[PATCH] Configure osc clock for d_can on am437x

[PATCH] Configure osc clock for d_can on am437x

[dillon.minfei]

From: dillon min <dillon.minfei@gmail.com>

Got following d_can probe errors with kernel 5.8-rc1 on am437x

[   10.730822] CAN device driver interface
Starting Wait for Network to be Configured...
[  OK  ] Reached target Network.
[   10.787363] c_can_platform 481cc000.can: probe failed
[   10.792484] c_can_platform: probe of 481cc000.can failed with
error -2
[   10.799457] c_can_platform 481d0000.can: probe failed
[   10.804617] c_can_platform: probe of 481d0000.can failed with
error -2

actually, Tony has fixed this issue on am335x, the patch [3]
commit messages:
"
The reason why the issue happens is because we now attempt to read the
interconnect target module revision register by first manually enabling
all the device clocks in sysc_probe(). And looks like d_can also needs
the osc clock in addition to the module clock, and it may or may not be
enabled depending on the bootloader version and if other devices have
already requested osc clock.

Let's fix the issue by adding osc clock as an optional clock for the
module for am335x. Note that am437x does not seem to list the osc clock
at all, so presumably it is not needed for am437x.
"

from TRM of am335x/am437x [1][2], they have the same clock structure,
so, we can just reuse [3] for am437x platform.

Tested on custom am4372 board.

[1]: https://www.ti.com/lit/pdf/spruh73 Chapter-23, Figure 23-1. DCAN
Integration
[2]: https://www.ti.com/lit/pdf/spruhl7 Chapter-25, Figure 25-1. DCAN
Integration
[3]: commit 516f1117d0fb ("ARM: dts: Configure osc clock for d_can on am335x")

dillon min (1):
  ARM: dts: Configure osc clock for d_can on am437x

 arch/arm/boot/dts/am437x-l4.dtsi | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

-- 
1.9.1

[PATCH] ARM: dts: Configure osc clock for d_can on am437x

[dillon.minfei]

From: dillon min <dillon.minfei@gmail.com>

Since am437x have the same clock structure with am335x [1][2],
reuse the code from Tony Lindgren's patch [3] to fix dcan probe
failed on am437x platform.

[1]: https://www.ti.com/lit/pdf/spruh73 Chapter-23, Figure 23-1. DCAN
Integration
[2]: https://www.ti.com/lit/pdf/spruhl7 Chapter-25, Figure 25-1. DCAN
Integration
[3]: commit 516f1117d0fb ("ARM: dts: Configure osc clock for d_can on
am335x")

Fixes: 1a5cd7c23cc5 ("bus: ti-sysc: Enable all clocks directly during init to
read revision")

Signed-off-by: dillon min <dillon.minfei@gmail.com>
---
 arch/arm/boot/dts/am437x-l4.dtsi | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/arm/boot/dts/am437x-l4.dtsi b/arch/arm/boot/dts/am437x-l4.dtsi
index 0d0f9fe4a882..4129affde54e 100644
--- a/arch/arm/boot/dts/am437x-l4.dtsi
+++ b/arch/arm/boot/dts/am437x-l4.dtsi
@@ -1541,8 +1541,9 @@
 			reg = <0xcc020 0x4>;
 			reg-names = "rev";
 			/* Domains (P, C): per_pwrdm, l4ls_clkdm */
-			clocks = <&l4ls_clkctrl AM4_L4LS_D_CAN0_CLKCTRL 0>;
-			clock-names = "fck";
+			clocks = <&l4ls_clkctrl AM4_L4LS_D_CAN0_CLKCTRL 0>,
+			<&dcan0_fck>;
+			clock-names = "fck", "osc";
 			#address-cells = <1>;
 			#size-cells = <1>;
 			ranges = <0x0 0xcc000 0x2000>;
@@ -1550,6 +1551,8 @@
 			dcan0: can@0 {
 				compatible = "ti,am4372-d_can", "ti,am3352-d_can";
 				reg = <0x0 0x2000>;
+				clocks = <&dcan0_fck>;
+				clock-names = "fck";
 				syscon-raminit = <&scm_conf 0x644 0>;
 				interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>;
 				status = "disabled";
@@ -1561,8 +1564,9 @@
 			reg = <0xd0020 0x4>;
 			reg-names = "rev";
 			/* Domains (P, C): per_pwrdm, l4ls_clkdm */
-			clocks = <&l4ls_clkctrl AM4_L4LS_D_CAN1_CLKCTRL 0>;
-			clock-names = "fck";
+			clocks = <&l4ls_clkctrl AM4_L4LS_D_CAN1_CLKCTRL 0>,
+			<&dcan1_fck>;
+			clock-names = "fck", "osc";
 			#address-cells = <1>;
 			#size-cells = <1>;
 			ranges = <0x0 0xd0000 0x2000>;
@@ -1570,6 +1574,8 @@
 			dcan1: can@0 {
 				compatible = "ti,am4372-d_can", "ti,am3352-d_can";
 				reg = <0x0 0x2000>;
+				clocks = <&dcan1_fck>;
+				clock-name = "fck";
 				syscon-raminit = <&scm_conf 0x644 1>;
 				interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>;
 				status = "disabled";
-- 
1.9.1

Re: [PATCH] ARM: dts: Configure osc clock for d_can on am437x

[Tony Lindgren]

* dillon.minfei@gmail.com <dillon.minfei@gmail.com> [200621 15:36]:
> From: dillon min <dillon.minfei@gmail.com>
> 
> Since am437x have the same clock structure with am335x [1][2],
> reuse the code from Tony Lindgren's patch [3] to fix dcan probe
> failed on am437x platform.
> 
> [1]: https://www.ti.com/lit/pdf/spruh73 Chapter-23, Figure 23-1. DCAN
> Integration
> [2]: https://www.ti.com/lit/pdf/spruhl7 Chapter-25, Figure 25-1. DCAN
> Integration
> [3]: commit 516f1117d0fb ("ARM: dts: Configure osc clock for d_can on
> am335x")
> 
> Fixes: 1a5cd7c23cc5 ("bus: ti-sysc: Enable all clocks directly during init to
> read revision")

Thanks applying into fixes.

Tony