summaryrefslogtreecommitdiffstats
path: root/drivers/char/tpm/st33zp24/i2c.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/char/tpm/st33zp24/i2c.c')
-rw-r--r--drivers/char/tpm/st33zp24/i2c.c312
1 files changed, 312 insertions, 0 deletions
diff --git a/drivers/char/tpm/st33zp24/i2c.c b/drivers/char/tpm/st33zp24/i2c.c
new file mode 100644
index 000000000..a3aa41138
--- /dev/null
+++ b/drivers/char/tpm/st33zp24/i2c.c
@@ -0,0 +1,312 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24
+ * Copyright (C) 2009 - 2016 STMicroelectronics
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/acpi.h>
+#include <linux/tpm.h>
+#include <linux/platform_data/st33zp24.h>
+
+#include "../tpm.h"
+#include "st33zp24.h"
+
+#define TPM_DUMMY_BYTE 0xAA
+
+struct st33zp24_i2c_phy {
+ struct i2c_client *client;
+ u8 buf[ST33ZP24_BUFSIZE + 1];
+ 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(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
+{
+ struct st33zp24_i2c_phy *phy = phy_id;
+
+ phy->buf[0] = tpm_register;
+ memcpy(phy->buf + 1, tpm_data, tpm_size);
+ return i2c_master_send(phy->client, phy->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(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
+{
+ struct st33zp24_i2c_phy *phy = phy_id;
+ u8 status = 0;
+ u8 data;
+
+ data = TPM_DUMMY_BYTE;
+ status = write8_reg(phy, tpm_register, &data, 1);
+ if (status == 2)
+ status = i2c_master_recv(phy->client, tpm_data, tpm_size);
+ return status;
+} /* read8_reg() */
+
+/*
+ * st33zp24_i2c_send
+ * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
+ * @param: phy_id, the phy 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.
+ */
+static int st33zp24_i2c_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
+ int tpm_size)
+{
+ return write8_reg(phy_id, tpm_register | TPM_WRITE_DIRECTION, tpm_data,
+ tpm_size);
+}
+
+/*
+ * st33zp24_i2c_recv
+ * Recv byte from the TIS register according to the ST33ZP24 I2C 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_i2c_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
+ int tpm_size)
+{
+ return read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
+}
+
+static const struct st33zp24_phy_ops i2c_phy_ops = {
+ .send = st33zp24_i2c_send,
+ .recv = st33zp24_i2c_recv,
+};
+
+static const struct acpi_gpio_params lpcpd_gpios = { 1, 0, false };
+
+static const struct acpi_gpio_mapping acpi_st33zp24_gpios[] = {
+ { "lpcpd-gpios", &lpcpd_gpios, 1 },
+ {},
+};
+
+static int st33zp24_i2c_acpi_request_resources(struct i2c_client *client)
+{
+ struct tpm_chip *chip = i2c_get_clientdata(client);
+ struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
+ struct st33zp24_i2c_phy *phy = tpm_dev->phy_id;
+ struct gpio_desc *gpiod_lpcpd;
+ struct device *dev = &client->dev;
+ int ret;
+
+ ret = devm_acpi_dev_add_driver_gpios(dev, acpi_st33zp24_gpios);
+ if (ret)
+ return ret;
+
+ /* Get LPCPD GPIO from ACPI */
+ gpiod_lpcpd = devm_gpiod_get(dev, "lpcpd", GPIOD_OUT_HIGH);
+ if (IS_ERR(gpiod_lpcpd)) {
+ dev_err(&client->dev,
+ "Failed to retrieve lpcpd-gpios from acpi.\n");
+ phy->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;
+ }
+
+ phy->io_lpcpd = desc_to_gpio(gpiod_lpcpd);
+
+ return 0;
+}
+
+static int st33zp24_i2c_of_request_resources(struct i2c_client *client)
+{
+ struct tpm_chip *chip = i2c_get_clientdata(client);
+ struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
+ struct st33zp24_i2c_phy *phy = tpm_dev->phy_id;
