Patch "mfd: cros ec: spi: Don't send first message too soon" has been added to the 3.18-stable tree

Patch "mfd: cros ec: spi: Don't send first message too soon" has been added to the 3.18-stable tree

[gregkh]

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 <stable@vger.kernel.org> know about it.


>From 15d8374874ded0bec37ef27f8301a6d54032c0e5 Mon Sep 17 00:00:00 2001
From: Jon Hunter <jonathanh@nvidia.com>
Date: Tue, 14 Nov 2017 14:43:27 +0000
Subject: mfd: cros ec: spi: Don't send first message too soon

From: Jon Hunter <jonathanh@nvidia.com>

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 <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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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 <linux/slab.h>
 #include <linux/spi/spi.h>
 
+	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

Re: Patch "mfd: cros ec: spi: Don't send first message too soon" has been added to the 3.18-stable tree

[Brian Norris]

Hi Greg,

On Wed, Dec 27, 2017 at 04:24:27PM +0100, Greg Kroah-Hartman wrote:
> 
> 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 <stable@vger.kernel.org> know about it.
> 
> 
> From 15d8374874ded0bec37ef27f8301a6d54032c0e5 Mon Sep 17 00:00:00 2001
> From: Jon Hunter <jonathanh@nvidia.com>
> Date: Tue, 14 Nov 2017 14:43:27 +0000
> Subject: mfd: cros ec: spi: Don't send first message too soon
> 
> From: Jon Hunter <jonathanh@nvidia.com>
> 
> 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 <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>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> ---
>  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 <linux/slab.h>
>  #include <linux/spi/spi.h>
>  
> +	ec_spi->last_transfer_ns = ktime_get_ns();

Umm, that's not even close to correct? You've stuck this line just below
the headers... You may still need to adjust for some context changes in
3.18 vs. Linus' latest, but this should at least be in
cros_ec_spi_probe().

(The kbuild bots are complaining about your RC branch.)

Brian

>  
>  /* 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

Re: Patch "mfd: cros ec: spi: Don't send first message too soon" has been added to the 3.18-stable tree

[Greg KH]

On Wed, Jan 03, 2018 at 10:49:21AM -0800, Brian Norris wrote:
> Hi Greg,
> 
> On Wed, Dec 27, 2017 at 04:24:27PM +0100, Greg Kroah-Hartman wrote:
> > 
> > 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 <stable@vger.kernel.org> know about it.
> > 
> > 
> > From 15d8374874ded0bec37ef27f8301a6d54032c0e5 Mon Sep 17 00:00:00 2001
> > From: Jon Hunter <jonathanh@nvidia.com>
> > Date: Tue, 14 Nov 2017 14:43:27 +0000
> > Subject: mfd: cros ec: spi: Don't send first message too soon
> > 
> > From: Jon Hunter <jonathanh@nvidia.com>
> > 
> > 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 <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>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > 
> > ---
> >  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 <linux/slab.h>
> >  #include <linux/spi/spi.h>
> >  
> > +	ec_spi->last_transfer_ns = ktime_get_ns();
> 
> Umm, that's not even close to correct? You've stuck this line just below
> the headers... You may still need to adjust for some context changes in
> 3.18 vs. Linus' latest, but this should at least be in
> cros_ec_spi_probe().
> 
> (The kbuild bots are complaining about your RC branch.)

This was long fixed, did your email just sync?

thanks,

greg k-h

Re: Patch "mfd: cros ec: spi: Don't send first message too soon" has been added to the 3.18-stable tree

[Brian Norris]

On Wed, Jan 03, 2018 at 08:44:25PM +0100, Greg Kroah-Hartman wrote:
> On Wed, Jan 03, 2018 at 10:49:21AM -0800, Brian Norris wrote:
> > Umm, that's not even close to correct? You've stuck this line just below
> > the headers... You may still need to adjust for some context changes in
> > 3.18 vs. Linus' latest, but this should at least be in
> > cros_ec_spi_probe().
> > 
> > (The kbuild bots are complaining about your RC branch.)
> 
> This was long fixed, did your email just sync?

No. I see no update in my mail (neither in reply to this thread nor to
the kbuild email I saw). However, I also don't see this patch in your
stable-rc repo now, so maybe you just backed the change out? Perhaps
there's some thread(s) where I'm CC'd and some where I'm not?

Anyway, if you aren't applying the previously-quoted patch, then we're
OK for now :) It might be good to see a corrected version of this show
up in 3.18 -stable still.

Brian

Re: Patch "mfd: cros ec: spi: Don't send first message too soon" has been added to the 3.18-stable tree

[Greg KH]

On Wed, Jan 03, 2018 at 12:35:45PM -0800, Brian Norris wrote:
> On Wed, Jan 03, 2018 at 08:44:25PM +0100, Greg Kroah-Hartman wrote:
> > On Wed, Jan 03, 2018 at 10:49:21AM -0800, Brian Norris wrote:
> > > Umm, that's not even close to correct? You've stuck this line just below
> > > the headers... You may still need to adjust for some context changes in
> > > 3.18 vs. Linus' latest, but this should at least be in
> > > cros_ec_spi_probe().
> > > 
> > > (The kbuild bots are complaining about your RC branch.)
> > 
> > This was long fixed, did your email just sync?
> 
> No. I see no update in my mail (neither in reply to this thread nor to
> the kbuild email I saw). However, I also don't see this patch in your
> stable-rc repo now, so maybe you just backed the change out? Perhaps
> there's some thread(s) where I'm CC'd and some where I'm not?

I dropped it.

> Anyway, if you aren't applying the previously-quoted patch, then we're
> OK for now :) It might be good to see a corrected version of this show
> up in 3.18 -stable still.

I'll take a working backport if you think it should be there :)

thanks,

greg k-h