tpm: st33zp24: Add tpm st33zp24 spi support

Add support for TPM ST33ZP24 spi.

The ST33ZP24 does have a spi interface.
The transport protocol is proprietary.

For spi we are relying only on DM_SPI.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>

README

@@ -1430,6 +1430,10 @@ The following options need to be configured:
 			Support for STMicroelectronics ST33ZP24 I2C devices.
 			Requires TPM_ST33ZP24 and I2C.
 
+			CONFIG_TPM_ST33ZP24_SPI
+			Support for STMicroelectronics ST33ZP24 SPI devices.
+			Requires TPM_ST33ZP24 and SPI.
+
 		CONFIG_TPM_ATMEL_TWI
 		Support for Atmel TWI TPM device. Requires I2C support.
 

drivers/tpm/Kconfig

@@ -73,4 +73,13 @@ config TPM_ST33ZP24_I2C
 	  to the device using the standard TPM Interface Specification (TIS)
 	  protocol
 
+config TPM_ST33ZP24_SPI
+	bool "STMicroelectronics ST33ZP24 SPI TPM"
+	depends on TPM && DM_SPI
+	---help---
+	  This driver supports STMicroelectronics TPM devices connected on the SPI 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
+
 endmenu

drivers/tpm/Makefile

@@ -10,3 +10,4 @@ obj-$(CONFIG_TPM_TIS_INFINEON) += tpm_tis_infineon.o
 obj-$(CONFIG_TPM_TIS_LPC) += tpm_tis_lpc.o
 obj-$(CONFIG_TPM_TIS_SANDBOX) += tpm_tis_sandbox.o
 obj-$(CONFIG_TPM_ST33ZP24_I2C) += tpm_tis_st33zp24_i2c.o
+obj-$(CONFIG_TPM_ST33ZP24_SPI) += tpm_tis_st33zp24_spi.o

