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From:   AceLan Kao <acelan.kao@canonical.com>
Date:   Mon, 31 Aug 2020 19:28:37 +0800
Message-ID: <CAFv23QmDwcrdxEndH=mKMAomzt9kxG_f1Z6=Fd8iuuvCoY92SA@mail.gmail.com>
Subject: Re: [PATCH] iio: dac: ad5593r: Dynamically set AD5593R channel modes
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     William Sung <william.sung@advantech.com.tw>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Michael Hennerich <Michael.Hennerich@analog.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Hartmut Knaack <knaack.h@gmx.de>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        linux-iio <linux-iio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Campion Kang <Campion.Kang@advantech.com.tw>
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Hi Jonathan and Andy,

This patch is mainly for Advantech's UNO-420[1] which is a x86-based platform.
This platform is more like a development platform for customers to
customize their products,
so, specify the channel modes in ACPI table is not generic enough,
that's why William submit this patch.

Are there other ways to specify or pass values to the module without
using module parameters?
It's good if we can leverage sysfs, but I don't know if there is one
for this scenario.

1. https://www.advantech.com/products/9a0cc561-8fc2-4e22-969c-9df90a3952b5/uno-420/mod_2d6a546b-39e3-4bc4-bbf4-ac89e6b7667c

Andy Shevchenko <andy.shevchenko@gmail.com> 於 2020年8月31日 週一 上午1:07寫道：
>
> On Mon, Aug 24, 2020 at 8:54 AM William Sung
> <william.sung@advantech.com.tw> wrote:
> >
> > To use ad5593r more flexibly, we use the module parameter to setting the
> > channel modes dynamically whenever the module probe up.
>
> > Users can pass
> > the channel modes to the module parameter for allocating the
> > functionality of channels as desired.
>
> NAK. We have a sysfs interface.
>
> > For example:
> > * Use in the kernel command line:
> > Users can add the module parameter in the kernel command line such as
> >
> >     "ad5593r.ch_mode_cmdline=88001122"
> >
> > "88001122" means the channel mode setting for each channel. The most
> > left side indicates the mode of channel 7, and the most right side
> > indicates the mode of channel 0.
> >
> > * Use when manually probe the module:
> > Similar to the kernel command line usage, users can enter
> >
> >     "modprobe ad5593r ch_mode_probe=88001122"
> >
> > to start the ad5593r module with the desired channel mode setting.
>
> Again NAK, this basically should come from Device Tree or ACPI.
>
> --
> With Best Regards,
> Andy Shevchenko