On Fri, Dec 11, 2020 at 08:34:57PM +0530, Aswath Govindraju wrote: > Hi, > On 11/12/20 9:03 am, Rob Herring wrote: > > On Wed, Dec 09, 2020 at 11:27:07PM +0530, Aswath Govindraju wrote: > >> Dummy zero bits are sent before data during a read transfer. This causes > >> the data read to be shifted to the right. To fix this send zero bits after > >> the address during a read transfer. > >> > >> Add property to send zero bits after the address during a read transfer. > > > > When is this necessary? Why can't it be implied by the compatible > > string which should be specific to the chip model? > > > > This is necessary for 93AA46A/B/C, 93LC46A/B/C, 93C46A/B/C eeproms, as > it can be seen in section 2.7 of [1]. We were not sure if these were the > only devices supported by the driver(eeprom_93xx46.c). So, in order to > apply this only to the above listed devices, we thought that it would be > better to apply this change when required by introducing a DT property. > > May I know how has this case been handled till now ?? > No idea. From the at93c46d (which has a compatible string) datasheet it looks like it has the same thing. > If this is required by all the devices then we can drop the property and > include the zero bit by default. Looks like you need a combination of compatible strings for the above devices and a property for the ORG pin state on the C devices. I assume s/w needs to know if x8 or x16? Rob
