From mboxrd@z Thu Jan 1 00:00:00 1970 From: Quentin Schulz Subject: Re: [PATCH 2/8] iio: adc: axp20x_adc: add support for AXP813 ADC Date: Mon, 11 Dec 2017 09:18:55 +0100 Message-ID: References: <20171210163655.43fbd3c0@archlinux> Reply-To: quentin.schulz-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <20171210163655.43fbd3c0@archlinux> Content-Language: en-US List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Jonathan Cameron Cc: sre-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, wens-jdAy2FN1RRM@public.gmane.org, linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org, maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org, lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, knaack.h-Mmb7MZpHnFY@public.gmane.org, lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org, pmeerw-jW+XmwGofnusTnJN9+BGXg@public.gmane.org, linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, icenowy-h8G6r0blFSE@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org List-Id: linux-pm@vger.kernel.org Hi Jonathan, On 10/12/2017 17:36, Jonathan Cameron wrote: > On Mon, 4 Dec 2017 15:12:48 +0100 > Quentin Schulz wrote: > >> The X-Powers AXP813 PMIC is really close to what is already done for >> AXP20X/AXP22X. >> >> There are two pairs of bits to set the rate (one for Voltage and Current >> measurements and one for TS/GPIO0 voltage measurements) instead of one. > > This would normally imply we need to split the device into two logical > IIO devices. However, that only becomes relevant if we are using > buffered output which this driver doesn't support. > > It'll be nasty to deal with this if we add that support down the line > though. Up to you though as it's more likely to be your problem than > anyone else's :) > I have no plans for supporting buffered output for the AXPs at the moment. But that's an interesting (and important) limitation to raise. Wouldn't be more of a hack to have two IIO devices representing the actual same IP? > For now you could elect to support the different sampling frequencies > if you wanted to but just providing controls for each channel. > I guess that you're offering to use IIO_CHAN_INFO_SAMP_FREQ in info_mask_separate for each channel? > Given the driver doesn't currently expose these at all (I think) > this is all rather immaterial ;) I'm not giving the user the option to chose the sampling frequency for now. I have no plans to do it either, but I think it would be rather simple to later add support for setting frequency sampling since we only need to add a sysfs entry (with IIO_CHAN_INFO_SAMP_FREQ) that does not exist yet. Don't you think? Am I missing something? Thanks, Quentin -- Quentin Schulz, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com