tpm: two-phase chip management functions

[deliverable/linux.git] / drivers / char / tpm / tpm_i2c_stm_st33.c

/*
 * STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24
 * Copyright (C) 2009, 2010, 2014  STMicroelectronics
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 * STMicroelectronics version 1.2.1, Copyright (C) 2014
 * STMicroelectronics comes with ABSOLUTELY NO WARRANTY.
 * This is free software, and you are welcome to redistribute it
 * under certain conditions.
 *
 * @Author: Christophe RICARD tpmsupport@st.com
 *
 * @File: tpm_stm_st33_i2c.c
 *
 * @Synopsis:
 *      09/15/2010:     First shot driver tpm_tis driver for
 *                       lpc is used as model.
 */

#include <linux/pci.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/freezer.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/sysfs.h>
#include <linux/gpio.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>

#include <linux/platform_data/tpm_i2c_stm_st33.h>
#include "tpm.h"

#define TPM_ACCESS                      0x0
#define TPM_STS                         0x18
#define TPM_HASH_END                    0x20
#define TPM_DATA_FIFO                   0x24
#define TPM_HASH_DATA                   0x24
#define TPM_HASH_START                  0x28
#define TPM_INTF_CAPABILITY             0x14
#define TPM_INT_STATUS                  0x10
#define TPM_INT_ENABLE                  0x08

#define TPM_DUMMY_BYTE                  0xAA
#define TPM_WRITE_DIRECTION             0x80
#define TPM_HEADER_SIZE                 10
#define TPM_BUFSIZE                     2048

#define LOCALITY0               0


enum stm33zp24_access {
        TPM_ACCESS_VALID = 0x80,
        TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
        TPM_ACCESS_REQUEST_PENDING = 0x04,
        TPM_ACCESS_REQUEST_USE = 0x02,
};

enum stm33zp24_status {
        TPM_STS_VALID = 0x80,
        TPM_STS_COMMAND_READY = 0x40,
        TPM_STS_GO = 0x20,
        TPM_STS_DATA_AVAIL = 0x10,
        TPM_STS_DATA_EXPECT = 0x08,
};

enum stm33zp24_int_flags {
        TPM_GLOBAL_INT_ENABLE = 0x80,
        TPM_INTF_CMD_READY_INT = 0x080,
        TPM_INTF_FIFO_AVALAIBLE_INT = 0x040,
        TPM_INTF_WAKE_UP_READY_INT = 0x020,
        TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
        TPM_INTF_STS_VALID_INT = 0x002,
        TPM_INTF_DATA_AVAIL_INT = 0x001,
};

enum tis_defaults {
        TIS_SHORT_TIMEOUT = 750,
        TIS_LONG_TIMEOUT = 2000,
};

struct tpm_stm_dev {
        struct i2c_client *client;
        struct tpm_chip *chip;
        u8 buf[TPM_BUFSIZE + 1];
        u32 intrs;
        int io_lpcpd;
};

/*
 * write8_reg
 * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
 * @param: tpm_register, the tpm tis register where the data should be written
 * @param: tpm_data, the tpm_data to write inside the tpm_register
 * @param: tpm_size, The length of the data
 * @return: Returns negative errno, or else the number of bytes written.
 */
static int write8_reg(struct tpm_stm_dev *tpm_dev, u8 tpm_register,
                      u8 *tpm_data, u16 tpm_size)
{
        tpm_dev->buf[0] = tpm_register;
        memcpy(tpm_dev->buf + 1, tpm_data, tpm_size);
        return i2c_master_send(tpm_dev->client, tpm_dev->buf, tpm_size + 1);
} /* write8_reg() */

