[PATCH v6 4/5] usb: host: dwc2: force reset assert

[Simon Goldschmidt]

Am 10.03.2020 um 11:09 schrieb Patrick Delaunay:
> Assert reset before deassert in dwc2_reset;
> this patch solve issues when the DWC2 registers are already
> initialized with value incompatible with host mode.
> 
> Force a hardware reset of the IP reset all the DWC2 registers at
> default value, the host driver start with a clean state
> (Core Soft reset doen in dwc_otg_core_reset is not enought
>  to reset all register).
> 
> The error can occurs in U-Boot when DWC2 device gadget driver
> force device mode (called by ums or dfu command, before to execute
> the usb start command).
> 
> Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>

Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>

> ---
> 
> Changes in v6: None
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2:
> - add clk_disable_bulk in dwc2_usb_remove
> 
>  drivers/usb/host/dwc2.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
> index b1b79d0a18..640ae3e730 100644
> --- a/drivers/usb/host/dwc2.c
> +++ b/drivers/usb/host/dwc2.c
> @@ -1151,6 +1151,8 @@ static int dwc2_reset(struct udevice *dev)
>  			return ret;
>  	}
>  
> +	/* force reset to clear all IP register */
> +	reset_assert_bulk(&priv->resets);
>  	ret = reset_deassert_bulk(&priv->resets);
>  	if (ret) {
>  		reset_release_bulk(&priv->resets);
>