From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Subject: Re: [PATCH v5 1/2] watchdog: imx2_wdt: add external reset support via dt prop To: Tim Harvey , linux-watchdog@vger.kernel.org, Shawn Guo References: <1459523804-11390-1-git-send-email-tharvey@gateworks.com> <1459523804-11390-2-git-send-email-tharvey@gateworks.com> Cc: linux-arm-kernel@lists.infradead.org, Fabio Estevam , Lucas Stach , Guenter Roeck , Wim Van Sebroeck , Stefan Roese , Iain Paton , Sascha Hauer From: Akshay Bhat Message-ID: <56FEA26A.5020805@timesys.com> Date: Fri, 1 Apr 2016 12:31:38 -0400 MIME-Version: 1.0 In-Reply-To: <1459523804-11390-2-git-send-email-tharvey@gateworks.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit List-ID: On 04/01/2016 11:16 AM, Tim Harvey wrote: > The IMX6 watchdog supports assertion of a signal (WDOG_B) which > can be pinmux'd to an external pin. This is typically used for boards that > have PMIC's in control of the IMX6 power rails. In fact, failure to use > such an external reset on boards with external PMIC's can result in various > hangs due to the IMX6 not being fully reset [1] as well as the board failing > to reset because its PMIC has not been reset to provide adequate voltage for > the CPU when coming out of reset at 800Mhz. > > This uses a new device-tree property 'fsl,ext-reset-output' to indicate the > board has such a reset and to cause the watchdog to be configured to assert > WDOG_B instead of an internal reset both on a watchdog timeout and in > system_restart. > > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/333689.html > > Cc: Fabio Estevam > Cc: Lucas Stach > Cc: Stefan Roese > Cc: Iain Paton > Cc: Sascha Hauer > Cc: Akshay Bhat > Cc: Guenter Roeck > Signed-off-by: Tim Harvey > Reviewed-by: Lucas Stach > Acked-by: Shawn Guo > --- > v5: > - rename property to 'fsl,ext-reset-output' > v4: > - change Property to Properties in documentation > v3: > - mandate use of 'either' internal or external reset but not both > simultaneously > v2: > - rename property to 'ext-reset-output' based on ML feedback > - simplify setting SRS bit if external-reset > - update comments and commit msg > > Signed-off-by: Tim Harvey > --- Tested-by: Akshay Bhat From mboxrd@z Thu Jan 1 00:00:00 1970 From: akshay.bhat@timesys.com (Akshay Bhat) Date: Fri, 1 Apr 2016 12:31:38 -0400 Subject: [PATCH v5 1/2] watchdog: imx2_wdt: add external reset support via dt prop In-Reply-To: <1459523804-11390-2-git-send-email-tharvey@gateworks.com> References: <1459523804-11390-1-git-send-email-tharvey@gateworks.com> <1459523804-11390-2-git-send-email-tharvey@gateworks.com> Message-ID: <56FEA26A.5020805@timesys.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/01/2016 11:16 AM, Tim Harvey wrote: > The IMX6 watchdog supports assertion of a signal (WDOG_B) which > can be pinmux'd to an external pin. This is typically used for boards that > have PMIC's in control of the IMX6 power rails. In fact, failure to use > such an external reset on boards with external PMIC's can result in various > hangs due to the IMX6 not being fully reset [1] as well as the board failing > to reset because its PMIC has not been reset to provide adequate voltage for > the CPU when coming out of reset at 800Mhz. > > This uses a new device-tree property 'fsl,ext-reset-output' to indicate the > board has such a reset and to cause the watchdog to be configured to assert > WDOG_B instead of an internal reset both on a watchdog timeout and in > system_restart. > > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/333689.html > > Cc: Fabio Estevam > Cc: Lucas Stach > Cc: Stefan Roese > Cc: Iain Paton > Cc: Sascha Hauer > Cc: Akshay Bhat > Cc: Guenter Roeck > Signed-off-by: Tim Harvey > Reviewed-by: Lucas Stach > Acked-by: Shawn Guo > --- > v5: > - rename property to 'fsl,ext-reset-output' > v4: > - change Property to Properties in documentation > v3: > - mandate use of 'either' internal or external reset but not both > simultaneously > v2: > - rename property to 'ext-reset-output' based on ML feedback > - simplify setting SRS bit if external-reset > - update comments and commit msg > > Signed-off-by: Tim Harvey > --- Tested-by: Akshay Bhat