BACKPORT: tpm: Add support for new Infineon I2C TPM (SLB 9645 TT 1.2 I2C)

This driver adds support for Infineon's new SLB 9645 TT 1.2 I2C TPMs,
which supports clockstretching, combined reads and a bus speed of
up to 400khz. The device also has a new device id.

The driver works now also fine with device trees, so you can instantiate
your device by adding:
 +       tpm {
 +               compatible = "infineon,slb9645tt";
 +               reg = <0x20>;
 +       };
for SLB 9645 devices or
 +       tpm {
 +               compatible = "infineon,slb9635tt";
 +               reg = <0x20>;
 +       };
for older SLB 9635 devices to your device tree.
tpm_i2c_infineon is also retained as a compatible id as a fallback to
slb9635 protocol.

The driver was tested on Beaglebone.

Signed-off-by: Peter Huewe <peter.huewe@infineon.com>
BUG=chrome-os-partner:17506
TEST=boot on Snow (with SLB9635) and Spring (with SLB9645)
and check tpm_tis_i2c traces in the kernel log.

Change-Id: I1d229a027dad193e7409261ee1039600cd7fdb01
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/42332
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>

diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
index 1a85f986961bf8f8d68909210d0fc8a1138d5d09..7ac513755066b08a73a32f5f57c93553a9e0f012 100644 (file)
--- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
+++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
@@ -35,6 +35,8 @@ fsl,mc13892           MC13892: Power Management Integrated Circuit (PMIC) for i.MX35/51
 fsl,mma8450            MMA8450Q: Xtrinsic Low-power, 3-axis Xtrinsic Accelerometer
 fsl,mpr121             MPR121: Proximity Capacitive Touch Sensor Controller
 fsl,sgtl5000           SGTL5000: Ultra Low-Power Audio Codec
+infineon,slb9635tt     Infineon SLB9635 (Soft-) I2C TPM (old protocol, max 100khz)
+infineon,slb9645tt     Infineon SLB9645 I2C TPM (new protocol, max 400khz)
 maxim,ds1050           5 Bit Programmable, Pulse-Width Modulator
 maxim,max1237          Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
 maxim,max6625          9-Bit/12-Bit Temperature Sensors with I²C-Compatible Serial Interface

diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c
index 393973358fc8de34a0f55dabdffb744e44eaee5e..bfb6ac9ff477121ec65afb61878f38646bc0cf85 100644 (file)
--- a/drivers/char/tpm/tpm_tis_i2c.c
+++ b/drivers/char/tpm/tpm_tis_i2c.c
@@ -52,7 +52,14 @@
 #define SLEEP_DURATION_LONG_HI 220
 
 /* expected value for DIDVID register */
-#define TPM_TIS_I2C_DID_VID 0x000b15d1L
+#define TPM_TIS_I2C_DID_VID_9635 0x000b15d1L
+#define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
+
+enum i2c_chip_type {
+       SLB9635,
+       SLB9645,
+       UNKNOWN,
+};
 
 /* Structure to store I2C TPM specific stuff */
 struct tpm_inf_dev {
@@ -61,6 +68,7 @@ struct tpm_inf_dev {
        struct tpm_chip *chip;
        bool powered_while_suspended;
        struct work_struct init_work;
+       enum i2c_chip_type chip_type;
 };
 
 static struct tpm_inf_dev tpm_dev;
@@ -104,9 +112,9 @@ static int i2c_transfer_nolock(struct i2c_adapter *adap, struct i2c_msg *msgs,
  */
 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
 {
-
        struct i2c_msg msg1 = { tpm_dev.client->addr, 0, 1, &addr };
        struct i2c_msg msg2 = { tpm_dev.client->addr, I2C_M_RD, len, buffer };
+       struct i2c_msg msgs[] = {msg1, msg2};
 
        int rc;
        int count;
@@ -119,30 +127,53 @@ static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
                return -EOPNOTSUPP;
        i2c_lock_adapter(tpm_dev.client->adapter);
 
-       for (count = 0; count < MAX_COUNT; count++) {
-               rc = i2c_transfer_nolock(tpm_dev.client->adapter, &msg1, 1);
-               if (rc > 0)
-                       break; /* break here to skip sleep */
+       if ((tpm_dev.chip_type == SLB9635) || (tpm_dev.chip_type == UNKNOWN)) {
+               /* slb9635 protocol should work in both cases */
+               for (count = 0; count < MAX_COUNT; count++) {
+                       rc = i2c_transfer_nolock(tpm_dev.client->adapter,
+                                                &msg1, 1);
+                       if (rc > 0)
+                               break; /* break here to skip sleep */
 
-               usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
-       }
+                       usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
+               }
 
-       if (rc <= 0)
-               goto out;
+               if (rc <= 0)
+                       goto out;
 
