From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philipp Zabel Subject: Re: [PATCH v13 03/10] mux: minimal mux subsystem and gpio-based mux controller Date: Fri, 21 Apr 2017 16:41:04 +0200 Message-ID: <1492785664.2364.13.camel@pengutronix.de> References: <1492101794-13444-1-git-send-email-peda@axentia.se> <1492101794-13444-4-git-send-email-peda@axentia.se> <1492784582.2364.10.camel@pengutronix.de> <9e3d48c4-0dbc-3e80-c653-b0357abf1d6f@axentia.se> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <9e3d48c4-0dbc-3e80-c653-b0357abf1d6f-koto5C5qi+TLoDKTGw+V6w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter Rosin Cc: Mark Rutland , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Lars-Peter Clausen , kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, Wolfram Sang , linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Greg Kroah-Hartman , Jonathan Corbet , linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Paul Gortmaker , Rob Herring , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Peter Meerwald-Stadler , Hartmut Knaack , Colin Ian King , Andrew Morton , Jonathan Cameron List-Id: devicetree@vger.kernel.org On Fri, 2017-04-21 at 16:32 +0200, Peter Rosin wrote: > On 2017-04-21 16:23, Philipp Zabel wrote: > > On Thu, 2017-04-13 at 18:43 +0200, Peter Rosin wrote: > > [...] > >> +int mux_chip_register(struct mux_chip *mux_chip) > >> +{ > >> + int i; > >> + int ret; > >> + > >> + for (i = 0; i < mux_chip->controllers; ++i) { > >> + struct mux_control *mux = &mux_chip->mux[i]; > >> + > >> + if (mux->idle_state == mux->cached_state) > >> + continue; > > > > I think this should be changed to > > > > - if (mux->idle_state == mux->cached_state) > > + if (mux->idle_state == mux->cached_state || > > + mux->idle_state == MUX_IDLE_AS_IS) > > continue; > > > > or the following mux_control_set will be called with state == > > MUX_IDLE_AS_IS. Alternatively, mux_control_set should return when passed > > this value. > > That cannot happen because ->cached_state is initialized to -1 > in mux_chip_alloc, so should always be == MUX_IDLE_AS_IS when > registering. And drivers are not supposed to touch ->cached_state. > I.e., ->cached_state is "owned" by the core. So this was caused by me filling cached_state from register reads in the mmio driver. Makes me wonder why I am not allowed to do this, though, if I am able to read back the initial state? regards Philipp -- 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