp->rx_buf,
                u_tmp->len))
                goto done;
            rx_buf += k_tmp->len;
        }
        if (u_tmp->tx_buf) {
            /* this transfer needs space in TX bounce buffer */
            tx_total += k_tmp->len;
            if (tx_total > bufsiz) {
                status = -EMSGSIZE;
                goto done;
            }
            k_tmp->tx_buf = tx_buf;
            if (copy_from_user(tx_buf,
                (const u8 __user *)(uintptr_t)u_tmp->tx_buf,
                u_tmp->len))
                goto done;
            tx_buf += k_tmp->len;
        }

        k_tmp->cs_change = !!u_tmp->cs_change;
        k_tmp->tx_nbits = u_tmp->tx_nbits;
        k_tmp->rx_nbits = u_tmp->rx_nbits;
        k_tmp->bits_per_word = u_tmp->bits_per_word;
        k_tmp->delay_usecs = u_tmp->delay_usecs;
        k_tmp->speed_hz = u_tmp->speed_hz;
        if (!k_tmp->speed_hz)
            k_tmp->speed_hz = st54spi->speed_hz;
#ifdef VERBOSE
        dev_dbg(&st54spi->spi->dev, "  xfer len %u %s%s%s%dbits %u usec %uHz\n",
            u_tmp->len, u_tmp->rx_buf ? "rx " : "", u_tmp->tx_buf ? "tx " : "",
            u_tmp->cs_change ? "cs " : "",
            u_tmp->bits_per_word ?: st54spi->spi->bits_per_word,
            u_tmp->delay_usecs, u_tmp->speed_hz ?: st54spi->spi->max_speed_hz);
#endif
        spi_message_add_tail(k_tmp, &msg);
    }

    status = st54spi_sync(st54spi, &msg);
    if (status < 0)
        goto done;

    /* copy any rx data out of bounce buffer */
    rx_buf = st54spi->rx_buffer;
    for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
        if (u_tmp->rx_buf) {
            if (__copy_to_user(
                (u8 __user *)(uintptr_t)u_tmp->rx_buf,
                rx_buf, u_tmp->len)) {
                status = -EFAULT;
                goto done;
            }
            rx_buf += u_tmp->len;
        }
    }
    status = total;

done:
    kfree(k_xfers);
    return status;
}

static struct spi_ioc_transfer *st54spi_get_ioc_message(
    unsigned int cmd,
    struct spi_ioc_transfer __user *u_ioc,
    unsigned int *n_ioc)
{
    struct spi_ioc_transfer *ioc;
    u32 tmp;

    /* Check type, command number and direction */
    if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC ||
        _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) ||
        _IOC_DIR(cmd) != _IOC_WRITE)
        return ERR_PTR(-ENOTTY);

    tmp = _IOC_SIZE(cmd);
    if ((tmp % sizeof(struct spi_ioc_transfer)) != 0)
        return ERR_PTR(-EINVAL);

    *n_ioc = tmp / sizeof(struct spi_ioc_transfer);
    if (*n_ioc == 0)
        return NULL;

    /* copy into scratch area */
    ioc = kmalloc(tmp, GFP_KERNEL);
    if (!ioc)
        return ERR_PTR(-ENOMEM);

    if (__copy_from_user(ioc, u_ioc, tmp)) {
        kfree(ioc);
        return ERR_PTR(-EFAULT);
    }
    return ioc;
}

static void st54spi_power_off(struct st54spi_data *st54spi)
{
    int ret;

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "%s\n", __func__);

    // Set NSS pin as highZ (ST54H and ST54J).

    // Change NSS polarity to have NSS low.
    ret = pinctrl_select_state(st54spi->pctrl, st54spi->pctrl_mode_idle);

    if (ret < 0)
        dev_err(&st54spi->spi->dev, "%s : change NSS management to High Z failed!\n", __func__);

    // Set SE_PWR_REQ / SE_nRESET to low
    if (st54spi->power_or_nreset_gpio)
        gpio_set_value(st54spi->power_or_nreset_gpio, 0);

    // if ST54H block access to SPI in case this is done during a CLF reset
    if (st54spi->power_or_nreset_gpio_mode == POWER_MODE_ST54H) {
        // disallow access to SPI r/w
        if (st54spi->spi) {
            spin_lock_irq(&st54spi->spi_lock);
            st54spi->spi_reset = st54spi->spi;
            st54spi->spi = NULL;
            spin_unlock_irq(&st54spi->spi_lock);
        }

