[PATCH 4.11 016/197] tpm: add sleep only for retry in i2c_nuvoton_write_status()

From: Greg Kroah-Hartman
Date: Tue May 23 2017 - 16:12:43 EST


4.11-stable review patch. If anyone has any objections, please let me know.

------------------

From: Nayna Jain <nayna@xxxxxxxxxxxxxxxxxx>

commit 0afb7118ae021e80ecf70f5a3336e0935505518a upstream.

Currently, there is an unnecessary 1 msec delay added in
i2c_nuvoton_write_status() for the successful case. This
function is called multiple times during send() and recv(),
which implies adding multiple extra delays for every TPM
operation.

This patch calls usleep_range() only if retry is to be done.

Signed-off-by: Nayna Jain <nayna@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/char/tpm/tpm_i2c_nuvoton.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/char/tpm/tpm_i2c_nuvoton.c
+++ b/drivers/char/tpm/tpm_i2c_nuvoton.c
@@ -124,8 +124,9 @@ static s32 i2c_nuvoton_write_status(stru
/* this causes the current command to be aborted */
for (i = 0, status = -1; i < TPM_I2C_RETRY_COUNT && status < 0; i++) {
status = i2c_nuvoton_write_buf(client, TPM_STS, 1, &data);
- usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
- + TPM_I2C_DELAY_RANGE);
+ if (status < 0)
+ usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
+ + TPM_I2C_DELAY_RANGE);
}
return status;
}