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Re: [PATCH v5] usb: renesas_usbhs: Allow an OTG PHY driver to provide VBUS

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  Re: [PATCH v5] usb: renesas_usbhs: Allow an OTG PHY driver to provide VBUS Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2015-07-08 01:10 +0200
    Re: [PATCH v5] usb: renesas_usbhs: Allow an OTG PHY driver to provide VBUS Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2015-07-09 03:10 +0200

#1179146 — Re: [PATCH v5] usb: renesas_usbhs: Allow an OTG PHY driver to provide VBUS

Hi Phil,

Thank you for the patch.

On Tuesday 07 July 2015 12:52:43 Phil Edworthy wrote:
> These changes allow a PHY driver to trigger a VBUS interrupt and
> to provide the value of VBUS.
> 
> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>

This looks much better to me. I just have two comments, please see below.

> ---
> v5:
>   - Avoid race when vbus_is_indirect may or may not be read
>     before the phy has called vbus_session. In doing so, the
>     changes have also been isolated to mod_gadget.c
> 
> v4:
>   - Use true/false with bool vars.
>   - Clean up "transceiver found" message.
> 
> v3:
>   - Changed how indirect vbus is plumbed in.
>   - Removed unnecessary (void) on call to otg_set_peripheral.
>   - Moved code that connects to bus through transceiver so it
>     is before setting gpriv->driver.
> 
> v2:
>   - vbus variables changed from int to bool.
>   - dev_info() changed to dev_err()
> ---
>  drivers/usb/renesas_usbhs/mod_gadget.c | 62 +++++++++++++++++++++++++++++++
>  1 file changed, 62 insertions(+)
> 
> diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
> b/drivers/usb/renesas_usbhs/mod_gadget.c index dc2aa32..19a22a3 100644
> --- a/drivers/usb/renesas_usbhs/mod_gadget.c
> +++ b/drivers/usb/renesas_usbhs/mod_gadget.c
> @@ -21,6 +21,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/usb/ch9.h>
>  #include <linux/usb/gadget.h>
> +#include <linux/usb/otg.h>
>  #include "common.h"
> 
>  /*
> @@ -50,6 +51,8 @@ struct usbhsg_gpriv {
>  	int			 uep_size;
> 
>  	struct usb_gadget_driver	*driver;
> +	struct usb_phy		*transceiver;
> +	bool 			 vbus_indirect_value;

How about naming this vbus_connected ? A boolean "value" doesn't mean much.

> 
>  	u32	status;
>  #define USBHSG_STATUS_STARTED		(1 << 0)
> @@ -873,6 +876,27 @@ static int usbhsg_try_stop(struct usbhs_priv *priv, u32
> status) }
> 
>  /*
> + * VBUS provided by the PHY
> + */
> +static int usbhsm_phy_get_vbus(struct platform_device *pdev)
> +{
> +	struct usbhs_priv *priv = usbhs_pdev_to_priv(pdev);
> +	struct usbhsg_gpriv *gpriv = usbhsg_priv_to_gpriv(priv);
> +
> +	return  gpriv->vbus_indirect_value;
> +}
> +
> +static void usbhs_mod_phy_mode(struct usbhs_priv *priv)
> +{
> +	struct usbhs_mod_info *info = &priv->mod_info;
> +
> +	info->irq_vbus		= NULL;
> +	priv->pfunc.get_vbus	= usbhsm_phy_get_vbus;
> +
> +	usbhs_irq_callback_update(priv, NULL);
> +}
> +
> +/*
>   *
>   *		linux usb function
>   *
> @@ -882,12 +906,28 @@ static int usbhsg_gadget_start(struct usb_gadget
> *gadget, {
>  	struct usbhsg_gpriv *gpriv = usbhsg_gadget_to_gpriv(gadget);
>  	struct usbhs_priv *priv = usbhsg_gpriv_to_priv(gpriv);
> +	struct device *dev = usbhs_priv_to_dev(priv);
> +	int ret;
> 
>  	if (!driver		||
>  	    !driver->setup	||
>  	    driver->max_speed < USB_SPEED_FULL)
>  		return -EINVAL;
> 
> +	/* connect to bus through transceiver */
> +	if (!IS_ERR_OR_NULL(gpriv->transceiver)) {
> +		ret = otg_set_peripheral(gpriv->transceiver->otg,
> +					&gpriv->gadget);
> +		if (ret) {
> +			dev_err(dev, "%s: can't bind to transceiver\n",
> +				gpriv->gadget.name);
> +			return ret;
> +		}
> +
> +		/* get vbus using phy versions */
> +		usbhs_mod_phy_mode(priv);

Given that the presence of an external PHY is known at probe time, couldn't 
this call be moved to the probe function ? It would then probably conflict 
with the usbhs_mod_autonomy_mode() call from usbhs_probe(), which would need 
to be fixed.

