Re: [RESEND] i2c: mediatek: Get device clock-stretch time via dts

2021-04-13 Thread Qii Wang
On Tue, 2021-04-13 at 22:17 +0200, Wolfram Sang wrote: > On Mon, Apr 12, 2021 at 08:03:14PM +0800, Qii Wang wrote: > > I can't see the relationship between "i2c-scl-falling-time-ns" and clock > > stretching, is there a parameter related to clock stretching? > > ( you wrote

Re: [RESEND] i2c: mediatek: Get device clock-stretch time via dts

2021-04-13 Thread Wolfram Sang
On Mon, Apr 12, 2021 at 08:03:14PM +0800, Qii Wang wrote: > On Wed, 2021-04-07 at 20:19 +0200, Wolfram Sang wrote: > > > Due to clock stretch, our HW IP cannot meet the ac-timing > > > spec(tSU;STA,tSU;STO). > > > There isn't a same delay for clock stretching, so we need pass a > > > parameter

Re: [RESEND] i2c: mediatek: Get device clock-stretch time via dts

2021-04-12 Thread Qii Wang
On Wed, 2021-04-07 at 20:19 +0200, Wolfram Sang wrote: > > Due to clock stretch, our HW IP cannot meet the ac-timing > > spec(tSU;STA,tSU;STO). > > There isn't a same delay for clock stretching, so we need pass a > > parameter which can be found through measurement to meet most > > conditions. >

Re: [RESEND] i2c: mediatek: Get device clock-stretch time via dts

2021-04-07 Thread Wolfram Sang
> Due to clock stretch, our HW IP cannot meet the ac-timing > spec(tSU;STA,tSU;STO). > There isn't a same delay for clock stretching, so we need pass a > parameter which can be found through measurement to meet most > conditions. What about using this existing binding? -

Re: [RESEND] i2c: mediatek: Get device clock-stretch time via dts

2021-04-07 Thread Qii Wang
On Tue, 2021-04-06 at 21:48 +0200, Wolfram Sang wrote: > On Sat, Mar 13, 2021 at 04:04:24PM +0800, qii.w...@mediatek.com wrote: > > From: Qii Wang > > > > tSU,STA/tHD,STA/tSU,STOP maybe out of spec due to device > > clock-stretching or circuit loss, we could get device > > clock-stretch time

Re: [RESEND] i2c: mediatek: Get device clock-stretch time via dts

2021-04-06 Thread Wolfram Sang
On Sat, Mar 13, 2021 at 04:04:24PM +0800, qii.w...@mediatek.com wrote: > From: Qii Wang > > tSU,STA/tHD,STA/tSU,STOP maybe out of spec due to device > clock-stretching or circuit loss, we could get device > clock-stretch time from dts to adjust these parameters > to meet the spec via EXT_CONF

Re: [RESEND] i2c: mediatek: Get device clock-stretch time via dts

2021-03-18 Thread Wolfram Sang
> tSU,STA/tHD,STA/tSU,STOP maybe out of spec due to device > clock-stretching or circuit loss, we could get device > clock-stretch time from dts to adjust these parameters > to meet the spec via EXT_CONF register. > > Signed-off-by: Qii Wang I will look at this next and think about it. New

[RESEND] i2c: mediatek: Get device clock-stretch time via dts

2021-03-13 Thread qii.wang
From: Qii Wang tSU,STA/tHD,STA/tSU,STOP maybe out of spec due to device clock-stretching or circuit loss, we could get device clock-stretch time from dts to adjust these parameters to meet the spec via EXT_CONF register. Signed-off-by: Qii Wang --- drivers/i2c/busses/i2c-mt65xx.c | 6 +-