/*
 * read8_reg
 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
 * @param: tpm_register, the tpm tis register where the data should be read
 * @param: tpm_data, the TPM response
 * @param: tpm_size, tpm TPM response size to read.
 * @return: number of byte read successfully: should be one if success.
 */
static int read8_reg(struct tpm_stm_dev *tpm_dev, u8 tpm_register,
                    u8 *tpm_data, int tpm_size)
{
        u8 status = 0;
        u8 data;

        data = TPM_DUMMY_BYTE;
        status = write8_reg(tpm_dev, tpm_register, &data, 1);
        if (status == 2)
                status = i2c_master_recv(tpm_dev->client, tpm_data, tpm_size);
        return status;
} /* read8_reg() */

/*
 * I2C_WRITE_DATA
 * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
 * @param: tpm_dev, the chip description
 * @param: tpm_register, the tpm tis register where the data should be written
 * @param: tpm_data, the tpm_data to write inside the tpm_register
 * @param: tpm_size, The length of the data
 * @return: number of byte written successfully: should be one if success.
 */
#define I2C_WRITE_DATA(tpm_dev, tpm_register, tpm_data, tpm_size) \
        (write8_reg(tpm_dev, tpm_register | \
        TPM_WRITE_DIRECTION, tpm_data, tpm_size))

/*
 * I2C_READ_DATA
 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
 * @param: tpm_dev, the chip description
 * @param: tpm_register, the tpm tis register where the data should be read
 * @param: tpm_data, the TPM response
 * @param: tpm_size, tpm TPM response size to read.
 * @return: number of byte read successfully: should be one if success.
 */
#define I2C_READ_DATA(tpm_dev, tpm_register, tpm_data, tpm_size) \
        (read8_reg(tpm_dev, tpm_register, tpm_data, tpm_size))

/*
 * clear_interruption
 * clear the TPM interrupt register.
 * @param: tpm, the chip description
 * @return: the TPM_INT_STATUS value
 */
static u8 clear_interruption(struct tpm_stm_dev *tpm_dev)
{
        u8 interrupt;

        I2C_READ_DATA(tpm_dev, TPM_INT_STATUS, &interrupt, 1);
        I2C_WRITE_DATA(tpm_dev, TPM_INT_STATUS, &interrupt, 1);
        return interrupt;
} /* clear_interruption() */

/*
 * tpm_stm_i2c_cancel, cancel is not implemented.
 * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
 */
static void tpm_stm_i2c_cancel(struct tpm_chip *chip)
{
        struct tpm_stm_dev *tpm_dev;
        u8 data;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);

        data = TPM_STS_COMMAND_READY;
        I2C_WRITE_DATA(tpm_dev, TPM_STS, &data, 1);
} /* tpm_stm_i2c_cancel() */

/*
 * tpm_stm_spi_status return the TPM_STS register
 * @param: chip, the tpm chip description
 * @return: the TPM_STS register value.
 */
static u8 tpm_stm_i2c_status(struct tpm_chip *chip)
{
        struct tpm_stm_dev *tpm_dev;
        u8 data;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);

        I2C_READ_DATA(tpm_dev, TPM_STS, &data, 1);
        return data;
} /* tpm_stm_i2c_status() */


/*
 * check_locality if the locality is active
 * @param: chip, the tpm chip description
 * @return: the active locality or -EACCESS.
 */
static int check_locality(struct tpm_chip *chip)
{
        struct tpm_stm_dev *tpm_dev;
        u8 data;
        u8 status;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);

        status = I2C_READ_DATA(tpm_dev, TPM_ACCESS, &data, 1);
        if (status && (data &
                (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
                (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
                return chip->vendor.locality;

        return -EACCES;

} /* check_locality() */

/*
 * request_locality request the TPM locality
 * @param: chip, the chip description
 * @return: the active locality or EACCESS.
 */
static int request_locality(struct tpm_chip *chip)
{
        unsigned long stop;
        long ret;
        struct tpm_stm_dev *tpm_dev;
        u8 data;

        if (check_locality(chip) == chip->vendor.locality)
                return chip->vendor.locality;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);

        data = TPM_ACCESS_REQUEST_USE;
        ret = I2C_WRITE_DATA(tpm_dev, TPM_ACCESS, &data, 1);
        if (ret < 0)
                goto end;

        stop = jiffies + chip->vendor.timeout_a;

