** Description changed:
+ [Impact]
+
To attach TFT touchscreens the pi-foundation kernel ships the fbtft
devicetree overlay along with rpi-display.
While you can attach a stand-alone TFT display just fine when only using
rpi-display to provide the drivers with hardcoded GPIO assignments, it
gets extremely tricky to even enable the touchscreen input or to use
such a TFT with other sensors attached since rpi-display does not allow
any re-assignment of the GPIO pins in use.
The upstream fbtft driver can make use of the already included rpi-display
drivers by defining "rpi-display" in its params. It also allows to freely
re-assign the GPIO pins for backlight, D/C and Reset to give you enough
flexibility to have the display co-exist with any attached sensors and touch
input devices that do not have the ability to re-assign GPIO pins and that
clash with the hardcoded numbering of rpi-display.
An example with freely assigned GPIOs can be seen in the upstream
(rpi-foundation) overlay README file at:
https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README#L884
Please include fbtft in the ubuntu kernels to allow a more flexible
usage of SPI based TFT touchscreens on the Pi.
+
+ [Test case]
+
+ See above.
+
+ [Fix]
+
+ Backport commit 6a4525924c43 ("overlays: Add fbtft overlay") from
+ rpi-5.15.y.
+
+ [Where Problems could occur]
+
+ Problems might show up when using the new DTB overlay on a Pi platform.
** Changed in: linux-raspi (Ubuntu Focal)
Status: New => In Progress
** Changed in: linux-raspi (Ubuntu Focal)
Assignee: (unassigned) => Juerg Haefliger (juergh)
** Changed in: linux-raspi (Ubuntu)
Status: Fix Released => Invalid
** No longer affects: linux-raspi2 (Ubuntu)
** Changed in: linux-raspi (Ubuntu Jammy)
Importance: Wishlist => Undecided
** Changed in: linux-raspi (Ubuntu)
Importance: Wishlist => Undecided
** Changed in: linux-raspi (Ubuntu Focal)
Importance: Undecided => Wishlist
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You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux-raspi2 in Ubuntu.
https://bugs.launchpad.net/bugs/1963919
Title:
fbtft overlay is missing
Status in linux-raspi package in Ubuntu:
Invalid
Status in linux-raspi source package in Focal:
In Progress
Status in linux-raspi2 source package in Focal:
Invalid
Status in linux-raspi source package in Impish:
Won't Fix
Status in linux-raspi2 source package in Impish:
Invalid
Status in linux-raspi source package in Jammy:
Fix Released
Status in linux-raspi2 source package in Jammy:
Invalid
Bug description:
[Impact]
To attach TFT touchscreens the pi-foundation kernel ships the fbtft
devicetree overlay along with rpi-display.
While you can attach a stand-alone TFT display just fine when only
using rpi-display to provide the drivers with hardcoded GPIO
assignments, it gets extremely tricky to even enable the touchscreen
input or to use such a TFT with other sensors attached since rpi-
display does not allow any re-assignment of the GPIO pins in use.
The upstream fbtft driver can make use of the already included rpi-display
drivers by defining "rpi-display" in its params. It also allows to freely
re-assign the GPIO pins for backlight, D/C and Reset to give you enough
flexibility to have the display co-exist with any attached sensors and touch
input devices that do not have the ability to re-assign GPIO pins and that
clash with the hardcoded numbering of rpi-display.
An example with freely assigned GPIOs can be seen in the upstream
(rpi-foundation) overlay README file at:
https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README#L884
Please include fbtft in the ubuntu kernels to allow a more flexible
usage of SPI based TFT touchscreens on the Pi.
[Test case]
See above.
[Fix]
Backport commit 6a4525924c43 ("overlays: Add fbtft overlay") from
rpi-5.15.y.
[Where Problems could occur]
Problems might show up when using the new DTB overlay on a Pi
platform.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/1963919/+subscriptions
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