        // Give time to the CLF to detect falling SE_PWR_REQ
        // and pull down the line before continue.
        usleep_range(2000, 4500);
    }

#ifdef WITH_SPI_CLK_MNGT
    // no need for the SPI clock to be enabled.
    dev_info(&st54spi->spi->dev, "%s : disabling PMU clock of SPI subsystem\n", __func__);
    mt_spi_disable_master_clk(st54spi->spi);
#endif  // WITH_SPI_CLK_MNGT

    st54spi->se_is_poweron = 0;
}

static void st54spi_power_on(struct st54spi_data *st54spi)
{
    int ret;

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "%s\n", __func__);
#ifdef WITH_SPI_CLK_MNGT
    // the SPI clock needs to be enabled.
    dev_info(&st54spi->spi->dev, "%s : enabling PMU clock of SPI subsystem\n", __func__);
    mt_spi_enable_master_clk(st54spi->spi);
#endif  // WITH_SPI_CLK_MNGT

    // set SE_PWR_REQ / SE_nRESET to high and wait for CLF + eSE reaction
    if (st54spi->power_or_nreset_gpio) {
        gpio_set_value(st54spi->power_or_nreset_gpio, 1);
        usleep_range(1000, 1500);
    }

    // Set NSS pin for the SPI function.
    ret = pinctrl_select_state(st54spi->pctrl, st54spi->pctrl_mode_spi);

    if (ret < 0)
        dev_err(&st54spi->spi->dev, "%s : change NSS management to SPI failed!\n", __func__);

    usleep_range(4000, 5000);

    if (st54spi->power_or_nreset_gpio_mode == POWER_MODE_ST54H) {
        // re-allow SPI xfers
        if (st54spi->spi_reset) {
            spin_lock_irq(&st54spi->spi_lock);
            st54spi->spi = st54spi->spi_reset;
            st54spi->spi_reset = NULL;
            spin_unlock_irq(&st54spi->spi_lock);
        }
    }

    st54spi->se_is_poweron = 1;
}

static void st54spi_power_set(struct st54spi_data *st54spi, int val)
{
    if (!st54spi)
        return;

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi sehal pwr_req: %d\n", val);

    if (val) {
        st54spi->sehal_needs_poweron = 1;
        if (st54spi->se_is_poweron == 0)
            st54spi_power_on(st54spi);
    } else {
        st54spi->sehal_needs_poweron = 0;
        if ((st54spi->se_is_poweron == 1) &&
            (st54spi->nfcc_needs_poweron == 0))
            // we don t need power anymore
            st54spi_power_off(st54spi);
    }
}

static int st54spi_power_get(struct st54spi_data *st54spi)
{
    if (st54spi->power_or_nreset_gpio)
        return gpio_get_value(st54spi->power_or_nreset_gpio);
    return 0;
}

static long st54spi_ioctl(
    struct file *filp, unsigned int cmd, unsigned long arg)
{
    int err = 0;
    int retval = 0;
    struct st54spi_data *st54spi;
    struct spi_device *spi;
    u32 tmp;
    unsigned int n_ioc;
    struct spi_ioc_transfer *ioc;

    /* Check type and command number */
    if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
        return -ENOTTY;

    /* Check access direction once here; don't repeat below.
     * IOC_DIR is from the user perspective, while access_ok is
     * from the kernel perspective; so they look reversed.
     */
    if (_IOC_DIR(cmd) & _IOC_READ)
        err = !access_ok(VERIFY_WRITE,
            (void __user *)arg, _IOC_SIZE(cmd));
    if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
        err = !access_ok(VERIFY_READ,
            (void __user *)arg, _IOC_SIZE(cmd));
    if (err)
        return -EFAULT;

    /* guard against device removal before, or while,
     * we issue this ioctl.
     */
    st54spi = filp->private_data;
    spin_lock_irq(&st54spi->spi_lock);
    spi = spi_dev_get(st54spi->spi);
    spin_unlock_irq(&st54spi->spi_lock);

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi ioctl cmd %d\n", cmd);

    if (spi == NULL)
        return -ESHUTDOWN;

