>> I have been using the LM93 kernel driver and I noticed that 'gpio' >> file in sysfs is read-only and that the GPIO pins of the LM93 chip can >> be used as input only. >> I attached a patch that allows to also use GPIO pins as output, by >> simply writing to 'gpio' in sysfs. The patch is against the current >> git revision of the mainstream kernel. >> I did not handle the case where the GPIO pins are used as inputs after >> being used as output (in which case, according to the datasheet, 0s >> should be written to the GPO register, and thus 1s should be written >> to the 'gpio' sysfs file). Also, if some pins are used as inputs and >> others as outputs, then, when writing to the 'gpio' file in sysfs, the >> pins used as inputs should be set to 1 (so that the corresponding bits >> in the GPO register are set to 0). >> >> Comments are welcome. > > IMO gpiolib would be better and more generic solution instead of creating > some custom sysfs entry... The sysfs entry already exists (and is present the mainstream kernel), so that's why I preferred to use it. I don't think the sysfs entry will be removed anyway, or will it ? Olivier
