Messages in this thread | | | Date | Wed, 28 Apr 2021 16:04:32 +0200 | From | Michael Walle <> | Subject | Re: [PATCH v4 1/2] gpio: Add support for IDT 79RC3243x GPIO controller |
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Am 2021-04-28 15:44, schrieb Andy Shevchenko: > On Wed, Apr 28, 2021 at 2:57 PM Michael Walle <michael@walle.cc> wrote: >> >> Am 2021-04-28 13:07, schrieb Andy Shevchenko: >> > On Wed, Apr 28, 2021 at 1:51 AM Michael Walle <michael@walle.cc> wrote: >> >> Am 2021-04-26 12:29, schrieb Andy Shevchenko: >> >> > On Mon, Apr 26, 2021 at 12:55 PM Thomas Bogendoerfer >> >> > <tsbogend@alpha.franken.de> wrote: >> >> > >> >> > 2) there is gpio-regmap generic code, that may be worth >> >> > considering. >> >> >> >> This driver uses memory mapped registers. While that is >> >> also possible with gpio-regmap, there is one drawback: >> >> it assumes gpiochip->can_sleep = true for now, see [1]. >> >> Unfortunately, there is no easy way to ask the regmap >> >> if its mmio/fastio. >> > >> > I don't see how it is an impediment. >> >> You'd have to use the *_cansleep() variants with the gpios, >> which cannot be used everywhere, no? > > *can* sleep means that it requires a sleeping context to run, if your > controller is fine with that, there are no worries. OTOH if you want > to run this in an atomic context, then consumers can't do with that > kind of controller.
Ok, then we are on the same track.
> What I meant above (and you stripped it here) is > to add a patch that will fix that and set it based on > gpio_regmap_config.
Yes, but ideally, it would ask the regmap. Otherwise that information is redundant and might mismatch, i.e. gpio_regmap_config tell can_sleep=false but the regmap is an I2C type for example. Also if a driver wants to support both regmap types, we are no step further.
-michael
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