> +	}
> +
>  	/* first hook up the driver ... */
>  	gpriv->driver = driver;
> 
> @@ -900,6 +940,10 @@ static int usbhsg_gadget_stop(struct usb_gadget
> *gadget) struct usbhs_priv *priv = usbhsg_gpriv_to_priv(gpriv);
> 
>  	usbhsg_try_stop(priv, USBHSG_STATUS_REGISTERD);
> +
> +	if (!IS_ERR_OR_NULL(gpriv->transceiver))
> +		otg_set_peripheral(gpriv->transceiver->otg, NULL);
> +
>  	gpriv->driver = NULL;
> 
>  	return 0;
> @@ -947,12 +991,26 @@ static int usbhsg_set_selfpowered(struct usb_gadget
> *gadget, int is_self) return 0;
>  }
> 
> +static int usbhsg_vbus_session(struct usb_gadget *gadget, int is_active)
> +{
> +	struct usbhsg_gpriv *gpriv = usbhsg_gadget_to_gpriv(gadget);
> +	struct usbhs_priv *priv = usbhsg_gpriv_to_priv(gpriv);
> +	struct platform_device *pdev = usbhs_priv_to_pdev(priv);
> +
> +	gpriv->vbus_indirect_value = !!is_active;
> +
> +	renesas_usbhs_call_notify_hotplug(pdev);
> +
> +	return 0;
> +}
> +
>  static const struct usb_gadget_ops usbhsg_gadget_ops = {
>  	.get_frame		= usbhsg_get_frame,
>  	.set_selfpowered	= usbhsg_set_selfpowered,
>  	.udc_start		= usbhsg_gadget_start,
>  	.udc_stop		= usbhsg_gadget_stop,
>  	.pullup			= usbhsg_pullup,
> +	.vbus_session		= usbhsg_vbus_session,
>  };
> 
>  static int usbhsg_start(struct usbhs_priv *priv)
> @@ -994,6 +1052,10 @@ int usbhs_mod_gadget_probe(struct usbhs_priv *priv)
>  		goto usbhs_mod_gadget_probe_err_gpriv;
>  	}
> 
> +	gpriv->transceiver = usb_get_phy(USB_PHY_TYPE_UNDEFINED);
> +	dev_info(dev, "%stransceiver found\n",
> +		 gpriv->transceiver ? "" : "no ");
> +
>  	/*
>  	 * CAUTION
>  	 *

-- 
Regards,

Laurent Pinchart

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#1180358

Hi Phil,

On Wednesday 08 July 2015 08:08:27 Phil Edworthy wrote:
> On 08 July 2015 00:08, Laurent wrote:
> > On Tuesday 07 July 2015 12:52:43 Phil Edworthy wrote:
> > > These changes allow a PHY driver to trigger a VBUS interrupt and
> > > to provide the value of VBUS.
> > > 
> > > Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
> > 
> > This looks much better to me. I just have two comments, please see below.
> > 
> > > ---
> > > 
> > > v5:
> > >   - Avoid race when vbus_is_indirect may or may not be read
> > >   
> > >     before the phy has called vbus_session. In doing so, the
> > >     changes have also been isolated to mod_gadget.c
> > > 
> > > v4:
> > >   - Use true/false with bool vars.
> > >   - Clean up "transceiver found" message.
> > > 
> > > v3:
> > >   - Changed how indirect vbus is plumbed in.
> > >   - Removed unnecessary (void) on call to otg_set_peripheral.
> > >   - Moved code that connects to bus through transceiver so it
> > >   
> > >     is before setting gpriv->driver.
> > > 
> > > v2:
> > >   - vbus variables changed from int to bool.
> > >   - dev_info() changed to dev_err()
> > > 
> > > ---
> > > 
> > >  drivers/usb/renesas_usbhs/mod_gadget.c | 62 +++++++++++++++++++++++++++
> > >  1 file changed, 62 insertions(+)
> > > 
> > > diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
> > > b/drivers/usb/renesas_usbhs/mod_gadget.c index dc2aa32..19a22a3 100644
> > > --- a/drivers/usb/renesas_usbhs/mod_gadget.c
> > > +++ b/drivers/usb/renesas_usbhs/mod_gadget.c

[snip]

> > > @@ -882,12 +906,28 @@ static int usbhsg_gadget_start(struct usb_gadget
> > > *gadget,
> > >  {
> > >  	struct usbhsg_gpriv *gpriv = usbhsg_gadget_to_gpriv(gadget);
> > >  	struct usbhs_priv *priv = usbhsg_gpriv_to_priv(gpriv);
> > > +	struct device *dev = usbhs_priv_to_dev(priv);
> > > +	int ret;
> > > 
> > >  	if (!driver		||
> > >  	    !driver->setup	||
> > >  	    driver->max_speed < USB_SPEED_FULL)
> > >  		return -EINVAL;
> > > 
> > > +	/* connect to bus through transceiver */
> > > +	if (!IS_ERR_OR_NULL(gpriv->transceiver)) {
> > > +		ret = otg_set_peripheral(gpriv->transceiver->otg,
> > > +					&gpriv->gadget);
> > > +		if (ret) {
> > > +			dev_err(dev, "%s: can't bind to transceiver\n",
> > > +				gpriv->gadget.name);
> > > +			return ret;
> > > +		}
> > > +
> > > +		/* get vbus using phy versions */
> > > +		usbhs_mod_phy_mode(priv);
> > 
> > Given that the presence of an external PHY is known at probe time,
> > couldn't this call be moved to the probe function ? It would then probably
> > conflict with the usbhs_mod_autonomy_mode() call from usbhs_probe(), which
> > would need to be fixed.
> 
> You could do this, but as you say it would conflict with usbhs_probe(). I
> can't see a simple way to check for the external phy connection, so I would
> prefer to keep it here.
> Is that ok?

I can live with that, but I can't help feeling that it's not the best 
architecture. Coming to think about it, why do we get the transceiver (by 
calling usb_get_phy) in the gadget code ? Isn't the transceiver shared between 
host and peripheral modes ? Shouldn't it be handled by core code then ? I 
might miss something as my knowledge of the USB subsystem isn't perfect.

If we decide to refactor the code it can be done in a follow-up patch, this 
patch has been delayed for long enough.

> > > +	}
> > > +
> > > 
> > >  	/* first hook up the driver ... */
> > >  	gpriv->driver = driver;

-- 
Regards,

Laurent Pinchart

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