Messages in this thread | | | Date | Fri, 28 Nov 2014 12:56:33 +0100 | Subject | Re: [PATCH 1/2] mmc: core: allow a reset gpio to be configured. | From | Ulf Hansson <> |
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On 8 November 2014 at 01:14, NeilBrown <neilb@suse.de> wrote: > If the regulator supplying an SDIO device is shared > with another device, the turning the regulator 'on' and 'off' > will not actually cycle power and so will not reset > the device. > > This is particularly a problem for some wi2si wireless modules which > have a BT module on chip and can share power lines. > Without the power-cycle, subsequent reset commands fail. > > So allow a 'reset' gpio to be specified. If provided, the > line is asserted during power-up.
There have been several attempts to fix similar issues as this patch does. The latest one I posted a few month ago, which wasn't accepted. http://comments.gmane.org/gmane.linux.power-management.general/46635
There has also been some off-list discussions on especially how we should describe this in DT and there were actually some consensus made around that. Still I haven't seen any patches on the mailing lists.
So to summarize, I am really concerned that we keep having these power sequence issues for SDIO devices and right now the discussion has been on hold. I am considering to hack on it myself, since I am tired of waiting. :-)
Regarding this patch, I don't intent to apply it.
Kind regards Uffe
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