    /*  use the buffer lock here for triple duty:
     *  - prevent I/O (from us) so calling spi_setup() is safe;
     *  - prevent concurrent SPI_IOC_WR_* from morphing
     *    data fields while SPI_IOC_RD_* reads them;
     *  - SPI_IOC_MESSAGE needs the buffer locked "normally".
     */
    mutex_lock(&st54spi->buf_lock);

    switch (cmd) {
    /* read requests */
    case SPI_IOC_RD_MODE:
        retval = __put_user(
            spi->mode & SPI_MODE_MASK, (__u8 __user *)arg);
        break;
    case SPI_IOC_RD_MODE32:
        retval = __put_user(
            spi->mode & SPI_MODE_MASK, (__u32 __user *)arg);
        break;
    case SPI_IOC_RD_LSB_FIRST:
        retval = __put_user(
            (spi->mode & SPI_LSB_FIRST) ?
                1 : 0, (__u8 __user *)arg);
        break;
    case SPI_IOC_RD_BITS_PER_WORD:
        retval = __put_user(
            spi->bits_per_word, (__u8 __user *)arg);
        break;
    case SPI_IOC_RD_MAX_SPEED_HZ:
        retval = __put_user(
            st54spi->speed_hz, (__u32 __user *)arg);
        break;
    case ST54SPI_IOC_RD_POWER:
        retval = __put_user(
            st54spi_power_get(st54spi), (__u32 __user *)arg);
        break;

    /* write requests */
    case SPI_IOC_WR_MODE:
    case SPI_IOC_WR_MODE32:
        if (cmd == SPI_IOC_WR_MODE)
            retval = __get_user(tmp, (u8 __user *)arg);
        else
            retval = __get_user(tmp, (u32 __user *)arg);
        if (retval == 0) {
            u32 save = spi->mode;

            if (tmp & ~SPI_MODE_MASK) {
                retval = -EINVAL;
                break;
            }

            tmp |= spi->mode & ~SPI_MODE_MASK;
            spi->mode = (u16)tmp;
            retval = spi_setup(spi);
            if (retval < 0)
                spi->mode = save;
            else
                dev_dbg(&spi->dev, "spi mode %x\n", tmp);
        }
        break;
    case SPI_IOC_WR_LSB_FIRST:
        retval = __get_user(tmp, (__u8 __user *)arg);
        if (retval == 0) {
            u32 save = spi->mode;

            if (tmp)
                spi->mode |= SPI_LSB_FIRST;
            else
                spi->mode &= ~SPI_LSB_FIRST;
            retval = spi_setup(spi);
            if (retval < 0)
                spi->mode = save;
            else
                dev_dbg(&spi->dev,
                    "%csb first\n", tmp ?
                    'l' : 'm');
        }
        break;
    case SPI_IOC_WR_BITS_PER_WORD:
        retval = __get_user(tmp, (__u8 __user *)arg);
        if (retval == 0) {
            u8 save = spi->bits_per_word;

            spi->bits_per_word = tmp;
            retval = spi_setup(spi);
            if (retval < 0)
                spi->bits_per_word = save;
            else
                dev_dbg(&spi->dev, "%d bits per word\n", tmp);
        }
        break;
    case SPI_IOC_WR_MAX_SPEED_HZ:
        retval = __get_user(tmp, (__u32 __user *)arg);
        if (retval == 0) {
            u32 save = spi->max_speed_hz;

            spi->max_speed_hz = tmp;
            retval = spi_setup(spi);
            if (retval >= 0)
                st54spi->speed_hz = tmp;
            else
                dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
            spi->max_speed_hz = save;
        }
        break;
    case ST54SPI_IOC_WR_POWER:
        retval = __get_user(tmp, (__u32 __user *)arg);
        if (retval == 0) {
            st54spi_power_set(st54spi, tmp ? 1 : 0);
            dev_dbg(&spi->dev, "SE_POWER_REQ/SE_NRESET set: %d\n", tmp);
        }
        break;

    default:
        /* segmented and/or full-duplex I/O request */
        /* Check message and copy into scratch area */
        ioc = st54spi_get_ioc_message(
            cmd, (struct spi_ioc_transfer __user *)arg, &n_ioc);
        if (IS_ERR(ioc)) {
            retval = PTR_ERR(ioc);
            break;
        }
        if (!ioc)
            break; /* n_ioc is also 0 */

