[PATCH v2] phy: stm32-usphyc: add mdelay(1) to fix timeout on some machines

[PATCH v2] phy: stm32-usphyc: add mdelay(1) to fix timeout on some machines

[Michael Grzeschik]

An mdelay of 1 seems to be necessary on some machines, since
the monsel status does not seem to be accurate. On rare occasions just
working with the phy after this pll check lead to no functional usb.
With this short mdelay this issue was not reported again.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
v1 -> v2: - reworded the comment

 drivers/phy/phy-stm32-usbphyc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/phy/phy-stm32-usbphyc.c b/drivers/phy/phy-stm32-usbphyc.c
index 657824405f..db4ccef920 100644
--- a/drivers/phy/phy-stm32-usbphyc.c
+++ b/drivers/phy/phy-stm32-usbphyc.c
@@ -271,6 +271,15 @@ static int stm32_usbphyc_phy_init(struct phy *phy)
 		goto pll_disable;
 	}
 
+	/* This mdelay seems to be necessary on some machines, since the
+	 * monsel status does not seem to be accurate. On rare occasions
+	 * just working with the phy after this pll check the usb
+	 * peripheral (e.g. on the dwc2) run into timeout issues and
+	 * leading to no functional usb. With this short mdelay this
+	 * issue was not reported again.
+	 */
+	mdelay(1);
+
 	usbphyc_phy->active = true;
 
 	return 0;
-- 
2.30.2

Re: [PATCH v2] phy: stm32-usphyc: add mdelay(1) to fix timeout on some machines

[Sascha Hauer]

On Tue, Jan 24, 2023 at 09:44:34PM +0100, Michael Grzeschik wrote:
> An mdelay of 1 seems to be necessary on some machines, since
> the monsel status does not seem to be accurate. On rare occasions just
> working with the phy after this pll check lead to no functional usb.
> With this short mdelay this issue was not reported again.
> 
> Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
> ---
> v1 -> v2: - reworded the comment
> 

And updated to this one.

Sascha

>  drivers/phy/phy-stm32-usbphyc.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/phy/phy-stm32-usbphyc.c b/drivers/phy/phy-stm32-usbphyc.c
> index 657824405f..db4ccef920 100644
> --- a/drivers/phy/phy-stm32-usbphyc.c
> +++ b/drivers/phy/phy-stm32-usbphyc.c
> @@ -271,6 +271,15 @@ static int stm32_usbphyc_phy_init(struct phy *phy)
>  		goto pll_disable;
>  	}
>  
> +	/* This mdelay seems to be necessary on some machines, since the
> +	 * monsel status does not seem to be accurate. On rare occasions
> +	 * just working with the phy after this pll check the usb
> +	 * peripheral (e.g. on the dwc2) run into timeout issues and
> +	 * leading to no functional usb. With this short mdelay this
> +	 * issue was not reported again.
> +	 */
> +	mdelay(1);
> +
>  	usbphyc_phy->active = true;
>  
>  	return 0;
> -- 
> 2.30.2
> 
> 
> 

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