diff options
| -rw-r--r-- | drivers/char/tpm/tpm_tis_spi.c | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c index 639614f2d415..62f50b6c9ef6 100644 --- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -85,25 +85,25 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (ret < 0) goto exit; - phy->tx_buf[0] = 0; - - /* According to TCG PTP specification, if there is no TPM present at - * all, then the design has a weak pull-up on MISO. If a TPM is not - * present, a pull-up on MISO means that the SB controller sees a 1, - * and will latch in 0xFF on the read. - */ - for (i = 0; (phy->rx_buf[0] & 0x01) == 0 && i < TPM_RETRY; i++) { - spi_xfer.len = 1; - spi_message_init(&m); - spi_message_add_tail(&spi_xfer, &m); - ret = spi_sync_locked(phy->spi_device, &m); - if (ret < 0) + if ((phy->rx_buf[3] & 0x01) == 0) { + // handle SPI wait states + phy->tx_buf[0] = 0; + + for (i = 0; i < TPM_RETRY; i++) { + spi_xfer.len = 1; + spi_message_init(&m); + spi_message_add_tail(&spi_xfer, &m); + ret = spi_sync_locked(phy->spi_device, &m); + if (ret < 0) + goto exit; + if (phy->rx_buf[0] & 0x01) + break; + } + + if (i == TPM_RETRY) { + ret = -ETIMEDOUT; goto exit; - } - - if (i == TPM_RETRY) { - ret = -ETIMEDOUT; - goto exit; + } } spi_xfer.cs_change = 0; |