From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laxman Dewangan Subject: Re: [rtc-linux] [PATCH V2 3/5] gpio: add support for AMS AS3722 gpio driver Date: Mon, 23 Sep 2013 15:31:32 +0530 Message-ID: <5240117C.8060300@nvidia.com> References: <1379680214-9143-1-git-send-email-ldewangan@nvidia.com> <1379680214-9143-4-git-send-email-ldewangan@nvidia.com> <524001F3.3060602@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linus Walleij Cc: "rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org" , Lee Jones , Samuel Ortiz , Mark Brown , Andrew Morton , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Rob Herring , Mark Rutland , Pawel Moll , Stephen Warren , Rob Landley , "ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org" , Grant Likely , Florian Lobmaier List-Id: devicetree@vger.kernel.org On Monday 23 September 2013 02:56 PM, Linus Walleij wrote: > On Mon, Sep 23, 2013 at 10:55 AM, Laxman Dewangan wrote: >> On Monday 23 September 2013 01:36 PM, Linus Walleij wrote: >>> This is pin control. Do not try to shoehorn pin control drivers into >>> the GPIO subsystem. Take a good day off, read through >>> Documentation/pinctrl.txt and come back with a thoroughly rewritten >>> driver in drivers/pinctrl/pinctrl-as3722.c. > (...) >> Yes, the appropriate location is pin control for pull up/down etc >> configuration but with this device, the actual issue is with the way it is >> require to configure the pull up/down and input/output of the pin. There is >> no separate bits for pull up/down and direction and it is clubbed together. >> The register's bits are defined as: >> >> Selects the GPIO mode (I, I/O, Tri, Pulls) (BIT 2:0) >> 0 : Input >> 1 : Output (push and pull) VSUP_GPIO >> 2 : Output/Input (open drain, only NMOS is active) >> 3 : ADC input (Tristate) >> 4 : Input with pull-up to VDD_GPIO_lv >> 5 : Input with pull-down >> 6 : Output/Input open drain (nmos) with pull-up to VDD_GPIO_lv, >> 7 : Output (push and pull) VDD_GPIO_lv >> >> So I can not actually configure the pull up/down, open drain and direction >> independently until every thing is known. >> Direction come from gpio driver but pull up/down and open drain >> configuration come from the pin control. >> And this is only the reason to make all configuration in single driver. > This is nothing special. Create a single combined GPIO and > pin control driver using the pin control framework and device > tree bindings. > Ok, I was thinking that we should not call gpiochip_add() from the pin control driver in any new driver and that's why I developed gpio driver but it seems it is allowed. I saw some of driver in pinctrl are doing pin control and gpio functionality in single driver i.e. pincntrl-nomadik, pinctrl-samsung, pincntrl-st etc. So this gpio driver can be moved now to the pincntrl folder and can use pincontrol and gpio framework. I will respin the change. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html