STM32MP135A Needs An LSE? (meta-st-stm32mp)

[ChrisRCAL]

So coincidental enough all the projects I have done before required a RTC /w LSE. I am now working on a project that does not need a LSE, and I am finding that TF-A keeps throwing a panic because of this. The protos we had fortunately had the circuit DNL, so adding an LSE clock fixed the problem. 

Is there a way to disable this? or at least use the LSI? I tried configuring it to use the LSI but still same panic. 
//Error Message

NOTICE: Early console setup
PANIC at PC : 0x2ffe6b5b

Exception mode=0x00000016 at: 0x2ffe6b5b

Thank you for any help. 

[OlivierK · Accepted solution]

Hello @ChrisRCAL 

Thank you for this, we have identify an issue in the OSTL DV6.1. A patch is available to deactivate the external oscillator when not available and prevent panic, but its frequency needs to be set to 0 in the DT. The following patch will be implemented in the next DV. Let us know if it fixes your issue.

stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27/sources/ostl-linux/tf-a-stm32mp-v2.10.13-stm32mp-r2-r0/tf-a-stm32mp-v2.10.13-stm32mp-r2/drivers/st/clk/clk-stm32mp2.c

diff --git a/drivers/st/clk/clk-stm32mp2.c b/drivers/st/clk/clk-stm32mp2.c

index 9c93db5..6552161 100644

---    a/drivers/st/clk/clk-stm32mp2.c

+++ b/drivers/st/clk/clk-stm32mp2.c

@@ -846,6 +846,10 @@

 {

  struct clk_oscillator_data *osc_data = clk_oscillator_get_data(priv, id);

+ if (osc_data->frequency == 0UL) {

+ return true;

+ }

+

  return _clk_stm32_gate_is_enabled(priv, osc_data->gate_id); }

[ChrisRCAL]

Took me a bit to get back to this topic, sorry for the delay. 

This did fix the issue - 

Step-by-step for anyone else like me.

1. Enable LSE in the Cube.
2. 

clk_lse: clk-lse {

clock-frequency = <32768>;

/* USER CODE BEGIN clk_lse */

clock-frequency = <0>;

/* USER CODE END clk_lse */

};

3. Patch it, as stated above. I had to change mine to stm32mp1 not mp2, since it was for the stm32mp135a.