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From: Guenter Roeck <linux@roeck-us.net>
To: Andrej Picej <andrej.picej@norik.com>
Cc: linux-watchdog@vger.kernel.org, shawnguo@kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	linux-imx@nxp.com, festevam@gmail.com, kernel@pengutronix.de,
	s.hauer@pengutronix.de, wim@linux-watchdog.org,
	robh+dt@kernel.org
Subject: Re: [PATCH 0/3] Suspending i.MX watchdog in WAIT mode
Date: Wed, 19 Oct 2022 08:30:54 -0700	[thread overview]
Message-ID: <20221019152915.GB4602@roeck-us.net> (raw)
In-Reply-To: <20221019111714.1953262-1-andrej.picej@norik.com>

On Wed, Oct 19, 2022 at 01:17:11PM +0200, Andrej Picej wrote:
> The i.MX6 watchdog can't be stopped once started. This means that
> special hardware suspend needs to be configured when the device enters
> low-power modes.
> Usually i.MX devices have two bits which deal with this:
> - WDZST bit disables the timer in "deeper" low power modes and
> - WDW bit disables the timer in "WAIT" mode which corresponds with
> Linux's "freeze" low-power mode.
> 
> WDZST bit support is already in place since 1a9c5efa576e ("watchdog: imx2_wdt: disable watchdog timer during low power mode").
> WDW bit is not common for all imx2-wdt supported devices, therefore use
> a new device-tree property "fsl,suspend-in-wait" which suspends the
> watchdog in "WAIT" mode.

I think that needs to be validated using the "compatible" property;
it should not be possible to set/accept the new flag for devices
which don't support it.

Thanks,
Guenter

> 
> Andrej Picej (3):
>   watchdog: imx2_wdg: suspend watchdog in WAIT mode
>   dt-bindings: watchdog: fsl-imx: document suspend in wait mode
>   ARM: dts: imx6ul/ull: suspend i.MX6UL watchdog in wait mode
> 
>  .../devicetree/bindings/watchdog/fsl-imx-wdt.yaml          | 5 +++++
>  arch/arm/boot/dts/imx6ul-phytec-phycore-som.dtsi           | 4 ++++
>  drivers/watchdog/imx2_wdt.c                                | 7 +++++++
>  3 files changed, 16 insertions(+)
> 
> -- 
> 2.25.1
> 

WARNING: multiple messages have this Message-ID (diff)
From: Guenter Roeck <linux@roeck-us.net>
To: Andrej Picej <andrej.picej@norik.com>
Cc: linux-watchdog@vger.kernel.org, shawnguo@kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	linux-imx@nxp.com, festevam@gmail.com, kernel@pengutronix.de,
	s.hauer@pengutronix.de, wim@linux-watchdog.org,
	robh+dt@kernel.org
Subject: Re: [PATCH 0/3] Suspending i.MX watchdog in WAIT mode
Date: Wed, 19 Oct 2022 08:30:54 -0700	[thread overview]
Message-ID: <20221019152915.GB4602@roeck-us.net> (raw)
In-Reply-To: <20221019111714.1953262-1-andrej.picej@norik.com>

On Wed, Oct 19, 2022 at 01:17:11PM +0200, Andrej Picej wrote:
> The i.MX6 watchdog can't be stopped once started. This means that
> special hardware suspend needs to be configured when the device enters
> low-power modes.
> Usually i.MX devices have two bits which deal with this:
> - WDZST bit disables the timer in "deeper" low power modes and
> - WDW bit disables the timer in "WAIT" mode which corresponds with
> Linux's "freeze" low-power mode.
> 
> WDZST bit support is already in place since 1a9c5efa576e ("watchdog: imx2_wdt: disable watchdog timer during low power mode").
> WDW bit is not common for all imx2-wdt supported devices, therefore use
> a new device-tree property "fsl,suspend-in-wait" which suspends the
> watchdog in "WAIT" mode.

I think that needs to be validated using the "compatible" property;
it should not be possible to set/accept the new flag for devices
which don't support it.

Thanks,
Guenter

> 
> Andrej Picej (3):
>   watchdog: imx2_wdg: suspend watchdog in WAIT mode
>   dt-bindings: watchdog: fsl-imx: document suspend in wait mode
>   ARM: dts: imx6ul/ull: suspend i.MX6UL watchdog in wait mode
> 
>  .../devicetree/bindings/watchdog/fsl-imx-wdt.yaml          | 5 +++++
>  arch/arm/boot/dts/imx6ul-phytec-phycore-som.dtsi           | 4 ++++
>  drivers/watchdog/imx2_wdt.c                                | 7 +++++++
>  3 files changed, 16 insertions(+)
> 
> -- 
> 2.25.1
> 

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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-10-19 15:37 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-19 11:17 [PATCH 0/3] Suspending i.MX watchdog in WAIT mode Andrej Picej
2022-10-19 11:17 ` Andrej Picej
2022-10-19 11:17 ` [PATCH 1/3] watchdog: imx2_wdg: suspend " Andrej Picej
2022-10-19 11:17   ` Andrej Picej
2022-10-19 15:33   ` Guenter Roeck
2022-10-19 15:33     ` Guenter Roeck
2022-10-20  6:02     ` Andrej Picej
2022-10-20  6:02       ` Andrej Picej
2022-10-19 11:17 ` [PATCH 2/3] dt-bindings: watchdog: fsl-imx: document suspend in wait mode Andrej Picej
2022-10-19 11:17   ` Andrej Picej
2022-10-19 13:00   ` Alexander Stein
2022-10-19 13:00     ` Alexander Stein
2022-10-19 15:51     ` Krzysztof Kozlowski
2022-10-19 15:51       ` Krzysztof Kozlowski
2022-10-20  6:23       ` Andrej Picej
2022-10-20  6:23         ` Andrej Picej
2022-10-20 12:18         ` Krzysztof Kozlowski
2022-10-20 12:18           ` Krzysztof Kozlowski
2022-10-20 12:36           ` Andrej Picej
2022-10-20 12:36             ` Andrej Picej
2022-10-20 12:41             ` Alexander Stein
2022-10-20 12:41               ` Alexander Stein
2022-10-20 13:05               ` Andrej Picej
2022-10-20 13:05                 ` Andrej Picej
2022-10-20 18:23                 ` Krzysztof Kozlowski
2022-10-20 18:23                   ` Krzysztof Kozlowski
2022-10-21  5:56                   ` Andrej Picej
2022-10-21  5:56                     ` Andrej Picej
2022-10-21 12:58   ` Krzysztof Kozlowski
2022-10-19 11:17 ` [PATCH 3/3] ARM: dts: imx6ul/ull: suspend i.MX6UL watchdog " Andrej Picej
2022-10-19 11:17   ` Andrej Picej
2022-10-19 12:16 ` [PATCH 0/3] Suspending i.MX watchdog in WAIT mode Fabio Estevam
2022-10-19 12:16   ` Fabio Estevam
2022-10-19 15:30 ` Guenter Roeck [this message]
2022-10-19 15:30   ` Guenter Roeck
2022-10-20  5:21   ` Andrej Picej
2022-10-20  5:21     ` Andrej Picej
2022-10-19 15:46 ` Krzysztof Kozlowski
2022-10-19 15:46   ` Krzysztof Kozlowski
2022-10-20  5:49   ` Andrej Picej
2022-10-20  5:49     ` Andrej Picej
2022-10-20 12:04     ` Krzysztof Kozlowski
2022-10-20 12:04       ` Krzysztof Kozlowski
2022-10-20 12:16       ` Andrej Picej
2022-10-20 12:16         ` Andrej Picej

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