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| Started by | Tim Harvey <tharvey@gateworks.com> |
|---|---|
| First post | 2015-12-17 16:10 +0100 |
| Last post | 2015-12-28 17:30 +0100 |
| Articles | 3 — 3 participants |
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Re: [PATCH v4 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop Tim Harvey <tharvey@gateworks.com> - 2015-12-17 16:10 +0100
Re: [PATCH v4 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop Guenter Roeck <linux@roeck-us.net> - 2015-12-17 16:40 +0100
Re: [PATCH v4 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop Wim Van Sebroeck <wim@iguana.be> - 2015-12-28 17:30 +0100
| From | Tim Harvey <tharvey@gateworks.com> |
|---|---|
| Date | 2015-12-17 16:10 +0100 |
| Subject | Re: [PATCH v4 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop |
| Message-ID | <qGIlP-154-13@gated-at.bofh.it> |
On Wed, Dec 2, 2015 at 12:54 PM, Tim Harvey <tharvey@gateworks.com> wrote: > > On Wed, Dec 2, 2015 at 11:11 AM, Akshay Bhat <akshay.bhat@timesys.com> wrote: > > > > > > On 11/06/2015 05:02 PM, Guenter Roeck wrote: > >> > >> On Fri, Nov 06, 2015 at 11:53:42AM -0800, Tim Harvey wrote: > >>> > >>> On Thu, Nov 5, 2015 at 2:23 PM, Guenter Roeck <linux@roeck-us.net> wrote: > >>>> > >>>> On Thu, Nov 05, 2015 at 04:19:21PM -0500, Akshay Bhat wrote: > >>>>> > >>>>> From: Tim Harvey <tharvey@gateworks.com> > >>>>> > >>>>> 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 '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: Lucas Stach <l.stach@pengutronix.de> > >>>>> Signed-off-by: Tim Harvey <tharvey@gateworks.com> > >>>>> --- > >>>>> .../devicetree/bindings/watchdog/fsl-imx-wdt.txt | 2 ++ > >>>>> drivers/watchdog/imx2_wdt.c | 20 > >>>>> ++++++++++++++++++-- > >>>>> 2 files changed, 20 insertions(+), 2 deletions(-) > >>>>> > >>>>> diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > >>>>> b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > >>>>> index 8dab6fd..9b89b3a 100644 > >>>>> --- a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > >>>>> +++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > >>>>> @@ -9,6 +9,8 @@ Optional property: > >>>> > >>>> > >>>> properties ? > >>>> > >>>>> - big-endian: If present the watchdog device's registers are > >>>>> implemented > >>>>> in big endian mode, otherwise in native mode(same with CPU), for > >>>>> more > >>>>> detail please see: > >>>>> Documentation/devicetree/bindings/regmap/regmap.txt. > >>>>> +- ext-reset-output: If present the watchdog device is configured to > >>>>> assert its > >>>> > >>>> > >>>> Should that have a vendor prefix ? Also, not sure if "-output" > >>>> has any real value in the property name. "fsl,external-reset", maybe ? > >>> > >>> > >>> Hi Guenter, > >>> > >>> I don't see why a vendor prefix is necessary - its a feature of the > >>> IMX6 watchdog supported by this driver to be able to trigger an > >>> internal chip-level reset and/or an external signal that can be hooked > >>> to additional hardware. > >>> > >> Sounded like vendor specific to me, but then I am not a devicetree > >> maintainer, > >> so I am not an authority on the subject. > > > > > > Devicetree maintainers, > > > > Any thoughts? > > > > Tim, > > > > After looking at all the other watchdog drivers, it does not appear that > > there is any other processor which uses a similar feature. Since imx is the > > only processor that appears to support this feature, it might make sense in > > making this vendor specific. If in the future it is found more processors > > support a similar functionality, it can be revisited and moved out from > > being vendor specific? > > > > I'm certainly no expert on device-tree policy. I understand your > point, but realize that the driver in question is imx2_wdt.c > (compatible = "fsl,imx21-wdt"). This is an IP block inside the silicon > of only Freescale chips, so its not like a future omap chip would be > using this driver - only fsl devices. So why would it need a 'vendor' > property any more than its other properties? > > Regards, > > Tim Wim, Does the lack of response mean overwhelming approval? I haven't heard any valid complaints - what does it take to get this approved? Regards, Tim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Guenter Roeck <linux@roeck-us.net> |
