| Message ID | 20171220082633.32237-2-brgl@bgdev.pl |
|---|---|
| State | Accepted |
| Delegated to: | Bartosz Golaszewski |
| Headers | show |
| Series | eeprom: at24: write-protect pin support | expand |
On Wed, Dec 20, 2017 at 09:26:32AM +0100, Bartosz Golaszewski wrote: > 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 > range). > > 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 > connected. > > Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl> > --- > Documentation/devicetree/bindings/eeprom/at24.txt | 3 +++ > 1 file changed, 3 insertions(+) Reviewed-by: Rob Herring <robh@kernel.org>
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. + Example: eeprom@52 { compatible = "atmel,24c32"; reg = <0x52>; pagesize = <32>; + wp-gpios = <&gpio1 3 0>; };
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 range). 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 connected. Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl> --- Documentation/devicetree/bindings/eeprom/at24.txt | 3 +++ 1 file changed, 3 insertions(+)