drivers/tpm/tpm_tis_st33zp24_spi.c

+/*
+ * STMicroelectronics TPM ST33ZP24 SPI UBOOT driver
+ *
+ * Copyright (C) 2016 STMicroelectronics
+ *
+ * Description: Device driver for ST33ZP24 SPI TPM TCG.
+ *
+ * This device driver implements the TPM interface as defined in
+ * the TCG TPM Interface Spec version 1.21, revision 1.0 and the
+ * STMicroelectronics Protocol Stack Specification version 1.2.0.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <spi.h>
+#include <tpm.h>
+#include <errno.h>
+#include <linux/types.h>
+#include <asm/unaligned.h>
+#include <linux/compat.h>
+
+#include "tpm_tis.h"
+#include "tpm_internal.h"
+
+#define TPM_ACCESS			0x0
+#define TPM_STS				0x18
+#define TPM_DATA_FIFO			0x24
+
+#define LOCALITY0			0
+
+#define TPM_DATA_FIFO				0x24
+#define TPM_INTF_CAPABILITY			0x14
+
+#define TPM_DUMMY_BYTE				0x00
+#define TPM_WRITE_DIRECTION			0x80
+
+#define MAX_SPI_LATENCY				15
+#define LOCALITY0				0
+
+#define ST33ZP24_OK					0x5A
+#define ST33ZP24_UNDEFINED_ERR				0x80
+#define ST33ZP24_BADLOCALITY				0x81
+#define ST33ZP24_TISREGISTER_UKNOWN			0x82
+#define ST33ZP24_LOCALITY_NOT_ACTIVATED			0x83
+#define ST33ZP24_HASH_END_BEFORE_HASH_START		0x84
+#define ST33ZP24_BAD_COMMAND_ORDER			0x85
+#define ST33ZP24_INCORECT_RECEIVED_LENGTH		0x86
+#define ST33ZP24_TPM_FIFO_OVERFLOW			0x89
+#define ST33ZP24_UNEXPECTED_READ_FIFO			0x8A
+#define ST33ZP24_UNEXPECTED_WRITE_FIFO			0x8B
+#define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END	0x90
+#define ST33ZP24_DUMMY_BYTES				0x00
+
+/*
+ * TPM command can be up to 2048 byte, A TPM response can be up to
+ * 1024 byte.
+ * Between command and response, there are latency byte (up to 15
+ * usually on st33zp24 2 are enough).
+ *
+ * Overall when sending a command and expecting an answer we need if
+ * worst case:
+ * 2048 (for the TPM command) + 1024 (for the TPM answer).  We need
+ * some latency byte before the answer is available (max 15).
+ * We have 2048 + 1024 + 15.
+ */
+#define ST33ZP24_SPI_BUFFER_SIZE (TPM_BUFSIZE + (TPM_BUFSIZE / 2) +\
+				  MAX_SPI_LATENCY)
+
+struct st33zp24_spi_phy {
+	int latency;
+
+	u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
+	u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
+};
+
+static int st33zp24_spi_status_to_errno(u8 code)
+{
+	switch (code) {
+	case ST33ZP24_OK:
+		return 0;
+	case ST33ZP24_UNDEFINED_ERR:
+	case ST33ZP24_BADLOCALITY:
+	case ST33ZP24_TISREGISTER_UKNOWN:
+	case ST33ZP24_LOCALITY_NOT_ACTIVATED:
+	case ST33ZP24_HASH_END_BEFORE_HASH_START:
+	case ST33ZP24_BAD_COMMAND_ORDER:
+	case ST33ZP24_UNEXPECTED_READ_FIFO:
+	case ST33ZP24_UNEXPECTED_WRITE_FIFO:
+	case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
+		return -EPROTO;
+	case ST33ZP24_INCORECT_RECEIVED_LENGTH:
+	case ST33ZP24_TPM_FIFO_OVERFLOW:
+		return -EMSGSIZE;
+	case ST33ZP24_DUMMY_BYTES:
+		return -ENOSYS;
+	}
+	return code;
+}
+
+/*
+ * st33zp24_spi_send
+ * Send byte to TPM register according to the ST33ZP24 SPI protocol.
+ * @param: tpm, 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: should be zero if success else a negative error code.
+ */
+static int st33zp24_spi_write(struct udevice *dev, u8 tpm_register,
