From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: [linux-sunxi] Re: [PATCH 5/5] ARM: dts: sun7i: Add dts file for Wits Pro A20 DKT Date: Fri, 31 Jul 2015 20:02:40 +0200 Message-ID: <55BBB840.80107@redhat.com> References: <1438333194-21181-1-git-send-email-hdegoede@redhat.com> <1438333194-21181-6-git-send-email-hdegoede@redhat.com> <20150731102028.GE2564@lukather> <20150731165655.GG2564@lukather> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150731165655.GG2564@lukather> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Maxime Ripard , Chen-Yu Tsai Cc: linux-arm-kernel , devicetree , linux-sunxi , Jelle de Jong List-Id: devicetree@vger.kernel.org Hi, On 31-07-15 18:56, Maxime Ripard wrote: > On Fri, Jul 31, 2015 at 06:25:29PM +0800, Chen-Yu Tsai wrote: >>> Note that it's a bit of a pain for now to support such cases, as >>> there's nothing to tie something from the DT to an SDIO device. I >>> don't have a better solution than marking it always-on at the moment, >>> with a big FIXME comment on top... :/ >> >> One could use the mmc-pwr-seq stuff. I don't know if it has been >> extended for multiple GPIOs, not that you would need it in this use >> case. > > It doesn't really improve the situation. It doesn't handle the > regulators, The regulator(s) are already handled by the vmmc and vqmcc regulators of the mmc controller binding. If more regulators are needed, we can easily extend mmc-pwrseq-simple to support them, or define a whole new powerseq driver. > it doesn't allow the real driver to get its resources > either, basically, it's just a hack. Not involving the real driver is by design really, the real driver cannot bind / have its probe function called until its sdio interface has been probed which is where the pwrseq driver comes in. This also allows re-using existing sdio drivers without needing them to be aware of certain board perculiarities If a special power on (or suspend) order is nescessary a custom pwrseq driver can be created for this, even one which is meant to work in tandem with a specific sdio device driver. The idea is that the device driver will ask the mmc core to powerdown the device for powersaving in certain cases (e.g. suspend) and then the mmc core will call into the powerseq driver. Granted there may be more complex scenarios where thighter control over the resources is needed, but for now this seems to work really well and it is much better then the deadlock we had before were all solutions were shot down as not flexible enough. >> Maybe we ought to fix up the other ones, like the CubieTruck and A31 >> Hummingbird? > > I'll do it. Thanks. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html