Hi Rob, On 15/12/20 3:53 am, Rob Herring wrote: > 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? > Yes, there are separate properties for indicating different types of types of eeproms. So, do you think that it is better to add it as a seperate property?? Thanks, Aswath > Rob >
