The cs cannot change back to 'high' when the count is TPM_RETRY. So the TPM chips thought this communication is not over. And next times communication cannot be effective because the communications mixed up with the last time.
v1 -> v2: - fix spi_xfer.cs_change to spi_xfer->cs_change Signed-off-by: wanghongzhe <[email protected]> --- drivers/char/tpm/tpm_tis_spi_main.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/char/tpm/tpm_tis_spi_main.c b/drivers/char/tpm/tpm_tis_spi_main.c index 3856f6ebcb34..6c52cbb28881 100644 --- a/drivers/char/tpm/tpm_tis_spi_main.c +++ b/drivers/char/tpm/tpm_tis_spi_main.c @@ -64,8 +64,18 @@ static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy, break; } - if (i == TPM_RETRY) + if (i == TPM_RETRY) { + /* change back to 'high', + * So the TPM chips thinks the last communication + * is done. + */ + spi_xfer->cs_change = 0; + spi_xfer->len = 1; + spi_message_init(&m); + spi_message_add_tail(spi_xfer, &m); + ret = spi_sync_locked(phy->spi_device, &m); return -ETIMEDOUT; + } } return 0; -- 2.19.1