        /* translate to spi_message, execute */
        retval = st54spi_message(st54spi, ioc, n_ioc);
        kfree(ioc);
        break;
    }

    mutex_unlock(&st54spi->buf_lock);
    spi_dev_put(spi);

    if (debug_enabled)
        dev_info(&spi->dev, "st54spi ioctl retval %d\n", retval);

    return retval;
}

#ifdef CONFIG_COMPAT
static long st54spi_compat_ioc_message(
    struct file *filp, unsigned int cmd, unsigned long arg) {
    struct spi_ioc_transfer __user *u_ioc;
    int retval = 0;
    struct st54spi_data *st54spi;
    struct spi_device *spi;
    unsigned int n_ioc, n;
    struct spi_ioc_transfer *ioc;

    u_ioc = (struct spi_ioc_transfer __user *)compat_ptr(arg);
    if (!access_ok(VERIFY_READ, u_ioc, _IOC_SIZE(cmd)))
        return -EFAULT;

    /* guard against device removal before, or while,
     * we issue this ioctl.
     */
    st54spi = filp->private_data;
    spin_lock_irq(&st54spi->spi_lock);
    spi = spi_dev_get(st54spi->spi);
    spin_unlock_irq(&st54spi->spi_lock);

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi compat_ioctl cmd %d\n", cmd);
    if (spi == NULL)
        return -ESHUTDOWN;

    /* SPI_IOC_MESSAGE needs the buffer locked "normally" */
    mutex_lock(&st54spi->buf_lock);

    /* Check message and copy into scratch area */
    ioc = st54spi_get_ioc_message(cmd, u_ioc, &n_ioc);
    if (IS_ERR(ioc)) {
        retval = PTR_ERR(ioc);
        goto done;
    }
    if (!ioc)
        goto done; /* n_ioc is also 0 */

    /* Convert buffer pointers */
    for (n = 0; n < n_ioc; n++) {
        ioc[n].rx_buf = (uintptr_t)compat_ptr(ioc[n].rx_buf);
        ioc[n].tx_buf = (uintptr_t)compat_ptr(ioc[n].tx_buf);
    }

    /* translate to spi_message, execute */
    retval = st54spi_message(st54spi, ioc, n_ioc);
    kfree(ioc);

done:
    mutex_unlock(&st54spi->buf_lock);
    spi_dev_put(spi);
    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi compat_ioctl retval %d\n", retval);
    return retval;
}

static long st54spi_compat_ioctl(
    struct file *filp, unsigned int cmd, unsigned long arg)
{
    if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC &&
        _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0)) &&
        _IOC_DIR(cmd) == _IOC_WRITE)
        return st54spi_compat_ioc_message(filp, cmd, arg);

    return st54spi_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
}
#else
#define st54spi_compat_ioctl NULL
#endif /* CONFIG_COMPAT */

static int st54spi_open(struct inode *inode, struct file *filp)
{
    struct st54spi_data *st54spi;
    int status = -ENXIO;

    mutex_lock(&device_list_lock);

    list_for_each_entry(st54spi, &device_list, device_entry) {
        if (st54spi->devt == inode->i_rdev) {
            status = 0;
            break;
        }
    }

    if (status) {
        dev_dbg(&st54spi->spi->dev, "st54spi: nothing for minor %d\n", iminor(inode));
        goto err_find_dev;
    }

    // Authorize only 1 process to open the device.
    if (st54spi->users > 0) {
        dev_err(&st54spi->spi->dev, "%d: already open\n");
        mutex_unlock(&device_list_lock);
        return -EBUSY;
    }

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi: open\n");

    if (!st54spi->tx_buffer) {
        st54spi->tx_buffer = kmalloc(bufsiz, GFP_KERNEL);
        if (!st54spi->tx_buffer) {
            // dev_dbg(&st54spi->spi->dev, "open/ENOMEM\n");
            status = -ENOMEM;
            goto err_find_dev;
        }
    }

    if (!st54spi->rx_buffer) {
        st54spi->rx_buffer = kmalloc(bufsiz, GFP_KERNEL);
        if (!st54spi->rx_buffer) {
            // dev_dbg(&st54spi->spi->dev, "open/ENOMEM\n");
            status = -ENOMEM;
            goto err_alloc_rx_buf;
        }
    }

    st54spi->users++;
    filp->private_data = st54spi;
    nonseekable_open(inode, filp);

    mutex_unlock(&device_list_lock);

