[00/17] auxdisplay: ht16k33: Add character display support
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Message ID 20210322144848.1065067-1-geert@linux-m68k.org
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  • auxdisplay: ht16k33: Add character display support
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Geert Uytterhoeven March 22, 2021, 2:48 p.m. UTC
Hi all,

The Holtek HT16K33 LED controller is not only used for driving
dot-matrix displays, but also for driving segment displays.
The current auxdisplay driver is limited to dot-matrix displays, which
are exposed as a frame buffer device.

This patch series extends the driver to 4-digit 7-segment and quad
14-segment alphanumeric displays, allowing the user to display and
scroll text messages.

List of patches:
  - Patch 1 provides font data for displaying ASCII characters on
    14-segment displays,
  - Patch 2 updates the HT16K33 DT bindings for segment displays,
  - Patches 3-5 contain a bug fix and small improvements for the
    Imagination Technologies ASCII LCD Display driver,
  - Patch 6 extracts the character line display core support from the
    Imagination Technologies ASCII LCD Display driver, for reuse,
  - Patches 7-8 contain cleanups and improvements for the character line
    display core driver,
  - Patches 9-15 contain cleanups and improvements for the HT16K33
    driver, to prepare for segment display support,
  - Patch 16 adds support for 7/14-segment displays to the HT16K33
  - Patch 17 adds segment display LED support to the HT16K33 driver,
    to make use of hardware blinking, and to expose display color.

This series has been tested using an Adafruit 0.54" Quad Alphanumeric
Red FeatherWing Display, plugged into an OrangeCrab ECP5-based FPGA
board running linux-on-litex-vexriscv.
7-segment display support is based purely on schematics, and has not
been tested on actual hardware.  The changes to img-ascii-lcd.c are also
untested, due to lack of hardware.

Thanks for your comments!

Geert Uytterhoeven (17):
  uapi: Add <linux/map_to_14segment.h>
  dt-bindings: auxdisplay: ht16k33: Document Adafruit segment displays
  auxdisplay: img-ascii-lcd: Fix lock-up when displaying empty string
  auxdisplay: img-ascii-lcd: Add helper variable dev
  auxdisplay: img-ascii-lcd: Convert device attribute to sysfs_emit()
  auxdisplay: Extract character line display core support
  auxdisplay: linedisp: Use kmemdup_nul() helper
  auxdisplay: linedisp: Add support for changing scroll rate
  auxdisplay: ht16k33: Use HT16K33_FB_SIZE in ht16k33_initialize()
  auxdisplay: ht16k33: Remove unneeded error check in keypad probe()
  auxdisplay: ht16k33: Convert to simple i2c probe function
  auxdisplay: ht16k33: Add helper variable dev
  auxdisplay: ht16k33: Move delayed work
  auxdisplay: ht16k33: Extract ht16k33_brightness_set()
  auxdisplay: ht16k33: Extract frame buffer probing
  auxdisplay: ht16k33: Add support for segment displays
  auxdisplay: ht16k33: Add segment display LED support

 .../bindings/auxdisplay/holtek,ht16k33.yaml   |  22 +-
 drivers/auxdisplay/Kconfig                    |   8 +
 drivers/auxdisplay/Makefile                   |   1 +
 drivers/auxdisplay/ht16k33.c                  | 451 ++++++++++++++----
 drivers/auxdisplay/img-ascii-lcd.c            | 199 +-------
 drivers/auxdisplay/line-display.c             | 261 ++++++++++
 drivers/auxdisplay/line-display.h             |  43 ++
 include/uapi/linux/map_to_14segment.h         | 240 ++++++++++
 8 files changed, 961 insertions(+), 264 deletions(-)
 create mode 100644 drivers/auxdisplay/line-display.c
 create mode 100644 drivers/auxdisplay/line-display.h
 create mode 100644 include/uapi/linux/map_to_14segment.h


Miguel Ojeda March 22, 2021, 5:03 p.m. UTC | #1
On Mon, Mar 22, 2021 at 3:48 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> Thanks for your comments!

We could use this as a showcase on how to structure and present a
patch series! ;-)