+			      const u8 *tpm_data, size_t tpm_size)
+{
+	int total_length = 0, ret;
+	struct spi_slave *slave = dev_get_parent_priv(dev);
+	struct st33zp24_spi_phy *phy = dev_get_platdata(dev);
+
+	u8 *tx_buf = (u8 *)phy->tx_buf;
+	u8 *rx_buf = phy->rx_buf;
+
+	tx_buf[total_length++] = TPM_WRITE_DIRECTION | LOCALITY0;
+	tx_buf[total_length++] = tpm_register;
+
+	if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
+		tx_buf[total_length++] = tpm_size >> 8;
+		tx_buf[total_length++] = tpm_size;
+	}
+	memcpy(tx_buf + total_length, tpm_data, tpm_size);
+	total_length += tpm_size;
+
+	memset(tx_buf + total_length, TPM_DUMMY_BYTE, phy->latency);
+
+	total_length += phy->latency;
+
+	ret = spi_claim_bus(slave);
+	if (ret < 0)
+		return ret;
+
+	ret = spi_xfer(slave, total_length * 8, tx_buf, rx_buf,
+		       SPI_XFER_BEGIN | SPI_XFER_END);
+	if (ret < 0)
+		return ret;
+
+	spi_release_bus(slave);
+
+	if (ret == 0)
+		ret = rx_buf[total_length - 1];
+
+	return st33zp24_spi_status_to_errno(ret);
+}
+
+/*
+ * spi_st33zp24_spi_read8_reg
+ * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
+ * @param: tpm, the chip description
+ * @param: tpm_loc, the locality to read register from
+ * @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: should be zero if success else a negative error code.
+ */
+static u8 st33zp24_spi_read8_reg(struct udevice *dev, u8 tpm_register,
+				 u8 *tpm_data, size_t tpm_size)
+{
+	int total_length = 0, ret;
+	struct spi_slave *slave = dev_get_parent_priv(dev);
+	struct st33zp24_spi_phy *phy = dev_get_platdata(dev);
+
+	u8 *tx_buf = (u8 *)phy->tx_buf;
+	u8 *rx_buf = phy->rx_buf;
+
+	/* Pre-Header */
+	tx_buf[total_length++] = LOCALITY0;
+	tx_buf[total_length++] = tpm_register;
+
+	memset(&tx_buf[total_length], TPM_DUMMY_BYTE,
+	       phy->latency + tpm_size);
+	total_length += phy->latency + tpm_size;
+
+	ret = spi_claim_bus(slave);
+	if (ret < 0)
+		return 0;
+
+	ret = spi_xfer(slave, total_length * 8, tx_buf, rx_buf,
+		       SPI_XFER_BEGIN | SPI_XFER_END);
+	if (ret < 0)
+		return 0;
+
+	spi_release_bus(slave);
+
+	if (tpm_size > 0 && ret == 0) {
+		ret = rx_buf[total_length - tpm_size - 1];
+		memcpy(tpm_data, rx_buf + total_length - tpm_size, tpm_size);
+	}
+	return ret;
+}
+
+/*
+ * st33zp24_spi_recv
+ * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
+ * @param: phy_id, the phy 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.
+ */
+static int st33zp24_spi_read(struct udevice *dev, u8 tpm_register,
+			     u8 *tpm_data, size_t tpm_size)
+{
+	int ret;
+
+	ret = st33zp24_spi_read8_reg(dev, tpm_register, tpm_data, tpm_size);
+	if (!st33zp24_spi_status_to_errno(ret))
+		return tpm_size;
+
+	return ret;
+}
+
+static int st33zp24_spi_evaluate_latency(struct udevice *dev)
+{
+	int latency = 1, status = 0;
+	u8 data = 0;
+	struct st33zp24_spi_phy *phy = dev_get_platdata(dev);
+
+	while (!status && latency < MAX_SPI_LATENCY) {
+		phy->latency = latency;
+		status = st33zp24_spi_read8_reg(dev, TPM_INTF_CAPABILITY,
+						&data, 1);
+		latency++;
+	}
+	if (status < 0)
+		return status;
+	if (latency == MAX_SPI_LATENCY)
+		return -ENODEV;
+
+	return latency - 1;
+}
+
+/*
+ * st33zp24_spi_release_locality release the active locality
