summaryrefslogtreecommitdiffstats
path: root/Documentation/input/devices/bcm5974.rst
diff options
context:
space:
mode:
authorDonggeun Yoo <donggeunyoo.kernel@gmail.com>2026-09-02 00:21:26 +0900
committerJonathan Cameron <jonathan.cameron@oss.qualcomm.com>2026-09-07 02:24:53 +0100
commite24328974a88aa8541e94e8bb8dfa2ade1b3c45d (patch)
tree43a2533acc955d11f5cb8be1ecba0ab8ba4cbb1e /Documentation/input/devices/bcm5974.rst
downloadlinux-stable-e24328974a88aa8541e94e8bb8dfa2ade1b3c45d.tar.gz
linux-stable-e24328974a88aa8541e94e8bb8dfa2ade1b3c45d.zip
iio: proximity: vl53l0x-i2c: claim direct mode for raw readsgrafted
vl53l0x_read_raw() starts a single-shot ranging measurement and reads back the result. Once the triggered buffer is enabled the sensor runs in continuous mode and its data-ready interrupt is routed to the trigger, so a concurrent in_distance_raw read disturbs the streaming setup and never gets its completion, returning -ETIMEDOUT. The original submission claimed direct mode here, but it was dropped during review because the driver had no buffer support at the time [1]. Continuous (buffered) mode was later added without restoring the claim [2], reintroducing the conflict. Reject direct reads while buffered capture is active by claiming direct mode around the measurement, as the vl53l1x sibling already does. Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support") Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1] Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2] Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Diffstat (limited to 'Documentation/input/devices/bcm5974.rst')
-rw-r--r--Documentation/input/devices/bcm5974.rst70
1 files changed, 70 insertions, 0 deletions
diff --git a/Documentation/input/devices/bcm5974.rst b/Documentation/input/devices/bcm5974.rst
new file mode 100644
index 000000000..4aca199b0
--- /dev/null
+++ b/Documentation/input/devices/bcm5974.rst
@@ -0,0 +1,70 @@
+.. include:: <isonum.txt>
+
+------------------------
+BCM5974 Driver (bcm5974)
+------------------------
+
+:Copyright: |copy| 2008-2009 Henrik Rydberg <rydberg@euromail.se>
+
+The USB initialization and package decoding was made by Scott Shawcroft as
+part of the touchd user-space driver project:
+
+:Copyright: |copy| 2008 Scott Shawcroft (scott.shawcroft@gmail.com)
+
+The BCM5974 driver is based on the appletouch driver:
+
+:Copyright: |copy| 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
+:Copyright: |copy| 2005 Johannes Berg (johannes@sipsolutions.net)
+:Copyright: |copy| 2005 Stelian Pop (stelian@popies.net)
+:Copyright: |copy| 2005 Frank Arnold (frank@scirocco-5v-turbo.de)
+:Copyright: |copy| 2005 Peter Osterlund (petero2@telia.com)
+:Copyright: |copy| 2005 Michael Hanselmann (linux-kernel@hansmi.ch)
+:Copyright: |copy| 2006 Nicolas Boichat (nicolas@boichat.ch)
+
+This driver adds support for the multi-touch trackpad on the new Apple
+Macbook Air and Macbook Pro laptops. It replaces the appletouch driver on
+those computers, and integrates well with the synaptics driver of the Xorg
+system.
+
+Known to work on Macbook Air, Macbook Pro Penryn and the new unibody
+Macbook 5 and Macbook Pro 5.
+
+Usage
+-----
+
+The driver loads automatically for the supported usb device ids, and
+becomes available both as an event device (/dev/input/event*) and as a
+mouse via the mousedev driver (/dev/input/mice).
+
+USB Race
+--------
+
+The Apple multi-touch trackpads report both mouse and keyboard events via
+different interfaces of the same usb device. This creates a race condition
+with the HID driver, which, if not told otherwise, will find the standard
+HID mouse and keyboard, and claim the whole device. To remedy, the usb
+product id must be listed in the mouse_ignore list of the hid driver.
+
+Debug output
+------------
+
+To ease the development for new hardware version, verbose packet output can
+be switched on with the debug kernel module parameter. The range [1-9]
+yields different levels of verbosity. Example (as root)::
+
+ echo -n 9 > /sys/module/bcm5974/parameters/debug
+
+ tail -f /var/log/debug
+
+ echo -n 0 > /sys/module/bcm5974/parameters/debug
+
+Trivia
+------
+
+The driver was developed at the ubuntu forums in June 2008 [#f1]_, and now has
+a more permanent home at bitmath.org [#f2]_.
+
+.. Links
+
+.. [#f1] http://ubuntuforums.org/showthread.php?t=840040
+.. [#f2] http://bitmath.org/code/