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Date: Sat, 12 Feb 2022 14:22:59 -0800
From: Andrey Smirnov <andrew.smirnov@...il.com>
To: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
Cc: Felipe Balbi <balbi@...nel.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: dwc3: Don't switch OTG -> peripheral if extcon is present
On Tue, Feb 8, 2022 at 11:54 AM Thinh Nguyen <Thinh.Nguyen@...opsys.com> wrote:
>
> Andrey Smirnov wrote:
> > It is necessary that:
> >
> > ROLE_SWITCH && device_property_read_bool(dwc->dev, "usb-role-switch")
> >
> > is true in order for dwc3_get_dr_mode() to _not_ force us from OTG to
> > PERIPHERAL mode here:
> >
> > if (mode == USB_DR_MODE_OTG &&
> > (!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
> > !device_property_read_bool(dwc->dev, "usb-role-switch")) &&
> > !DWC3_VER_IS_PRIOR(DWC3, 330A))
> > mode = USB_DR_MODE_PERIPHERAL;
> >
> > and dwc3_drd_init() to be called later in dwc3_core_init_mode(). To
> > avoid always ignoring extcon device returned by dwc3_get_extcon()
> > modify the above check to also account for dwc->edev.
> >
>
> I think the commit message is a bit difficult to follow. Can we rephrase
> it to something like this:
>
> If the extcon device exists, get the mode from the extcon device. If the
> controller is DRD and the driver is unable to determine the mode, only
> then default the dr_mode to USB_DR_MODE_PERIPHERAL.
>
Sure, will do.
>
> > Cc: Felipe Balbi <balbi@...nel.org>
> > Cc: Thinh Nguyen <thinhn@...opsys.com>
> > Cc: linux-usb@...r.kernel.org
> > Cc: linux-kernel@...r.kernel.org
> > Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
> > ---
> >
> > Previous discussion:
> >
> > https://urldefense.com/v3/__https://lore.kernel.org/linux-usb/20220131192102.4115473-1-andrew.smirnov@gmail.com/__;!!A4F2R9G_pg!OlXelv3-qdUChbfoT9-Qttv4PH8DDro1dSzIj6xEN7x3Vkv8jeh8unvO4RvolUA$
> >
> > drivers/usb/dwc3/core.c | 55 ++++++++++++++++++++++++++++++++++++++++-
> > drivers/usb/dwc3/drd.c | 50 -------------------------------------
> > 2 files changed, 54 insertions(+), 51 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index f2448d0a9d39..0ae152e47a00 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -23,6 +23,7 @@
> > #include <linux/delay.h>
> > #include <linux/dma-mapping.h>
> > #include <linux/of.h>
> > +#include <linux/of_graph.h>
> > #include <linux/acpi.h>
> > #include <linux/pinctrl/consumer.h>
> > #include <linux/reset.h>
> > @@ -84,7 +85,7 @@ static int dwc3_get_dr_mode(struct dwc3 *dwc)
> > * mode. If the controller supports DRD but the dr_mode is not
> > * specified or set to OTG, then set the mode to peripheral.
> > */
> > - if (mode == USB_DR_MODE_OTG &&
> > + if (mode == USB_DR_MODE_OTG && !dwc->edev &&
> > (!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
> > !device_property_read_bool(dwc->dev, "usb-role-switch")) &&
> > !DWC3_VER_IS_PRIOR(DWC3, 330A))
> > @@ -1462,6 +1463,51 @@ static void dwc3_check_params(struct dwc3 *dwc)
> > }
> > }
> >
> > +static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> > +{
> > + struct device *dev = dwc->dev;
> > + struct device_node *np_phy;
> > + struct extcon_dev *edev = NULL;
> > + const char *name;
> > +
> > + if (device_property_read_bool(dev, "extcon"))
> > + return extcon_get_edev_by_phandle(dev, 0);
> > +
> > + /*
> > + * Device tree platforms should get extcon via phandle.
> > + * On ACPI platforms, we get the name from a device property.
> > + * This device property is for kernel internal use only and
> > + * is expected to be set by the glue code.
> > + */
> > + if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> > + edev = extcon_get_extcon_dev(name);
> > + if (!edev)
> > + return ERR_PTR(-EPROBE_DEFER);
> > +
> > + return edev;
> > + }
> > +
> > + /*
> > + * Try to get an extcon device from the USB PHY controller's "port"
> > + * node. Check if it has the "port" node first, to avoid printing the
> > + * error message from underlying code, as it's a valid case: extcon
> > + * device (and "port" node) may be missing in case of "usb-role-switch"
> > + * or OTG mode.