        /* Request locality is usually effective after the request */
        do {
                if (check_locality(chip) >= 0)
                        return chip->vendor.locality;
                msleep(TPM_TIMEOUT);
        } while (time_before(jiffies, stop));
        ret = -EACCES;
end:
        return ret;
} /* request_locality() */

/*
 * release_locality release the active locality
 * @param: chip, the tpm chip description.
 */
static void release_locality(struct tpm_chip *chip)
{
        struct tpm_stm_dev *tpm_dev;
        u8 data;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);
        data = TPM_ACCESS_ACTIVE_LOCALITY;

        I2C_WRITE_DATA(tpm_dev, TPM_ACCESS, &data, 1);
}

/*
 * get_burstcount return the burstcount address 0x19 0x1A
 * @param: chip, the chip description
 * return: the burstcount.
 */
static int get_burstcount(struct tpm_chip *chip)
{
        unsigned long stop;
        int burstcnt, status;
        u8 tpm_reg, temp;
        struct tpm_stm_dev *tpm_dev;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);

        stop = jiffies + chip->vendor.timeout_d;
        do {
                tpm_reg = TPM_STS + 1;
                status = I2C_READ_DATA(tpm_dev, tpm_reg, &temp, 1);
                if (status < 0)
                        goto end;

                tpm_reg = tpm_reg + 1;
                burstcnt = temp;
                status = I2C_READ_DATA(tpm_dev, tpm_reg, &temp, 1);
                if (status < 0)
                        goto end;

                burstcnt |= temp << 8;
                if (burstcnt)
                        return burstcnt;
                msleep(TPM_TIMEOUT);
        } while (time_before(jiffies, stop));

end:
        return -EBUSY;
} /* get_burstcount() */

static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
                                bool check_cancel, bool *canceled)
{
        u8 status = chip->ops->status(chip);

        *canceled = false;
        if ((status & mask) == mask)
                return true;
        if (check_cancel && chip->ops->req_canceled(chip, status)) {
                *canceled = true;
                return true;
        }
        return false;
}

/*
 * interrupt_to_status
 * @param: irq_mask, the irq mask value to wait
 * @return: the corresponding tpm_sts value
 */
static u8 interrupt_to_status(u8 irq_mask)
{
        u8 status = 0;

        if ((irq_mask & TPM_INTF_STS_VALID_INT) ==  TPM_INTF_STS_VALID_INT)
                status |= TPM_STS_VALID;
        if ((irq_mask & TPM_INTF_DATA_AVAIL_INT) == TPM_INTF_DATA_AVAIL_INT)
                status |= TPM_STS_DATA_AVAIL;
        if ((irq_mask & TPM_INTF_CMD_READY_INT) == TPM_INTF_CMD_READY_INT)
                status |= TPM_STS_COMMAND_READY;

        return status;
} /* status_to_interrupt() */

/*
 * wait_for_stat wait for a TPM_STS value
 * @param: chip, the tpm chip description
 * @param: mask, the value mask to wait
 * @param: timeout, the timeout
 * @param: queue, the wait queue.
 * @param: check_cancel, does the command can be cancelled ?
 * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
 */
static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
                        wait_queue_head_t *queue, bool check_cancel)
{
        unsigned long stop;
        int r;
        bool canceled = false;
        bool condition;
        u32 cur_intrs;
        u8 interrupt, status;
        struct tpm_stm_dev *tpm_dev;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);

