/*
 *  Shared Transport Line discipline driver Core
 *      Init Manager module responsible for GPIO control
 *      and firmware download
 *  Copyright (C) 2009-2010 Texas Instruments
 *  Author: Pavan Savoy <pavan_savoy@ti.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.
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#define pr_fmt(fmt) "(stk) :" fmt
#include <linux/platform_device.h>
#include <linux/jiffies.h>
#include <linux/firmware.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/gpio.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/sched.h>
#include <linux/sysfs.h>
#include <linux/tty.h>

#include <linux/skbuff.h>
#include <linux/ti_wilink_st.h>
#include <linux/module.h>


#define MAX_ST_DEVICES  3       /* Imagine 1 on each UART for now */
static struct platform_device *st_kim_devices[MAX_ST_DEVICES];

/**********************************************************************/
/* internal functions */

/**
 * st_get_plat_device -
 *      function which returns the reference to the platform device
 *      requested by id. As of now only 1 such device exists (id=0)
 *      the context requesting for reference can get the id to be
 *      requested by a. The protocol driver which is registering or
 *      b. the tty device which is opened.
 */
static struct platform_device *st_get_plat_device(int id)
{
        return st_kim_devices[id];
}

/**
 * validate_firmware_response -
 *      function to return whether the firmware response was proper
 *      in case of error don't complete so that waiting for proper
 *      response times out
 */
void validate_firmware_response(struct kim_data_s *kim_gdata)
{
        struct sk_buff *skb = kim_gdata->rx_skb;
        if (unlikely(skb->data[5] != 0)) {
                pr_err("no proper response during fw download");
                pr_err("data6 %x", skb->data[5]);
                kfree_skb(skb);
                return;         /* keep waiting for the proper response */
        }
        /* becos of all the script being downloaded */
        complete_all(&kim_gdata->kim_rcvd);
        kfree_skb(skb);
}

/* check for data len received inside kim_int_recv
 * most often hit the last case to update state to waiting for data
 */
static inline int kim_check_data_len(struct kim_data_s *kim_gdata, int len)
{
        register int room = skb_tailroom(kim_gdata->rx_skb);

        pr_debug("len %d room %d", len, room);

        if (!len) {
                validate_firmware_response(kim_gdata);
        } else if (len > room) {
                /* Received packet's payload length is larger.
                 * We can't accommodate it in created skb.
                 */
                pr_err("Data length is too large len %d room %d", len,
                           room);
                kfree_skb(kim_gdata->rx_skb);
        } else {
                /* Packet header has non-zero payload length and
                 * we have enough space in created skb. Lets read
                 * payload data */
                kim_gdata->rx_state = ST_W4_DATA;
                kim_gdata->rx_count = len;
                return len;
        }

        /* Change ST LL state to continue to process next
         * packet */
        kim_gdata->rx_state = ST_W4_PACKET_TYPE;
        kim_gdata->rx_skb = NULL;
        kim_gdata->rx_count = 0;

        return 0;
}

/**
 * kim_int_recv - receive function called during firmware download
 *      firmware download responses on different UART drivers
 *      have been observed to come in bursts of different
 *      tty_receive and hence the logic
 */
void kim_int_recv(struct kim_data_s *kim_gdata,
        const unsigned char *data, long count)
{
        const unsigned char *ptr;
        int len = 0, type = 0;
        unsigned char *plen;

        pr_debug("%s", __func__);
        /* Decode received bytes here */
        ptr = data;
        if (unlikely(ptr == NULL)) {
                pr_err(" received null from TTY ");
                return;
        }

        while (count) {
                if (kim_gdata->rx_count) {
                        len = min_t(unsigned int, kim_gdata->rx_count, count);
                        memcpy(skb_put(kim_gdata->rx_skb, len), ptr, len);
                        kim_gdata->rx_count -= len;
                        count -= len;
                        ptr += len;

                        if (kim_gdata->rx_count)
                                continue;

