[PATCH u-boot v2019.04-aspeed-openbmc 2/5] tpm: Add I2C driver for TPMv2 devices

Joel Stanley joel at jms.id.au
Tue May 10 12:42:46 AEST 2022


On Thu, 5 May 2022 at 20:28, Eddie James <eajames at linux.ibm.com> wrote:
>
> Add a driver to communicate with TPMv2 chips over I2C, such
> as the NPCT75X.
>
> Signed-off-by: Eddie James <eajames at linux.ibm.com>
> ---
>  drivers/tpm/Kconfig        |   9 +
>  drivers/tpm/Makefile       |   1 +
>  drivers/tpm/tpm2_tis_i2c.c | 593 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 603 insertions(+)
>  create mode 100644 drivers/tpm/tpm2_tis_i2c.c
>
> diff --git a/drivers/tpm/Kconfig b/drivers/tpm/Kconfig
> index 94629dffd2..6fd98ac057 100644
> --- a/drivers/tpm/Kconfig
> +++ b/drivers/tpm/Kconfig
> @@ -145,6 +145,15 @@ config TPM2_TIS_SPI
>           to the device using the standard TPM Interface Specification (TIS)
>           protocol.
>
> +config TPM2_TIS_I2C
> +       bool "Enable support for TPMv2.x I2C chips"
> +       depends on TPM_V2 && DM_I2C
> +       help
> +         This driver supports TPMv2.x devices connected on the I2C bus.
> +         The usual TPM operations and the 'tpm' command can be used to talk
> +         to the device using the standard TPM Interface Specification (TIS)
> +         protocol.
> +
>  endif # TPM_V2
>
>  endmenu
> diff --git a/drivers/tpm/Makefile b/drivers/tpm/Makefile
> index 94c337b8ed..220f03253c 100644
> --- a/drivers/tpm/Makefile
> +++ b/drivers/tpm/Makefile
> @@ -12,3 +12,4 @@ obj-$(CONFIG_TPM_ST33ZP24_SPI) += tpm_tis_st33zp24_spi.o
>
>  obj-$(CONFIG_TPM2_TIS_SANDBOX) += tpm2_tis_sandbox.o
>  obj-$(CONFIG_TPM2_TIS_SPI) += tpm2_tis_spi.o
> +obj-$(CONFIG_TPM2_TIS_I2C) += tpm2_tis_i2c.o
> diff --git a/drivers/tpm/tpm2_tis_i2c.c b/drivers/tpm/tpm2_tis_i2c.c
> new file mode 100644
> index 0000000000..5fab9122e6
> --- /dev/null
> +++ b/drivers/tpm/tpm2_tis_i2c.c
> @@ -0,0 +1,593 @@
> +// SPDX-License-Identifier: GPL-2.0

Add:

Copyright 2022 IBM Corp.

> +
> +#include <common.h>
> +#include <dm.h>
> +#include <fdtdec.h>
> +#include <i2c.h>
> +#include <tpm-v1.h>
> +#include <linux/errno.h>
> +#include <linux/compiler.h>
> +#include <linux/types.h>
> +#include <linux/unaligned/be_byteshift.h>
> +
> +#include "tpm_tis.h"
> +#include "tpm_internal.h"
> +
> +enum i2c_chip_type {
> +       NPCT75X,
> +       UNKNOWN,
> +};
> +
> +/* expected value for DIDVID register */
> +#define TPM2_TIS_I2C_DID_VID_NPCT75X 0x5010FC00L
> +
> +static const char * const chip_name[] = {
> +       [NPCT75X] = "npct75X",
> +       [UNKNOWN] = "unknown/fallback to npct75X",
> +};
> +
> +#define TPM_LOC_SEL            0x00
> +#define        TPM_ACCESS              0x04
> +#define        TPM_STS                 0x18
> +#define        TPM_DATA_FIFO           0x24
> +#define        TPM_DID_VID             0x48
> +
> +/*
> + * tpm2_tis_i2c_read() - read from TPM register
> + * @addr: register address to read from
> + * @buffer: provided by caller
> + * @len: number of bytes to read
> + *
> + * Read len bytes from TPM register and put them into
> + * buffer (little-endian format, i.e. first byte is put into buffer[0]).
> + *
> + * NOTE: TPM is big-endian for multi-byte values. Multi-byte
> + * values have to be swapped.
> + *
> + * Return -EIO on error, 0 on success.
> + */
> +static int tpm2_tis_i2c_read(struct udevice *dev, u8 addr, u8 *buffer,
> +                            size_t len)
> +{
> +       int rc;
> +       int count;
> +
> +       for (count = 0; count < MAX_COUNT; count++) {
> +               rc = dm_i2c_read(dev, addr, buffer, len);
> +               if (rc == 0) {
> +                       debug("read addr[%02x] len[%u] data[%02x %02x %02x %02x%s]\n", addr, len, len > 0 ? buffer[0] : 0, len > 1 ? buffer[1] : 0, len > 2 ? buffer[2] : 0, len > 3 ? buffer[3] : 0, len > 4 ? " ..." : "");
> +                       break;  /* break here to skip sleep */
> +               }
> +               udelay(SLEEP_DURATION_US);
> +       }
> +
> +       /* Take care of 'guard time' */
> +       udelay(SLEEP_DURATION_US);