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi: open - force power on\n");
    st54spi_power_set(st54spi, 1);
    return 0;

err_alloc_rx_buf:
    kfree(st54spi->tx_buffer);
    st54spi->tx_buffer = NULL;
err_find_dev:
    mutex_unlock(&device_list_lock);
    return status;
}

static int st54spi_release(struct inode *inode, struct file *filp)
{
    struct st54spi_data *st54spi;

    mutex_lock(&device_list_lock);
    st54spi = filp->private_data;
    filp->private_data = NULL;

    if (debug_enabled)
        dev_info(&st54spi->spi->dev, "st54spi: release\n");

    /* last close? */
    st54spi->users--;
    if (!st54spi->users) {
        int dofree;

        if (debug_enabled)
            dev_info(&st54spi->spi->dev, "st54spi: release - may allow power off\n");

        st54spi_power_set(st54spi, 0);

        kfree(st54spi->tx_buffer);
        st54spi->tx_buffer = NULL;

        kfree(st54spi->rx_buffer);
        st54spi->rx_buffer = NULL;

        spin_lock_irq(&st54spi->spi_lock);
        if (st54spi->spi)
            st54spi->speed_hz = st54spi->spi->max_speed_hz;

        /* ... after we unbound from the underlying device? */
        dofree = ((st54spi->spi == NULL) &&
            (st54spi->spi_reset == NULL));
        spin_unlock_irq(&st54spi->spi_lock);

        if (dofree)
            kfree(st54spi);
    }
    mutex_unlock(&device_list_lock);

    return 0;
}

static const struct file_operations st54spi_fops = {
    .owner = THIS_MODULE,
    /* REVISIT switch to aio primitives, so that userspace
     * gets more complete API coverage.  It'll simplify things
     * too, except for the locking.
     */
    .write = st54spi_write,
    .read = st54spi_read,
    .unlocked_ioctl = st54spi_ioctl,
    .compat_ioctl = st54spi_compat_ioctl,
    .open = st54spi_open,
    .release = st54spi_release,
    .llseek = no_llseek,
};

/*-------------------------------------------------------------------------*/

/* The main reason to have this class is to make mdev/udev create the
 * /dev/st54spi character device nodes exposing our userspace API.
 * It also simplifies memory management.
 */

static struct class *st54spi_class;

static const struct of_device_id st54spi_dt_ids[] = {
    {.compatible = "st,st54spi"},
    {},
};
MODULE_DEVICE_TABLE(of, st54spi_dt_ids);

#ifdef CONFIG_ACPI

/* Dummy SPI devices not to be used in production systems */
#define SPIDEV_ACPI_DUMMY 1

static const struct acpi_device_id st54spi_acpi_ids[] = {
    /*
     * The ACPI SPT000* devices are only meant for development and
     * testing. Systems used in production should have a proper ACPI
     * description of the connected peripheral and they should also use
     * a proper driver instead of poking directly to the SPI bus.
     */
    {"SPT0001", SPIDEV_ACPI_DUMMY},
    {"SPT0002", SPIDEV_ACPI_DUMMY},
    {"SPT0003", SPIDEV_ACPI_DUMMY},
    {},
};
MODULE_DEVICE_TABLE(acpi, st54spi_acpi_ids);

static void st54spi_probe_acpi(struct spi_device *spi)
{
    const struct acpi_device_id *id;

    if (!has_acpi_companion(&spi->dev))
        return;

    id = acpi_match_device(st54spi_acpi_ids, &spi->dev);
    if (WARN_ON(!id))
        return;
}
#else
static inline void st54spi_probe_acpi(struct spi_device *spi) {}
#endif

/*-------------------------------------------------------------------------*/

static int st54spi_parse_dt(struct device *dev, struct st54spi_data *pdata)
{
    int r = 0;
    struct device_node *np = dev->of_node;

    np = of_find_compatible_node(NULL, NULL, "st,st54spi");

    if (np) {
        const char *power_mode;
#if (!defined(CONFIG_MTK_GPIO) || defined(CONFIG_MTK_GPIOLIB_STAND))
        r = of_get_named_gpio(np, "gpio-power_nreset-std", 0);
        if (r < 0)
            dev_info(dev, "%s: get ST54 failed (%d)", __FILE__, r);
        else
            pdata->power_or_nreset_gpio = r;
        r = 0;
#else
        of_property_read_u32_array(
            np, "gpio-power_nreset", &(pdata->power_or_nreset_gpio), 1);
#endif