                        /* Check ST RX state machine , where are we? */
                        switch (kim_gdata->rx_state) {
                                /* Waiting for complete packet ? */
                        case ST_W4_DATA:
                                pr_debug("Complete pkt received");
                                validate_firmware_response(kim_gdata);
                                kim_gdata->rx_state = ST_W4_PACKET_TYPE;
                                kim_gdata->rx_skb = NULL;
                                continue;
                                /* Waiting for Bluetooth event header ? */
                        case ST_W4_HEADER:
                                plen =
                                (unsigned char *)&kim_gdata->rx_skb->data[1];
                                pr_debug("event hdr: plen 0x%02x\n", *plen);
                                kim_check_data_len(kim_gdata, *plen);
                                continue;
                        }       /* end of switch */
                }               /* end of if rx_state */
                switch (*ptr) {
                        /* Bluetooth event packet? */
                case 0x04:
                        kim_gdata->rx_state = ST_W4_HEADER;
                        kim_gdata->rx_count = 2;
                        type = *ptr;
                        break;
                default:
                        pr_info("unknown packet");
                        ptr++;
                        count--;
                        continue;
                }
                ptr++;
                count--;
                kim_gdata->rx_skb =
                        alloc_skb(1024+8, GFP_ATOMIC);
                if (!kim_gdata->rx_skb) {
                        pr_err("can't allocate mem for new packet");
                        kim_gdata->rx_state = ST_W4_PACKET_TYPE;
                        kim_gdata->rx_count = 0;
                        return;
                }
                skb_reserve(kim_gdata->rx_skb, 8);
                kim_gdata->rx_skb->cb[0] = 4;
                kim_gdata->rx_skb->cb[1] = 0;

        }
        return;
}

static long read_local_version(struct kim_data_s *kim_gdata, char *bts_scr_name)
{
        unsigned short version = 0, chip = 0, min_ver = 0, maj_ver = 0;
        const char read_ver_cmd[] = { 0x01, 0x01, 0x10, 0x00 };

        pr_debug("%s", __func__);

        INIT_COMPLETION(kim_gdata->kim_rcvd);
        if (4 != st_int_write(kim_gdata->core_data, read_ver_cmd, 4)) {
                pr_err("kim: couldn't write 4 bytes");
                return -EIO;
        }

        if (!wait_for_completion_timeout
            (&kim_gdata->kim_rcvd, msecs_to_jiffies(CMD_RESP_TIME))) {
                pr_err(" waiting for ver info- timed out ");
                return -ETIMEDOUT;
        }
        INIT_COMPLETION(kim_gdata->kim_rcvd);

        version =
                MAKEWORD(kim_gdata->resp_buffer[13],
                                kim_gdata->resp_buffer[14]);
        chip = (version & 0x7C00) >> 10;
        min_ver = (version & 0x007F);
        maj_ver = (version & 0x0380) >> 7;

        if (version & 0x8000)
                maj_ver |= 0x0008;

        sprintf(bts_scr_name, "TIInit_%d.%d.%d.bts", chip, maj_ver, min_ver);

        /* to be accessed later via sysfs entry */
        kim_gdata->version.full = version;
        kim_gdata->version.chip = chip;
        kim_gdata->version.maj_ver = maj_ver;
        kim_gdata->version.min_ver = min_ver;

        pr_info("%s", bts_scr_name);
        return 0;
}

void skip_change_remote_baud(unsigned char **ptr, long *len)
{
        unsigned char *nxt_action, *cur_action;
        cur_action = *ptr;

        nxt_action = cur_action + sizeof(struct bts_action) +
                ((struct bts_action *) cur_action)->size;

        if (((struct bts_action *) nxt_action)->type != ACTION_WAIT_EVENT) {
                pr_err("invalid action after change remote baud command");
        } else {
                *ptr = *ptr + sizeof(struct bts_action) +
                        ((struct bts_action *)cur_action)->size;
                *len = *len - (sizeof(struct bts_action) +
                                ((struct bts_action *)cur_action)->size);
                /* warn user on not commenting these in firmware */
                pr_warn("skipping the wait event of change remote baud");
        }
}

