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

[PATCH] 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>
---
 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..aff6b60d5e 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 is a workaround that 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] phy: stm32-usphyc: add mdelay(1) to fix timeout on some machines

[Sascha Hauer]

On Tue, Jan 24, 2023 at 09:31:19PM +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>
> ---
>  drivers/phy/phy-stm32-usbphyc.c | 9 +++++++++
>  1 file changed, 9 insertions(+)

Applied, thanks

Sascha

> 
> diff --git a/drivers/phy/phy-stm32-usbphyc.c b/drivers/phy/phy-stm32-usbphyc.c
> index 657824405f..aff6b60d5e 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 is a workaround that 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
> 
> 
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |