On 30/08/2022 12:36, Michael Walle wrote: > Am 2022-08-30 11:21, schrieb Krzysztof Kozlowski: >> On 29/08/2022 12:05, Sai Krishna Potthuri wrote: >>> SPI-NOR flashes have RESET pin which can be toggled using GPIO >>> controller, for those platforms reset-gpios property can be used to >>> reset the flash device. >>> >>> Signed-off-by: Sai Krishna Potthuri <sai.krishna.potthuri@xxxxxxx> >>> --- >>> Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 6 ++++++ >>> 1 file changed, 6 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml >>> b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml >>> index 7149784a36ac..d2fc8e9c787f 100644 >>> --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml >>> +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml >>> @@ -70,6 +70,12 @@ properties: >>> be used on such systems, to denote the absence of a reliable >>> reset >>> mechanism. >>> >>> + reset-gpios: >>> + description: >>> + contains a GPIO specifier. >> >> Skip this part - obvious. >> >>> The reset GPIO is asserted and then deasserted >>> + to perform device reset. If "broken-flash-reset" is present >>> then having >>> + this property does not make any difference. >> >> Isn't then broken-flash-reset conflicting with this one (e.g. >> disallowing it)? > > Sometimes the spi-nor driver needs to switch modes, which are persistent > until you either switch em back or do a hardware reset (or software > reset IIRC) of the flash. If broken-flash-reset is set, we try hard > to leave the flash in the mode which it is normally in after reset or > don't switch modes at all. > Of course we cannot make sure, our shutdown gets called in each case, > thus there is may be warning during startup. > > So, even if you have a reset-gpio it might be broken I guess. Think > of it being high active, but someone forgot the pull-up. So, if you > do an unexpected reset, the flash chip might not be reset > automatically. So yes, I think, even if there is a dedicated reset > gpio, it could still be messed up. How likely is it? I don't know, > probably not very. OK, so let's keep it and allow both. Best regards, Krzysztof