This will sleep again if the read has reached MAX_COUNT. Could it
return an error straight away? Or is this a TPM spec thing?

Why are you looping several times? Is that a TPM spec thing?

The kernel does this:

do {
 ret = i2c_transfer()
 sleep(GUARD_TIME)
} while (ret < 0 && count++ < GUARD_TIME)

Which makes more sense.

> +       if (rc)
> +               return rc;
> +
> +       return 0;
> +}
> +
> +static int tpm2_tis_i2c_write_generic(struct udevice *dev, u8 addr,
> +                                     const u8 *buffer, size_t len,
> +                                     unsigned int sleep_time_us, u8 max_count)
> +{
> +       int rc = 0;
> +       int count;
> +
> +       for (count = 0; count < max_count; count++) {
> +               rc = dm_i2c_write(dev, addr, buffer, len);
> +               if (rc == 0) {
> +                       debug("write addr[%02x] len[%u] data[%02x %02x %02x %02x%s]\n", addr, len, len > 0 ? buffer[0] : 0, len > 1 ? buffer[1] : 0, len > 2 ? buffer[2] : 0, len > 3 ? buffer[3] : 0, len > 4 ? " ..." : "");
> +                       break;  /* Success, break to skip sleep */
> +               }
> +               udelay(sleep_time_us);
> +       }
> +
> +       /* take care of 'guard time' */
> +       udelay(sleep_time_us);
> +       if (rc)
> +               return rc;
> +
> +       return 0;
> +}
> +
> +/*
> + * tpm2_tis_i2c_write() - write to TPM register
> + * @addr: register address to write to
> + * @buffer: containing data to be written
> + * @len: number of bytes to write
> + *
> + * Write len bytes from provided buffer to TPM register (little
> + * endian format, i.e. buffer[0] is written as first byte).
> + *
> + * NOTE: TPM is big-endian for multi-byte values. Multi-byte
> + * values have to be swapped.
> + *
> + * NOTE: use this function instead of the tpm2_tis_i2c_write_generic function.

Why the extra indirection?

Actually, I see why. This code is a copy of
drivers/tpm/tpm_tis_infineon.c with some things changed. Can you go
through the patch and remove things that don't need to be in this
driver?

The kernel driver is a good reference for things that might be
required for the spec, vs coding decisions made by the infineon driver
author.