        /* check current status */
        status = tpm_stm_i2c_status(chip);
        if ((status & mask) == mask)
                return 0;

        stop = jiffies + timeout;

        if (chip->vendor.irq) {
                cur_intrs = tpm_dev->intrs;
                interrupt = clear_interruption(tpm_dev);
                enable_irq(chip->vendor.irq);

again:
                timeout = stop - jiffies;
                if ((long) timeout <= 0)
                        return -1;

                r = wait_event_interruptible_timeout(*queue,
                                        cur_intrs != tpm_dev->intrs, timeout);

                interrupt |= clear_interruption(tpm_dev);
                status = interrupt_to_status(interrupt);
                condition = wait_for_tpm_stat_cond(chip, mask,
                                                   check_cancel, &canceled);

                if (r >= 0 && condition) {
                        if (canceled)
                                return -ECANCELED;
                        return 0;
                }
                if (r == -ERESTARTSYS && freezing(current)) {
                        clear_thread_flag(TIF_SIGPENDING);
                        goto again;
                }
                disable_irq_nosync(chip->vendor.irq);

        } else {
                do {
                        msleep(TPM_TIMEOUT);
                        status = chip->ops->status(chip);
                        if ((status & mask) == mask)
                                return 0;
                } while (time_before(jiffies, stop));
        }

        return -ETIME;
} /* wait_for_stat() */

/*
 * recv_data receive data
 * @param: chip, the tpm chip description
 * @param: buf, the buffer where the data are received
 * @param: count, the number of data to receive
 * @return: the number of bytes read from TPM FIFO.
 */
static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
{
        int size = 0, burstcnt, len;
        struct tpm_stm_dev *tpm_dev;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);

        while (size < count &&
               wait_for_stat(chip,
                             TPM_STS_DATA_AVAIL | TPM_STS_VALID,
                             chip->vendor.timeout_c,
                             &chip->vendor.read_queue, true) == 0) {
                burstcnt = get_burstcount(chip);
                if (burstcnt < 0)
                        return burstcnt;
                len = min_t(int, burstcnt, count - size);
                I2C_READ_DATA(tpm_dev, TPM_DATA_FIFO, buf + size, len);
                size += len;
        }
        return size;
}

/*
 * tpm_ioserirq_handler the serirq irq handler
 * @param: irq, the tpm chip description
 * @param: dev_id, the description of the chip
 * @return: the status of the handler.
 */
static irqreturn_t tpm_ioserirq_handler(int irq, void *dev_id)
{
        struct tpm_chip *chip = dev_id;
        struct tpm_stm_dev *tpm_dev;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);

        tpm_dev->intrs++;
        wake_up_interruptible(&chip->vendor.read_queue);
        disable_irq_nosync(chip->vendor.irq);

        return IRQ_HANDLED;
} /* tpm_ioserirq_handler() */


/*
 * tpm_stm_i2c_send send TPM commands through the I2C bus.
 *
 * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
 * @param: buf, the buffer to send.
 * @param: count, the number of bytes to send.
 * @return: In case of success the number of bytes sent.
 *                      In other case, a < 0 value describing the issue.
 */
static int tpm_stm_i2c_send(struct tpm_chip *chip, unsigned char *buf,
                            size_t len)
{
        u32 status, i, size;
        int burstcnt = 0;
        int ret;
        u8 data;
        struct i2c_client *client;
        struct tpm_stm_dev *tpm_dev;

        if (!chip)
                return -EBUSY;
        if (len < TPM_HEADER_SIZE)
                return -EBUSY;

        tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);
        client = tpm_dev->client;

        client->flags = 0;

        ret = request_locality(chip);
        if (ret < 0)
                return ret;

        status = tpm_stm_i2c_status(chip);
        if ((status & TPM_STS_COMMAND_READY) == 0) {
                tpm_stm_i2c_cancel(chip);
                if (wait_for_stat
                    (chip, TPM_STS_COMMAND_READY, chip->vendor.timeout_b,
                     &chip->vendor.read_queue, false) < 0) {
                        ret = -ETIME;
                        goto out_err;
                }
        }

        for (i = 0; i < len - 1;) {
                burstcnt = get_burstcount(chip);
                if (burstcnt < 0)
                        return burstcnt;
                size = min_t(int, len - i - 1, burstcnt);
                ret = I2C_WRITE_DATA(tpm_dev, TPM_DATA_FIFO, buf + i, size);
                if (ret < 0)
                        goto out_err;