        // Read power mode.
        power_mode = of_get_property(np, "power_mode", NULL);
        if (!power_mode) {
            dev_info(dev, "%s: Default power mode: ST54H\n", __FILE__);
            pdata->power_or_nreset_gpio_mode = POWER_MODE_ST54H;
        } else if (!strcmp(power_mode, "ST54J")) {
            dev_info(dev, "%s: Power mode: ST54J\n", __FILE__);
            pdata->power_or_nreset_gpio_mode = POWER_MODE_ST54J;
        } else if (!strcmp(power_mode, "ST54H")) {
            dev_info(dev, "%s: Power mode: ST54H\n", __FILE__);
            pdata->power_or_nreset_gpio_mode = POWER_MODE_ST54H;
        } else if (!strcmp(power_mode, "none")) {
            dev_info(dev, "%s: Power mode: none\n", __FILE__);
            pdata->power_or_nreset_gpio_mode = POWER_MODE_NONE;
        } else {
            dev_err(dev, "%s: Power mode unknown: %s\n", __FILE__, power_mode);
            return -1;
        }
    } else {
        dev_info(dev, "%s : get num err.\n", __func__);
        return -1;
    }

    // We need to use pinmux to control NSS
    pdata->pctrl = devm_pinctrl_get(dev);
    if (IS_ERR(pdata->pctrl)) {
        dev_err(dev, "%s: Unable to allocate pinctrl: %d\n", __FILE__, PTR_ERR(pdata->pctrl));
        return -1;
    }

    pdata->pctrl_mode_spi = pinctrl_lookup_state(pdata->pctrl, "pinctrl_state_mode_spi");
    if (IS_ERR(pdata->pctrl_mode_spi)) {
        dev_err(dev, "%s: Unable to find pinctrl_state_mode_spi: %d\n",
            __FILE__, PTR_ERR(pdata->pctrl_mode_spi));
        return -1;
    }

    pdata->pctrl_mode_idle = pinctrl_lookup_state(pdata->pctrl, "pinctrl_state_mode_idle");
    if (IS_ERR(pdata->pctrl_mode_idle)) {
        dev_err(dev, "%s: Unable to find pinctrl_state_mode_idle: %d\n",
            __FILE__, PTR_ERR(pdata->pctrl_mode_idle));
        return -1;
    }
    dev_info(dev, "[dsc]%s : pinctrl initialized\n", __func__);

    dev_info(dev, "[dsc]%s : get power_or_nreset_gpio[%d]\n", __func__, pdata->power_or_nreset_gpio);
    return r;
}

#ifndef MODULE
static void st54spi_st21nfc_cb(int dir, void *data)
{
    struct st54spi_data *st54spi = (struct st54spi_data *)data;

    if (!st54spi)
        return;
    dev_info(&st54spi->spi->dev, "%s : dir %d data %p\n", __func__, dir, st54spi);

    switch (dir) {
    case ST54SPI_CB_RESET_START:
        if (st54spi->se_is_poweron)
            st54spi_power_off(st54spi);
        break;

    case ST54SPI_CB_RESET_END:
        // wait for the CLF to boot once nRESET is released
        usleep_range(4000, 8000);

        st54spi_power_on(st54spi);
        break;

    case ST54SPI_CB_ESE_USED:
        st54spi->nfcc_needs_poweron = 1;
        if (st54spi->se_is_poweron == 0)
            st54spi_power_on(st54spi);
        break;

    case ST54SPI_CB_ESE_NOT_USED:
        st54spi->nfcc_needs_poweron = 0;
        if ((st54spi->se_is_poweron == 1) &&
            (st54spi->sehal_needs_poweron == 0))
            // we don t need power anymore
            st54spi_power_off(st54spi);
        break;
    }
}
#endif  // !MODULE