> + *
> + * Return -EIO on error, 0 on success
> + */
> +static int tpm2_tis_i2c_write(struct udevice *dev, u8 addr, const u8 *buffer,
> +                             size_t len)
> +{
> +       return tpm2_tis_i2c_write_generic(dev, addr, buffer, len,
> +                                         SLEEP_DURATION_US, MAX_COUNT);
> +}
> +
> +/*
> + * This function is needed especially for the cleanup situation after
> + * sending TPM_READY
> + */
> +static int tpm2_tis_i2c_write_long(struct udevice *dev, u8 addr, u8 *buffer,
> +                                  size_t len)
> +{
> +       return tpm2_tis_i2c_write_generic(dev, addr, buffer, len,
> +                                         SLEEP_DURATION_LONG_US,
> +                                         MAX_COUNT_LONG);
> +}
> +
> +static int tpm2_tis_i2c_check_locality(struct udevice *dev, int loc)
> +{
> +       const u8 mask = TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID;
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +       u8 buf;
> +       int rc;
> +
> +       buf = loc;
> +       rc = tpm2_tis_i2c_write(dev, TPM_LOC_SEL, &buf, 1);
> +       if (rc < 0)
> +               return rc;
> +
> +       rc = tpm2_tis_i2c_read(dev, TPM_ACCESS, &buf, 1);
> +       if (rc < 0)
> +               return rc;
> +
> +       if ((buf & mask) == mask) {
> +               chip->locality = loc;
> +               return loc;
> +       }
> +
> +       return -ENOENT;
> +}
> +
> +static void tpm2_tis_i2c_release_locality(struct udevice *dev, int loc,
> +                                        int force)
> +{
> +       const u8 mask = TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID;
> +       u8 buf;
> +
> +       buf = loc;
> +       if (tpm2_tis_i2c_write(dev, TPM_LOC_SEL, &buf, 1) < 0)
> +               return;
> +
> +       if (tpm2_tis_i2c_read(dev, TPM_ACCESS, &buf, 1) < 0)
> +               return;
> +
> +       if (force || (buf & mask) == mask) {
> +               buf = TPM_ACCESS_ACTIVE_LOCALITY;
> +               tpm2_tis_i2c_write(dev, TPM_ACCESS, &buf, 1);
> +       }
> +}
> +
> +static int tpm2_tis_i2c_request_locality(struct udevice *dev, int loc)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +       unsigned long start, stop;
> +       u8 buf = 0;
> +       int rc;
> +
> +       rc = tpm2_tis_i2c_check_locality(dev, loc);
> +       if (rc >= 0) {
> +               debug("%s: Already have locality\n", __func__);
> +               return loc;  /* We already have the locality */
> +       } else if (rc != -ENOENT) {
> +               debug("%s: Failed to get locality: %d\n", __func__, rc);
> +               return rc;
> +       }
> +
> +       buf = loc;
> +       rc = tpm2_tis_i2c_write(dev, TPM_LOC_SEL, &buf, 1);
> +       if (rc) {
> +               debug("%s: Failed to write to TPM: %d\n", __func__, rc);
> +               return rc;
> +       }
> +
> +       buf = TPM_ACCESS_REQUEST_USE;
> +       rc = tpm2_tis_i2c_write(dev, TPM_ACCESS, &buf, 1);
> +       if (rc) {
> +               debug("%s: Failed to write to TPM: %d\n", __func__, rc);
> +               return rc;
> +       }
> +
> +       /* Wait for burstcount */
> +       start = get_timer(0);
> +       stop = chip->timeout_a;
> +       do {
> +               rc = tpm2_tis_i2c_check_locality(dev, loc);
> +               if (rc >= 0) {
> +                       debug("%s: Have locality\n", __func__);
> +                       return loc;
> +               } else if (rc != -ENOENT) {
> +                       debug("%s: Failed to get locality: %d\n", __func__, rc);
> +                       return rc;
> +               }
> +               mdelay(TPM_TIMEOUT_MS);
> +       } while (get_timer(start) < stop);
> +       debug("%s: Timeout getting locality: %d\n", __func__, rc);
> +
> +       return rc;
> +}
> +
> +static u8 tpm2_tis_i2c_status(struct udevice *dev)
> +{
> +       /* NOTE: Since i2c read may fail, return 0 in this case --> time-out */
> +       u8 buf;
> +
> +       if (tpm2_tis_i2c_read(dev, TPM_STS, &buf, 1) < 0)
> +               return 0;
> +       else
