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authorLinus Torvalds <torvalds@linux-foundation.org>2021-09-12 16:00:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-12 16:00:49 -0700
commitd41adc4e22c62640fa7de93f713a3c5b3638ab2e (patch)
tree6510e7f3d1226e602c28701110ea169991cb3e8b /Documentation
parentf306b90c69ce3994bb8046b54374a90a27f66be6 (diff)
parent24ebc044c72ee6e88dc902a0041bac672f012537 (diff)
downloadlinux-sh-d41adc4e22c62640fa7de93f713a3c5b3638ab2e.tar.gz
Merge tag 'auxdisplay-for-linus-v5.15-rc1' of git://github.com/ojeda/linux
Pull auxdisplay updates from Miguel Ojeda: "An assortment of improvements for auxdisplay: - Replace symbolic permissions with octal permissions (Jinchao Wang) - ks0108: Switch to use module_parport_driver() (Andy Shevchenko) - charlcd: Drop unneeded initializers and switch to C99 style (Andy Shevchenko) - hd44780: Fix oops on module unloading (Lars Poeschel) - Add I2C gpio expander example (Ralf Schlatterbeck)" * tag 'auxdisplay-for-linus-v5.15-rc1' of git://github.com/ojeda/linux: auxdisplay: Replace symbolic permissions with octal permissions auxdisplay: ks0108: Switch to use module_parport_driver() auxdisplay: charlcd: Drop unneeded initializers and switch to C99 style auxdisplay: hd44780: Fix oops on module unloading auxdisplay: Add I2C gpio expander example
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/auxdisplay/hit,hd44780.yaml31
1 files changed, 30 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.yaml b/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.yaml
index 9222b06e93a0..fde07e4b119d 100644
--- a/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.yaml
+++ b/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.yaml
@@ -12,7 +12,10 @@ maintainers:
description:
The Hitachi HD44780 Character LCD Controller is commonly used on character
LCDs that can display one or more lines of text. It exposes an M6800 bus
- interface, which can be used in either 4-bit or 8-bit mode.
+ interface, which can be used in either 4-bit or 8-bit mode. By using a
+ GPIO expander it is possible to use the driver with one of the popular I2C
+ expander boards based on the PCF8574 available for these displays. For
+ an example see below.
properties:
compatible:
@@ -94,3 +97,29 @@ examples:
display-height-chars = <2>;
display-width-chars = <16>;
};
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pcf8574: pcf8574@27 {
+ compatible = "nxp,pcf8574";
+ reg = <0x27>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ };
+ };
+ hd44780 {
+ compatible = "hit,hd44780";
+ display-height-chars = <2>;
+ display-width-chars = <16>;
+ data-gpios = <&pcf8574 4 0>,
+ <&pcf8574 5 0>,
+ <&pcf8574 6 0>,
+ <&pcf8574 7 0>;
+ enable-gpios = <&pcf8574 2 0>;
+ rs-gpios = <&pcf8574 0 0>;
+ rw-gpios = <&pcf8574 1 0>;
+ backlight-gpios = <&pcf8574 3 0>;
+ };