/* Change CS_TIME for ST54 */
#ifdef ST21NFCD_MTK
// Unit is 1/109.2 us.
static struct mtk_chip_config st54spi_chip_info = {
    .cs_setuptime = 2184, // 20 us
};
#endif

static int st54spi_probe(struct spi_device *spi)
{
    struct st54spi_data *st54spi;
    int status, ret;
    unsigned long minor;
#ifdef ST21NFCD_MTK
    struct mtk_chip_config *chip_config = spi->controller_data;
#endif
        //#ifdef VENDOR_EDIT
        //Zhou.Zheng@CN.NFC.Basic.Hardware,2674926, 2019/12/16,
       //Add for : ST NXP chip common software
       CHECK_NFC_CHIP(ST54H);
      //#endif /* VENDOR_EDIT */

    /*
     * st54spi should never be referenced in DT without a specific
     * compatible string, it is a Linux implementation thing
     * rather than a description of the hardware.
     */

    st54spi_probe_acpi(spi);

    /* Allocate driver data */
    st54spi = kzalloc(sizeof(*st54spi), GFP_KERNEL);
    if (!st54spi)
        return -ENOMEM;

    /* Initialize the driver data */
    st54spi->spi = spi;
    spin_lock_init(&st54spi->spi_lock);
    mutex_init(&st54spi->buf_lock);

    INIT_LIST_HEAD(&st54spi->device_entry);

    /* If we can allocate a minor number, hook up this device.
     * Reusing minors is fine so long as udev or mdev is working.
     */
    mutex_lock(&device_list_lock);
    minor = find_first_zero_bit(minors, N_SPI_MINORS);
    if (minor < N_SPI_MINORS) {
        struct device *dev;

        st54spi->devt = MKDEV(spidev_major, minor);
        dev = device_create(st54spi_class, &spi->dev, st54spi->devt,
            // spidev, "spidev%d.%d",
            // spi->master->bus_num, spi->chip_select);
            st54spi, "st54spi");
        status = PTR_ERR_OR_ZERO(dev);
    } else {
        dev_dbg(&spi->dev, "no minor number available!\n");
        status = -ENODEV;
    }
    if (status == 0) {
        set_bit(minor, minors);
        list_add(&st54spi->device_entry, &device_list);
    }
    mutex_unlock(&device_list_lock);

    st54spi->speed_hz = spi->max_speed_hz;
    dev_dbg(&spi->dev, "st54spi->speed_hz=%d\n", st54spi->speed_hz);
    // {
    // /* fixed SPI clock speed: 109200000 */
    // int period = DIV_ROUND_UP(109200000, st54spi->speed_hz);

    // st54spi_chip_info.cs_idletime = period;
    // st54spi_chip_info.cs_holdtime = period;
    // }

#ifdef ST21NFCD_MTK
    // set timings for ST54
    if (chip_config == NULL) {
        spi->controller_data = (void *)&st54spi_chip_info;
        dev_dbg(&spi->dev, "Replaced chip_info!\n");
    } else {
        chip_config->cs_setuptime = st54spi_chip_info.cs_setuptime;
        chip_config->cs_idletime = st54spi_chip_info.cs_idletime;
        chip_config->cs_holdtime = st54spi_chip_info.cs_holdtime;
        dev_dbg(&spi->dev, "Added into chip_info!\n");
    }
#else
    dev_err(&spi->dev, "%s : TSU_NSS configuration be implemented!\n", __func__);
    // platform-specific method to configure the delay beween NSS slave
    // selection and the start of data transfer (clk).
    // If no specific method required, you can comment above line.
#endif

  //#ifndef VENDOR_EDIT
  //Zhou.Zheng@CN.NFC.Basic.Hardware,2674926, 2020/01/21,
  //Modify for : fix coverity 85484
  // if (status == 0)
  //   spi_set_drvdata(spi, st54spi);
  // else
  //   kfree(st54spi);
  //#else
  if (status == 0) {
    spi_set_drvdata(spi, st54spi);
  } else {
    kfree(st54spi);
    return -ENODEV;
  }
  //#endif /* VENDOR_EDIT */