> +               return buf;
> +}
> +
> +static int tpm2_tis_i2c_ready(struct udevice *dev)
> +{
> +       int rc;
> +
> +       /* This causes the current command to be aborted */
> +       u8 buf = TPM_STS_COMMAND_READY;
> +
> +       debug("%s\n", __func__);
> +       rc = tpm2_tis_i2c_write_long(dev, TPM_STS, &buf, 1);
> +       if (rc)
> +               debug("%s: rc=%d\n", __func__, rc);
> +
> +       return rc;
> +}
> +
> +static ssize_t tpm2_tis_i2c_get_burstcount(struct udevice *dev)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +       unsigned long start, stop;
> +       ssize_t burstcnt;
> +       u8 addr, buf[3];
> +
> +       /* Wait for burstcount */
> +       /* XXX: Which timeout value? Spec has 2 answers (c & d) */
> +       start = get_timer(0);
> +       stop = chip->timeout_d;
> +       do {
> +               /* Note: STS is little endian */
> +               addr = TPM_STS + 1;
> +               if (tpm2_tis_i2c_read(dev, addr, buf, 2) < 0)
> +                       burstcnt = 0;
> +               else
> +                       burstcnt = (buf[1] << 8) + buf[0];
> +
> +               if (burstcnt)
> +                       return burstcnt;
> +               mdelay(TPM_TIMEOUT_MS);
> +       } while (get_timer(start) < stop);
> +
> +       return -EBUSY;
> +}
> +
> +static int tpm2_tis_i2c_wait_for_stat(struct udevice *dev, u8 mask,
> +                                     unsigned long timeout, int *status)
> +{
> +       unsigned long start, stop;
> +
> +       /* Check current status */
> +       *status = tpm2_tis_i2c_status(dev);
> +       if ((*status & mask) == mask)
> +               return 0;
> +
> +       start = get_timer(0);
> +       stop = timeout;
> +       do {
> +               mdelay(TPM_TIMEOUT_MS);
> +               *status = tpm2_tis_i2c_status(dev);
> +               if ((*status & mask) == mask)
> +                       return 0;
> +       } while (get_timer(start) < stop);
> +
> +       return -ETIMEDOUT;
> +}
> +
> +static int tpm2_tis_i2c_recv_data(struct udevice *dev, u8 *buf, size_t count)
> +{
> +       size_t size = 0;
> +       ssize_t burstcnt;
> +       int rc;
> +
> +       while (size < count) {
> +               burstcnt = tpm2_tis_i2c_get_burstcount(dev);
> +
> +               /* burstcount < 0 -> tpm is busy */
> +               if (burstcnt < 0)
> +                       return burstcnt;
> +
> +               /* Limit received data to max left */
> +               if (burstcnt > (count - size))
> +                       burstcnt = count - size;
> +
> +               rc = tpm2_tis_i2c_read(dev, TPM_DATA_FIFO,
> +                                      &(buf[size]), burstcnt);
> +               if (rc == 0)
> +                       size += burstcnt;
> +       }
> +
> +       return size;
> +}
> +
> +static int tpm2_tis_i2c_recv(struct udevice *dev, u8 *buf, size_t count)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +       int size = 0;
> +       int status;
> +       unsigned int expected;
> +       int rc;
> +
> +       status = tpm2_tis_i2c_status(dev);
> +       if (status == TPM_STS_COMMAND_READY)
> +               return -EINTR;
> +       if ((status & (TPM_STS_DATA_AVAIL | TPM_STS_VALID)) !=
> +           (TPM_STS_DATA_AVAIL | TPM_STS_VALID))
> +               return -EAGAIN;
> +
> +       debug("...got it;\n");
> +
> +       /* Read first 10 bytes, including tag, paramsize, and result */
> +       size = tpm2_tis_i2c_recv_data(dev, buf, TPM_HEADER_SIZE);
> +       if (size < TPM_HEADER_SIZE) {
> +               debug("Unable to read header\n");
> +               return size < 0 ? size : -EIO;
> +       }
> +
> +       expected = get_unaligned_be32(buf + TPM_RSP_SIZE_BYTE);
> +       if ((size_t)expected > count || (size_t)expected < TPM_HEADER_SIZE) {
> +               debug("Error size=%x, expected=%x, count=%x\n", size, expected,
> +                     count);
> +               return -ENOSPC;
> +       }
> +
> +       size += tpm2_tis_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE],
