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

[Chuanhua Han]

> -----Original Message-----
> From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> Sent: 2019年4月30日 20:51
> To: Chuanhua Han <chuanhua.han@xxxxxxx>
> Cc: shawnguo@xxxxxxxxxx; Leo Li <leoyang.li@xxxxxxx>; robh+dt@xxxxxxxxxx;
> mark.rutland@xxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> linux-i2c@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; festevam@xxxxxxxxx; dl-linux-imx
> <linux-imx@xxxxxxx>; wsa+renesas@xxxxxxxxxxxxxxxxxxxx;
> u.kleine-koenig@xxxxxxxxxxxxxx; eha@xxxxxxxx; linux@xxxxxxxxxxxxxxxx;
> l.stach@xxxxxxxxxxxxxx; peda@xxxxxxxxxx; Sumit Batra
> <sumit.batra@xxxxxxx>
> 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
> 
> --
> Pengutronix e.K.                           |
> |
> Industrial Linux Solutions                 |
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.pe
> ngutronix.de%2F&amp;data=02%7C01%7Cchuanhua.han%40nxp.com%7C2bb
> a89c908fb4bd37b6708d6cd6a7ff7%7C686ea1d3bc2b4c6fa92cd99c5c301635
> %7C0%7C0%7C636922254625472037&amp;sdata=eC4bGDNAOhEu24xt9F0h
> kxE%2B1ffooCZ4CUr4o0gQGD4%3D&amp;reserved=0  |
> Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0
> |
> Amtsgericht Hildesheim, HRA 2686           | Fax:
> +49-5121-206917-5555 |