From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: =?iso-8859-1?q?=5BPATCH=5D_spi=3A_pxa2xx=5Fsp?= =?iso-8859-1?q?i_introduce_chip=09select_gpio_to_simplify_the_comm?= =?iso-8859-1?q?on_cases?= Date: Wed, 10 Sep 2008 23:08:31 -0700 Message-ID: <200809102308.31675.david-b@pacbell.net> References: <200809081704.43404.david-b@pacbell.net> <48C64EBE.6090003@cam.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: Ned Forrester , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Eric Miao , Russell King - ARM Linux To: Jonathan Cameron Return-path: In-Reply-To: <48C64EBE.6090003-KWPb1pKIrIJaa/9Udqfwiw@public.gmane.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org On Tuesday 09 September 2008, Jonathan Cameron wrote: > = > > =A0- It's probably worth removing support for the SSFRM > > =A0 =A0mechanism and requiring gpio_cs or (at least as a > > =A0 =A0transitional scheme) the cs_control() thing. > > I disagree strongly with this. > = > By all means issue a warning that cs_change will be > effectively 1 in all cases. However, with many real setups > this is absolutely fine. Leave getting this right to a > combination of the board config writers and some good > documentation! My logic is as follows: (a) it's superfluous given that the pin used for SSFRM can be managed as a GPIO; (b) it's less capable than managing it as a GPIO, examples being lack of SPI_CS_HIGH support and broken cs_change; (c) given (b) and what you noted, it's error prone; (d) given (a-c) it's confusing In short, removing this mechanism would improve quality and maintainability. Needing *more* documentation for core functionality is a red flag. Notice I'm not saying it can't (or doesn't) work, within its constraints (b). I'm just saying that if it's removed, the driver will be better and won't lose *ANY* functionality. - Dave ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great priz= es Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=3D100&url=3D/