Messages in this thread | | | Date | Thu, 6 Mar 2014 14:31:52 +0100 | From | Mike Looijmans <> | Subject | Re: [PATCH v2] mmc: sdhci: add quirk for broken write protect detection |
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On 03/04/2014 10:00 PM, Sören Brinkmann wrote: > On Tue, 2014-03-04 at 10:06PM +0200, Eli Billauer wrote: >> Hello Sören, >> >> 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 value > 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, because on our boards, the "wp" value appears to be sort of random. Out of 5 prototype boards, 3 would only boot with wp-inverted while the other 2 wouldn't boot with wp-inverted set.
In our case I really don't know (and I don't care either) to which logic level the wp happens to think it's wired. I just want to be able to tell the driver that the WP line is free-floating-and-might-have-any-random-value-at-any-given-moment which is a 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
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