Merge branch 'next' into for-linus

[linux-2.6-microblaze.git] / drivers / mfd / cros_ec_spi.c

diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
index 1b52b85..2060d14 100644 (file)
--- a/drivers/mfd/cros_ec_spi.c
+++ b/drivers/mfd/cros_ec_spi.c
@@ -419,10 +419,25 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
                /* Verify that EC can process command */
                for (i = 0; i < len; i++) {
                        rx_byte = rx_buf[i];
+                       /*
+                        * Seeing the PAST_END, RX_BAD_DATA, or NOT_READY
+                        * markers are all signs that the EC didn't fully
+                        * receive our command. e.g., if the EC is flashing
+                        * itself, it can't respond to any commands and instead
+                        * clocks out EC_SPI_PAST_END from its SPI hardware
+                        * buffer. Similar occurrences can happen if the AP is
+                        * too slow to clock out data after asserting CS -- the
+                        * EC will abort and fill its buffer with
+                        * EC_SPI_RX_BAD_DATA.
+                        *
+                        * In all cases, these errors should be safe to retry.
+                        * Report -EAGAIN and let the caller decide what to do
+                        * about that.
+                        */
                        if (rx_byte == EC_SPI_PAST_END  ||
                            rx_byte == EC_SPI_RX_BAD_DATA ||
                            rx_byte == EC_SPI_NOT_READY) {
-                               ret = -EREMOTEIO;
+                               ret = -EAGAIN;
                                break;
                        }
                }
@@ -431,7 +446,7 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
        if (!ret)
                ret = cros_ec_spi_receive_packet(ec_dev,
                                ec_msg->insize + sizeof(*response));
-       else
+       else if (ret != -EAGAIN)
                dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
 
        final_ret = terminate_request(ec_dev);
@@ -537,10 +552,11 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
                /* Verify that EC can process command */
                for (i = 0; i < len; i++) {
                        rx_byte = rx_buf[i];
+                       /* See comments in cros_ec_pkt_xfer_spi() */
                        if (rx_byte == EC_SPI_PAST_END  ||
                            rx_byte == EC_SPI_RX_BAD_DATA ||
                            rx_byte == EC_SPI_NOT_READY) {
-                               ret = -EREMOTEIO;
+                               ret = -EAGAIN;
                                break;
                        }
                }
@@ -549,7 +565,7 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
        if (!ret)
                ret = cros_ec_spi_receive_response(ec_dev,
                                ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
-       else
+       else if (ret != -EAGAIN)
                dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
 
        final_ret = terminate_request(ec_dev);