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From: Bastien Nocera <hadess@hadess.net>
To: linux-usb@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	Bastien Nocera <hadess@hadess.net>,
	Alan Stern <stern@rowland.harvard.edu>
Subject: [PATCH v3 2/6] USB: Make it possible to "subclass" usb_device_driver
Date: Wed, 16 Oct 2019 11:39:29 +0200
Message-ID: <20191016093933.693-3-hadess@hadess.net> (raw)
In-Reply-To: <20191016093933.693-1-hadess@hadess.net>

The kernel currenly has only 2 usb_device_drivers, one generic one, one
that completely replaces the generic one to make USB devices usable over
a network.

Use the newly exported generic driver functions when a driver declares
to want them run, in addition to its own code. This makes it possible to
write drivers that extend the generic USB driver.

Note that this patch is not enough for another driver to automatically
get selected.

Signed-off-by: Bastien Nocera <hadess@hadess.net>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
---
 drivers/usb/core/driver.c | 26 +++++++++++++++++++++-----
 include/linux/usb.h       |  4 ++++
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git drivers/usb/core/driver.c drivers/usb/core/driver.c
index 2b27d232d7a7..d3787d084937 100644
--- drivers/usb/core/driver.c
+++ drivers/usb/core/driver.c
@@ -261,9 +261,16 @@ static int usb_probe_device(struct device *dev)
 	 */
 	if (!udriver->supports_autosuspend)
 		error = usb_autoresume_device(udev);
+	if (error)
+		return error;
 
-	if (!error)
-		error = udriver->probe(udev);
+	if (udriver->generic_subclass)
+		error = usb_generic_driver_probe(udev);
+	if (error)
+		return error;
+
+	error = udriver->probe(udev);
+	/* TODO: fallback to generic driver in case of error */
 	return error;
 }
 
@@ -273,7 +280,10 @@ static int usb_unbind_device(struct device *dev)
 	struct usb_device *udev = to_usb_device(dev);
 	struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
 
-	udriver->disconnect(udev);
+	if (udriver->disconnect)
+		udriver->disconnect(udev);
+	if (udriver->generic_subclass)
+		usb_generic_driver_disconnect(udev);
 	if (!udriver->supports_autosuspend)
 		usb_autosuspend_device(udev);
 	return 0;
@@ -1149,7 +1159,10 @@ static int usb_suspend_device(struct usb_device *udev, pm_message_t msg)
 		udev->do_remote_wakeup = 0;
 		udriver = &usb_generic_driver;
 	}
-	status = udriver->suspend(udev, msg);
+	if (udriver->suspend)
+		status = udriver->suspend(udev, msg);
+	if (status == 0 && udriver->generic_subclass)
+		status = usb_generic_driver_suspend(udev, msg);
 
  done:
 	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
@@ -1181,7 +1194,10 @@ static int usb_resume_device(struct usb_device *udev, pm_message_t msg)
 		udev->reset_resume = 1;
 
 	udriver = to_usb_device_driver(udev->dev.driver);
-	status = udriver->resume(udev, msg);
+	if (udriver->generic_subclass)
+		status = usb_generic_driver_resume(udev, msg);
+	if (status == 0 && udriver->resume)
+		status = udriver->resume(udev, msg);
 
  done:
 	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
diff --git include/linux/usb.h include/linux/usb.h
index e656e7b4b1e4..94bd3b48a485 100644
--- include/linux/usb.h
+++ include/linux/usb.h
@@ -1228,6 +1228,9 @@ struct usb_driver {
  * @drvwrap: Driver-model core structure wrapper.
  * @supports_autosuspend: if set to 0, the USB core will not allow autosuspend
  *	for devices bound to this driver.
+ * @generic_subclass: if set to 1, the generic USB driver's probe, disconnect,
+ *	resume and suspend functions will be called in addition to the driver's
+ *	own, so this part of the setup does not need to be replicated.
  *
  * USB drivers must provide all the fields listed above except drvwrap.
  */
@@ -1242,6 +1245,7 @@ struct usb_device_driver {
 	const struct attribute_group **dev_groups;
 	struct usbdrv_wrap drvwrap;
 	unsigned int supports_autosuspend:1;
+	unsigned int generic_subclass:1;
 };
 #define	to_usb_device_driver(d) container_of(d, struct usb_device_driver, \
 		drvwrap.driver)
-- 
2.21.0


  parent reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-16  9:39 [PATCH v3 0/6] Add Apple MFi fastcharge USB device driver Bastien Nocera
2019-10-16  9:39 ` [PATCH v3 1/6] USB: Export generic USB device driver functions Bastien Nocera
2019-10-16  9:39 ` Bastien Nocera [this message]
2019-10-16  9:39 ` [PATCH v3 3/6] USB: Implement usb_device_match_id() Bastien Nocera
2019-10-16  9:39 ` [PATCH v3 4/6] USB: Select better matching USB drivers when available Bastien Nocera
2019-10-16  9:39 ` [PATCH v3 5/6] USB: Fallback to generic driver when specific driver fails Bastien Nocera
2019-10-16  9:39 ` [PATCH v3 6/6] USB: Add driver to control USB fast charge for iOS devices Bastien Nocera
2019-11-21 15:20 ` [PATCH v3 0/6] Add Apple MFi fastcharge USB device driver Bastien Nocera
2020-01-07  8:46   ` Bastien Nocera
2020-01-07  9:35     ` Greg Kroah-Hartman
2020-01-07  9:48       ` Bastien Nocera
2020-02-11  0:21       ` Bastien Nocera
2020-02-12 17:52         ` Greg Kroah-Hartman
2020-02-12 19:06 ` Greg Kroah-Hartman
2020-02-12 23:05   ` Bastien Nocera
2020-02-12 23:17     ` Greg Kroah-Hartman
2020-02-12 23:24       ` Bastien Nocera

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