ARM: dts: rk3288: pull up cts lines
diff mbox

Message ID 1441232406-32628-1-git-send-email-amstan@chromium.org
State New
Headers show

Commit Message

Alexandru M Stan Sept. 2, 2015, 10:20 p.m. UTC
The flow control lines from a user accessible UART are optional,
the user might not have anything connected to those pins.
In order to prevent random interrupts happening and noise affecting
that pin it should be pulled up.

Note that the default state for those pins on the rk3288 is pulled up,
so this patch merely restores them.

Suggested-by: Neil Hendin <nhendin@chromium.org>
Signed-off-by: Alexandru M Stan <amstan@chromium.org>
---
 arch/arm/boot/dts/rk3288.dtsi | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

Doug Anderson Sept. 2, 2015, 10:57 p.m. UTC | #1
Alex,

On Wed, Sep 2, 2015 at 3:20 PM, Alexandru M Stan <amstan@chromium.org> wrote:
> The flow control lines from a user accessible UART are optional,
> the user might not have anything connected to those pins.
> In order to prevent random interrupts happening and noise affecting
> that pin it should be pulled up.
>
> Note that the default state for those pins on the rk3288 is pulled up,
> so this patch merely restores them.
>
> Suggested-by: Neil Hendin <nhendin@chromium.org>
> Signed-off-by: Alexandru M Stan <amstan@chromium.org>
> ---
>  arch/arm/boot/dts/rk3288.dtsi | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
> index 906e938..a059367 100644
> --- a/arch/arm/boot/dts/rk3288.dtsi
> +++ b/arch/arm/boot/dts/rk3288.dtsi
> @@ -1211,11 +1211,11 @@
>                         };
>
>                         uart0_cts: uart0-cts {
> -                               rockchip,pins = <4 18 RK_FUNC_1 &pcfg_pull_none>;
> +                               rockchip,pins = <4 18 RK_FUNC_1 &pcfg_pull_up>;
>                         };
>
>                         uart0_rts: uart0-rts {
> -                               rockchip,pins = <4 19 RK_FUNC_1 &pcfg_pull_none>;
> +                               rockchip,pins = <4 19 RK_FUNC_1 &pcfg_pull_up>;

I would probably do just CTS.  That would match the TX / RX lines
where the RX is pulled but not the TX.

You might also mention in the commit message that this really should
be safe since we're already doing something similar for RX.


-Doug

Patch
diff mbox

diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
index 906e938..a059367 100644
--- a/arch/arm/boot/dts/rk3288.dtsi
+++ b/arch/arm/boot/dts/rk3288.dtsi
@@ -1211,11 +1211,11 @@ 
 			};
 
 			uart0_cts: uart0-cts {
-				rockchip,pins = <4 18 RK_FUNC_1 &pcfg_pull_none>;
+				rockchip,pins = <4 18 RK_FUNC_1 &pcfg_pull_up>;
 			};
 
 			uart0_rts: uart0-rts {
-				rockchip,pins = <4 19 RK_FUNC_1 &pcfg_pull_none>;
+				rockchip,pins = <4 19 RK_FUNC_1 &pcfg_pull_up>;
 			};
 		};
 
@@ -1226,11 +1226,11 @@ 
 			};
 
 			uart1_cts: uart1-cts {
-				rockchip,pins = <5 10 RK_FUNC_1 &pcfg_pull_none>;
+				rockchip,pins = <5 10 RK_FUNC_1 &pcfg_pull_up>;
 			};
 
 			uart1_rts: uart1-rts {
-				rockchip,pins = <5 11 RK_FUNC_1 &pcfg_pull_none>;
+				rockchip,pins = <5 11 RK_FUNC_1 &pcfg_pull_up>;
 			};
 		};
 
@@ -1249,11 +1249,11 @@ 
 			};
 
 			uart3_cts: uart3-cts {
-				rockchip,pins = <7 9 RK_FUNC_1 &pcfg_pull_none>;
+				rockchip,pins = <7 9 RK_FUNC_1 &pcfg_pull_up>;
 			};
 
 			uart3_rts: uart3-rts {
-				rockchip,pins = <7 10 RK_FUNC_1 &pcfg_pull_none>;
+				rockchip,pins = <7 10 RK_FUNC_1 &pcfg_pull_up>;
 			};
 		};
 
@@ -1264,11 +1264,11 @@ 
 			};
 
 			uart4_cts: uart4-cts {
-				rockchip,pins = <5 14 3 &pcfg_pull_none>;
+				rockchip,pins = <5 14 3 &pcfg_pull_up>;
 			};
 
 			uart4_rts: uart4-rts {
-				rockchip,pins = <5 15 3 &pcfg_pull_none>;
+				rockchip,pins = <5 15 3 &pcfg_pull_up>;
 			};
 		};