From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v3 02/13] mfd: wcd9335: add support to wcd9335 core Date: Wed, 12 Sep 2018 11:59:41 +0100 Message-ID: <20180912105941.GS4185@dell> References: <20180904102500.30318-1-srinivas.kandagatla@linaro.org> <20180904102500.30318-3-srinivas.kandagatla@linaro.org> <20180911153340.GY4185@dell> <94c68436-b618-40fc-46d6-165799312289@linaro.org> <20180912085848.GP4185@dell> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Srinivas Kandagatla Cc: robh+dt@kernel.org, broonie@kernel.org, mark.rutland@arm.com, lgirdwood@gmail.com, bgoswami@codeaurora.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, vkoul@kernel.org, alsa-devel@alsa-project.org List-Id: devicetree@vger.kernel.org On Wed, 12 Sep 2018, Srinivas Kandagatla wrote: > > > On 12/09/18 09:58, Lee Jones wrote: > > > > > +static const struct mfd_cell wcd9335_devices[] = { > > > > > + { .name = "wcd9335-codec", }, > > > > > +}; > > > > Are there more devices to come? > > > > > > > Yes, that is the plan, we are kind of limited in hardware setup to test few > > > things like soundwire controller. We are exploring other ways to test these. > > I normally don't accept MFDs with just one device enabled. Since it's > > not really an MFD (M == Multi) until it has more than one function. > > > > WCD9335 Codec hw itself has multiple hw blocks. > > If the issue is about adding more entries to mfd cells then we should be > able to add below entry: > > { .name = "wcd9335-soundwire-controller", }, > > Actual driver for soundwire controller is not something We can test with > regular dragon boards, it needs special hw for smart speakers. Once we have > that we can test and post the drivers for that. > > Otherwise > > Are you suggesting that I move everything to sound/soc/codecs and then back > to mfd once soundwire controller driver is added? My preference would be for you to add at least one other (tested) device. However, in your case I know where you live, so I can throw tomatoes at your house if you don't upstream more device support promptly! ;) When will you be enabling more devices? If the answer is 'never', then creating an MFD is a waste of time. > > [...] > > > > > > > + struct device_node *ifc_dev_np; > > > > ifc isn't very forthcoming. Any way you can improve the name? > > > ifc was suggested in dt bindings by Rob, I can proably rename to > > > interface_node. > > ifc is a horrible variable name - just sayin'. > > > > [...] > > > > > > > + ret = wcd9335_bring_up(wcd); > > > > So the device_status call-back brings up the hardware? > > > > > > > device status reports the device status at runtime. We can not communicate > > > with the device until it is up, enumerated by slimbus and a logical address > > > is assigned to it. So the best place to initialize it is in status callback > > > where all the above are expected to be done. > > Right, I understand what's happening. I just think the semantics are > > wrong. The Subsystem (I'm assuming it's a Subsystem) requests for > > status and it ends up initiating a start-up sequence. Just from a > > purist's point of view (I understand that it "works"), it's not good > > practice. > > > > > Probe is expected to setup the external configurations like regulators/pins > > > and so on which gets the device out of reset and ready to be enumerated by > > > the slimbus controller. > > I suggest fully starting the device in probe() is a better approach. > > > Its catch-22 situation, without device being powered up and reset correctly > there is no way to enumerate it. Isn't power-up and reset also done in probe()? What am I missing? > > [...] > > > > > > > +struct wcd9335 { > > > > > + int version; > > > > > + int intr1; > > > > What's this? If I have to ask, it's probably not a good name. > > > > > > > This is a hardware pin name for interrupt line 1. > > I don't see how this is used, so it's difficult for me to advise > > fully, but I find this confusing. Pin name/number? Shouldn't this be > > handed by Pinctrl? > > > This is represented as proper irq line in dt via pintrl irq controller. So why can't it just be 'irq' like most of the time? What is the 1 in reference to? Will there be a 2? > > intr1 could be quite ambiguous. Especually as the '1' could easily be > > read as an 'l'. Suggest that 'irq1' or 'irq_1' or 'irq_one'. > > I can change this to something more readable in next version or may be I can > even remove it may be just use a local variable. If it's possible for it to be a local variable, then it should not be placed in device data. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog