RE: [EXT] Re: [PATCH 1/2] i2c: imx: I2C Driver doesn't consider I2C_IPGCLK_SEL RCW bit when using ls1046a SoC

[Chuanhua Han <chuanhua.han@nxp.com>]

> -----Original Message-----
> From: Sascha Hauer <s.hauer@pengutronix.de>
> Sent: 2019年4月30日 20:51
> To: Chuanhua Han <chuanhua.han@nxp.com>
> Cc: shawnguo@kernel.org; Leo Li <leoyang.li@nxp.com>; robh+dt@kernel.org;
> mark.rutland@arm.com; linux-kernel@vger.kernel.org;
> linux-i2c@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> devicetree@vger.kernel.org; festevam@gmail.com; dl-linux-imx
> <linux-imx@nxp.com>; wsa+renesas@sang-engineering.com;
> u.kleine-koenig@pengutronix.de; eha@deif.com; linux@rempel-privat.de;
> l.stach@pengutronix.de; peda@axentia.se; Sumit Batra
> <sumit.batra@nxp.com>
> Subject: [EXT] Re: [PATCH 1/2] i2c: imx: I2C Driver doesn't consider
> I2C_IPGCLK_SEL RCW bit when using ls1046a SoC
> 
> Caution: EXT Email
> 
> On Tue, Apr 30, 2019 at 12:47:18PM +0800, Chuanhua Han wrote:
> > The current kernel driver does not consider I2C_IPGCLK_SEL (424 bit of
> > RCW) in deciding  i2c_clk_rate in function i2c_imx_set_clk() { 0
> > Platform clock/4, 1 Platform clock/2}.
> >
> > When using ls1046a SoC, this populates incorrect value in IBFD
> > register if I2C_IPGCLK_SEL = 0, which generates half of the desired Clock.
> >
> > Therefore, if ls1046a SoC is used, we need to set the i2c clock
> > according to the corresponding RCW.
> 
> So the clock driver reports the wrong clock. Please fix the clock driver then.
No, this is a problem with the i2c driver. It is not a problem with the clock driver, so the i2c driver needs to be modified.
> 
> Sascha
> 
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