From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Looijmans Subject: Re: [PATCH v2] mmc: sdhci: add quirk for broken write protect detection Date: Thu, 6 Mar 2014 14:31:52 +0100 Message-ID: <531878C8.2020001@topic.nl> References: <1393759200-22819-1-git-send-email-eli.billauer@gmail.com> <74003aec-1707-4f43-b947-df148d573fa1@TX2EHSMHS038.ehs.local> <53163247.8000904@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org To: =?UTF-8?B?U8O2cmVuIEJyaW5rbWFubg==?= , Eli Billauer Cc: chris@printf.net, michal.simek@xilinx.com, linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org =EF=BB=BFOn 03/04/2014 10:00 PM, S=C3=B6ren Brinkmann wrote: > On Tue, 2014-03-04 at 10:06PM +0200, Eli Billauer wrote: >> Hello S=C3=B6ren, >> >> wp-inverted solves the practical problem indeed, and fools the >> driver into thinking that the card has an inverted write protection >> sensor, and the logic zero that it finds in the hardware register >> means that the card isn't write protected. >> >> I'm insisting on this patch, because I think that the device tree >> should describe the hardware as it is, and not fool the driver into >> behaving the way we want it to. These tricks always bite back later >> on. > Well, why is broken-wp more accurate than wp-inverted? Strictly > speaking the WP is there and working, it's just tied off to some valu= e > you want to have interpreted the other way. > Anyway, seems like this is solvable with wp-inverted and whether the > additional quirk is needed I leave to others do decide. I've begged for this patch - or a similar one - to be included too, bec= ause on=20 our boards, the "wp" value appears to be sort of random. Out of 5 proto= type=20 boards, 3 would only boot with wp-inverted while the other 2 wouldn't b= oot=20 with wp-inverted set. In our case I really don't know (and I don't care either) to which logi= c level=20 the wp happens to think it's wired. I just want to be able to tell the = driver=20 that the WP line is=20 free-floating-and-might-have-any-random-value-at-any-given-moment which= is a=20 bit long, so I'd go for disable-wp instead. Mike. Met vriendelijke groet / kind regards, Mike Looijmans TOPIC Embedded Systems Eindhovenseweg 32-C, NL-5683 KH Best Postbus 440, NL-5680 AK Best Telefoon: (+31) (0) 499 33 69 79 Telefax: (+31) (0) 499 33 69 70 E-mail: mike.looijmans@topic.nl Website: www.topic.nl Please consider the environment before printing this e-mail