|---|---|
| Date | 2015-12-17 16:40 +0100 |
| Message-ID | <qGIOS-1gS-13@gated-at.bofh.it> |
| In reply to | #1293966 |
On 12/17/2015 07:02 AM, Tim Harvey wrote: > On Wed, Dec 2, 2015 at 12:54 PM, Tim Harvey <tharvey@gateworks.com> wrote: >> >> On Wed, Dec 2, 2015 at 11:11 AM, Akshay Bhat <akshay.bhat@timesys.com> wrote: >>> >>> >>> On 11/06/2015 05:02 PM, Guenter Roeck wrote: >>>> >>>> On Fri, Nov 06, 2015 at 11:53:42AM -0800, Tim Harvey wrote: >>>>> >>>>> On Thu, Nov 5, 2015 at 2:23 PM, Guenter Roeck <linux@roeck-us.net> wrote: >>>>>> >>>>>> On Thu, Nov 05, 2015 at 04:19:21PM -0500, Akshay Bhat wrote: >>>>>>> >>>>>>> From: Tim Harvey <tharvey@gateworks.com> >>>>>>> >>>>>>> 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 '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: Lucas Stach <l.stach@pengutronix.de> >>>>>>> Signed-off-by: Tim Harvey <tharvey@gateworks.com> >>>>>>> --- >>>>>>> .../devicetree/bindings/watchdog/fsl-imx-wdt.txt | 2 ++ >>>>>>> drivers/watchdog/imx2_wdt.c | 20 >>>>>>> ++++++++++++++++++-- >>>>>>> 2 files changed, 20 insertions(+), 2 deletions(-) >>>>>>> >>>>>>> diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt >>>>>>> b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt >>>>>>> index 8dab6fd..9b89b3a 100644 >>>>>>> --- a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt >>>>>>> +++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt >>>>>>> @@ -9,6 +9,8 @@ Optional property: >>>>>> >>>>>> >>>>>> properties ? >>>>>> >>>>>>> - big-endian: If present the watchdog device's registers are >>>>>>> implemented >>>>>>> in big endian mode, otherwise in native mode(same with CPU), for >>>>>>> more >>>>>>> detail please see: >>>>>>> Documentation/devicetree/bindings/regmap/regmap.txt. >>>>>>> +- ext-reset-output: If present the watchdog device is configured to >>>>>>> assert its >>>>>> >>>>>> >>>>>> Should that have a vendor prefix ? Also, not sure if "-output" >>>>>> has any real value in the property name. "fsl,external-reset", maybe ? >>>>> >>>>> >>>>> Hi Guenter, >>>>> >>>>> I don't see why a vendor prefix is necessary - its a feature of the >>>>> IMX6 watchdog supported by this driver to be able to trigger an >>>>> internal chip-level reset and/or an external signal that can be hooked >>>>> to additional hardware. >>>>> >>>> Sounded like vendor specific to me, but then I am not a devicetree >>>> maintainer, >>>> so I am not an authority on the subject. >>> >>> >>> Devicetree maintainers, >>> >>> Any thoughts? >>> >>> Tim, >>> >>> After looking at all the other watchdog drivers, it does not appear that >>> there is any other processor which uses a similar feature. Since imx is the >>> only processor that appears to support this feature, it might make sense in >>> making this vendor specific. If in the future it is found more processors >>> support a similar functionality, it can be revisited and moved out from >>> being vendor specific? >>> >> >> I'm certainly no expert on device-tree policy. I understand your >> point, but realize that the driver in question is imx2_wdt.c >> (compatible = "fsl,imx21-wdt"). This is an IP block inside the silicon >> of only Freescale chips, so its not like a future omap chip would be >> using this driver - only fsl devices. So why would it need a 'vendor' >> property any more than its other properties? >> >> Regards, >> >> Tim > > Wim, > > Does the lack of response mean overwhelming approval? > > I haven't heard any valid complaints - what does it take to get this approved? > Tim, Do you have an Ack from a devicetree maintainer ? I don't recall seeing one. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Wim Van Sebroeck <wim@iguana.be> |
|---|---|
