Hi Michael, > -----Original Message----- > From: Michael Walle <michael@xxxxxxxx> > Sent: Tuesday, August 30, 2022 12:40 PM > To: Potthuri, Sai Krishna <sai.krishna.potthuri@xxxxxxx> > Cc: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>; Pratyush Yadav > <pratyush@xxxxxxxxxx>; Miquel Raynal <miquel.raynal@xxxxxxxxxxx>; > Richard Weinberger <richard@xxxxxx>; Vignesh Raghavendra > <vigneshr@xxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Krzysztof Kozlowski > <krzysztof.kozlowski+dt@xxxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx; linux- > mtd@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > saikrishna12468@xxxxxxxxx; git (AMD-Xilinx) <git@xxxxxxx> > Subject: Re: [PATCH 2/2] mtd: spi-nor: Add support for flash reset > > Hi, > > Am 2022-08-30 08:32, schrieb Potthuri, Sai Krishna: > > >> > + if (ret) > >> > + return ret; > >> > + > >> > + /* > >> > + * Experimental Minimum Chip select high to Reset delay value > >> > + * based on the flash device spec. > >> > + */ > >> > >> Which flash device spec? > > I referred some of the qspi, ospi flash vendors datasheets like > > Micron, Macronix, ISSI, gigadevice, spansion. > > Please mention here that you've looked at datasheets of different vendors. > And maybe instead of doing three comments, just one and then the reset > sequence. Ok, I will update in v2. > > >> > >> > + usleep_range(1, 5); > >> > + gpiod_set_value(reset, 0); > >> > >> Mh, is your logic inverted here? If I read the code correctly, you > >> should use a value of 1 to take the device into reset. The device > >> tree should then have a flag "active low", which will > > Reset Sequence which I implemented here is high(1)->low(0)->high(1). > > By doing this sequence (active low), flash device is getting reset, > > this sequence is tested using Octal SPI flash device. > > How does the device tree property for your look like? > Has it the GPIO_ACTIVE_LOW flag set? Sorry, I misunderstand your initial ask, This logic is developed by keeping the GPIO_ACTIVE_HIGH flag set in the device-tree. Agree this will violate the flash reset sequence (active low reset). I will update the sequence in v2 to match with the "active low" flag in the device tree. Regards Sai Krishna > > -michael
