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authorJon Hunter <jonathanh@nvidia.com>2017-11-14 17:43:27 +0300
committerLee Jones <lee.jones@linaro.org>2017-11-29 19:28:23 +0300
commit15d8374874ded0bec37ef27f8301a6d54032c0e5 (patch)
tree13063d2045d6479d3ecbe8d5c1fc373bdde813c1 /drivers/mfd
parent4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323 (diff)
downloadlinux-15d8374874ded0bec37ef27f8301a6d54032c0e5.tar.xz
mfd: cros ec: spi: Don't send first message too soon
On the Tegra124 Nyan-Big chromebook the very first SPI message sent to the EC is failing. The Tegra SPI driver configures the SPI chip-selects to be active-high by default (and always has for many years). The EC SPI requires an active-low chip-select and so the Tegra chip-select is reconfigured to be active-low when the EC SPI driver calls spi_setup(). The problem is that if the first SPI message to the EC is sent too soon after reconfiguring the SPI chip-select, it fails. The EC SPI driver prevents back-to-back SPI messages being sent too soon by keeping track of the time the last transfer was sent via the variable 'last_transfer_ns'. To prevent the very first transfer being sent too soon, initialise the 'last_transfer_ns' variable after calling spi_setup() and before sending the first SPI message. Cc: <stable@vger.kernel.org> Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Reviewed-by: Brian Norris <briannorris@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Acked-by: Benson Leung <bleung@chromium.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd')
-rw-r--r--drivers/mfd/cros_ec_spi.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
index c9714072e224..a14196e95e9b 100644
--- a/drivers/mfd/cros_ec_spi.c
+++ b/drivers/mfd/cros_ec_spi.c
@@ -667,6 +667,7 @@ static int cros_ec_spi_probe(struct spi_device *spi)
sizeof(struct ec_response_get_protocol_info);
ec_dev->dout_size = sizeof(struct ec_host_request);
+ ec_spi->last_transfer_ns = ktime_get_ns();
err = cros_ec_register(ec_dev);
if (err) {