| Date | 2015-12-28 17:30 +0100 |
| Subject | Re: [PATCH v4 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop |
| Message-ID | <qKIQj-4yb-11@gated-at.bofh.it> |
| In reply to | #1293966 |
Hi Tim, > On Wed, Dec 2, 2015 at 12:54 PM, Tim Harvey <tharvey@gateworks.com> wrote: > > > > On Wed, Dec 2, 2015 at 11:11 AM, Akshay Bhat <akshay.bhat@timesys.com> wrote: > > > > > > > > > On 11/06/2015 05:02 PM, Guenter Roeck wrote: > > >> > > >> On Fri, Nov 06, 2015 at 11:53:42AM -0800, Tim Harvey wrote: > > >>> > > >>> On Thu, Nov 5, 2015 at 2:23 PM, Guenter Roeck <linux@roeck-us.net> wrote: > > >>>> > > >>>> On Thu, Nov 05, 2015 at 04:19:21PM -0500, Akshay Bhat wrote: > > >>>>> > > >>>>> From: Tim Harvey <tharvey@gateworks.com> > > >>>>> > > >>>>> 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 '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: Lucas Stach <l.stach@pengutronix.de> > > >>>>> Signed-off-by: Tim Harvey <tharvey@gateworks.com> > > >>>>> --- > > >>>>> .../devicetree/bindings/watchdog/fsl-imx-wdt.txt | 2 ++ > > >>>>> drivers/watchdog/imx2_wdt.c | 20 > > >>>>> ++++++++++++++++++-- > > >>>>> 2 files changed, 20 insertions(+), 2 deletions(-) > > >>>>> > > >>>>> diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > > >>>>> b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > > >>>>> index 8dab6fd..9b89b3a 100644 > > >>>>> --- a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > > >>>>> +++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > > >>>>> @@ -9,6 +9,8 @@ Optional property: > > >>>> > > >>>> > > >>>> properties ? > > >>>> > > >>>>> - big-endian: If present the watchdog device's registers are > > >>>>> implemented > > >>>>> in big endian mode, otherwise in native mode(same with CPU), for > > >>>>> more > > >>>>> detail please see: > > >>>>> Documentation/devicetree/bindings/regmap/regmap.txt. > > >>>>> +- ext-reset-output: If present the watchdog device is configured to > > >>>>> assert its > > >>>> > > >>>> > > >>>> Should that have a vendor prefix ? Also, not sure if "-output" > > >>>> has any real value in the property name. "fsl,external-reset", maybe ? > > >>> > > >>> > > >>> Hi Guenter, > > >>> > > >>> I don't see why a vendor prefix is necessary - its a feature of the > > >>> IMX6 watchdog supported by this driver to be able to trigger an > > >>> internal chip-level reset and/or an external signal that can be hooked > > >>> to additional hardware. > > >>> > > >> Sounded like vendor specific to me, but then I am not a devicetree > > >> maintainer, > > >> so I am not an authority on the subject. > > > > > > > > > Devicetree maintainers, > > > > > > Any thoughts? > > > > > > Tim, > > > > > > After looking at all the other watchdog drivers, it does not appear that > > > there is any other processor which uses a similar feature. Since imx is the > > > only processor that appears to support this feature, it might make sense in > > > making this vendor specific. If in the future it is found more processors > > > support a similar functionality, it can be revisited and moved out from > > > being vendor specific? > > > > > > > I'm certainly no expert on device-tree policy. I understand your > > point, but realize that the driver in question is imx2_wdt.c > > (compatible = "fsl,imx21-wdt"). This is an IP block inside the silicon > > of only Freescale chips, so its not like a future omap chip would be > > using this driver - only fsl devices. So why would it need a 'vendor' > > property any more than its other properties? > > > > Regards, > > > > Tim > > Wim, > > Does the lack of response mean overwhelming approval? > > I haven't heard any valid complaints - what does it take to get this approved? > > Regards, > > Tim I have no objections against the idea and the code itself. But as Guenter pointed out: it would be handy to get feedback from the devicetree maintainers on the above discussion. Kind regards, Wim. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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