Hi Mike, On Mon, Dec 5, 2011 at 7:55 PM, Mike Frysinger <vap...@gentoo.org> wrote: > On Monday 05 December 2011 17:52:01 Simon Glass wrote: >> On Mon, Dec 5, 2011 at 2:22 PM, Stephen Warren wrote: >> > On 12/05/2011 02:56 PM, Simon Glass wrote: >> > * A system-wide GPIO ID, in which case the numbering is "virtual" (e.g. >> > a concatenation of the GPIOs on all the present controllers), and you >> > can choose to start the first controller's GPIOs at 0, 1, 1000 etc., >> > thus leaving -1, 0, -n..999 etc. as invalid GPIOs. This is what the >> > Linux kernel's gpiolib uses (and some say this global numbering scheme >> > was a mistake). >> >> Well maybe it was a mistake, but it seems painful for the user to >> translate GPIO numbers in this way. U-Boot's GPIO command takes a GPIO >> number, which starts at zero. > > u-boot should simply follow what linux is doing as it keeps things a hell of a > lot simpler for us: the code is done, people moving between the worlds don't > get surprised and screw something up, and we don't accidentally forget "oh, in > u-boot we do XXX instead of YYY" and screw things up ourselves.
Good, I think that is what we are doing. But if Linux changes the GPIO numbering we may need to do something. > >> >> I currently use the max value available to the u8. We can change it at >> >> will when we update the u8 type to u16 which is why I made it a >> >> constant. >> > >> > include/asm-generic/gpio.h seems to use an int to represent a GPIO. I'd >> > suggest these APIs do the same, rather than use a u8. >> >> Do you mean the fdt_gpio_state structure? I have not used u8 for any >> function calls and would not. > > the asm-generic/gpio.h using "int" as a gpio is wrong. it should be > "unsigned". there's a patch somewhere to fix this. OK, will wait to see it. > >> This adds 3 bytes for every entry. What is the benefit? People get >> upset when we waste memory! > > some systems have more than 256 GPIOs. it's actually not that hard to hit the > limit. > -mike Not for me so far, but I don't doubt it. I have changed it to uint in the series. Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