+ struct device_node *pp;
+ int gpio;
+ int ret;
+
+ pp = client->dev.of_node;
+ if (!pp) {
+ dev_err(&client->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(&client->dev,
+ "Failed to retrieve lpcpd-gpios from dts.\n");
+ phy->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(&client->dev, "Failed to request lpcpd pin\n");
+ return -ENODEV;
+ }
+ phy->io_lpcpd = gpio;
+
+ return 0;
+}
+
+static int st33zp24_i2c_request_resources(struct i2c_client *client)
+{
+ struct tpm_chip *chip = i2c_get_clientdata(client);
+ struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
+ struct st33zp24_i2c_phy *phy = tpm_dev->phy_id;
+ struct st33zp24_platform_data *pdata;
+ int ret;
+
+ pdata = client->dev.platform_data;
+ if (!pdata) {
+ dev_err(&client->dev, "No platform data\n");
+ return -ENODEV;
+ }
+
+ /* store for late use */
+ phy->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(&client->dev, "Failed to request lpcpd pin\n");
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * st33zp24_i2c_probe initialize the TPM device
+ * @param: client, the i2c_client description (TPM I2C description).
+ * @param: id, the i2c_device_id struct.
+ * @return: 0 in case of success.
+ * -1 in other case.
+ */
+static int st33zp24_i2c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct st33zp24_platform_data *pdata;
+ struct st33zp24_i2c_phy *phy;
+
+ 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;
+ }
+
+ phy = devm_kzalloc(&client->dev, sizeof(struct st33zp24_i2c_phy),
+ GFP_KERNEL);
+ if (!phy)
+ return -ENOMEM;
+
+ phy->client = client;
+
+ pdata = client->dev.platform_data;
+ if (!pdata && client->dev.of_node) {
+ ret = st33zp24_i2c_of_request_resources(client);
+ if (ret)
+ return ret;
+ } else if (pdata) {
+ ret = st33zp24_i2c_request_resources(client);
+ if (ret)
+ return ret;
+ } else if (ACPI_HANDLE(&client->dev)) {
+ ret = st33zp24_i2c_acpi_request_resources(client);
+ if (ret)
+ return ret;
+ }
+
+ return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq,
+ phy->io_lpcpd);
+}
+
+/*
+ * st33zp24_i2c_remove remove the TPM device
+ * @param: client, the i2c_client description (TPM I2C description).
+ * @return: 0 in case of success.
+ */
+static void st33zp24_i2c_remove(struct i2c_client *client)
+{
+ struct tpm_chip *chip = i2c_get_clientdata(client);
+
+ st33zp24_remove(chip);
+}
+
+static const struct i2c_device_id st33zp24_i2c_id[] = {
+ {TPM_ST33_I2C, 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id);
+
+static const struct of_device_id of_st33zp24_i2c_match[] = {
+ { .compatible = "st,st33zp24-i2c", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match);
+
+static const struct acpi_device_id st33zp24_i2c_acpi_match[] = {
+ {"SMO3324"},
+ {}
+};
+MODULE_DEVICE_TABLE(acpi, st33zp24_i2c_acpi_match);
+
+static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend,
+ st33zp24_pm_resume);
+
+static struct i2c_driver st33zp24_i2c_driver = {
+ .driver = {
+ .name = TPM_ST33_I2C,
+ .pm = &st33zp24_i2c_ops,
+ .of_match_table = of_match_ptr(of_st33zp24_i2c_match),
+ .acpi_match_table = ACPI_PTR(st33zp24_i2c_acpi_match),
+ },
+ .probe = st33zp24_i2c_probe,
+ .remove = st33zp24_i2c_remove,
+ .id_table = st33zp24_i2c_id
+};
+
+module_i2c_driver(st33zp24_i2c_driver);
+
+MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
+MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver");
+MODULE_VERSION("1.3.0");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-28 06:36:48 +0000