mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-14 08:57:58 +00:00
2ac8490412
A rather common kind of external watchdog circuit is one that is kept alive by toggling a gpio. Add a driver for handling such a watchdog. The corresponding linux driver apparently has support for some watchdog circuits which can be disabled by tri-stating the gpio, but I have never actually encountered such a chip in the wild; the whole point of adding an external watchdog is usually that it is not in any way under software control. For forward-compatibility, and to make DT describe the hardware, the current driver only supports devices that have the always-running property. I went a little back and forth on whether I should fail ->probe or only ->start, and ended up deciding ->start was the right place. The compatible string is probably a little odd as it has nothing to do with linux per se - however, I chose that to make .dts snippets reusable between device trees used with U-Boot and linux, and this is the (only) compatible string that linux' corresponding driver and DT binding accepts. I have asked whether one should/could add "wdt-gpio" to that binding, but the answer was no: https://lore.kernel.org/lkml/CAL_JsqKEGaFpiFV_oAtE+S_bnHkg4qry+bhx2EDs=NSbVf_giA@mail.gmail.com/ If someone feels strongly about this, I can certainly remove the "linux," part from the string - it probably wouldn't the only place where one can't reuse a DT snippet as-is between linux and U-Boot. Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: Stefan Roese <sr@denx.de> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
19 lines
468 B
Text
19 lines
468 B
Text
GPIO watchdog timer
|
|
|
|
Describes a simple watchdog timer which is reset by toggling a gpio.
|
|
|
|
Required properties:
|
|
|
|
- compatible: Must be "linux,wdt-gpio".
|
|
- gpios: gpio to toggle when wdt driver reset method is called.
|
|
- always-running: Boolean property indicating that the watchdog cannot
|
|
be disabled. At present, U-Boot only supports this kind of GPIO
|
|
watchdog.
|
|
|
|
Example:
|
|
|
|
gpio-wdt {
|
|
gpios = <&gpio0 1 0>;
|
|
compatible = "linux,wdt-gpio";
|
|
always-running;
|
|
};
|