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| Started by | Alexandru M Stan <amstan@chromium.org> |
|---|---|
| First post | 2015-09-03 01:30 +0200 |
| Last post | 2015-09-03 21:10 +0200 |
| Articles | 4 — 3 participants |
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[PATCH v2 0/2] ARM: dts: rockchip: pull up cts lines Alexandru M Stan <amstan@chromium.org> - 2015-09-03 01:30 +0200
[PATCH v2 1/2] ARM: dts: rockchip: pull up cts lines on rk3288 Alexandru M Stan <amstan@chromium.org> - 2015-09-03 01:30 +0200
Re: [PATCH v2 1/2] ARM: dts: rockchip: pull up cts lines on rk3288 Doug Anderson <dianders@chromium.org> - 2015-09-03 01:40 +0200
Re: [PATCH v2 0/2] ARM: dts: rockchip: pull up cts lines Heiko Stuebner <heiko@sntech.de> - 2015-09-03 21:10 +0200
| From | Alexandru M Stan <amstan@chromium.org> |
|---|---|
| Date | 2015-09-03 01:30 +0200 |
| Subject | [PATCH v2 0/2] ARM: dts: rockchip: pull up cts lines |
| Message-ID | <q4pDz-2R2-5@gated-at.bofh.it> |
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. The only boards affected (that care about uart*_cts ) are the veyron chromeos devices and the firefly. Veyron already has something like that, which I now have to remove in the second patch. Firefly uses uart0_cts for the wifi chip communications, same thing as veyron, so it should be fine having it. Changes in v2: - Restrict changes only to cts pin, leave rts alone - CC people with the firefly board - New patch removing redundant pullup code from veyron - cover letter Alexandru M Stan (2): ARM: dts: rockchip: pull up cts lines on rk3288 ARM: dts: rockchip: Remove specific cts pullup from veyron arch/arm/boot/dts/rk3288-veyron.dtsi | 12 ------------ arch/arm/boot/dts/rk3288.dtsi | 8 ++++---- 2 files changed, 4 insertions(+), 16 deletions(-) -- 2.5.0.457.gab17608 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Alexandru M Stan <amstan@chromium.org> |
|---|---|
| Date | 2015-09-03 01:30 +0200 |
| Subject | [PATCH v2 1/2] ARM: dts: rockchip: pull up cts lines on rk3288 |
| Message-ID | <q4pDz-2R2-7@gated-at.bofh.it> |
| In reply to | #1217915 |
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
--
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| From | Doug Anderson <dianders@chromium.org> |
|---|---|
| Date | 2015-09-03 01:40 +0200 |
| Subject | Re: [PATCH v2 1/2] ARM: dts: rockchip: pull up cts lines on rk3288 |
| Message-ID | <q4pNf-32i-1@gated-at.bofh.it> |
| In reply to | #1217916 |
Alex, On Wed, Sep 2, 2015 at 4:27 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 > 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 Probably not entirely true. ;) > arch/arm/boot/dts/rk3288.dtsi | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) Looks good to me. Reviewed-by: Douglas Anderson <dianders@chromium.org> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Heiko Stuebner <heiko@sntech.de> |
|---|---|
| Date | 2015-09-03 21:10 +0200 |
| Message-ID | <q4I3w-45w-7@gated-at.bofh.it> |
| In reply to | #1217915 |
Hi Alex, Am Mittwoch, 2. September 2015, 16:27:57 schrieb Alexandru M Stan: > 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. > > The only boards affected (that care about uart*_cts ) are the veyron > chromeos devices and the firefly. Veyron already has something like that, > which I now have to remove in the second patch. Firefly uses uart0_cts > for the wifi chip communications, same thing as veyron, so it should be > fine having it. applied both to my dts branch for 4.4 with Doug's Review-tag (Currently only on github and becomes really public after 4.3-rc1) Heiko -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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