+ * @param: chip, the tpm chip description.
+ */
+static void st33zp24_spi_release_locality(struct udevice *dev)
+{
+	u8 data = TPM_ACCESS_ACTIVE_LOCALITY;
+
+	st33zp24_spi_write(dev, TPM_ACCESS, &data, 1);
+}
+
+/*
+ * st33zp24_spi_check_locality if the locality is active
+ * @param: chip, the tpm chip description
+ * @return: the active locality or -EACCES.
+ */
+static int st33zp24_spi_check_locality(struct udevice *dev)
+{
+	u8 data;
+	u8 status;
+	struct tpm_chip *chip = dev_get_priv(dev);
+
+	status = st33zp24_spi_read(dev, TPM_ACCESS, &data, 1);
+	if (status && (data &
+		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
+		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
+		return chip->locality;
+
+	return -EACCES;
+}
+
+/*
+ * st33zp24_spi_request_locality request the TPM locality
+ * @param: chip, the chip description
+ * @return: the active locality or negative value.
+ */
+static int st33zp24_spi_request_locality(struct udevice *dev)
+{
+	unsigned long start, stop;
+	long ret;
+	u8 data;
+	struct tpm_chip *chip = dev_get_priv(dev);
+
+	if (st33zp24_spi_check_locality(dev) == chip->locality)
+		return chip->locality;
+
+	data = TPM_ACCESS_REQUEST_USE;
+	ret = st33zp24_spi_write(dev, TPM_ACCESS, &data, 1);
+	if (ret < 0)
+		return ret;
+
+	/* wait for locality activated */
+	start = get_timer(0);
+	stop = chip->timeout_a;
+	do {
+		if (st33zp24_spi_check_locality(dev) >= 0)
+			return chip->locality;
+		udelay(TPM_TIMEOUT_MS * 1000);
+	} while	 (get_timer(start) < stop);
+
+	return -EACCES;
+}
+
+/*
+ * st33zp24_spi_status return the TPM_STS register
+ * @param: chip, the tpm chip description
+ * @return: the TPM_STS register value.
+ */
+static u8 st33zp24_spi_status(struct udevice *dev)
+{
+	u8 data;
+
+	st33zp24_spi_read(dev, TPM_STS, &data, 1);
+	return data;
+}
+
+/*
+ * st33zp24_spi_get_burstcount return the burstcount address 0x19 0x1A
+ * @param: chip, the chip description
+ * return: the burstcount or -TPM_DRIVER_ERR in case of error.
+ */
+static int st33zp24_spi_get_burstcount(struct udevice *dev)
+{
+	struct tpm_chip *chip = dev_get_priv(dev);
+	unsigned long start, stop;
+	int burstcnt, status;
+	u8 tpm_reg, temp;
+
+	/* wait for burstcount */
+	start = get_timer(0);
+	stop = chip->timeout_d;
+	do {
+		tpm_reg = TPM_STS + 1;
+		status = st33zp24_spi_read(dev, tpm_reg, &temp, 1);
+		if (status < 0)
+			return -EBUSY;
+
+		tpm_reg = TPM_STS + 2;
+		burstcnt = temp;
+		status = st33zp24_spi_read(dev, tpm_reg, &temp, 1);
+		if (status < 0)
+			return -EBUSY;
+
+		burstcnt |= temp << 8;
+		if (burstcnt)
+			return burstcnt;
+		udelay(TIS_SHORT_TIMEOUT_MS * 1000);
+	} while (get_timer(start) < stop);
+
+	return -EBUSY;
+}
+
+/*
+ * st33zp24_spi_cancel, cancel the current command execution or
+ * set STS to COMMAND READY.
+ * @param: chip, tpm_chip description.
+ */
+static void st33zp24_spi_cancel(struct udevice *dev)
+{
+	u8 data;
+
+	data = TPM_STS_COMMAND_READY;
+	st33zp24_spi_write(dev, TPM_STS, &data, 1);
+}
+
+/*
+ * st33zp24_spi_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: status,
+ * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
+ */