/**
 * download_firmware -
 *      internal function which parses through the .bts firmware
 *      script file intreprets SEND, DELAY actions only as of now
 */
static long download_firmware(struct kim_data_s *kim_gdata)
{
        long err = 0;
        long len = 0;
        unsigned char *ptr = NULL;
        unsigned char *action_ptr = NULL;
        unsigned char bts_scr_name[30] = { 0 }; /* 30 char long bts scr name? */
        int wr_room_space;
        int cmd_size;
        unsigned long timeout;

        err = read_local_version(kim_gdata, bts_scr_name);
        if (err != 0) {
                pr_err("kim: failed to read local ver");
                return err;
        }
        err =
            request_firmware(&kim_gdata->fw_entry, bts_scr_name,
                             &kim_gdata->kim_pdev->dev);
        if (unlikely((err != 0) || (kim_gdata->fw_entry->data == NULL) ||
                     (kim_gdata->fw_entry->size == 0))) {
                pr_err(" request_firmware failed(errno %ld) for %s", err,
                           bts_scr_name);
                return -EINVAL;
        }
        ptr = (void *)kim_gdata->fw_entry->data;
        len = kim_gdata->fw_entry->size;
        /* bts_header to remove out magic number and
         * version
         */
        ptr += sizeof(struct bts_header);
        len -= sizeof(struct bts_header);

        while (len > 0 && ptr) {
                pr_debug(" action size %d, type %d ",
                           ((struct bts_action *)ptr)->size,
                           ((struct bts_action *)ptr)->type);

                switch (((struct bts_action *)ptr)->type) {
                case ACTION_SEND_COMMAND:       /* action send */
                        pr_debug("S");
                        action_ptr = &(((struct bts_action *)ptr)->data[0]);
                        if (unlikely
                            (((struct hci_command *)action_ptr)->opcode ==
                             0xFF36)) {
                                /* ignore remote change
                                 * baud rate HCI VS command */
                                pr_warn("change remote baud"
                                    " rate command in firmware");
                                skip_change_remote_baud(&ptr, &len);
                                break;
                        }
                        /*
                         * Make sure we have enough free space in uart
                         * tx buffer to write current firmware command
                         */
                        cmd_size = ((struct bts_action *)ptr)->size;
                        timeout = jiffies + msecs_to_jiffies(CMD_WR_TIME);
                        do {
                                wr_room_space =
                                        st_get_uart_wr_room(kim_gdata->core_data);
                                if (wr_room_space < 0) {
                                        pr_err("Unable to get free "
                                                        "space info from uart tx buffer");
                                        release_firmware(kim_gdata->fw_entry);
                                        return wr_room_space;
                                }
                                mdelay(1); /* wait 1ms before checking room */
                        } while ((wr_room_space < cmd_size) &&
                                        time_before(jiffies, timeout));

                        /* Timeout happened ? */
                        if (time_after_eq(jiffies, timeout)) {
                                pr_err("Timeout while waiting for free "
                                                "free space in uart tx buffer");
                                release_firmware(kim_gdata->fw_entry);
                                return -ETIMEDOUT;
                        }
                        /* reinit completion before sending for the
                         * relevant wait
                         */
                        INIT_COMPLETION(kim_gdata->kim_rcvd);

