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Date:   Mon, 25 Sep 2023 14:04:15 +0200
From:   Andreas Kemnade <andreas@kemnade.info>
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     jic23@kernel.org, lars@metafoo.de, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        bcousson@baylibre.com, tony@atomide.com,
        jean-baptiste.maneyrol@tdk.com, chenhuiz@axis.com,
        linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org
Subject: Re: [PATCH 2/3] iio: imu: mpu6050: add level shifter flag
Message-ID: <20230925140415.00130082@aktux>
In-Reply-To: <CAHp75VfvmED4ZsmrH4B6m9kGsH=68-zjQd5JMszb6UBTtbF0bw@mail.gmail.com>
References: <20230924222559.2038721-1-andreas@kemnade.info>
        <20230924222559.2038721-3-andreas@kemnade.info>
        <CAHp75VfvmED4ZsmrH4B6m9kGsH=68-zjQd5JMszb6UBTtbF0bw@mail.gmail.com>
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On Mon, 25 Sep 2023 14:07:58 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Mon, Sep 25, 2023 at 1:26 AM Andreas Kemnade <andreas@kemnade.info> wrote:
> >
> > Some boards fail in magnetometer probe if flag is not set.  
> 
> Which flag? Can you elaborate a bit more?
> 
well see $subj. The level shifter flag.

> Does it deserve the Fixes tag?
> 
As there are only certain boards affected, they would also have
to add the flag in dtb, I do not think it deservers a Fixes tag.
Even in the board I have here, there are basically two
mpu9150 connected per cable, only one of them needs the flag.

> ...
> 
> >         unsigned int val;
> >         int ret;  
> 
> > +       ret = regmap_update_bits(st->map, 0x1, 0x80,
> > +                                st->level_shifter ? 0x80 : 0);  
> 
> This is a bit cryptic, what does 1 stand for?
> 
Well, I do not find anything in
https://invensense.tdk.com/wp-content/uploads/2015/02/MPU-9150-Register-Map.pdf
I have just found a similar line in the ancient 3.0 vendor kernel. No symbolic
names there.

Regards,
Andreas