| Message ID | 1624271985-23591-3-git-send-email-kewei.xu@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce an attribute to choose timing setting | expand |
On Mon, Jun 21, 2021 at 06:39:44PM +0800, kewei.xu@mediatek.com wrote: > From: Kewei Xu <kewei.xu@mediatek.com> > > Add attribute default-timing-adjust for DT-binding document. > > Fixes: be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing adjust support") You want to fix a kernel change with a DT change? That's not a compatible change (and I guess neither was the kernel change). Sounds like the above commit should be reverted and rethink how to add a new feature... > Signed-off-by: Kewei Xu <kewei.xu@mediatek.com> > --- > Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt b/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt > index 7c4915bc..7b80a11 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt > @@ -33,6 +33,8 @@ Optional properties: > - mediatek,have-pmic: platform can control i2c form special pmic side. > Only mt6589 and mt8135 support this feature. > - mediatek,use-push-pull: IO config use push-pull mode. > + - mediatek,default-timing-adjust: use default timing calculation, no timing > + adjustment. > > Example: > > -- > 1.9.1 > >
On Mon, 2021-07-12 at 14:53 -0600, Rob Herring wrote: > On Mon, Jun 21, 2021 at 06:39:44PM +0800, kewei.xu@mediatek.com wrote: > > From: Kewei Xu <kewei.xu@mediatek.com> > > > > Add attribute default-timing-adjust for DT-binding document. > > > > Fixes: be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing adjust support") > > You want to fix a kernel change with a DT change? That's not a > compatible change (and I guess neither was the kernel change). Sounds > like the above commit should be reverted and rethink how to add a new > feature... > > > Signed-off-by: Kewei Xu <kewei.xu@mediatek.com> > > --- > > Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt b/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt > > index 7c4915bc..7b80a11 100644 > > --- a/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt > > +++ b/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt > > @@ -33,6 +33,8 @@ Optional properties: > > - mediatek,have-pmic: platform can control i2c form special pmic side. > > Only mt6589 and mt8135 support this feature. > > - mediatek,use-push-pull: IO config use push-pull mode. > > + - mediatek,default-timing-adjust: use default timing calculation, no timing > > + adjustment. > > > > Example: > > > > -- > > 1.9.1 > > > > Hi Rob, In the commit be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing adjust support"), the I2C timing calculation has been revised to support ac-timing adjustment.But in our design, it will make tSU,STA/tHD,STA/tSU,STO shorter when the slave device have clock-stretching feature. Then we upload the commit a80f24945fcf ("i2c: mediatek: Use scl_int_delay_ns to compensate clock-stretching") to support adjusting tSU,STA/tHD,STA/tSU,STO when the slave device clock-stretching. But if the slave device stretch the SCL line for too long time, our design still cannot make tSU,STA/tHD,STA/tSU,STO meet spec. However in the old (default) timing algorithm before the commit be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing adjust support"), tSU,STA/tHD,STA/tSU,STO can meet spec. So we want to define a new setting "default-adjust-timing" for using the old (default) timing algorithm. thanks kewei
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt b/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt index 7c4915bc..7b80a11 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt @@ -33,6 +33,8 @@ Optional properties: - mediatek,have-pmic: platform can control i2c form special pmic side. Only mt6589 and mt8135 support this feature. - mediatek,use-push-pull: IO config use push-pull mode. + - mediatek,default-timing-adjust: use default timing calculation, no timing + adjustment. Example: