From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52570 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751028AbdL0P1X (ORCPT ); Wed, 27 Dec 2017 10:27:23 -0500 Subject: Patch "mfd: cros ec: spi: Don't send first message too soon" has been added to the 3.18-stable tree To: jonathanh@nvidia.com, bleung@chromium.org, briannorris@chromium.org, dianders@chromium.org, gregkh@linuxfoundation.org, lee.jones@linaro.org Cc: , From: Date: Wed, 27 Dec 2017 16:24:27 +0100 Message-ID: <15143882673143@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled mfd: cros ec: spi: Don't send first message too soon to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mfd-cros-ec-spi-don-t-send-first-message-too-soon.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 15d8374874ded0bec37ef27f8301a6d54032c0e5 Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Tue, 14 Nov 2017 14:43:27 +0000 Subject: mfd: cros ec: spi: Don't send first message too soon From: Jon Hunter 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 --- drivers/mfd/cros_ec_spi.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/mfd/cros_ec_spi.c +++ b/drivers/mfd/cros_ec_spi.c @@ -23,6 +23,7 @@ #include #include + ec_spi->last_transfer_ns = ktime_get_ns(); /* The header byte, which follows the preamble */ #define EC_MSG_HEADER 0xec Patches currently in stable-queue which might be from jonathanh@nvidia.com are queue-3.18/mfd-cros-ec-spi-don-t-send-first-message-too-soon.patch