From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH 2/3] pinctrl: tegra-xusb: Fix allocation of pins Date: Tue, 19 May 2015 16:09:26 +0100 Message-ID: <555B5226.3090500@nvidia.com> References: <1432044863-2035-1-git-send-email-jonathanh@nvidia.com> <1432044863-2035-3-git-send-email-jonathanh@nvidia.com> <20150519143041.GD26748@ulmo.nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150519143041.GD26748-AwZRO8vwLAwmlAP/+Wk3EA@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Thierry Reding Cc: Linus Walleij , Stephen Warren , Alexandre Courbot , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-gpio@vger.kernel.org On 19/05/15 15:30, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Tue, May 19, 2015 at 03:14:22PM +0100, Jon Hunter wrote: >> Commit e5b3b2d9ed20 ("pinctrl: allows not to define the get_group_pins >> operation") allows pin controllers not to register the get_group_pins() >> function. However, a side-effect of not registering this function is >> that pins are not allocated and potentially multiple devices could >> attempt to configure the same pins [1]. Although this problem exists in >> the pinctrl core, because only a few devices are impacted by this, fix >> this for tegra-xusb by adding the get_group_pins() function. > > If I understand correctly this effectively makes get_group_pins() > mandatory, doesn't it? In that case, shouldn't commit e5b3b2d9ed20 be > reverted? Yes may be it should. I will defer to Linus here. >> Please note that in addition to adding the get_group_pins() functions >> the pins/lanes for the tegra-xusb also need to be registered when >> calling pinctrl_register(). This also allows the current pinmux state >> to be viewed by the debugfs node "pinmux-pins" for the tegra-xusb pad >> controller. > > This sounds like a logically separate change and hence could warrant a > separate patch. I'll defer to Linus on this, though, so: It needs to be registered as part of this patch otherwise the pins will not be registered and pin_request() will fail. Today pin_request() does not even get called for these pins. So I believe that this is needed as part of this patch. May be I was not clear above, but the debugfs "pinmux-pins" entry shows nothing today for these pins. A by-product of this fix is that now we can view the pinmux state of the pins via the debugfs. > Acked-by: Thierry Reding Cheers Jon