    (void)st54spi_parse_dt(&spi->dev, st54spi);

    if (st54spi->power_or_nreset_gpio != 0) {
        int default_value = 0;


        ret = gpio_request(st54spi->power_or_nreset_gpio,
#if (!defined(CONFIG_MTK_GPIO) || defined(CONFIG_MTK_GPIOLIB_STAND))
            "gpio-power_nreset-std"
#else
            "gpio-power_nreset"
#endif
        );
        if (ret)
            dev_info(&spi->dev, "%s : power request failed (%d)\n",
                __FILE__, ret);

        dev_info(&spi->dev, "%s : power/nreset GPIO = %d\n", __func__,
            st54spi->power_or_nreset_gpio);
        ret = gpio_direction_output(st54spi->power_or_nreset_gpio, default_value);
        if (ret)
            dev_info(&spi->dev, "%s : reset direction_output failed\n", __FILE__);

        /* active high */
        gpio_set_value(st54spi->power_or_nreset_gpio, default_value);
    }

    if (st54spi->power_or_nreset_gpio_mode == POWER_MODE_ST54H) {
#ifndef MODULE
        dev_info(&spi->dev, "%s : Register with st21nfc driver, %p\n",
            __func__, st54spi);
        st21nfc_register_st54spi_cb(st54spi_st21nfc_cb, st54spi);
#else
        dev_err(&spi->dev, "%s : st54spi as module cannot use ST54H fully\n",
            __func__);
#endif
    }

    return status;
}

static int st54spi_remove(struct spi_device *spi)
{
    struct st54spi_data *st54spi = spi_get_drvdata(spi);

    if (st54spi->power_or_nreset_gpio_mode == POWER_MODE_ST54H) {
#ifndef MODULE
        dev_info(&st54spi->spi->dev, "%s : Unregister from st21nfc driver\n",
            __func__);
        st21nfc_unregister_st54spi_cb();
#endif
    }
    /* make sure ops on existing fds can abort cleanly */
    spin_lock_irq(&st54spi->spi_lock);
    st54spi->spi = NULL;
    st54spi->spi_reset = NULL;
    spin_unlock_irq(&st54spi->spi_lock);

    /* prevent new opens */
    mutex_lock(&device_list_lock);
    list_del(&st54spi->device_entry);
    device_destroy(st54spi_class, st54spi->devt);
    clear_bit(MINOR(st54spi->devt), minors);
    if (st54spi->users == 0)
        kfree(st54spi);

    mutex_unlock(&device_list_lock);

    return 0;
}

static struct spi_driver st54spi_spi_driver = {
    .driver = {
            .name = "st54spi",
            .of_match_table = of_match_ptr(st54spi_dt_ids),
            .acpi_match_table = ACPI_PTR(st54spi_acpi_ids),
        },
    .probe = st54spi_probe,
    .remove = st54spi_remove,

    /* NOTE:  suspend/resume methods are not necessary here.
     * We don't do anything except pass the requests to/from
     * the underlying controller.  The refrigerator handles
     * most issues; the controller driver handles the rest.
     */
};

/*-------------------------------------------------------------------------*/

static int __init st54spi_init(void)
{
    int status;

    pr_info("Loading st54spi driver\n");

    /* Claim our 256 reserved device numbers.  Then register a class
     * that will key udev/mdev to add/remove /dev nodes.  Last, register
     * the driver which manages those device numbers.
     */
    BUILD_BUG_ON(N_SPI_MINORS > 256);
    spidev_major = __register_chrdev(0, 0, N_SPI_MINORS,
        "spi", &st54spi_fops);
    pr_info("Loading st54spi driver, major: %d\n", spidev_major);

    st54spi_class = class_create(THIS_MODULE, "spidev");
    if (IS_ERR(st54spi_class)) {
        unregister_chrdev(spidev_major, st54spi_spi_driver.driver.name);
        return PTR_ERR(st54spi_class);
    }

    status = spi_register_driver(&st54spi_spi_driver);
    if (status < 0) {
        class_destroy(st54spi_class);
        unregister_chrdev(spidev_major, st54spi_spi_driver.driver.name);
    }
    pr_info("Loading st54spi driver: %d\n", status);
    return status;
}
module_init(st54spi_init);

static void __exit st54spi_exit(void)
{
    spi_unregister_driver(&st54spi_spi_driver);
    class_destroy(st54spi_class);
    unregister_chrdev(spidev_major, st54spi_spi_driver.driver.name);
}
module_exit(st54spi_exit);

MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
MODULE_DESCRIPTION("User mode SPI device interface");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:st54spi");