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Date: Tue, 8 Feb 2022 19:54:13 +0000
From: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To: Andrey Smirnov <andrew.smirnov@...il.com>,
Felipe Balbi <balbi@...nel.org>
CC: "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
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.
> 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" ?
> + 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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