                        /*
                         * Free space found in uart buffer, call st_int_write
                         * to send current firmware command to the uart tx
                         * buffer.
                         */
                        err = st_int_write(kim_gdata->core_data,
                        ((struct bts_action_send *)action_ptr)->data,
                                           ((struct bts_action *)ptr)->size);
                        if (unlikely(err < 0)) {
                                release_firmware(kim_gdata->fw_entry);
                                return err;
                        }
                        /*
                         * Check number of bytes written to the uart tx buffer
                         * and requested command write size
                         */
                        if (err != cmd_size) {
                                pr_err("Number of bytes written to uart "
                                                "tx buffer are not matching with "
                                                "requested cmd write size");
                                release_firmware(kim_gdata->fw_entry);
                                return -EIO;
                        }
                        break;
                case ACTION_WAIT_EVENT:  /* wait */
                        pr_debug("W");
                        if (!wait_for_completion_timeout
                                        (&kim_gdata->kim_rcvd,
                                         msecs_to_jiffies(CMD_RESP_TIME))) {
                                pr_err("response timeout during fw download ");
                                /* timed out */
                                release_firmware(kim_gdata->fw_entry);
                                return -ETIMEDOUT;
                        }
                        INIT_COMPLETION(kim_gdata->kim_rcvd);
                        break;
                case ACTION_DELAY:      /* sleep */
                        pr_info("sleep command in scr");
                        action_ptr = &(((struct bts_action *)ptr)->data[0]);
                        mdelay(((struct bts_action_delay *)action_ptr)->msec);
                        break;
                }
                len =
                    len - (sizeof(struct bts_action) +
                           ((struct bts_action *)ptr)->size);
                ptr =
                    ptr + sizeof(struct bts_action) +
                    ((struct bts_action *)ptr)->size;
        }
        /* fw download complete */
        release_firmware(kim_gdata->fw_entry);
        return 0;
}

/**********************************************************************/
/* functions called from ST core */
/* called from ST Core, when REG_IN_PROGRESS (registration in progress)
 * can be because of
 * 1. response to read local version
 * 2. during send/recv's of firmware download
 */
void st_kim_recv(void *disc_data, const unsigned char *data, long count)
{
        struct st_data_s        *st_gdata = (struct st_data_s *)disc_data;
        struct kim_data_s       *kim_gdata = st_gdata->kim_data;

        /* copy to local buffer */
        if (unlikely(data[4] == 0x01 && data[5] == 0x10 && data[0] == 0x04)) {
                /* must be the read_ver_cmd */
                memcpy(kim_gdata->resp_buffer, data, count);
                complete_all(&kim_gdata->kim_rcvd);
                return;
        } else {
                kim_int_recv(kim_gdata, data, count);
                /* either completes or times out */
        }
        return;
}

/* to signal completion of line discipline installation
 * called from ST Core, upon tty_open
 */
void st_kim_complete(void *kim_data)
{
        struct kim_data_s       *kim_gdata = (struct kim_data_s *)kim_data;
        complete(&kim_gdata->ldisc_installed);
}

/**
 * st_kim_start - called from ST Core upon 1st registration
 *      This involves toggling the chip enable gpio, reading
 *      the firmware version from chip, forming the fw file name
 *      based on the chip version, requesting the fw, parsing it
 *      and perform download(send/recv).
 */
long st_kim_start(void *kim_data)
{
        long err = 0;
        long retry = POR_RETRY_COUNT;
        struct ti_st_plat_data  *pdata;
        struct kim_data_s       *kim_gdata = (struct kim_data_s *)kim_data;

        pr_info(" %s", __func__);
        pdata = kim_gdata->kim_pdev->dev.platform_data;

        do {
                /* platform specific enabling code here */
                if (pdata->chip_enable)
                        pdata->chip_enable(kim_gdata);

                /* Configure BT nShutdown to HIGH state */
                gpio_set_value(kim_gdata->nshutdown, GPIO_LOW);
                mdelay(5);      /* FIXME: a proper toggle */
                gpio_set_value(kim_gdata->nshutdown, GPIO_HIGH);
                mdelay(100);
                /* re-initialize the completion */
                INIT_COMPLETION(kim_gdata->ldisc_installed);
                /* send notification to UIM */
                kim_gdata->ldisc_install = 1;
                pr_info("ldisc_install = 1");
                sysfs_notify(&kim_gdata->kim_pdev->dev.kobj,
                                NULL, "install");
                /* wait for ldisc to be installed */
                err = wait_for_completion_timeout(&kim_gdata->ldisc_installed,
                                msecs_to_jiffies(LDISC_TIME));
                if (!err) {
                        /* ldisc installation timeout,
                         * flush uart, power cycle BT_EN */
                        pr_err("ldisc installation timeout");
                        err = st_kim_stop(kim_gdata);
                        continue;
                } else {
                        /* ldisc installed now */
                        pr_info("line discipline installed");
                        err = download_firmware(kim_gdata);
                        if (err != 0) {
                                /* ldisc installed but fw download failed,
                                 * flush uart & power cycle BT_EN */
                                pr_err("download firmware failed");
                                err = st_kim_stop(kim_gdata);
                                continue;
                        } else {        /* on success don't retry */
                                break;
                        }
                }
        } while (retry--);
        return err;
}