+static int st33zp24_spi_wait_for_stat(struct udevice *dev, u8 mask,
+				  unsigned long timeout, int *status)
+{
+	unsigned long start, stop;
+
+	/* Check current status */
+	*status = st33zp24_spi_status(dev);
+	if ((*status & mask) == mask)
+		return 0;
+
+	start = get_timer(0);
+	stop = timeout;
+	do {
+		udelay(TPM_TIMEOUT_MS * 1000);
+		*status = st33zp24_spi_status(dev);
+		if ((*status & mask) == mask)
+			return 0;
+	} while (get_timer(start) < stop);
+
+	return -ETIME;
+}
+
+/*
+ * st33zp24_spi_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 st33zp24_spi_recv_data(struct udevice *dev, u8 *buf, size_t count)
+{
+	struct tpm_chip *chip = dev_get_priv(dev);
+	int size = 0, burstcnt, len, ret, status;
+
+	while (size < count &&
+	       st33zp24_spi_wait_for_stat(dev, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+				chip->timeout_c, &status) == 0) {
+		burstcnt = st33zp24_spi_get_burstcount(dev);
+		if (burstcnt < 0)
+			return burstcnt;
+		len = min_t(int, burstcnt, count - size);
+		ret = st33zp24_spi_read(dev, TPM_DATA_FIFO, buf + size, len);
+		if (ret < 0)
+			return ret;
+
+		size += len;
+	}
+	return size;
+}
+
+/*
+ * st33zp24_spi_recv received TPM response through TPM phy.
+ * @param: chip, tpm_chip description.
+ * @param: buf,	the buffer to store data.
+ * @param: count, the number of bytes that can received (sizeof buf).
+ * @return: Returns zero in case of success else -EIO.
+ */
+static int st33zp24_spi_recv(struct udevice *dev, u8 *buf, size_t count)
+{
+	struct tpm_chip *chip = dev_get_priv(dev);
+	int size, expected;
+
+	if (!chip)
+		return -ENODEV;
+
+	if (count < TPM_HEADER_SIZE) {
+		size = -EIO;
+		goto out;
+	}
+
+	size = st33zp24_spi_recv_data(dev, buf, TPM_HEADER_SIZE);
+	if (size < TPM_HEADER_SIZE) {
+		debug("TPM error, unable to read header\n");
+		goto out;
+	}
+
+	expected = get_unaligned_be32(buf + 2);
+	if (expected > count) {
+		size = -EIO;
+		goto out;
+	}
+
+	size += st33zp24_spi_recv_data(dev, &buf[TPM_HEADER_SIZE],
+				   expected - TPM_HEADER_SIZE);
+	if (size < expected) {
+		debug("TPM error, unable to read remaining bytes of result\n");
+		size = -EIO;
+		goto out;
+	}
+
+out:
+	st33zp24_spi_cancel(dev);
+	st33zp24_spi_release_locality(dev);
+
+	return size;
+}
+
+/*
+ * st33zp24_spi_send send TPM commands through TPM phy.
+ * @param: chip, tpm_chip description.
+ * @param: buf,	the buffer to send.
+ * @param: len, the number of bytes to send.
+ * @return: Returns zero in case of success else the negative error code.
+ */
+static int st33zp24_spi_send(struct udevice *dev, const u8 *buf, size_t len)
+{
+	struct tpm_chip *chip = dev_get_priv(dev);
+	u32 i, size;
+	int burstcnt, ret, status;
+	u8 data, tpm_stat;
+
+	if (!chip)
+		return -ENODEV;
+	if (len < TPM_HEADER_SIZE)
+		return -EIO;
+
+	ret = st33zp24_spi_request_locality(dev);
+	if (ret < 0)
+		return ret;
+
+	tpm_stat = st33zp24_spi_status(dev);
+	if ((tpm_stat & TPM_STS_COMMAND_READY) == 0) {
+		st33zp24_spi_cancel(dev);
+		if (st33zp24_spi_wait_for_stat(dev, TPM_STS_COMMAND_READY,
+					       chip->timeout_b, &status) < 0) {
+			ret = -ETIME;
+			goto out_err;
+		}
+	}
+
+	for (i = 0; i < len - 1;) {
+		burstcnt = st33zp24_spi_get_burstcount(dev);
