From: Jon Hunter Date: Tue, 14 Nov 2017 14:43:27 +0000 (+0000) Subject: mfd: cros ec: spi: Don't send first message too soon X-Git-Tag: v4.9.73~19 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2db85cb211d0e5ce01922f1afec159769b408be7;p=platform%2Fkernel%2Flinux-amlogic.git mfd: cros ec: spi: Don't send first message too soon commit 15d8374874ded0bec37ef27f8301a6d54032c0e5 upstream. 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. Signed-off-by: Jon Hunter Reviewed-by: Brian Norris Reviewed-by: Douglas Anderson Acked-by: Benson Leung Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c index a518832..59dbdaa 100644 --- a/drivers/mfd/cros_ec_spi.c +++ b/drivers/mfd/cros_ec_spi.c @@ -664,6 +664,7 @@ 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) {