> +                                      expected - TPM_HEADER_SIZE);
> +       if (size < expected) {
> +               debug("Unable to read remainder of result\n");
> +               return -ETIMEDOUT;
> +       }
> +
> +       rc = tpm2_tis_i2c_wait_for_stat(dev, TPM_STS_VALID, chip->timeout_c,
> +                                       &status);
> +       if (rc)
> +               return rc;
> +       if (status & TPM_STS_DATA_AVAIL) {  /* Retry? */
> +               debug("Error left over data\n");
> +               return -EIO;
> +       }
> +
> +       return size;
> +}
> +
> +static int tpm2_tis_i2c_send(struct udevice *dev, const u8 *buf, size_t len)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +       int rc, status;
> +       size_t burstcnt;
> +       size_t count = 0;
> +       int retry = 0;
> +       u8 sts = TPM_STS_GO;
> +
> +       debug("%s: len=%d\n", __func__, len);
> +       if (len > TPM_DEV_BUFSIZE)
> +               return -E2BIG;  /* Command is too long for our tpm, sorry */
> +
> +       if (tpm2_tis_i2c_request_locality(dev, 0) < 0)
> +               return -EBUSY;
> +
> +       status = tpm2_tis_i2c_status(dev);
> +       if ((status & TPM_STS_COMMAND_READY) == 0) {
> +               rc = tpm2_tis_i2c_ready(dev);
> +               if (rc)
> +                       return rc;
> +               rc = tpm2_tis_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY,
> +                                               chip->timeout_b, &status);
> +               if (rc)
> +                       return rc;
> +       }
> +
> +       burstcnt = tpm2_tis_i2c_get_burstcount(dev);
> +
> +       /* burstcount < 0 -> tpm is busy */
> +       if (burstcnt < 0)
> +               return burstcnt;
> +
> +       while (count < len) {
> +               udelay(300);
> +               if (burstcnt > len - count)
> +                       burstcnt = len - count;
> +
> +#ifdef CONFIG_TPM2_TIS_I2C_BURST_LIMITATION
> +               if (retry && burstcnt > CONFIG_TPM2_TIS_I2C_BURST_LIMITATION_LEN)
> +                       burstcnt = CONFIG_TPM2_TIS_I2C_BURST_LIMITATION_LEN;
> +#endif /* CONFIG_TPM2_TIS_I2C_BURST_LIMITATION */
> +
> +               rc = tpm2_tis_i2c_write(dev, TPM_DATA_FIFO,
> +                                       &(buf[count]), burstcnt);
> +               if (rc == 0)
> +                       count += burstcnt;
> +               else {
> +                       debug("%s: error\n", __func__);
> +                       if (retry++ > 10)
> +                               return -EIO;
> +                       rc = tpm2_tis_i2c_wait_for_stat(dev, TPM_STS_VALID,
> +                                                       chip->timeout_c,
> +                                                       &status);
> +                       if (rc)
> +                               return rc;
> +
> +                       if ((status & TPM_STS_DATA_EXPECT) == 0)
> +                               return -EIO;
> +               }
> +       }
> +
> +       /* Go and do it */
> +       rc = tpm2_tis_i2c_write(dev, TPM_STS, &sts, 1);
> +       if (rc < 0)
> +               return rc;
> +       debug("%s: done, rc=%d\n", __func__, rc);
> +
> +       return len;
> +}
> +
> +static int tpm2_tis_i2c_cleanup(struct udevice *dev)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +
> +       tpm2_tis_i2c_ready(dev);
> +       /*
> +        * The TPM needs some time to clean up here,
> +        * so we sleep rather than keeping the bus busy
> +        */
> +       mdelay(2);
> +       tpm2_tis_i2c_release_locality(dev, chip->locality, 0);
> +
> +       return 0;
> +}
> +
> +static int tpm2_tis_i2c_init(struct udevice *dev)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +       u32 vendor;
> +       u32 expected_did_vid;
> +       int rc;
> +
> +       chip->is_open = 1;
> +
> +       /* Default timeouts - these could move to the device tree */
> +       chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
> +       chip->timeout_b = TIS_LONG_TIMEOUT_MS;
> +       chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
