300 lines
7.2 KiB
C
300 lines
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2015 Infineon Technologies AG
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* Copyright (C) 2016 STMicroelectronics SAS
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*
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* Authors:
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* Peter Huewe <peter.huewe@infineon.com>
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* Christophe Ricard <christophe-h.ricard@st.com>
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*
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* Maintained by: <tpmdd-devel@lists.sourceforge.net>
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*
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* Device driver for TCG/TCPA TPM (trusted platform module).
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* Specifications at www.trustedcomputinggroup.org
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*
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* This device driver implements the TPM interface as defined in
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* the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native
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* SPI access_.
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*
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* It is based on the original tpm_tis device driver from Leendert van
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* Dorn and Kyleen Hall and Jarko Sakkinnen.
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*/
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#include <linux/acpi.h>
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#include <linux/completion.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/of_device.h>
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#include <linux/spi/spi.h>
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#include <linux/tpm.h>
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#include "tpm.h"
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#include "tpm_tis_core.h"
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#include "tpm_tis_spi.h"
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#define MAX_SPI_FRAMESIZE 64
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/*
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* TCG SPI flow control is documented in section 6.4 of the spec[1]. In short,
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* keep trying to read from the device until MISO goes high indicating the
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* wait state has ended.
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*
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* [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
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*/
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static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
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struct spi_transfer *spi_xfer)
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{
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struct spi_message m;
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int ret, i;
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if ((phy->iobuf[3] & 0x01) == 0) {
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// handle SPI wait states
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for (i = 0; i < TPM_RETRY; i++) {
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spi_xfer->len = 1;
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spi_message_init(&m);
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spi_message_add_tail(spi_xfer, &m);
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ret = spi_sync_locked(phy->spi_device, &m);
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if (ret < 0)
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return ret;
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if (phy->iobuf[0] & 0x01)
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break;
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}
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if (i == TPM_RETRY)
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return -ETIMEDOUT;
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}
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return 0;
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}
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int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
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u8 *in, const u8 *out)
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{
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struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
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int ret = 0;
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struct spi_message m;
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struct spi_transfer spi_xfer;
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u8 transfer_len;
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spi_bus_lock(phy->spi_device->master);
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while (len) {
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transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
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phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
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phy->iobuf[1] = 0xd4;
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phy->iobuf[2] = addr >> 8;
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phy->iobuf[3] = addr;
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memset(&spi_xfer, 0, sizeof(spi_xfer));
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spi_xfer.tx_buf = phy->iobuf;
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spi_xfer.rx_buf = phy->iobuf;
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spi_xfer.len = 4;
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spi_xfer.cs_change = 1;
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spi_message_init(&m);
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spi_message_add_tail(&spi_xfer, &m);
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ret = spi_sync_locked(phy->spi_device, &m);
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if (ret < 0)
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goto exit;
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/* Flow control transfers are receive only */
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spi_xfer.tx_buf = NULL;
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ret = phy->flow_control(phy, &spi_xfer);
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if (ret < 0)
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goto exit;
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spi_xfer.cs_change = 0;
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spi_xfer.len = transfer_len;
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spi_xfer.delay.value = 5;
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spi_xfer.delay.unit = SPI_DELAY_UNIT_USECS;
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if (out) {
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spi_xfer.tx_buf = phy->iobuf;
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spi_xfer.rx_buf = NULL;
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memcpy(phy->iobuf, out, transfer_len);
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out += transfer_len;
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}
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spi_message_init(&m);
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spi_message_add_tail(&spi_xfer, &m);
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reinit_completion(&phy->ready);
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ret = spi_sync_locked(phy->spi_device, &m);
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if (ret < 0)
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goto exit;
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if (in) {
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memcpy(in, phy->iobuf, transfer_len);
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in += transfer_len;
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}
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len -= transfer_len;
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}
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exit:
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spi_bus_unlock(phy->spi_device->master);
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return ret;
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}
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static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
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u16 len, u8 *result)
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{
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return tpm_tis_spi_transfer(data, addr, len, result, NULL);
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}
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static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
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u16 len, const u8 *value)
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{
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return tpm_tis_spi_transfer(data, addr, len, NULL, value);
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}
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int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
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{
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__le16 result_le;
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int rc;
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rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
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(u8 *)&result_le);
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if (!rc)
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*result = le16_to_cpu(result_le);
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return rc;
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}
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int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
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{
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__le32 result_le;
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int rc;
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rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
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(u8 *)&result_le);
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if (!rc)
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*result = le32_to_cpu(result_le);
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return rc;
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}
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int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
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{
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__le32 value_le;
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int rc;
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value_le = cpu_to_le32(value);
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rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
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(u8 *)&value_le);
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return rc;
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}
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int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
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int irq, const struct tpm_tis_phy_ops *phy_ops)
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{
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phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
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if (!phy->iobuf)
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return -ENOMEM;
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phy->spi_device = spi;
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return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL);
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}
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static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
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.read_bytes = tpm_tis_spi_read_bytes,
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.write_bytes = tpm_tis_spi_write_bytes,
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.read16 = tpm_tis_spi_read16,
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.read32 = tpm_tis_spi_read32,
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.write32 = tpm_tis_spi_write32,
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};
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static int tpm_tis_spi_probe(struct spi_device *dev)
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{
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struct tpm_tis_spi_phy *phy;
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int irq;
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phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
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GFP_KERNEL);
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if (!phy)
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return -ENOMEM;
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phy->flow_control = tpm_tis_spi_flow_control;
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/* If the SPI device has an IRQ then use that */
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if (dev->irq > 0)
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irq = dev->irq;
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else
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irq = -1;
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init_completion(&phy->ready);
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return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops);
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}
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typedef int (*tpm_tis_spi_probe_func)(struct spi_device *);
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static int tpm_tis_spi_driver_probe(struct spi_device *spi)
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{
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const struct spi_device_id *spi_dev_id = spi_get_device_id(spi);
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tpm_tis_spi_probe_func probe_func;
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probe_func = of_device_get_match_data(&spi->dev);
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if (!probe_func && spi_dev_id)
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probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
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if (!probe_func)
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return -ENODEV;
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return probe_func(spi);
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}
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static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume);
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static int tpm_tis_spi_remove(struct spi_device *dev)
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{
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struct tpm_chip *chip = spi_get_drvdata(dev);
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tpm_chip_unregister(chip);
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tpm_tis_remove(chip);
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return 0;
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}
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static const struct spi_device_id tpm_tis_spi_id[] = {
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{ "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe },
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{ "cr50", (unsigned long)cr50_spi_probe },
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{}
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};
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MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
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static const struct of_device_id of_tis_spi_match[] = {
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{ .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe },
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{ .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe },
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{ .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe },
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{ .compatible = "google,cr50", .data = cr50_spi_probe },
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{}
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};
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MODULE_DEVICE_TABLE(of, of_tis_spi_match);
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static const struct acpi_device_id acpi_tis_spi_match[] = {
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{"SMO0768", 0},
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{}
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};
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MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
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static struct spi_driver tpm_tis_spi_driver = {
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.driver = {
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.name = "tpm_tis_spi",
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.pm = &tpm_tis_pm,
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.of_match_table = of_match_ptr(of_tis_spi_match),
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.acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
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.probe_type = PROBE_PREFER_ASYNCHRONOUS,
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},
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.probe = tpm_tis_spi_driver_probe,
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.remove = tpm_tis_spi_remove,
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.id_table = tpm_tis_spi_id,
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};
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module_spi_driver(tpm_tis_spi_driver);
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MODULE_DESCRIPTION("TPM Driver for native SPI access");
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MODULE_LICENSE("GPL");
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