-       /* After the TPM has successfully received the register address it needs
-        * some time, thus we're sleeping here again, before retrieving the data
-        */
-       for (count = 0; count < MAX_COUNT; count++) {
-               usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
-               rc = i2c_transfer_nolock(tpm_dev.client->adapter, &msg2, 1);
-               if (rc > 0)
-                       break;
+               /* After the TPM has successfully received the register address
+                * it needs some time, thus we're sleeping here again, before
+                * retrieving the data
+                */
+               for (count = 0; count < MAX_COUNT; count++) {
+                       usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
+                       rc = i2c_transfer_nolock(tpm_dev.client->adapter,
+                                                &msg2, 1);
+                       if (rc > 0)
+                               break;
 
+               }
+       } else {
+               /* use a combined read for newer chips
+                * unfortunately the smbus functions are not suitable due to
+                * the 32 byte limit of the smbus.
+                * retries should usually not be needed, but are kept just to
+                * be safe on the safe side.
+               */
+               for (count = 0; count < MAX_COUNT; count++) {
+                       rc = i2c_transfer_nolock(tpm_dev.client->adapter,
+                                                msgs, 2);
+                       if (rc > 0)
+                               break;  /* break here to skip sleep */
+                       usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
+               }
        }
 
 out:
        i2c_unlock_adapter(tpm_dev.client->adapter);
+       /* take care of 'guard time' */
+       usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
+
        if (rc <= 0)
                return -EIO;
 
@@ -178,6 +209,8 @@ static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
        }
 
        i2c_unlock_adapter(tpm_dev.client->adapter);
+       /* take care of 'guard time' */
+       usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
        if (rc <= 0)
                return -EIO;
 
@@ -565,6 +598,7 @@ static void tpm_tis_i2c_selftest(struct work_struct *work)
 static int tpm_tis_i2c_init(struct device *dev)
 {
        u32 vendor;
+       u32 expected_did_vid;
        int rc = 0;
        struct tpm_chip *chip;
 
@@ -597,11 +631,16 @@ static int tpm_tis_i2c_init(struct device *dev)
                goto out_vendor;
        }
 
-       /* create DID_VID register value, after swapping to little-endian */
-       vendor = be32_to_cpu((__be32) vendor);
+       if (tpm_dev.chip_type == SLB9635) {
+               vendor = be32_to_cpu((__be32) vendor);
+               expected_did_vid = TPM_TIS_I2C_DID_VID_9635;
+       } else {
+               /* device id and byte order has changed for newer i2c tpms */
+               expected_did_vid = TPM_TIS_I2C_DID_VID_9645;
+       }
 
-       if (vendor != TPM_TIS_I2C_DID_VID) {
-               dev_dbg(dev, "bad vendor id\n");
+       if (tpm_dev.chip_type != UNKNOWN && vendor != expected_did_vid) {
+               dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
                rc = -ENODEV;
                goto out_release;
        }
@@ -641,6 +680,7 @@ out_err:
 
 static const struct i2c_device_id tpm_i2c_tis_table[] = {
        { "slb9635tt", 0 },
+       { "slb9645tt", 0 },
        { "tpm_tis_i2c", 0 },
        { },
 };
@@ -728,8 +768,23 @@ static struct i2c_driver tpm_i2c_tis_driver = {
 static int __devinit tpm_tis_i2c_probe(struct i2c_client *client,
                                        const struct i2c_device_id *dev_id)
 {
+       struct device *dev = &(client->dev);
+       char *name = client->name;
+
        tpm_dev.client = client;
        dev_dbg(&client->dev, "tpm_tis_i2c probe\n");
+
+       if (strncmp(name, "slb9645tt", strlen("slb9645tt")) == 0) {
+               dev_dbg(dev, "Chiptype: slb9645tt\n");
+               tpm_dev.chip_type = SLB9645;
+       } else if (strncmp(name, "slb9635tt", strlen("slb9635tt")) == 0) {
+               dev_dbg(dev, "Chiptype: slb9635tt\n");
+               tpm_dev.chip_type = SLB9635;
+       } else {
+               dev_notice(dev, "No chiptype was provided, fallback to slb9635\n");
+               tpm_dev.chip_type = UNKNOWN;
+       }
+
        return tpm_tis_i2c_init(&client->dev);
 }
 
@@ -760,5 +815,5 @@ module_i2c_driver(tpm_i2c_tis_driver);
 
 MODULE_AUTHOR("Peter Huewe <huewe.external@infineon.com>");
 MODULE_DESCRIPTION("TPM TIS I2C Driver");
-MODULE_VERSION("2.1.2");
+MODULE_VERSION("2.1.6");
 MODULE_LICENSE("GPL");