From mboxrd@z Thu Jan 1 00:00:00 1970 From: josh.wu@atmel.com (Josh Wu) Date: Mon, 26 Aug 2013 18:03:31 +0800 Subject: [PATCH v2 2/4] iio: at91: Use different prescal, startup mask in MR for different IP In-Reply-To: <20130826083207.GB7468@ludovic.desroches@atmel.com> References: <1376219071-29946-1-git-send-email-josh.wu@atmel.com> <1376219071-29946-3-git-send-email-josh.wu@atmel.com> <20130815192044.GD12162@lukather> <5215DF2C.3050502@atmel.com> <5215DF7C.2020909@atmel.com> <20130823154603.GA7468@ludovic.desroches@atmel.com> <20130823165936.GC1230@lukather> <20130826083207.GB7468@ludovic.desroches@atmel.com> Message-ID: <521B27F3.1050203@atmel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Ludovic and Maxime On 8/26/2013 4:32 PM, Ludovic Desroches wrote: > On Fri, Aug 23, 2013 at 06:59:36PM +0200, Maxime Ripard wrote: >> Hi Ludovic, Josh, >> >> On Fri, Aug 23, 2013 at 05:46:03PM +0200, Desroches, Ludovic wrote: >>> On Thu, Aug 22, 2013 at 05:53:00PM +0800, Josh Wu wrote: >>>> On 8/22/2013 5:51 PM, Josh Wu wrote: >>>>> Hi, Maxime >>>>> >>>>> On 8/16/2013 3:20 AM, Maxime Ripard wrote: >>>>>> Hi Josh, >>>>>> >>>>>> On Sun, Aug 11, 2013 at 07:04:29PM +0800, Josh Wu wrote: >>>>>>> For at91 boards, there are different IPs for adc. Different IPs has >>>>>>> different STARTUP & PRESCAL mask in ADC_MR. >>>>>>> >>>>>>> This patch introduce the multiple compatible string for those >>>>>>> different IPs. >>>>>>> >>>>>>> Signed-off-by: Josh Wu >>>>>> Overall it looks like the right ways, but I think we can take it a step >>>>>> further. >>>>>> >>>>>> I'd drop at least the atmel,adc-drdy-mask, atmel,adc-num-channels, >>>>>> atmel,adc-status-register, atmel,adc-trigger-register properties (and >>>>>> probably the triggers as well description as well). >>>>> yeah, right. Currently I want to drop following: >>>>> >>>>> atmel,adc-drdy-mask, atmel,adc-status-register, >>>>> atmel,adc-trigger-register, atmel,adc-channel-base >>>>> >>>>> For the adc-num-channels, I'd like to leave it in dt parameters. >>>>> It is a description for an adc capablity. >>> About this parameter, I'll remove it too from the dt bindings. To set it you >>> need to have a look to the datasheet and to copy a constant value into the >>> dt. From my point of view, it means than this parameter should be managed by >>> the driver and by the dt. >>> >>> On the other side since there are some dynamic allocation depending on this >>> parameter maybe it makes sense to keep it in the dt. If the user wants to use >>> only 2 channels why doing allocation for max channel number. By the way, this >>> case is only valid if he uses the two first channels. >> I don't recall it very well, is there any reason to not have it in the >> DT? Can the ADC channels be used for something else? Or is it just some >> IP-specific number of channels? >> > It is IP-specific. I don't see what benefit we could have to keep it in the DT? > But Josh seems to have arguments to keep it. I'm ok to remove the channel number. What I worried is there also has a channel-used mask in DT. This mask should be removed too if channel number is removed. So maybe we can also use the sysfs to set the mask. > >>>>> For the triggers, I am not decided. An obvious benifit to remove >>>>> trigger in dt will save many lines of code. >>>>> >>>>>> Maxime >>>>>> >>>>> Best Regards, >>>>> Josh Wu >>> Since we are talking about reworking this binding I was thinking about >>> resolution stuff. Filling atmel,adc-res is also copying constant value from >>> the device datasheet, so if I was consistent I would say it has to be removed >>> too. But I am not consistent! I mean by doing this the only thing the user >>> will have to fill is the resolution value. He can't set the value he wants, >>> there are only two choices. By keeping it into the dt then he will immediately >>> see the choices he has. >> But the resolution should probably be somehow user-defined, probably not >> really related to the DT has well. I think some other IIO ADC drivers >> are using sysfs files for this purpose, maybe that would be a better >> fit? > It sounds to be a good solution. ok, I will check the other IIO ADC driver about this point. Maybe this sysfs replacement need a bit more time. I prefer to send out the patches first without the sysfs implement in v3. And the sysfs replacement patch will be send out serperately. What do you think? Maxime. > > > Ludovic Best Regards, Josh Wu