                i += size;
        }

        status = tpm_stm_i2c_status(chip);
        if ((status & TPM_STS_DATA_EXPECT) == 0) {
                ret = -EIO;
                goto out_err;
        }

        ret = I2C_WRITE_DATA(tpm_dev, TPM_DATA_FIFO, buf + len - 1, 1);
        if (ret < 0)
                goto out_err;

        status = tpm_stm_i2c_status(chip);
        if ((status & TPM_STS_DATA_EXPECT) != 0) {
                ret = -EIO;
                goto out_err;
        }

        data = TPM_STS_GO;
        I2C_WRITE_DATA(tpm_dev, TPM_STS, &data, 1);

        return len;
out_err:
        tpm_stm_i2c_cancel(chip);
        release_locality(chip);
        return ret;
}

/*
 * tpm_stm_i2c_recv received TPM response through the I2C bus.
 * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
 * @param: buf, the buffer to store datas.
 * @param: count, the number of bytes to send.
 * @return: In case of success the number of bytes received.
 *              In other case, a < 0 value describing the issue.
 */
static int tpm_stm_i2c_recv(struct tpm_chip *chip, unsigned char *buf,
                            size_t count)
{
        int size = 0;
        int expected;

        if (!chip)
                return -EBUSY;

        if (count < TPM_HEADER_SIZE) {
                size = -EIO;
                goto out;
        }

        size = recv_data(chip, buf, TPM_HEADER_SIZE);
        if (size < TPM_HEADER_SIZE) {
                dev_err(chip->dev, "Unable to read header\n");
                goto out;
        }

        expected = be32_to_cpu(*(__be32 *)(buf + 2));
        if (expected > count) {
                size = -EIO;
                goto out;
        }

        size += recv_data(chip, &buf[TPM_HEADER_SIZE],
                        expected - TPM_HEADER_SIZE);
        if (size < expected) {
                dev_err(chip->dev, "Unable to read remainder of result\n");
                size = -ETIME;
                goto out;
        }

out:
        chip->ops->cancel(chip);
        release_locality(chip);
        return size;
}

static bool tpm_stm_i2c_req_canceled(struct tpm_chip *chip, u8 status)
{
        return (status == TPM_STS_COMMAND_READY);
}

static const struct tpm_class_ops st_i2c_tpm = {
        .send = tpm_stm_i2c_send,
        .recv = tpm_stm_i2c_recv,
        .cancel = tpm_stm_i2c_cancel,
        .status = tpm_stm_i2c_status,
        .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
        .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
        .req_canceled = tpm_stm_i2c_req_canceled,
};

#ifdef CONFIG_OF
static int tpm_stm_i2c_of_request_resources(struct tpm_chip *chip)
{
        struct device_node *pp;
        struct tpm_stm_dev *tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);
        struct i2c_client *client = tpm_dev->client;

        int gpio;
        int ret;

        pp = client->dev.of_node;
        if (!pp) {
                dev_err(chip->dev, "No platform data\n");
                return -ENODEV;
        }

        /* Get GPIO from device tree */
        gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
        if (gpio < 0) {
                dev_err(chip->dev, "Failed to retrieve lpcpd-gpios from dts.\n");
                tpm_dev->io_lpcpd = -1;
                /*
                 * lpcpd pin is not specified. This is not an issue as
                 * power management can be also managed by TPM specific
                 * commands. So leave with a success status code.
                 */
                return 0;
        }
        /* GPIO request and configuration */
        ret = devm_gpio_request_one(&client->dev, gpio,
                        GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
        if (ret) {
                dev_err(chip->dev, "Failed to request lpcpd pin\n");
                return -ENODEV;
        }
        tpm_dev->io_lpcpd = gpio;

        return 0;
}
#else
static int tpm_stm_i2c_of_request_resources(struct tpm_chip *chip)
{
        return -ENODEV;
}
#endif

static int tpm_stm_i2c_request_resources(struct i2c_client *client,
                                         struct tpm_chip *chip)
{
        struct st33zp24_platform_data *pdata;
        struct tpm_stm_dev *tpm_dev = (struct tpm_stm_dev *)TPM_VPRIV(chip);
        int ret;

        pdata = client->dev.platform_data;
        if (!pdata) {
                dev_err(chip->dev, "No platform data\n");
                return -ENODEV;
        }

