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Date:   Thu, 9 May 2019 09:55:28 +0200
From:   Wolfram Sang <wsa@the-dreams.de>
To:     Sascha Hauer <s.hauer@pengutronix.de>
Cc:     Sumit Batra <sumit.batra@nxp.com>,
        Chuanhua Han <chuanhua.han@nxp.com>,
        "shawnguo@kernel.org" <shawnguo@kernel.org>,
        Leo Li <leoyang.li@nxp.com>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "mark.rutland@arm.com" <mark.rutland@arm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "festevam@gmail.com" <festevam@gmail.com>,
        dl-linux-imx <linux-imx@nxp.com>,
        "wsa+renesas@sang-engineering.com" <wsa+renesas@sang-engineering.com>,
        "u.kleine-koenig@pengutronix.de" <u.kleine-koenig@pengutronix.de>,
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        "l.stach@pengutronix.de" <l.stach@pengutronix.de>,
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Subject: Re: [EXT] Re: [PATCH 1/2] i2c: imx: I2C Driver doesn't consider
 I2C_IPGCLK_SEL RCW bit when using ls1046a SoC
Message-ID: <20190509075528.obzchc3midbjpvzs@katana>
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> > There are 2 places where clock division takes place -
> >=20
> > 1) There is a clock divider outside of I2C block, which makes the clock=
 reaching
> >    I2C module as - Platform Clock/2
> > 2) There is another clock divider which specifically divides the clock =
to the I2C block,
> >    based on RCW bit 424 (if 424th bit is 0 then the baud clock source i=
s Platform Clock/4,
> >    if 424th bit is 1 then it remains Platform Clock/2)
>=20
> So there is a clock divider which based on RCW bit 424 divides the clock
> *to* the i2c module. This suggests the divider is outside of the i2c
> module itself and thus part of the clock module.
>=20
> We could argue that this divider sits between the clock module and the
> i2c module, but for sure it's not in the i2c module. I really suggest to
> put this SoC specific into the SoC specific clock driver rather than
> littering the i2c driver with it.

I am with Sascha here. The fact that you need to of_ioremap some
registers is a really strong indication that the code should go
somewhere else. I can't tell the best place (clock driver or seperate
GUTS driver or syscon driver), but the I2C bus driver seems not
suitable.


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