On Wed, Jun 7, 2023 at 7:07 PM Hawkins, Nick <nick.hawkins@xxxxxxx> wrote: ... > > > > Why are you not using gpio-regmap? > > > > > > Is there are good example or previous commit you would recommend > > > looking at that shows how to convert from regmap to gpio-regmap? > > > Later in the code I am using regmap_read and regmap_update_bits > > > with large differences in offset registers, and not so much a > > > contiguous block. > > > > I don't know how good these are, but that's what we have currently as > > most prominent use of gpio-regmap > > > > 1) (ongoing) https://lore.kernel.org/linux-gpio/20230606092107.764621-6-jiawenwu@xxxxxxxxxxxxxx <mailto:20230606092107.764621-6-jiawenwu@xxxxxxxxxxxxxx>/ > > 2) (in the repo) > > https://elixir.bootlin.com/linux/v6.4-rc4/source/drivers/gpio/gpio-i8255.c <https://elixir.bootlin.com/linux/v6.4-rc4/source/drivers/gpio/gpio-i8255.c> > > 3) (in the repo) > > https://elixir.bootlin.com/linux/v6.4-rc4/source/drivers/gpio/gpio-104-idi-48.c <https://elixir.bootlin.com/linux/v6.4-rc4/source/drivers/gpio/gpio-104-idi-48.c> > > > > 2) & 3) were converted, so you may see by executing respective `git > > log -p -- drivers/gpio/...`. > > Greetings Andy, > > Thank you for those links, I have observed the gpio_regmap code > they have implemented in that case. It appears that the regmap > code is opening the entire range of memory to be read. For my > particular purpose I am not wanting to expose all the 0-0xff byte > range of the GPIOs. This is also supported by regmap (and regmap has caches for the sparse registers as well). > In my case is it still necessary to use the > gpio_regmap code? It does care about things the average GPIO controller driver needs to repeat. So at least you may try and see how it will look. > If gpio_regmap is required, how do I create a direct correlation > between a specific gpio-line and a register offset? For example, in > gpio-gxp-pl.c. Gpio-line at offset 0 (IOPLED) is at register 0x04. The > gpio-line at offset 8 (FAN_INST) is at register 0x27. You may remap registers. See, for example, gpio-pca953x, where some of the registers (with high bit set) are actually virtual rather than real offsets. Similar idea can be used in your case. > Additionally, is it required to remove gpio_chip if gpio_regmap is > used? I don't think gpio_chip will be needed. -- With Best Regards, Andy Shevchenko
