Messages in this thread | | | Date | Tue, 25 Oct 2022 13:21:18 +0200 | Subject | Re: [PATCH v2 1/3] watchdog: imx2_wdg: suspend watchdog in WAIT mode | From | Andrej Picej <> |
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Hi Alexander,
On 25. 10. 22 11:38, Alexander Stein wrote: > Am Dienstag, 25. Oktober 2022, 09:25:31 CEST schrieb Andrej Picej: >> Putting device into the "Suspend-To-Idle" mode causes watchdog to >> trigger and reset the board after set watchdog timeout period elapses. >> >> Introduce new device-tree property "fsl,suspend-in-wait" which suspends >> watchdog in WAIT mode. This is done by setting WDW bit in WCR >> (Watchdog Control Register) Watchdog operation is restored after exiting >> WAIT mode as expected. WAIT mode coresponds with Linux's >> "Suspend-To-Idle". >> >> Signed-off-by: Andrej Picej <andrej.picej@norik.com> >> Reviewed-by: Fabio Estevam <festevam@gmail.com> >> --- >> Changes in v2: >> - validate the property with compatible string, as this functionality >> is not supported by all devices. >> --- >> drivers/watchdog/imx2_wdt.c | 37 +++++++++++++++++++++++++++++++++++++ >> 1 file changed, 37 insertions(+) >> >> diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c >> index d0c5d47ddede..dd9866c6f1e5 100644 >> --- a/drivers/watchdog/imx2_wdt.c >> +++ b/drivers/watchdog/imx2_wdt.c >> @@ -35,6 +35,7 @@ >> >> #define IMX2_WDT_WCR 0x00 /* Control > Register */ >> #define IMX2_WDT_WCR_WT (0xFF << 8) /* -> > Watchdog Timeout Field */ >> +#define IMX2_WDT_WCR_WDW BIT(7) /* -> Watchdog disable > for WAIT */ >> #define IMX2_WDT_WCR_WDA BIT(5) /* -> External Reset > WDOG_B */ >> #define IMX2_WDT_WCR_SRS BIT(4) /* -> Software Reset > Signal */ >> #define IMX2_WDT_WCR_WRE BIT(3) /* -> WDOG Reset Enable > */ >> @@ -67,6 +68,27 @@ struct imx2_wdt_device { >> bool ext_reset; >> bool clk_is_on; >> bool no_ping; >> + bool sleep_wait; >> +}; >> + >> +static const char * const wdw_boards[] __initconst = { >> + "fsl,imx25-wdt", >> + "fsl,imx35-wdt", >> + "fsl,imx50-wdt", >> + "fsl,imx51-wdt", >> + "fsl,imx53-wdt", >> + "fsl,imx6q-wdt", >> + "fsl,imx6sl-wdt", >> + "fsl,imx6sll-wdt", >> + "fsl,imx6sx-wdt", >> + "fsl,imx6ul-wdt", >> + "fsl,imx7d-wdt", >> + "fsl,imx8mm-wdt", >> + "fsl,imx8mn-wdt", >> + "fsl,imx8mp-wdt", >> + "fsl,imx8mq-wdt", >> + "fsl,vf610-wdt", >> + NULL >> }; > > So the models listed in Documentation/devicetree/bindings/watchdog/fsl-imx- > wdt.yaml not supporting this feature are > * fsl,imx21-wdt > * fsl,imx27-wdt > * fsl,imx31-wdt > * fsl,ls1012a-wdt > * fsl,ls1043a-wdt > ? yes, you are correct.
> > But all models are listed as compatible to fsl,imx21-wdt. So there is > something wrong here. IMHO this sounds like the compatible list has to be > split and updated. Depending on that this feature can be detected. Maintaining > another list seems error prone to me. >
So basically the compatible lists would be split into two groups, one for the devices which support this WDW bit and the rest which don't support this? You got a point here, but...this means that every processors device-tree, which has two compatible strings (with "fsl,imx21-wdt") should be updated, right? That sounds like quite a lot of changes, which I'd like to avoid if possible.
Best regards, Andrej
> Best regards, > Alexander > >> static bool nowayout = WATCHDOG_NOWAYOUT; >> @@ -129,6 +151,9 @@ static inline void imx2_wdt_setup(struct watchdog_device >> *wdog) >> >> /* Suspend timer in low power mode, write once-only */ >> val |= IMX2_WDT_WCR_WDZST; >> + /* Suspend timer in low power WAIT mode, write once-only */ >> + if (wdev->sleep_wait) >> + val |= IMX2_WDT_WCR_WDW; >> /* Strip the old watchdog Time-Out value */ >> val &= ~IMX2_WDT_WCR_WT; >> /* Generate internal chip-level reset if WDOG times out */ >> @@ -313,6 +338,18 @@ static int __init imx2_wdt_probe(struct platform_device >> *pdev) >> >> wdev->ext_reset = of_property_read_bool(dev->of_node, >> "fsl,ext- > reset-output"); >> + >> + if (of_property_read_bool(dev->of_node, "fsl,suspend-in-wait")) >> + if (of_device_compatible_match(dev->of_node, > wdw_boards)) >> + wdev->sleep_wait = 1; >> + else { >> + dev_warn(dev, "Warning: Suspending watchdog > during " \ >> + "WAIT mode is not supported for > this device.\n"); >> + wdev->sleep_wait = 0; >> + } >> + else >> + wdev->sleep_wait = 0; >> + >> /* >> * The i.MX7D doesn't support low power mode, so we need to ping > the >> watchdog * during suspend. > > > >
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