Messages in this thread | | | Date | Wed, 25 May 2011 15:07:33 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH 1/2] misc/eeprom: add driver for 93xx46 EEPROMs over GPIO |
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On 05/25/11 14:35, Anatolij Gustschin wrote: > On Wed, 25 May 2011 10:31:46 +0100 > Jonathan Cameron <jic23@cam.ac.uk> wrote: > >> On 05/24/11 17:02, Anatolij Gustschin wrote: >>> 93xx46 EEPROMs can be connected using GPIO lines. Add a generic >>> 93xx46 EEPROM driver using common GPIO API for such configurations. >>> A platform is supposed to register appropriate 93xx46 gpio device >>> providing GPIO interface description and using this driver >>> read/write/erase access to the EEPROM chip can be easily done >>> over sysfs files. >> Could you explain why this makes more sense than an spi driver and >> use of spi_gpio ? >> >> It's microwire compatible according to random google provided datasheet, >> which iirc is a particular form of spi (half duplex, spi mode 0 according >> to wikipedia) >> >> That would give us a more generally useful driver. > > I thought about using spi_gpio first, then I decided to > do it in an independent driver since on the hardware the > driver was written for we additionally need to control > logic to hold pixel link chips in reset when eeprom access > is performed. Putting appropriate hacks to spi_gpio driver > didn't seem to be right approach. Controlling this logic > from user space is error-prone, too. Why would you need to put hacks in the spi bus driver?
Surely they would still be in your eeprom driver. Basically hold the pin down - do spi transfer - raise it again
Might need some callbacks to platform data (From the eeprom driver) to deal with this case...
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