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From: Alexandru M Stan <amstan@chromium.org>
To: Heiko Stuebner <heiko@sntech.de>
Cc: Romain Perier <romain.perier@gmail.com>,
	FUKAUMI Naoki <naobsd@gmail.com>,
	Neil Hendin <nhendin@chromium.org>,
	Douglas Anderson <dianders@chromium.org>,
	Jeffy Chen <jeffy.chen@rock-chips.com>,
	Caesar Wang <wxt@rock-chips.com>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Alexandru M Stan <amstan@chromium.org>
Subject: [PATCH v2 1/2] ARM: dts: rockchip: pull up cts lines on rk3288
Date: Wed,  2 Sep 2015 16:27:58 -0700	[thread overview]
Message-ID: <1441236479-4941-2-git-send-email-amstan@chromium.org> (raw)
In-Reply-To: <1441236479-4941-1-git-send-email-amstan@chromium.org>

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
the cts pin should be pulled up.

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

This is similar to what we're already doing with the RX pin,
so it should be safe. At worst it might be a slightly higher power usage
(through ~50 kohms) when the cts is low.

Suggested-by: Neil Hendin <nhendin@chromium.org>
Signed-off-by: Alexandru M Stan <amstan@chromium.org>
---
Changes in v2: None

 arch/arm/boot/dts/rk3288.dtsi | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
index 906e938..0e8fd53 100644
--- a/arch/arm/boot/dts/rk3288.dtsi
+++ b/arch/arm/boot/dts/rk3288.dtsi
@@ -1211,7 +1211,7 @@
 			};
 
 			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 {
@@ -1226,7 +1226,7 @@
 			};
 
 			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 {
@@ -1249,7 +1249,7 @@
 			};
 
 			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 {
@@ -1264,7 +1264,7 @@
 			};
 
 			uart4_cts: uart4-cts {
-				rockchip,pins = <5 14 3 &pcfg_pull_none>;
+				rockchip,pins = <5 14 3 &pcfg_pull_up>;
 			};
 
 			uart4_rts: uart4-rts {
-- 
2.5.0.457.gab17608

  reply	other threads:[~2015-09-02 23:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-02 23:27 [PATCH v2 0/2] ARM: dts: rockchip: pull up cts lines Alexandru M Stan
2015-09-02 23:27 ` Alexandru M Stan [this message]
2015-09-02 23:34   ` [PATCH v2 1/2] ARM: dts: rockchip: pull up cts lines on rk3288 Doug Anderson
2015-09-02 23:27 ` [PATCH v2 2/2] ARM: dts: rockchip: Remove specific cts pullup from veyron Alexandru M Stan
     [not found]   ` <1441236479-4941-3-git-send-email-amstan-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2015-09-02 23:35     ` Doug Anderson
     [not found] ` <1441236479-4941-1-git-send-email-amstan-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2015-09-03 19:03   ` [PATCH v2 0/2] ARM: dts: rockchip: pull up cts lines Heiko Stuebner

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