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 9-16 contain a bug fix, cleanups and improvements for the
HT16K33 driver, to prepare for segment display support,
- Patch 17 adds support for 7/14-segment displays to the HT16K33
driver,
- Patch 18 updates the HT16K33 DT bindings to document an LED subnode,
- Patch 19 adds segment display LED support to the HT16K33 driver,
to make use of hardware blinking, and to expose display color.
Changes compared to v3[1]:
- Combine compatible values for 7/14 segment displays into an enum,
- Add Reviewed-by,
- Add missing select LEDS_CLASS.
Changes compared to v2[2]:
- Drop color property from display node,
- Use compat_only_sysfs_link_entry_to_kobj() instead of cooking our
own helper on top of kernfs_create_link(),
- Use "err" instead of "error" to be consistent with existing driver
naming style,
- Pass "dev" instead of "client" to ht16k33_fbdev_probe() and
ht16k33_seg_probe(),
- Drop local variable "node",
- Remove unneeded inclusion of <linux/leds.h> and <linux/of_device.h>,
- Document LED subnode,
- Remove unneeded C++ comment,
- Make the creation of the LED device dependent on the presence of the
"led" subnode in DT, so it can be used in dot-matrix mode too.
- Use led_init_data() and devm_led_classdev_register_ext() to retrieve
all LED properties from DT, instead of manual LED name construction
based on just the "color" property.
Changes compared to v1[3]:
- Fix type of color to uint32,
- "refresh-rate-hz" is still required for dot-matrix displays.
- Move "select LINEDISP" for HT16K33 symbol to correct patch,
- Add backwards compatibility "message" symlink to img-ascii-lcd,
- Connect backlight to fbdev in ht16k33 dot-matrix mode,
- Set "err = -EINVAL" in switch() case that cannot happen,
- Use "auxdisplay" instead of DRIVER_NAME in LED name.
This series has been tested using an Adafruit 0.54" Quad Alphanumeric
Red FeatherWing Display, connected to an OrangeCrab ECP5 FPGA board
running a 64 MHz VexRiscv RISC-V softcore.
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!
[1] "[PATCH v3 00/19] auxdisplay: ht16k33: Add character display support"
https://lore.kernel.org/r/20210714151130.2531831-1-geert@xxxxxxxxxxxxxx/
[2] "[PATCH v2 00/18] auxdisplay: ht16k33: Add character display support"
https://lore.kernel.org/r/20210625125902.1162428-1-geert@xxxxxxxxxxxxxx/
[3] "[PATCH 00/17] auxdisplay: ht16k33: Add character display support"
https://lore.kernel.org/r/20210322144848.1065067-1-geert@xxxxxxxxxxxxxx/
Geert Uytterhoeven (19):
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: Connect backlight to fbdev
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
dt-bindings: auxdisplay: ht16k33: Document LED subnode
auxdisplay: ht16k33: Add LED support
.../bindings/auxdisplay/holtek,ht16k33.yaml | 31 +-
drivers/auxdisplay/Kconfig | 9 +
drivers/auxdisplay/Makefile | 1 +
drivers/auxdisplay/ht16k33.c | 473 ++++++++++++++----
drivers/auxdisplay/img-ascii-lcd.c | 205 ++------
drivers/auxdisplay/line-display.c | 261 ++++++++++
drivers/auxdisplay/line-display.h | 43 ++
include/uapi/linux/map_to_14segment.h | 239 +++++++++
8 files changed, 995 insertions(+), 267 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
--
2.25.1
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
