Re: [PATCH] tpm: cr50: Add new device/vendor ID 0x504a6666

From: Paul Menzel
Date: Thu Apr 14 2022 - 11:46:00 EST


Dear Jarkko,


Am 14.04.22 um 14:08 schrieb Jarkko Sakkinen:
On Thu, Apr 07, 2022 at 12:21:44PM +0200, Paul Menzel wrote:

Thank you for your patch.

Am 05.04.22 um 19:37 schrieb Jes B. Klinke:
Accept one additional numerical value of DID:VID for next generation
Google TPM, to be used in future Chromebooks.

Maybe extend:

… Google TPM with new firmware …

The TPM with the new firmware has the code name TI50, and going to use the
same interfaces.

This patch touches more lines than may seem necessary, as a result of
the need to move the error case to sit after the two recognized cases.

Signed-off-by: Jes B. Klinke <jbk@xxxxxxxxxxxx>
---

drivers/char/tpm/tpm_tis_i2c_cr50.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_i2c_cr50.c b/drivers/char/tpm/tpm_tis_i2c_cr50.c
index f6c0affbb4567..bf54ebd6724b0 100644
--- a/drivers/char/tpm/tpm_tis_i2c_cr50.c
+++ b/drivers/char/tpm/tpm_tis_i2c_cr50.c
@@ -31,6 +31,7 @@
#define TPM_CR50_TIMEOUT_SHORT_MS 2 /* Short timeout during transactions */
#define TPM_CR50_TIMEOUT_NOIRQ_MS 20 /* Timeout for TPM ready without IRQ */
#define TPM_CR50_I2C_DID_VID 0x00281ae0L /* Device and vendor ID reg value */
+#define TPM_TI50_I2C_DID_VID 0x504a6666L /* Device and vendor ID reg value */
#define TPM_CR50_I2C_MAX_RETRIES 3 /* Max retries due to I2C errors */
#define TPM_CR50_I2C_RETRY_DELAY_LO 55 /* Min usecs between retries on I2C */
#define TPM_CR50_I2C_RETRY_DELAY_HI 65 /* Max usecs between retries on I2C */
@@ -742,16 +743,20 @@ static int tpm_cr50_i2c_probe(struct i2c_client *client)
}
vendor = le32_to_cpup((__le32 *)buf);
- if (vendor != TPM_CR50_I2C_DID_VID) {
- dev_err(dev, "Vendor ID did not match! ID was %08x\n", vendor);
- tpm_cr50_release_locality(chip, true);
- return -ENODEV;
+ if (vendor == TPM_CR50_I2C_DID_VID) {
+ dev_info(dev, "cr50 TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
+ client->addr, client->irq, vendor >> 16);
+ return tpm_chip_register(chip);
+ }
+ if (vendor == TPM_TI50_I2C_DID_VID) {
+ dev_info(dev, "ti50 TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
+ client->addr, client->irq, vendor >> 16);
+ return tpm_chip_register(chip);
}

Both branches are quite similar. Can a ternary operator be used?

dev_info(dev, "%s TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
(vendor == TPM_CR50_I2C_DID_VID) ? "cr50" : "ti50", client->addr,
client->irq, vendor >> 16);
return tpm_chip_register(chip);

and the original flow be left? (A separate variable can also be added.)

- dev_info(dev, "cr50 TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
- client->addr, client->irq, vendor >> 16);
-
- return tpm_chip_register(chip);
+ dev_err(dev, "Vendor ID did not match! ID was %08x\n", vendor);
+ tpm_cr50_release_locality(chip, true);
+ return -ENODEV;
}
/**

OK, these are legit suggestions. Paul, can you do these changes and add my
reviewed-by for the +1 version?

I guess you mean Jes?


Kind regards,

Paul