> > + */
> > + np_phy = of_parse_phandle(dev->of_node, "phys", 0);
> > + if (of_graph_is_present(np_phy)) {
> > + struct device_node *np_conn;
> > +
> > + np_conn = of_graph_get_remote_node(np_phy, -1, -1);
> > + if (np_conn)
> > + edev = extcon_find_edev_by_node(np_conn);
> > + of_node_put(np_conn);
> > + }
> > + of_node_put(np_phy);
> > +
> > + return edev;
> > +}
> > +
> > static int dwc3_probe(struct platform_device *pdev)
> > {
> > struct device *dev = &pdev->dev;
> > @@ -1561,6 +1607,13 @@ static int dwc3_probe(struct platform_device *pdev)
> > goto err2;
> > }
> >
> > + dwc->edev = dwc3_get_extcon(dwc);
> > + if (IS_ERR(dwc->edev)) {
> > + ret = PTR_ERR(dwc->edev);
> > + dev_err_probe(dwc->dev, ret, "failed to get extcon");
>
> add "\n" ?
Sure, will do.
>
> > + goto err3;
> > + }
> > +
> > ret = dwc3_get_dr_mode(dwc);
> > if (ret)
> > goto err3;
> > diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> > index e2b68bb770d1..9a414edc439a 100644
> > --- a/drivers/usb/dwc3/drd.c
> > +++ b/drivers/usb/dwc3/drd.c
> > @@ -8,7 +8,6 @@
> > */
> >
> > #include <linux/extcon.h>
> > -#include <linux/of_graph.h>
> > #include <linux/platform_device.h>
> > #include <linux/property.h>
> >
> > @@ -438,51 +437,6 @@ static int dwc3_drd_notifier(struct notifier_block *nb,
> > return NOTIFY_DONE;
> > }
> >
> > -static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> > -{
> > - struct device *dev = dwc->dev;
> > - struct device_node *np_phy;
> > - struct extcon_dev *edev = NULL;
> > - const char *name;
> > -
> > - if (device_property_read_bool(dev, "extcon"))
> > - return extcon_get_edev_by_phandle(dev, 0);
> > -
> > - /*
> > - * Device tree platforms should get extcon via phandle.
> > - * On ACPI platforms, we get the name from a device property.
> > - * This device property is for kernel internal use only and
> > - * is expected to be set by the glue code.
> > - */
> > - if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> > - edev = extcon_get_extcon_dev(name);
> > - if (!edev)
> > - return ERR_PTR(-EPROBE_DEFER);
> > -
> > - return edev;
> > - }
> > -
> > - /*
> > - * Try to get an extcon device from the USB PHY controller's "port"
> > - * node. Check if it has the "port" node first, to avoid printing the
> > - * error message from underlying code, as it's a valid case: extcon
> > - * device (and "port" node) may be missing in case of "usb-role-switch"
> > - * or OTG mode.
> > - */
> > - np_phy = of_parse_phandle(dev->of_node, "phys", 0);
> > - if (of_graph_is_present(np_phy)) {
> > - struct device_node *np_conn;
> > -
> > - np_conn = of_graph_get_remote_node(np_phy, -1, -1);
> > - if (np_conn)
> > - edev = extcon_find_edev_by_node(np_conn);
> > - of_node_put(np_conn);
> > - }
> > - of_node_put(np_phy);
> > -
> > - return edev;
> > -}
> > -
> > #if IS_ENABLED(CONFIG_USB_ROLE_SWITCH)
> > #define ROLE_SWITCH 1
> > static int dwc3_usb_role_switch_set(struct usb_role_switch *sw,
> > @@ -575,10 +529,6 @@ int dwc3_drd_init(struct dwc3 *dwc)
> > {
> > int ret, irq;
> >
> > - dwc->edev = dwc3_get_extcon(dwc);
> > - if (IS_ERR(dwc->edev))
> > - return PTR_ERR(dwc->edev);
> > -
> > if (ROLE_SWITCH &&
> > device_property_read_bool(dwc->dev, "usb-role-switch")) {
> > ret = dwc3_setup_role_switch(dwc);
> > --
> > 2.25.1
>
> Reviewed-by: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
>
> Thanks,
> Thinh
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