Subject: [PATCH 1/2] phy-sun4i-usb: Add sun4i_usb_phy_force_session_end() function

From: [email-masked] (Kishon Vijay Abraham I)
Date: Tue, 20 Sep 2016 10:15:19 +0530

Hi,

On Sunday 18 September 2016 10:20 PM, Hans de Goede wrote:
> The sunxi musb has a bug where sometimes it will generate a babble
> error on device disconnect instead of a disconnect irq. When this
> happens the musb-controller switches from host mode to device mode
> (it clears MUSB_DEVCTL_SESSION and sets MUSB_DEVCTL_BDEVICE) and
> gets stuck in this state.
> 
> Clearing this requires reporting Vbus low for 200 or more ms, but
> on some devices Vbus is simply always high (host-only mode, no Vbus
> control). The phy-sun4i-usb code already has code to force a session
> end for devices without Vbus control.
> 
> This commit adds a sun4i_usb_phy_force_session_end() function exporting
> this functionality to the sunxi-musb glue, so that it can force a session
> end to fixup the stuck state after a babble error.
> 
> Signed-off-by: Hans de Goede <[email-masked]>
> ---
>  drivers/phy/phy-sun4i-usb.c       | 11 +++++++++++
>  include/linux/phy/phy-sun4i-usb.h |  7 +++++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/phy/phy-sun4i-usb.c b/drivers/phy/phy-sun4i-usb.c
> index 43c0d98..06f4e11a 100644
> --- a/drivers/phy/phy-sun4i-usb.c
> +++ b/drivers/phy/phy-sun4i-usb.c
> @@ -470,6 +470,17 @@ void sun4i_usb_phy_set_squelch_detect(struct phy *_phy, bool enabled)
>  }
>  EXPORT_SYMBOL_GPL(sun4i_usb_phy_set_squelch_detect);
>  
> +void sun4i_usb_phy_force_session_end(struct phy *_phy)
> +{
> +	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
> +	struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
> +
> +	data->id_det = -1;
> +	data->force_session_end = true;
> +	queue_delayed_work(system_wq, &data->detect, 0);
> +}
> +EXPORT_SYMBOL_GPL(sun4i_usb_phy_force_session_end);

Er.. one more export symbol :-(
> +
>  static const struct phy_ops sun4i_usb_phy_ops = {
>  	.init		= sun4i_usb_phy_init,
>  	.exit		= sun4i_usb_phy_exit,
> diff --git a/include/linux/phy/phy-sun4i-usb.h b/include/linux/phy/phy-sun4i-usb.h
> index 50aed92..3bb773f 100644
> --- a/include/linux/phy/phy-sun4i-usb.h
> +++ b/include/linux/phy/phy-sun4i-usb.h
> @@ -23,4 +23,11 @@
>   */
>  void sun4i_usb_phy_set_squelch_detect(struct phy *phy, bool enabled);
>  
> +/**
> + * sun4i_usb_force_session_end() - Force the current session to end
> + *				   by reporting VBus low for 200+ ms
> + * @phy: reference to a sun4i usb phy
> + */
> +void sun4i_usb_phy_force_session_end(struct phy *phy);

Should we include a static inline function if sun4i phy is not defined?

Thanks
Kishon