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From: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
To: Lee Jones <lee.jones@linaro.org>
Cc: "Wolfram Sang" <wsa@the-dreams.de>,
	"Dmitry Torokhov" <dmitry.torokhov@gmail.com>,
	"Doug Anderson" <dianders@chromium.org>,
	"Simon Glass" <sjg@chromium.org>,
	"Bill Richardson" <wfrichar@chromium.org>,
	"Andrew Bresticker" <abrestic@chromium.org>,
	"Derek Basehore" <dbasehore@chromium.org>,
	"Todd Broch" <tbroch@chromium.org>,
	"Olof Johansson" <olof@lixom.net>,
	"Andreas Färber" <afaerber@suse.de>,
	linux-i2c@vger.kernel.org, linux-input@vger.kernel.org,
	linux-samsung-soc@vger.kernel.org,
	"Javier Martinez Canillas" <javier.martinez@collabora.co.uk>
Subject: [RESEND PATCH 1/7] mfd: cros_ec: Delay for 50ms when we see EC_CMD_REBOOT_EC
Date: Wed, 20 Aug 2014 14:13:26 +0200	[thread overview]
Message-ID: <1408536812-7836-2-git-send-email-javier.martinez@collabora.co.uk> (raw)
In-Reply-To: <1408536812-7836-1-git-send-email-javier.martinez@collabora.co.uk>

From: Doug Anderson <dianders@chromium.org>

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>
---
 drivers/mfd/cros_ec_spi.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
index 588c700..b396705 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;
 }
-- 
2.0.1


  reply	other threads:[~2014-08-20 12:13 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-20 12:13 [RESEND PATCH 0/7] Second batch of cleanups for cros_ec Javier Martinez Canillas
2014-08-20 12:13 ` Javier Martinez Canillas [this message]
2014-08-21 13:37   ` [RESEND PATCH 1/7] mfd: cros_ec: Delay for 50ms when we see EC_CMD_REBOOT_EC Lee Jones
2014-08-21 13:49     ` Javier Martinez Canillas
     [not found] ` <1408536812-7836-1-git-send-email-javier.martinez-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>
2014-08-20 12:13   ` [RESEND PATCH 2/7] i2c: i2c-cros-ec-tunnel: Set retries to 3 Javier Martinez Canillas
2014-08-20 12:13   ` [RESEND PATCH 3/7] mfd: cros_ec: stop calling ->cmd_xfer() directly Javier Martinez Canillas
2014-08-20 22:33     ` Doug Anderson
2014-08-21 14:08     ` Lee Jones
2014-08-20 12:13   ` [RESEND PATCH 6/7] mfd: cros_ec: Instantiate sub-devices from device tree Javier Martinez Canillas
     [not found]     ` <1408536812-7836-7-git-send-email-javier.martinez-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>
2014-08-21 14:25       ` Lee Jones
2014-08-22 11:27         ` Javier Martinez Canillas
2014-08-20 12:13   ` [RESEND PATCH 7/7] Input: cros_ec_keyb: Optimize ghosting algorithm Javier Martinez Canillas
2014-08-20 12:13 ` [RESEND PATCH 4/7] mfd: cros_ec: move locking into cros_ec_cmd_xfer Javier Martinez Canillas
2014-08-20 22:36   ` Doug Anderson
2014-08-21 10:24     ` Javier Martinez Canillas
2014-08-21 14:09   ` Lee Jones
2014-08-20 12:13 ` [RESEND PATCH 5/7] mfd: cros_ec: wait for completion of commands that return IN_PROGRESS Javier Martinez Canillas
     [not found]   ` <1408536812-7836-6-git-send-email-javier.martinez-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>
2014-08-21 14:21     ` Lee Jones
2014-08-22 11:24       ` Javier Martinez Canillas

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