From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Fried, Ramon" Subject: Re: RFC: gpio: mmio: add support for 3 direction regs Date: Thu, 3 Jan 2019 10:51:02 +0200 Message-ID: <28205214-d395-1c17-51ee-970300b6a14e@linux.intel.com> References: <32edfd70-95dc-26a1-2ea6-143344cb2384@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Vladimir Zapolskiy , linus.walleij@linaro.org, bgolaszewski@baylibre.com, linux-gpio@vger.kernel.org Cc: linux-kernel@vger.kernel.org, vladimir.kondratiev@linux.intel.com List-Id: linux-gpio@vger.kernel.org On 1/3/2019 10:07, Vladimir Zapolskiy wrote: > Hi Ramon, > > On 01/03/2019 09:36 AM, Fried, Ramon wrote: >> Hi. >> >> I'm working on a driver for STA2X11 GPIO controller who seems to fit >> best to the generic mmio driver, > I hope you have seen the existing driver drivers/gpio/gpio-sta2x11.c I surely did. we have the same IP in our soc but it was changed a lot internally, don't want to litter the original. > >> the only problem I have is with the dir register case. The STA2X11 >> has 3 registers for dir, one for data, one for set and one for >> clear. The generic-mmio driver has support for this fashion for the >> dat & set & clear registers but not for dirout/dirin registers. >> >> I wonder if support for this is generic enough to deserve a patch, if >> so I'm willing to quickly add this support, if not, adding a flag >> such as below, will allow partly using the generic mmio driver only >> for set/get and the direction can be handled outside the driver. >> > If gpio-mmio fits well, then it might be simpler to set a flag > BGPIOF_UNREADABLE_REG_DIR, then call bgpio_init() and then overwrite > .direction_input, .direction_output and .get_direction callbacks, > as a reference you can take a look at gpio-74xx-mmio.c Nice. That's an option I didn't think of, better than setting the flag. what about adding the generic support ? > > -- > Best wishes, > Vladimir