drivers: clk: stm32h7: Endless loop of dead in driver probe function

Hi,

Some IMHO fatal issues in the the clock driver for the STM32H7 series driver.

Affected driver: drivers/clk/clk_stm32h7.c

Affected configs (boards): configs/stm32h750-art-pi_defconfig configs/stm32h743-disco_defconfig configs/stm32h743-eval_defconfig

Description: The driver currently requires a external working clock source (HSE). No issues in the circuit are accepted by the current implementation. Also a fixed (defined) frequency of the external clock source.

In the probe function stm32_clk_probe() from the driver there will be configure_clocks() called. Here are the issues.

As code snippet from configure_clocks():

/* Switch on HSE */ setbits_le32(&regs->cr, RCC_CR_HSEON); while (!(readl(&regs->cr) & RCC_CR_HSERDY)) ;

RCC_CR_HSERDY will here never set, when there is no external clock source or an issue in the circuit. -> Endless loop of dead.

My possible fixes: At a timeout when reading the register and if the timeout is elapsed, print an error message and return with ETIMEDOUT, so the dm manger can call the hang() function.

Johannes K.