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Date: Mon, 06 Jul 2015 11:20:25 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Phil Edworthy <phil.edworthy@...esas.com>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Felipe Balbi <balbi@...com>,
Ulrich Hecht <ulrich.hecht@...il.com>,
Kishon Vijay Abraham I <kishon@...com>,
Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
linux-sh@...r.kernel.org
Subject: Re: [PATCH v3] usb: renesas_usbhs: Allow an OTG PHY driver to provide VBUS
Hi Phil,
Thank you for the patch.
On Thursday 02 July 2015 11:26:33 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@...esas.com>
>
> ---
> 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/common.c | 8 +++++--
> drivers/usb/renesas_usbhs/common.h | 2 ++
> drivers/usb/renesas_usbhs/mod_gadget.c | 38 +++++++++++++++++++++++++++++++
> 3 files changed, 46 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/renesas_usbhs/common.c
> b/drivers/usb/renesas_usbhs/common.c index 0f7e850..15e67d8 100644
> --- a/drivers/usb/renesas_usbhs/common.c
> +++ b/drivers/usb/renesas_usbhs/common.c
> @@ -379,7 +379,10 @@ static void usbhsc_hotplug(struct usbhs_priv *priv)
> /*
> * get vbus status from platform
> */
> - enable = usbhs_platform_call(priv, get_vbus, pdev);
> + if (priv->vbus_is_indirect)
> + enable = priv->vbus_indirect_value;
> + else
> + enable = usbhs_platform_call(priv, get_vbus, pdev);
>
> /*
> * get id from platform
> @@ -662,7 +665,8 @@ static int usbhs_probe(struct platform_device *pdev)
> pm_runtime_enable(&pdev->dev);
> if (!usbhsc_flags_has(priv, USBHSF_RUNTIME_PWCTRL)) {
> usbhsc_power_ctrl(priv, 1);
> - usbhs_mod_autonomy_mode(priv);
> + if (!priv->vbus_is_indirect)
Isn't this racy ? The vbus_session operation is called by transceivers from
interrupt handlers or work queues. Do we have a guarantee that it will be
called at least once before this code is reached ? Please see below for a
possible way to fix this.
> + usbhs_mod_autonomy_mode(priv);
> }
>
> /*
> diff --git a/drivers/usb/renesas_usbhs/common.h
> b/drivers/usb/renesas_usbhs/common.h index 8c5fc12..478700c 100644
> --- a/drivers/usb/renesas_usbhs/common.h
> +++ b/drivers/usb/renesas_usbhs/common.h
> @@ -255,6 +255,8 @@ struct usbhs_priv {
> struct renesas_usbhs_driver_param dparam;
>
> struct delayed_work notify_hotplug_work;
> + bool vbus_is_indirect;
> + bool vbus_indirect_value;
> struct platform_device *pdev;
>
> struct extcon_dev *edev;
> diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
> b/drivers/usb/renesas_usbhs/mod_gadget.c index dc2aa32..93ad4ea 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 +51,7 @@ struct usbhsg_gpriv {
> int uep_size;
>
> struct usb_gadget_driver *driver;
> + struct usb_phy *transceiver;
>
> u32 status;
> #define USBHSG_STATUS_STARTED (1 << 0)
> @@ -882,12 +884,25 @@ 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;
> + }
> + }
> +
How is this change related to the topic ? I'm not too familiar with this
driver so I might just have missed something, but then others could as well,
and the commit message could do with a bit more information.
> /* first hook up the driver ... */
> gpriv->driver = driver;
>
> @@ -900,6 +915,10 @@ 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 +966,27 @@ 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);
> +
> + priv->vbus_is_indirect = 1;
vbus_is_indirect is never reset to 0. Shouldn't you set it to 1 (or rather to
true) in usbhs_mod_gadget_probe() if an external transceiver is found ?
What would you think of implementing and wiring up the get_vbus operation in
usbhs_mod_gadget_probe() in the same way that usbhs_mod_autonomy_mode() does,
and return the value of vbus_indirect_value there ? You could then get rid of
the vbus_is_indirect field and move the vbus_indirect_value field to struct
usbhsg_gpriv, removing the need to modify drivers/usb/renesas_usbhs/common.c.
It should also solve the race condition mentioned above.
> + priv->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 +1028,10 @@ 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, "%s transceiver found\n",
> + gpriv->transceiver ? "" : "No");
> +
> /*
> * CAUTION
> *
--
Regards,
Laurent Pinchart
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