        /* store for late use */
        tpm_dev->io_lpcpd = pdata->io_lpcpd;

        if (gpio_is_valid(pdata->io_lpcpd)) {
                ret = devm_gpio_request_one(&client->dev,
                                pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
                                "TPM IO_LPCPD");
                if (ret) {
                        dev_err(chip->dev, "%s : reset gpio_request failed\n",
                                __FILE__);
                        return ret;
                }
        }

        return 0;
}

/*
 * tpm_stm_i2c_probe initialize the TPM device
 * @param: client, the i2c_client drescription (TPM I2C description).
 * @param: id, the i2c_device_id struct.
 * @return: 0 in case of success.
 *       -1 in other case.
 */
static int
tpm_stm_i2c_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
        int ret;
        u8 intmask = 0;
        struct tpm_chip *chip;
        struct st33zp24_platform_data *platform_data;
        struct tpm_stm_dev *tpm_dev;

        if (!client) {
                pr_info("%s: i2c client is NULL. Device not accessible.\n",
                        __func__);
                return -ENODEV;
        }

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                dev_info(&client->dev, "client not i2c capable\n");
                return -ENODEV;
        }

        tpm_dev = devm_kzalloc(&client->dev, sizeof(struct tpm_stm_dev),
                               GFP_KERNEL);
        if (!tpm_dev)
                return -ENOMEM;

        chip = tpmm_chip_alloc(&client->dev, &st_i2c_tpm);
        if (IS_ERR(chip))
                return PTR_ERR(chip);

        TPM_VPRIV(chip) = tpm_dev;
        tpm_dev->client = client;

        platform_data = client->dev.platform_data;
        if (!platform_data && client->dev.of_node) {
                ret = tpm_stm_i2c_of_request_resources(chip);
                if (ret)
                        goto _tpm_clean_answer;
        } else if (platform_data) {
                ret = tpm_stm_i2c_request_resources(client, chip);
                if (ret)
                        goto _tpm_clean_answer;
        }

        chip->vendor.timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
        chip->vendor.timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
        chip->vendor.timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
        chip->vendor.timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);

        chip->vendor.locality = LOCALITY0;

        if (client->irq) {
                /* INTERRUPT Setup */
                init_waitqueue_head(&chip->vendor.read_queue);
                tpm_dev->intrs = 0;

                if (request_locality(chip) != LOCALITY0) {
                        ret = -ENODEV;
                        goto _tpm_clean_answer;
                }

                clear_interruption(tpm_dev);
                ret = devm_request_irq(&client->dev, client->irq,
                                tpm_ioserirq_handler,
                                IRQF_TRIGGER_HIGH,
                                "TPM SERIRQ management", chip);
                if (ret < 0) {
                        dev_err(chip->dev , "TPM SERIRQ signals %d not available\n",
                                client->irq);
                        goto _tpm_clean_answer;
                }

                intmask |= TPM_INTF_CMD_READY_INT
                        |  TPM_INTF_STS_VALID_INT
                        |  TPM_INTF_DATA_AVAIL_INT;

                ret = I2C_WRITE_DATA(tpm_dev, TPM_INT_ENABLE, &intmask, 1);
                if (ret < 0)
                        goto _tpm_clean_answer;

                intmask = TPM_GLOBAL_INT_ENABLE;
                ret = I2C_WRITE_DATA(tpm_dev, (TPM_INT_ENABLE + 3),
                                     &intmask, 1);
                if (ret < 0)
                        goto _tpm_clean_answer;

                chip->vendor.irq = client->irq;

                disable_irq_nosync(chip->vendor.irq);

                tpm_gen_interrupt(chip);
        }

        tpm_get_timeouts(chip);
        tpm_do_selftest(chip);

        return tpm_chip_register(chip);
_tpm_clean_answer:
        dev_info(chip->dev, "TPM I2C initialisation fail\n");
        return ret;
}

