* [PATCH 1/4] ARM: imx: update i.MX6Q dts setting of VDDARM_CAP voltage
@ 2013-12-16 21:07 Anson Huang
2013-12-17 1:36 ` Shawn Guo
2013-12-19 3:03 ` Shawn Guo
0 siblings, 2 replies; 3+ messages in thread
From: Anson Huang @ 2013-12-16 21:07 UTC (permalink / raw)
To: linux-arm-kernel
According to datasheet, VDD_CACHE_CAP must not exceed VDDARM_CAP
by more than 200mV, as all of i.MX6Q boards' VDD_CACHE_CAP currently
are connected to VDDSOC_CAP, so we need to follow this rule by
increasing VDDARM_CAP's voltage.
Signed-off-by: Anson Huang <b20788@freescale.com>
---
arch/arm/boot/dts/imx6q.dtsi | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi
index 101c434..e7e8332 100644
--- a/arch/arm/boot/dts/imx6q.dtsi
+++ b/arch/arm/boot/dts/imx6q.dtsi
@@ -28,7 +28,7 @@
1200000 1275000
996000 1250000
792000 1150000
- 396000 950000
+ 396000 975000
>;
clock-latency = <61036>; /* two CLK32 periods */
clocks = <&clks 104>, <&clks 6>, <&clks 16>,
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 1/4] ARM: imx: update i.MX6Q dts setting of VDDARM_CAP voltage
2013-12-16 21:07 [PATCH 1/4] ARM: imx: update i.MX6Q dts setting of VDDARM_CAP voltage Anson Huang
@ 2013-12-17 1:36 ` Shawn Guo
2013-12-19 3:03 ` Shawn Guo
1 sibling, 0 replies; 3+ messages in thread
From: Shawn Guo @ 2013-12-17 1:36 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Dec 16, 2013 at 04:07:37PM -0500, Anson Huang wrote:
> According to datasheet, VDD_CACHE_CAP must not exceed VDDARM_CAP
> by more than 200mV, as all of i.MX6Q boards' VDD_CACHE_CAP currently
> are connected to VDDSOC_CAP, so we need to follow this rule by
> increasing VDDARM_CAP's voltage.
The commit log is a little bit vague, and you should probably make the
following points clearer.
1. This is only a problem for 396MHz operating-point, and the other 3
are fine.
2. What's the VDDSOC_CAP value for 396MHz operating-point right now?
From what I read drivers/cpufreq/imx6q-cpufreq.c, it's 1250mV. Then
the obvious question is why we're not increasing VDDARM_CAP to
1250 - 200 = 1050mV but 975mV?
Shawn
>
> Signed-off-by: Anson Huang <b20788@freescale.com>
> ---
> arch/arm/boot/dts/imx6q.dtsi | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi
> index 101c434..e7e8332 100644
> --- a/arch/arm/boot/dts/imx6q.dtsi
> +++ b/arch/arm/boot/dts/imx6q.dtsi
> @@ -28,7 +28,7 @@
> 1200000 1275000
> 996000 1250000
> 792000 1150000
> - 396000 950000
> + 396000 975000
> >;
> clock-latency = <61036>; /* two CLK32 periods */
> clocks = <&clks 104>, <&clks 6>, <&clks 16>,
> --
> 1.7.9.5
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/4] ARM: imx: update i.MX6Q dts setting of VDDARM_CAP voltage
2013-12-16 21:07 [PATCH 1/4] ARM: imx: update i.MX6Q dts setting of VDDARM_CAP voltage Anson Huang
2013-12-17 1:36 ` Shawn Guo
@ 2013-12-19 3:03 ` Shawn Guo
1 sibling, 0 replies; 3+ messages in thread
From: Shawn Guo @ 2013-12-19 3:03 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Dec 16, 2013 at 04:07:37PM -0500, Anson Huang wrote:
> According to datasheet, VDD_CACHE_CAP must not exceed VDDARM_CAP
> by more than 200mV, as all of i.MX6Q boards' VDD_CACHE_CAP currently
> are connected to VDDSOC_CAP, so we need to follow this rule by
> increasing VDDARM_CAP's voltage.
>
> Signed-off-by: Anson Huang <b20788@freescale.com>
Applied after reword the patch subject as 'ARM: dts: imx6q: update
setting of VDDARM_CAP voltage'.
Note, for IMX dts changes, we generally use 'ARM: dts: imxXXX:' as
prefix in patch subject.
Shawn
> ---
> arch/arm/boot/dts/imx6q.dtsi | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi
> index 101c434..e7e8332 100644
> --- a/arch/arm/boot/dts/imx6q.dtsi
> +++ b/arch/arm/boot/dts/imx6q.dtsi
> @@ -28,7 +28,7 @@
> 1200000 1275000
> 996000 1250000
> 792000 1150000
> - 396000 950000
> + 396000 975000
> >;
> clock-latency = <61036>; /* two CLK32 periods */
> clocks = <&clks 104>, <&clks 6>, <&clks 16>,
> --
> 1.7.9.5
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-12-19 3:03 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-12-16 21:07 [PATCH 1/4] ARM: imx: update i.MX6Q dts setting of VDDARM_CAP voltage Anson Huang
2013-12-17 1:36 ` Shawn Guo
2013-12-19 3:03 ` Shawn Guo
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).