+		if (burstcnt < 0)
+			return burstcnt;
+
+		size = min_t(int, len - i - 1, burstcnt);
+		ret = st33zp24_spi_write(dev, TPM_DATA_FIFO, buf + i, size);
+		if (ret < 0)
+			goto out_err;
+
+		i += size;
+	}
+
+	tpm_stat = st33zp24_spi_status(dev);
+	if ((tpm_stat & TPM_STS_DATA_EXPECT) == 0) {
+		ret = -EIO;
+		goto out_err;
+	}
+
+	ret = st33zp24_spi_write(dev, TPM_DATA_FIFO, buf + len - 1, 1);
+	if (ret < 0)
+		goto out_err;
+
+	tpm_stat = st33zp24_spi_status(dev);
+	if ((tpm_stat & TPM_STS_DATA_EXPECT) != 0) {
+		ret = -EIO;
+		goto out_err;
+	}
+
+	data = TPM_STS_GO;
+	ret = st33zp24_spi_write(dev, TPM_STS, &data, 1);
+	if (ret < 0)
+		goto out_err;
+
+	return len;
+
+out_err:
+	st33zp24_spi_cancel(dev);
+	st33zp24_spi_release_locality(dev);
+
+	return ret;
+}
+
+static int st33zp24_spi_cleanup(struct udevice *dev)
+{
+	st33zp24_spi_cancel(dev);
+	/*
+	 * The TPM needs some time to clean up here,
+	 * so we sleep rather than keeping the bus busy
+	 */
+	mdelay(2);
+	st33zp24_spi_release_locality(dev);
+
+	return 0;
+}
+
+static int st33zp24_spi_init(struct udevice *dev)
+{
+	struct tpm_chip *chip = dev_get_priv(dev);
+	struct st33zp24_spi_phy *phy = dev_get_platdata(dev);
+
+	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;
+
+	chip->locality = LOCALITY0;
+
+	phy->latency = st33zp24_spi_evaluate_latency(dev);
+	if (phy->latency <= 0)
+		return -ENODEV;
+
+	/*
+	 * A timeout query to TPM can be placed here.
+	 * Standard timeout values are used so far
+	 */
+
+	return 0;
+}
+
+static int st33zp24_spi_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 = st33zp24_spi_init(dev);
+	if (rc < 0)
+		chip->is_open = 0;
+
+	return rc;
+}
+
+static int st33zp24_spi_close(struct udevice *dev)
+{
+	struct tpm_chip *chip = dev_get_priv(dev);
+
+	if (chip->is_open) {
+		st33zp24_spi_release_locality(dev);
+		chip->is_open = 0;
+		chip->vend_dev = 0;
+	}
+
+	return 0;
+}
+
+static int st33zp24_spi_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, "1.2 TPM (%s, chip type %s device-id 0x%x)",
+			chip->is_open ? "open" : "closed",
+			dev->name,
+			chip->vend_dev >> 16);
+}
+
+const struct tpm_ops st33zp24_spi_tpm_ops = {
+	.open = st33zp24_spi_open,
+	.close = st33zp24_spi_close,
+	.recv = st33zp24_spi_recv,
+	.send = st33zp24_spi_send,
+	.cleanup = st33zp24_spi_cleanup,
+	.get_desc = st33zp24_spi_get_desc,
+};
+
+static int st33zp24_spi_probe(struct udevice *dev)
+{
+	struct tpm_chip_priv *uc_priv = dev_get_uclass_priv(dev);
+
+	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;
+
+	debug("ST33ZP24 SPI TPM from STMicroelectronics found\n");
+
+	return 0;
+}
+
+static int st33zp24_spi_remove(struct udevice *dev)
+{
+	st33zp24_spi_release_locality(dev);
+
+	return 0;
+}
+
+static const struct udevice_id st33zp24_spi_ids[] = {
+	{ .compatible = "st,st33zp24-spi" },
+	{ }
+};
+
+U_BOOT_DRIVER(st33zp24_spi_spi) = {
+	.name   = "st33zp24-spi",
+	.id     = UCLASS_TPM,
+	.of_match = of_match_ptr(st33zp24_spi_ids),
+	.probe  = st33zp24_spi_probe,
+	.remove = st33zp24_spi_remove,
+	.ops = &st33zp24_spi_tpm_ops,
+	.priv_auto_alloc_size = sizeof(struct tpm_chip),
+	.platdata_auto_alloc_size = sizeof(struct st33zp24_spi_phy),
+};