From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cyril Chemparathy Subject: Re: [PATCH v2 08/12] gpio: add ti-ssp virtual gpio driver Date: Thu, 21 Oct 2010 19:40:44 -0400 Message-ID: <4CC0CF7C.1030908@ti.com> References: <1287429922-18870-1-git-send-email-cyril@ti.com> <1287429922-18870-9-git-send-email-cyril@ti.com> <1287700882.2038.135.camel@helium> Reply-To: cyril-l0cyMroinI0@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org" , "dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" , "broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org" , "grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org" , "spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" , "lrg-kDsPt+C1G03kYMGBc/C6ZA@public.gmane.org" To: David Brownell Return-path: In-Reply-To: <1287700882.2038.135.camel@helium> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: davinci-linux-open-source-bounces-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org Errors-To: davinci-linux-open-source-bounces-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org List-Id: linux-spi.vger.kernel.org Hi David, On 10/21/2010 06:41 PM, David Brownell wrote: > On Mon, 2010-10-18 at 15:25 -0400, Cyril Chemparathy wrote: >> This patch adds a GPIO driver based on TI's SSP device. This driver does not >> support GPIO-IRQs. > > Doesn't look particularly evil, except I don't much like the notion of > needing a "stack" if it's not being used like an MFD where numerous > functions are accessed concurrently, better IMO to just have each > function's driver bind exclusively to the chip (and drive it in the > mode it supports -- SPI, GPIO etc). SPI and GPIO are not the only modes that this hardware can be programmed to behave in. In future, other functions may be added as needed. I thought it would be best to keep the shared stuff reusable. > Also, the patch description is weak/confusing. First, there's not a > thing "virtual" about this. Second, just say that this GPIO driver is > bypassing pretty much everything in the SSP module (notably, all the > silicon support for serial protocols) and just driving some of the > pins as GPIOs. (Right?) Sure. [...] >> +config GPIO_TI_SSP >> + tristate "TI SSP Controller GPIO Driver" >> + depends on GPIOLIB && TI_SSP >> + help >> + Say yes here to support a virtual GPIO interface on TI SSP ports. >> + Each SSP port translates into 4 GPIOs, with no IRQ support. > > Don't emphasize the "no IRQ part so much; lots of GPIOs don't do IRQs. > If a board uses SSP this way, it won't care; Kconfig users have no > control over such board wiring issues. Agreed. Thanks Cyril.