/**
 * st_kim_stop - stop communication with chip.
 *      This can be called from ST Core/KIM, on the-
 *      (a) last un-register when chip need not be powered there-after,
 *      (b) upon failure to either install ldisc or download firmware.
 *      The function is responsible to (a) notify UIM about un-installation,
 *      (b) flush UART if the ldisc was installed.
 *      (c) reset BT_EN - pull down nshutdown at the end.
 *      (d) invoke platform's chip disabling routine.
 */
long st_kim_stop(void *kim_data)
{
        long err = 0;
        struct kim_data_s       *kim_gdata = (struct kim_data_s *)kim_data;
        struct ti_st_plat_data  *pdata =
                kim_gdata->kim_pdev->dev.platform_data;
        struct tty_struct       *tty = kim_gdata->core_data->tty;

        INIT_COMPLETION(kim_gdata->ldisc_installed);

        if (tty) {      /* can be called before ldisc is installed */
                /* Flush any pending characters in the driver and discipline. */
                tty_ldisc_flush(tty);
                tty_driver_flush_buffer(tty);
                tty->ops->flush_buffer(tty);
        }

        /* send uninstall notification to UIM */
        pr_info("ldisc_install = 0");
        kim_gdata->ldisc_install = 0;
        sysfs_notify(&kim_gdata->kim_pdev->dev.kobj, NULL, "install");

        /* wait for ldisc to be un-installed */
        err = wait_for_completion_timeout(&kim_gdata->ldisc_installed,
                        msecs_to_jiffies(LDISC_TIME));
        if (!err) {             /* timeout */
                pr_err(" timed out waiting for ldisc to be un-installed");
                return -ETIMEDOUT;
        }

        /* By default configure BT nShutdown to LOW state */
        gpio_set_value(kim_gdata->nshutdown, GPIO_LOW);
        mdelay(1);
        gpio_set_value(kim_gdata->nshutdown, GPIO_HIGH);
        mdelay(1);
        gpio_set_value(kim_gdata->nshutdown, GPIO_LOW);

        /* platform specific disable */
        if (pdata->chip_disable)
                pdata->chip_disable(kim_gdata);
        return err;
}

/**********************************************************************/
/* functions called from subsystems */
/* called when debugfs entry is read from */

static int show_version(struct seq_file *s, void *unused)
{
        struct kim_data_s *kim_gdata = (struct kim_data_s *)s->private;
        seq_printf(s, "%04X %d.%d.%d\n", kim_gdata->version.full,
                        kim_gdata->version.chip, kim_gdata->version.maj_ver,
                        kim_gdata->version.min_ver);
        return 0;
}

static int show_list(struct seq_file *s, void *unused)
{
        struct kim_data_s *kim_gdata = (struct kim_data_s *)s->private;
        kim_st_list_protocols(kim_gdata->core_data, s);
        return 0;
}

static ssize_t show_install(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct kim_data_s *kim_data = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n", kim_data->ldisc_install);
}