> +       chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
> +
> +       rc = tpm2_tis_i2c_request_locality(dev, 0);
> +       if (rc < 0)
> +               return rc;
> +
> +       /* Read four bytes from DID_VID register */
> +       if (tpm2_tis_i2c_read(dev, TPM_DID_VID, (uchar *)&vendor, 4) < 0) {
> +               tpm2_tis_i2c_release_locality(dev, 0, 1);
> +               return -EIO;
> +       }
> +
> +       if (chip->chip_type == NPCT75X) {
> +               vendor = be32_to_cpu(vendor);
> +               expected_did_vid = TPM2_TIS_I2C_DID_VID_NPCT75X;
> +       }
> +
> +       if (chip->chip_type != UNKNOWN && vendor != expected_did_vid) {
> +               pr_err("Vendor id did not match! ID was %08x\n", vendor);
> +               return -ENODEV;
> +       }
> +
> +       chip->vend_dev = vendor;
> +       debug("2.0 TPM (chip type %s device-id 0x%X)\n",
> +             chip_name[chip->chip_type], vendor >> 16);
> +
> +       /*
> +        * A timeout query to TPM can be placed here.
> +        * Standard timeout values are used so far
> +        */
> +
> +       return 0;
> +}
> +
> +static int tpm2_tis_i2c_open(struct udevice *dev)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +       int rc;
> +
> +       debug("%s: start\n", __func__);
> +       if (chip->is_open)
> +               return -EBUSY;
> +       rc = tpm2_tis_i2c_init(dev);
> +       if (rc < 0)
> +               chip->is_open = 0;
> +
> +       return rc;
> +}
> +
> +static int tpm2_tis_i2c_close(struct udevice *dev)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +
> +       if (chip->is_open) {
> +               tpm2_tis_i2c_release_locality(dev, chip->locality, 1);
> +               chip->is_open = 0;
> +               chip->vend_dev = 0;
> +       }
> +
> +       return 0;
> +}
> +
> +static int tpm2_tis_get_desc(struct udevice *dev, char *buf, int size)
> +{
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +
> +       if (size < 50)
> +               return -ENOSPC;
> +
> +       return snprintf(buf, size, "2.0 TPM (%s, chip type %s device-id 0x%x)",
> +                       chip->is_open ? "open" : "closed",
> +                       chip_name[chip->chip_type],
> +                       chip->vend_dev >> 16);
> +}
> +
> +static int tpm2_tis_i2c_probe(struct udevice *dev)
> +{
> +       struct tpm_chip_priv *uc_priv = dev_get_uclass_priv(dev);
> +       struct tpm_chip *chip = dev_get_priv(dev);
> +
> +       chip->chip_type = dev_get_driver_data(dev);
> +       chip->locality = 0;
> +       chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
> +       chip->timeout_b = TIS_LONG_TIMEOUT_MS;
> +       chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
> +       chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
> +
> +       /* TODO: These need to be checked and tuned */
> +       uc_priv->duration_ms[TPM_SHORT] = TIS_SHORT_TIMEOUT_MS;
> +       uc_priv->duration_ms[TPM_MEDIUM] = TIS_LONG_TIMEOUT_MS;
> +       uc_priv->duration_ms[TPM_LONG] = TIS_LONG_TIMEOUT_MS;
> +       uc_priv->retry_time_ms = TPM_TIMEOUT_MS;
> +       uc_priv->pcr_count = 24;
> +       uc_priv->pcr_select_min = 3;
> +       uc_priv->version = TPM_V2;
> +
> +       return 0;
> +}
> +
> +static const struct tpm_ops tpm2_tis_i2c_ops = {
> +       .open           = tpm2_tis_i2c_open,
> +       .close          = tpm2_tis_i2c_close,
> +       .get_desc       = tpm2_tis_get_desc,
> +       .send           = tpm2_tis_i2c_send,
> +       .recv           = tpm2_tis_i2c_recv,
> +       .cleanup        = tpm2_tis_i2c_cleanup,
> +};
> +
> +static const struct udevice_id tpm2_tis_i2c_ids[] = {
> +       { .compatible = "nuvoton,npct75x", .data = NPCT75X },
> +       { }
> +};
> +
> +U_BOOT_DRIVER(tpm2_tis_i2c) = {
> +       .name   = "tpm2_tis_i2c",
> +       .id     = UCLASS_TPM,
> +       .of_match = tpm2_tis_i2c_ids,
> +       .ops    = &tpm2_tis_i2c_ops,
> +       .probe  = tpm2_tis_i2c_probe,
> +       .priv_auto_alloc_size = sizeof(struct tpm_chip),
> +};
> --
> 2.27.0
>


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