From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Meerwald Subject: Re: [PATCH] [TWL4030 MADC] Fix ADC[3:6] readings Date: Fri, 17 Jul 2015 11:42:47 +0200 (CEST) Message-ID: References: <1437085227-28845-1-git-send-email-adam.yh.lee@gmail.com> <1437085227-28845-2-git-send-email-adam.yh.lee@gmail.com> <20150717090039.GC9331@earth> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <20150717090039.GC9331@earth> Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sebastian Reichel Cc: Adam YH Lee , linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-omap@vger.kernel.org Hello, adding linux-iio... > To get a chance of this patch being considered for inclusion, you > should send this to the maintainers of the phy and iio framework. > There is a high chance, that none of them will see your mail. > > On Thu, Jul 16, 2015 at 03:20:27PM -0700, Adam YH Lee wrote: > > MADC[3:6] reads incorrect values without these two following changes: > > uhm MADC[3:6] are externally available analog inputs. Your > change will result in them being tied to the USB module. change regarding TWL4030_USB_SEL_MADC_MCPC is necessary at least for some hardware revisions to get proper ADC values > > - enable the 3v1 bias regulator for ADC[3:6] > > The regulator is not required for correct MADC functionality, but > for correct USB measureing. The regulator should not be requested > by the madc module, but by the usb module, which is connected to > the madc. in my experience, the MADC exhibits several strange things, I wouldn't be surprised that this bias is somehow necessary for operation even if it is not what the spec says -- has this been tested? > > - configure ADC[3:6] lines as input, not as USB > > I don't think that should be done for all boards. > > > [...] > > -- Sebastian > -- Peter Meerwald +43-664-2444418 (mobile)