#ifdef DEBUG
static ssize_t store_dev_name(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct kim_data_s *kim_data = dev_get_drvdata(dev);
        pr_debug("storing dev name >%s<", buf);
        strncpy(kim_data->dev_name, buf, count);
        pr_debug("stored dev name >%s<", kim_data->dev_name);
        return count;
}

static ssize_t store_baud_rate(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct kim_data_s *kim_data = dev_get_drvdata(dev);
        pr_debug("storing baud rate >%s<", buf);
        sscanf(buf, "%ld", &kim_data->baud_rate);
        pr_debug("stored baud rate >%ld<", kim_data->baud_rate);
        return count;
}
#endif  /* if DEBUG */

static ssize_t show_dev_name(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct kim_data_s *kim_data = dev_get_drvdata(dev);
        return sprintf(buf, "%s\n", kim_data->dev_name);
}

static ssize_t show_baud_rate(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct kim_data_s *kim_data = dev_get_drvdata(dev);
        return sprintf(buf, "%ld\n", kim_data->baud_rate);
}

static ssize_t show_flow_cntrl(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct kim_data_s *kim_data = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n", kim_data->flow_cntrl);
}

/* structures specific for sysfs entries */
static struct kobj_attribute ldisc_install =
__ATTR(install, 0444, (void *)show_install, NULL);

static struct kobj_attribute uart_dev_name =
#ifdef DEBUG    /* TODO: move this to debug-fs if possible */
__ATTR(dev_name, 0644, (void *)show_dev_name, (void *)store_dev_name);
#else
__ATTR(dev_name, 0444, (void *)show_dev_name, NULL);
#endif

static struct kobj_attribute uart_baud_rate =
#ifdef DEBUG    /* TODO: move to debugfs */
__ATTR(baud_rate, 0644, (void *)show_baud_rate, (void *)store_baud_rate);
#else
__ATTR(baud_rate, 0444, (void *)show_baud_rate, NULL);
#endif

static struct kobj_attribute uart_flow_cntrl =
__ATTR(flow_cntrl, 0444, (void *)show_flow_cntrl, NULL);

static struct attribute *uim_attrs[] = {
        &ldisc_install.attr,
        &uart_dev_name.attr,
        &uart_baud_rate.attr,
        &uart_flow_cntrl.attr,
        NULL,
};

static struct attribute_group uim_attr_grp = {
        .attrs = uim_attrs,
};

/**
 * st_kim_ref - reference the core's data
 *      This references the per-ST platform device in the arch/xx/
 *      board-xx.c file.
 *      This would enable multiple such platform devices to exist
 *      on a given platform
 */
void st_kim_ref(struct st_data_s **core_data, int id)
{
        struct platform_device  *pdev;
        struct kim_data_s       *kim_gdata;
        /* get kim_gdata reference from platform device */
        pdev = st_get_plat_device(id);
        if (!pdev) {
                *core_data = NULL;
                return;
        }
        kim_gdata = dev_get_drvdata(&pdev->dev);
        *core_data = kim_gdata->core_data;
}

static int kim_version_open(struct inode *i, struct file *f)
{
        return single_open(f, show_version, i->i_private);
}

static int kim_list_open(struct inode *i, struct file *f)
{
        return single_open(f, show_list, i->i_private);
}

static const struct file_operations version_debugfs_fops = {
        /* version info */
        .open = kim_version_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};
static const struct file_operations list_debugfs_fops = {
        /* protocols info */
        .open = kim_list_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

/**********************************************************************/
/* functions called from platform device driver subsystem
 * need to have a relevant platform device entry in the platform's
 * board-*.c file
 */

struct dentry *kim_debugfs_dir;
static int kim_probe(struct platform_device *pdev)
{
        long status;
        struct kim_data_s       *kim_gdata;
        struct ti_st_plat_data  *pdata = pdev->dev.platform_data;

        if ((pdev->id != -1) && (pdev->id < MAX_ST_DEVICES)) {
                /* multiple devices could exist */
                st_kim_devices[pdev->id] = pdev;
        } else {
                /* platform's sure about existence of 1 device */
                st_kim_devices[0] = pdev;
        }

        kim_gdata = kzalloc(sizeof(struct kim_data_s), GFP_ATOMIC);
        if (!kim_gdata) {
                pr_err("no mem to allocate");
                return -ENOMEM;
        }
        dev_set_drvdata(&pdev->dev, kim_gdata);

        status = st_core_init(&kim_gdata->core_data);
        if (status != 0) {
                pr_err(" ST core init failed");
                return -EIO;
        }
        /* refer to itself */
        kim_gdata->core_data->kim_data = kim_gdata;

