diff options
| author | Doug Anderson <dianders@chromium.org> | 2014-09-18 17:18:54 +0200 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2014-10-06 21:28:48 +0100 |
| commit | 659e142be09482cfd8b9017f616afebc7cf48fa3 (patch) | |
| tree | c26148959a3cbe749c7084dcf1579573ccb047d9 /drivers/mfd | |
| parent | 48b490d23ef5aaf65e16e194e0fd2578a9b6497f (diff) | |
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.c | 9 |
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; } |