/*
 * tpm_stm_i2c_remove remove the TPM device
 * @param: client, the i2c_client drescription (TPM I2C description).
 *              clear_bit(0, &chip->is_open);
 * @return: 0 in case of success.
 */
static int tpm_stm_i2c_remove(struct i2c_client *client)
{
        struct tpm_chip *chip =
                (struct tpm_chip *) i2c_get_clientdata(client);

        if (chip)
                tpm_chip_unregister(chip);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
/*
 * tpm_stm_i2c_pm_suspend suspend the TPM device
 * @param: client, the i2c_client drescription (TPM I2C description).
 * @param: mesg, the power management message.
 * @return: 0 in case of success.
 */
static int tpm_stm_i2c_pm_suspend(struct device *dev)
{
        struct st33zp24_platform_data *pin_infos = dev->platform_data;
        int ret = 0;

        if (gpio_is_valid(pin_infos->io_lpcpd))
                gpio_set_value(pin_infos->io_lpcpd, 0);
        else
                ret = tpm_pm_suspend(dev);

        return ret;
}                               /* tpm_stm_i2c_suspend() */

/*
 * tpm_stm_i2c_pm_resume resume the TPM device
 * @param: client, the i2c_client drescription (TPM I2C description).
 * @return: 0 in case of success.
 */
static int tpm_stm_i2c_pm_resume(struct device *dev)
{
        struct tpm_chip *chip = dev_get_drvdata(dev);
        struct st33zp24_platform_data *pin_infos = dev->platform_data;

        int ret = 0;

        if (gpio_is_valid(pin_infos->io_lpcpd)) {
                gpio_set_value(pin_infos->io_lpcpd, 1);
                ret = wait_for_stat(chip,
                                TPM_STS_VALID, chip->vendor.timeout_b,
                                &chip->vendor.read_queue, false);
        } else {
                ret = tpm_pm_resume(dev);
                if (!ret)
                        tpm_do_selftest(chip);
        }
        return ret;
} /* tpm_stm_i2c_pm_resume() */
#endif

static const struct i2c_device_id tpm_stm_i2c_id[] = {
        {TPM_ST33_I2C, 0},
        {}
};
MODULE_DEVICE_TABLE(i2c, tpm_stm_i2c_id);

#ifdef CONFIG_OF
static const struct of_device_id of_st33zp24_i2c_match[] = {
        { .compatible = "st,st33zp24-i2c", },
        {}
};
MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match);
#endif

static SIMPLE_DEV_PM_OPS(tpm_stm_i2c_ops, tpm_stm_i2c_pm_suspend,
        tpm_stm_i2c_pm_resume);
static struct i2c_driver tpm_stm_i2c_driver = {
        .driver = {
                .owner = THIS_MODULE,
                .name = TPM_ST33_I2C,
                .pm = &tpm_stm_i2c_ops,
                .of_match_table = of_match_ptr(of_st33zp24_i2c_match),
        },
        .probe = tpm_stm_i2c_probe,
        .remove = tpm_stm_i2c_remove,
        .id_table = tpm_stm_i2c_id
};

module_i2c_driver(tpm_stm_i2c_driver);

MODULE_AUTHOR("Christophe Ricard (tpmsupport@st.com)");
MODULE_DESCRIPTION("STM TPM I2C ST33 Driver");
MODULE_VERSION("1.2.1");
MODULE_LICENSE("GPL");