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ARM: mvebu: armada-xp-openblocks-ax3-4: Disable internal RTC

PATCH New Gregory CLEMENT 4 participants 6 messages Apr 15, 2015 – Apr 27, 2015

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Gregory CLEMENT

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#0 lore raw

PATCH 1/1 ARM: mvebu: armada-xp-openblocks-ax3-4: Disable internal RTC

There is no crystal connected to the internal RTC on the Open Block AX3. So let's disable it in order to prevent the kernel probing the driver uselessly. Eventually this patches removes the following warning message from the boot log:
"rtc-mv d0010300.rtc: internal RTC not ticking"

Signed-off-by Gregory CLEMENT <[email protected]>
Cc <[email protected]> # v3.8 +

---
Hi,

I plan to add this patch to mvebu/fixes once the v4.1-rc1 will be released. I don't expect much comments about it, but there is time for them if needed until the next PR.

Thanks,

Gregory

 arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts | 4 ++++
 1 file changed, 4 insertions(+)
arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts +4 -0
index 0c76d9f05fd0..f4838ebd918b 100644
@@ -105,6 +105,10 @@
 		};
 
 		internal-regs {
+			rtc at 10300 {
+				/* No crystal connected to the internal RTC */
+				status = "disabled";
+			};
 			serial at 12000 {
 				status = "okay";
 			};
Signature · 1 line
2.1.0
#1 lore raw

PATCH 1/1 ARM: mvebu: armada-xp-openblocks-ax3-4: Disable internal RTC

Quoted 5 lines · Gregory CLEMENT

There is no crystal connected to the internal RTC on the Open Block AX3. So let's disable it in order to prevent the kernel probing the driver uselessly. Eventually this patches removes the following warning message from the boot log:
"rtc-mv d0010300.rtc: internal RTC not ticking"

Hi Gregory

I've seen this as well with my device.

Acked-by Andrew Lunn <[email protected]>

Andrew

Quoted 36 lines
Signed-off-by Gregory CLEMENT <[email protected]>
Cc <[email protected]> # v3.8 +

---
Hi,

I plan to add this patch to mvebu/fixes once the v4.1-rc1 will be released. I don't expect much comments about it, but there is time for them if needed until the next PR.

Thanks,

Gregory

 arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts | 4 ++++
 1 file changed, 4 insertions(+)
arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts +4 -0
index 0c76d9f05fd0..f4838ebd918b 100644
@@ -105,6 +105,10 @@
 		};
 
 		internal-regs {
+			rtc at 10300 {
+				/* No crystal connected to the internal RTC */
+				status = "disabled";
+			};
 			serial at 12000 {
 				status = "okay";
 			};
Signature · 1 line
2.1.0
#2 lore raw

PATCH 1/1 ARM: mvebu: armada-xp-openblocks-ax3-4: Disable internal RTC

In reply to Gregory CLEMENT

Dear Gregory CLEMENT,

Quoted 8 lines · Gregory CLEMENT

There is no crystal connected to the internal RTC on the Open Block AX3. So let's disable it in order to prevent the kernel probing the driver uselessly. Eventually this patches removes the following warning message from the boot log:
"rtc-mv d0010300.rtc: internal RTC not ticking"

Signed-off-by Gregory CLEMENT <[email protected]>
Cc <[email protected]> # v3.8 +

If an external crystal is needed on the board for the internal RTC, then shouldn't instead the RTC have status = "disabled" in the SoC-level .dtsi, and each board enabling it in its own specific .dts, like we do for all other hardware blocks that require/use external components/connexions?

Or, because the AX3 appears to be the only board in this case, we decide to factorize enabling the RTC in the .dtsi, and leave it as a special case to handle in the AX3 .dts ?

Thanks,

Thomas

Signature · 3 lines
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
#3 lore raw

PATCH 1/1 ARM: mvebu: armada-xp-openblocks-ax3-4: Disable internal RTC

Quoted 18 lines · Thomas Petazzoni

Dear Gregory CLEMENT,

Quoted 8 lines · Gregory CLEMENT

There is no crystal connected to the internal RTC on the Open Block AX3. So let's disable it in order to prevent the kernel probing the driver uselessly. Eventually this patches removes the following warning message from the boot log:
"rtc-mv d0010300.rtc: internal RTC not ticking"

Signed-off-by Gregory CLEMENT <[email protected]>
Cc <[email protected]> # v3.8 +

If an external crystal is needed on the board for the internal RTC, then shouldn't instead the RTC have status = "disabled" in the SoC-level .dtsi, and each board enabling it in its own specific .dts, like we do for all other hardware blocks that require/use external components/connexions?

Quoted 3 lines

Or, because the AX3 appears to be the only board in this case, we decide to factorize enabling the RTC in the .dtsi, and leave it as a special case to handle in the AX3 .dts ?

Hi Thomas

Experience from Kirkwood is that the majority of boards use the internal RTC. Not having a crystal is the exception. So think default enabled makes sense.

The only side affect of having the RTC enabled when there is no crystal is the warning message. It makes no difference to the active RTC on the i2c bus, it becomes rtc0.

Andrew

#4 lore raw

PATCH 1/1 ARM: mvebu: armada-xp-openblocks-ax3-4: Disable internal RTC

In reply to Gregory CLEMENT
Quoted 5 lines · Gregory CLEMENT

There is no crystal connected to the internal RTC on the Open Block AX3. So let's disable it in order to prevent the kernel probing the driver uselessly. Eventually this patches removes the following warning message from the boot log:
"rtc-mv d0010300.rtc: internal RTC not ticking"

Now I understand why I was getting this message. Everytime it booted I thought to myself "I have to debug this thing", now I understand better.

Thanks,
Willy

author
#5 lore raw

PATCH 1/1 ARM: mvebu: armada-xp-openblocks-ax3-4: Disable internal RTC

In reply to Gregory CLEMENT
Quoted 8 lines · Gregory CLEMENT

There is no crystal connected to the internal RTC on the Open Block AX3. So let's disable it in order to prevent the kernel probing the driver uselessly. Eventually this patches removes the following warning message from the boot log:
"rtc-mv d0010300.rtc: internal RTC not ticking"

Signed-off-by Gregory CLEMENT <[email protected]>
Cc <[email protected]> # v3.8 +

applied on mvebu/fixes with Andrew's acked-by

Thanks,

Gregory

Quoted 31 lines

---
Hi,

I plan to add this patch to mvebu/fixes once the v4.1-rc1 will be released. I don't expect much comments about it, but there is time for them if needed until the next PR.

Thanks,

Gregory

 arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts | 4 ++++
 1 file changed, 4 insertions(+)
arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts +4 -0
index 0c76d9f05fd0..f4838ebd918b 100644
@@ -105,6 +105,10 @@
 		};
 
 		internal-regs {
+			rtc at 10300 {
+				/* No crystal connected to the internal RTC */
+				status = "disabled";
+			};
 			serial at 12000 {
 				status = "okay";
 			};
Signature · 4 lines
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com