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authorDoug Anderson <dianders@chromium.org>2014-09-18 17:18:54 +0200
committerLee Jones <lee.jones@linaro.org>2014-10-06 21:28:48 +0100
commit659e142be09482cfd8b9017f616afebc7cf48fa3 (patch)
treec26148959a3cbe749c7084dcf1579573ccb047d9 /drivers/mfd
parent48b490d23ef5aaf65e16e194e0fd2578a9b6497f (diff)
downloadlinux-659e142be09482cfd8b9017f616afebc7cf48fa3.tar.bz2
mfd: cros_ec: Delay for 50ms when we see EC_CMD_REBOOT_EC
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 <dianders@chromium.org> Reviewed-by: Randall Spangler <rspangler@chromium.org> Reviewed-by: Vadim Bendebury <vbendeb@chromium.org> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd')
-rw-r--r--drivers/mfd/cros_ec_spi.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
index 588c700af39c..b396705203fc 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;
}