blob: 933a76847aab42feee37a219fe858d2e2219ef70 [file] [log] [blame]
From cd352f491c0979826b29b1a6d3220d5c6cf8b304 Mon Sep 17 00:00:00 2001
From: Bartosz Golaszewski <>
Date: Tue, 19 Dec 2017 12:09:23 +0100
Subject: [PATCH 0412/1795] dt-bindings: at24: new optional property - wp-gpios
AT24 EEPROMs have a write-protect pin, which - when pulled high -
inhibits writes to the upper quadrant of memory (although it has been
observed that on some chips it disables writing to the entire memory
On some boards, this pin is connected to a GPIO and pulled high by
default, which forces the user to manually change its state before
writing. On linux this means that we either need to hog the line all
the time, or set the GPIO value before writing from outside of the
at24 driver.
Add a new optional property to the device tree binding document, which
allows to specify the GPIO line to which the write-protect pin is
Signed-off-by: Bartosz Golaszewski <>
Reviewed-by: Andy Shevchenko <>
Reviewed-by: Rob Herring <>
(cherry picked from commit 3f3d8ef7f4eff5909b0cc996718de81de99af1e6)
Signed-off-by: Simon Horman <>
Signed-off-by: Geert Uytterhoeven <>
Documentation/devicetree/bindings/eeprom/at24.txt | 3 +++
1 file changed, 3 insertions(+)
diff --git a/Documentation/devicetree/bindings/eeprom/at24.txt b/Documentation/devicetree/bindings/eeprom/at24.txt
index a0415b8471bb..cbc80e194ac6 100644
--- a/Documentation/devicetree/bindings/eeprom/at24.txt
+++ b/Documentation/devicetree/bindings/eeprom/at24.txt
@@ -43,10 +43,13 @@ Optional properties:
eeprom does not automatically roll over reads to the next
slave address. Please consult the manual of your device.
+ - wp-gpios: GPIO to which the write-protect pin of the chip is connected.
eeprom@52 {
compatible = "atmel,24c32";
reg = <0x52>;
pagesize = <32>;
+ wp-gpios = <&gpio1 3 0>;