From: Doug Anderson <diand...@chromium.org>
If someone sends a EC_CMD_REBOOT_EC to the EC, the EC will likely be
unresponsive for quite a while. Add a delay to the end of the command
to prevent random failures of future commands.
NOTES:
* This could be optimized a bit by simply delaying the next command
sent, but EC_CMD_REBOOT_EC is such a rare command that the extra
complexity doesn't seem worth it.
* This is a bit of an "ugly hack" since the SPI driver is effectively
snooping on the communication and making a lot of assumptions. It
would be nice to architect in some better solution long term.
* This same logic probably needs to be applied to the i2c driver.
Signed-off-by: Doug Anderson <diand...@chromium.org>
Reviewed-by: Randall Spangler <rspang...@chromium.org>
Reviewed-by: Vadim Bendebury <vben...@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.marti...@collabora.co.uk>
Acked-by: Lee Jones <lee.jo...@linaro.org>
---
drivers/mfd/cros_ec_spi.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
index 588c700..b396705 100644
--- a/drivers/mfd/cros_ec_spi.c
+++ b/drivers/mfd/cros_ec_spi.c
@@ -65,6 +65,12 @@
*/
#define EC_SPI_RECOVERY_TIME_NS (200 * 1000)
+/*
+ * The EC is unresponsive for a time after a reboot command. Add a
+ * simple delay to make sure that the bus stays locked.
+ */
+#define EC_REBOOT_DELAY_MS 50
+
/**
* struct cros_ec_spi - information about a SPI-connected EC
*
@@ -318,6 +324,9 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device
*ec_dev,
ret = len;
exit:
+ if (ec_msg->command == EC_CMD_REBOOT_EC)
+ msleep(EC_REBOOT_DELAY_MS);
+
mutex_unlock(&ec_spi->lock);
return ret;
}
--
2.1.0
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