        /* Claim the chip enable nShutdown gpio from the system */
        kim_gdata->nshutdown = pdata->nshutdown_gpio;
        status = gpio_request(kim_gdata->nshutdown, "kim");
        if (unlikely(status)) {
                pr_err(" gpio %ld request failed ", kim_gdata->nshutdown);
                return status;
        }

        /* Configure nShutdown GPIO as output=0 */
        status = gpio_direction_output(kim_gdata->nshutdown, 0);
        if (unlikely(status)) {
                pr_err(" unable to configure gpio %ld", kim_gdata->nshutdown);
                return status;
        }
        /* get reference of pdev for request_firmware
         */
        kim_gdata->kim_pdev = pdev;
        init_completion(&kim_gdata->kim_rcvd);
        init_completion(&kim_gdata->ldisc_installed);

        status = sysfs_create_group(&pdev->dev.kobj, &uim_attr_grp);
        if (status) {
                pr_err("failed to create sysfs entries");
                return status;
        }

        /* copying platform data */
        strncpy(kim_gdata->dev_name, pdata->dev_name, UART_DEV_NAME_LEN);
        kim_gdata->flow_cntrl = pdata->flow_cntrl;
        kim_gdata->baud_rate = pdata->baud_rate;
        pr_info("sysfs entries created\n");

        kim_debugfs_dir = debugfs_create_dir("ti-st", NULL);
        if (IS_ERR(kim_debugfs_dir)) {
                pr_err(" debugfs entries creation failed ");
                kim_debugfs_dir = NULL;
                return -EIO;
        }

        debugfs_create_file("version", S_IRUGO, kim_debugfs_dir,
                                kim_gdata, &version_debugfs_fops);
        debugfs_create_file("protocols", S_IRUGO, kim_debugfs_dir,
                                kim_gdata, &list_debugfs_fops);
        pr_info(" debugfs entries created ");
        return 0;
}

static int kim_remove(struct platform_device *pdev)
{
        /* free the GPIOs requested */
        struct ti_st_plat_data  *pdata = pdev->dev.platform_data;
        struct kim_data_s       *kim_gdata;

        kim_gdata = dev_get_drvdata(&pdev->dev);

        /* Free the Bluetooth/FM/GPIO
         * nShutdown gpio from the system
         */
        gpio_free(pdata->nshutdown_gpio);
        pr_info("nshutdown GPIO Freed");

        debugfs_remove_recursive(kim_debugfs_dir);
        sysfs_remove_group(&pdev->dev.kobj, &uim_attr_grp);
        pr_info("sysfs entries removed");

        kim_gdata->kim_pdev = NULL;
        st_core_exit(kim_gdata->core_data);

        kfree(kim_gdata);
        kim_gdata = NULL;
        return 0;
}

int kim_suspend(struct platform_device *pdev, pm_message_t state)
{
        struct ti_st_plat_data  *pdata = pdev->dev.platform_data;

        if (pdata->suspend)
                return pdata->suspend(pdev, state);

        return -EOPNOTSUPP;
}

int kim_resume(struct platform_device *pdev)
{
        struct ti_st_plat_data  *pdata = pdev->dev.platform_data;

        if (pdata->resume)
                return pdata->resume(pdev);

        return -EOPNOTSUPP;
}

/**********************************************************************/
/* entry point for ST KIM module, called in from ST Core */
static struct platform_driver kim_platform_driver = {
        .probe = kim_probe,
        .remove = kim_remove,
        .suspend = kim_suspend,
        .resume = kim_resume,
        .driver = {
                .name = "kim",
                .owner = THIS_MODULE,
        },
};

module_platform_driver(kim_platform_driver);

MODULE_AUTHOR("Pavan Savoy <pavan_savoy@ti.com>");
MODULE_DESCRIPTION("Shared Transport Driver for TI BT/FM/GPS combo chips ");
MODULE_LICENSE("GPL");