| Message ID | 20191126123116.56244-1-linus.walleij@linaro.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 27e7c033d3b4101bc3b9a344265de5ae89e09b42 |
| Headers | show |
| Series | ARM: dts: ux500: Drop pulls on I2C buses | expand |
On Tue, Nov 26, 2019 at 01:31:16PM +0100, Linus Walleij wrote: > The I2C block in the Ux500 uses internal pull-ups on the > SoC, in fact it has to: in HS mode, the I2C block will need > to autonomously take control over the pull-up line to do > its job. This can be clearly seen from the SoC manual which > states that the silicon has a line named "en_cspu_hs" which > enables current source pull-up for high speed mode. Another > hint is that the vendor code tree never enabled the pull > up on these lines, despite being deployed on boards that > lack external pull-up resistors. > > Tested on the Ux500 reference designs without any problems. > > Cc: Stephan Gerhold <stephan@gerhold.net> > Reported-by: Stephan Gerhold <stephan@gerhold.net> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Stephan Gerhold <stephan@gerhold.net> FWIW, on samsung,golden: Tested-by: Stephan Gerhold <stephan@gerhold.net> > --- > arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi b/arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi > index e85a08ad2ea7..7bf7a2d34cbc 100644 > --- a/arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi > +++ b/arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi > @@ -130,7 +130,7 @@ > }; > default_cfg1 { > pins = "GPIO147_C15", "GPIO148_B16"; /* SDA/SCL */ > - ste,config = <&in_pu>; > + ste,config = <&in_nopull>; > }; > }; > > @@ -150,7 +150,7 @@ > }; > default_cfg1 { > pins = "GPIO16_AD3", "GPIO17_AD4"; /* SDA/SCL */ > - ste,config = <&in_pu>; > + ste,config = <&in_nopull>; > }; > }; > > @@ -170,7 +170,7 @@ > }; > default_cfg1 { > pins = "GPIO10_AF5", "GPIO11_AG4"; /* SDA/SCL */ > - ste,config = <&in_pu>; > + ste,config = <&in_nopull>; > }; > }; > > @@ -190,7 +190,7 @@ > }; > default_cfg1 { > pins = "GPIO229_AG7", "GPIO230_AF7"; /* SDA/SCL */ > - ste,config = <&in_pu>; > + ste,config = <&in_nopull>; > }; > }; > > @@ -214,7 +214,7 @@ > }; > default_cfg1 { > pins = "GPIO4_AH6", "GPIO5_AG6"; /* SDA/SCL */ > - ste,config = <&in_pu>; > + ste,config = <&in_nopull>; > }; > }; > > -- > 2.23.0 >
diff --git a/arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi b/arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi index e85a08ad2ea7..7bf7a2d34cbc 100644 --- a/arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi +++ b/arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi @@ -130,7 +130,7 @@ }; default_cfg1 { pins = "GPIO147_C15", "GPIO148_B16"; /* SDA/SCL */ - ste,config = <&in_pu>; + ste,config = <&in_nopull>; }; }; @@ -150,7 +150,7 @@ }; default_cfg1 { pins = "GPIO16_AD3", "GPIO17_AD4"; /* SDA/SCL */ - ste,config = <&in_pu>; + ste,config = <&in_nopull>; }; }; @@ -170,7 +170,7 @@ }; default_cfg1 { pins = "GPIO10_AF5", "GPIO11_AG4"; /* SDA/SCL */ - ste,config = <&in_pu>; + ste,config = <&in_nopull>; }; }; @@ -190,7 +190,7 @@ }; default_cfg1 { pins = "GPIO229_AG7", "GPIO230_AF7"; /* SDA/SCL */ - ste,config = <&in_pu>; + ste,config = <&in_nopull>; }; }; @@ -214,7 +214,7 @@ }; default_cfg1 { pins = "GPIO4_AH6", "GPIO5_AG6"; /* SDA/SCL */ - ste,config = <&in_pu>; + ste,config = <&in_nopull>; }; };
The I2C block in the Ux500 uses internal pull-ups on the SoC, in fact it has to: in HS mode, the I2C block will need to autonomously take control over the pull-up line to do its job. This can be clearly seen from the SoC manual which states that the silicon has a line named "en_cspu_hs" which enables current source pull-up for high speed mode. Another hint is that the vendor code tree never enabled the pull up on these lines, despite being deployed on boards that lack external pull-up resistors. Tested on the Ux500 reference designs without any problems. Cc: Stephan Gerhold <stephan@gerhold.net> Reported-by: Stephan Gerhold <stephan@gerhold.net> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- arch/arm/boot/dts/ste-dbx5x0-pinctrl.dtsi | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)