[PATCH v2] phy: stm32-usphyc: add 200 to 300 us delay to fix timeout on some machines

[Fabrice Gasnier]

On 2/27/23 16:13, Michael Grzeschik wrote:
> An minimum udelay of 200 us seems to be necessary on some machines. After
> the setup of the pll, which needs about 100 us to be locked there seem
> to be additional 100 us to get the phy really functional. Without this
> delay the usb runs not functional. With this additional short udelay
> this issue was not reported again.
> 
> Signed-off-by: Michael Grzeschik <m.grzeschik at pengutronix.de>
> 

Hi Michael,

Thank you for the updates,

Fell free to add my:
Reviewed-by: Fabrice Gasnier <fabrice.gasnier at foss.st.com>

Best Regards,
Fabrice

> ---
> v1 -> v2: - changed the mdelay to udelay_range(200, 300), like suggested by fabrice
>           - moved the delay to pll enable so it will only be triggered once
> 
>  drivers/phy/st/phy-stm32-usbphyc.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/phy/st/phy-stm32-usbphyc.c b/drivers/phy/st/phy-stm32-usbphyc.c
> index 5bb9647b078f12..dd469f57fba7eb 100644
> --- a/drivers/phy/st/phy-stm32-usbphyc.c
> +++ b/drivers/phy/st/phy-stm32-usbphyc.c
> @@ -317,6 +317,9 @@ static int stm32_usbphyc_pll_enable(struct stm32_usbphyc *usbphyc)
>  
>  	stm32_usbphyc_set_bits(pll_reg, PLLEN);
>  
> +	/* Wait for maximum lock time */
> +	usleep_range(200, 300);
> +
>  	return 0;
>  
>  reg_disable: