[PATCH] arm: dts: socfpga: cyclone5: Update i2c-scl-falling-time-ns

Tan, Ley Foon ley.foon.tan at intel.com
Tue Jun 9 11:54:45 CEST 2020



> -----Original Message-----
> From: Marek Vasut <marex at denx.de>
> Sent: Tuesday, June 9, 2020 5:53 PM
> To: Tan, Ley Foon <ley.foon.tan at intel.com>; u-boot at lists.denx.de
> Cc: Ley Foon Tan <lftan.linux at gmail.com>; See, Chin Liang
> <chin.liang.see at intel.com>; Simon Goldschmidt
> <simon.k.r.goldschmidt at gmail.com>; Ang, Chee Hong
> <chee.hong.ang at intel.com>
> Subject: Re: [PATCH] arm: dts: socfpga: cyclone5: Update i2c-scl-falling-
> time-ns
> 
> On 6/9/20 8:33 AM, Tan, Ley Foon wrote:
> [...]
> >>> Commit e71b6f6622d6 ("i2c: designware_i2c: Rewrite timing
> >>> calculation") change the hcnt and lcnt timing calculation.
> >>>
> >>> After this new timing calculation, hcnt will have negative value
> >>> with i2c-scl-falling-time-ns 5000 that set in socfpga_cyclone5_socdk.dts.
> >> Shouldn't either the driver or the calculation be fixed instead ?
> > The original timing calculation in driver doesn't take fall time or rise time
> into calculation.
> > The new i2c timing calculation is based on calculation from Designware i2c
> databook. So, I don't think need fix in driver.
> 
> Then just mention it in the commit message that it's from the databook
> please.
Okay.

Regards
Ley Foon


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