watchdog: introduce a u-boot,autostart property

This is a companion to u-boot,noautostart. If one has a single
watchdog device that one does want to have auto-started, but several
others that one doesn't, the only way currently is to set the
CONFIG_WATCHDOG_AUTOSTART and then use the opt-out for the majority.

The main motivation for this is to add an autostarted watchdog device
to the sandbox (to test a fix) without having to set AUTOSTART in
sandbox_defconfig and add the noautostart property to the existing
devices. But it's also nice for symmetry, and the logic in
init_watchdog_dev() becomes simpler to read because we avoid all the
negations.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>

diff --git a/doc/device-tree-bindings/watchdog/common.txt b/doc/device-tree-bindings/watchdog/common.txt
index 9db6dd6..d041fea 100644 (file)
--- a/doc/device-tree-bindings/watchdog/common.txt
+++ b/doc/device-tree-bindings/watchdog/common.txt
@@ -6,7 +6,8 @@ Optional properties:
                 be used instead.
 - hw_margin_ms : Period used to reset the watchdog in ms
                  If this period is not defined, the default value is 1000.
-- u-boot,noautostart : Specify that this watchdog should not autostart
-                       When the config option WATCHDOG_AUTOSTART is set, all enabled
-                       watchdogs are started. This property allows specifying that this
-                       watchdog should NOT be started.
+- u-boot,noautostart :
+- u-boot,autostart : These (mutually exclusive) boolean properties can be used to control
+                     whether the watchdog is automatically started when probed. If neither
+                     are present, the behaviour is determined by the config option
+                     WATCHDOG_AUTOSTART.

diff --git a/drivers/watchdog/wdt-uclass.c b/drivers/watchdog/wdt-uclass.c
index 3f342cd..82df0ff 100644 (file)
--- a/drivers/watchdog/wdt-uclass.c
+++ b/drivers/watchdog/wdt-uclass.c
@@ -37,8 +37,8 @@ struct wdt_priv {
        ulong next_reset;
        /* Whether watchdog_start() has been called on the device. */
        bool running;
-       /* No autostart */
-       bool noautostart;
+       /* autostart */
+       bool autostart;
 
        struct cyclic_info *cyclic;
 };
@@ -72,7 +72,7 @@ static void init_watchdog_dev(struct udevice *dev)
                               dev->name);
        }
 
-       if (!IS_ENABLED(CONFIG_WATCHDOG_AUTOSTART) || priv->noautostart) {
+       if (!priv->autostart) {
                printf("WDT:   Not starting %s\n", dev->name);
                return;
        }
@@ -267,19 +267,22 @@ static int wdt_pre_probe(struct udevice *dev)
         * indicated by a hw_margin_ms property.
         */
        ulong reset_period = 1000;
-       bool noautostart = false;
+       bool autostart = IS_ENABLED(CONFIG_WATCHDOG_AUTOSTART);
        struct wdt_priv *priv;
 
        if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) {
                timeout = dev_read_u32_default(dev, "timeout-sec", timeout);
                reset_period = dev_read_u32_default(dev, "hw_margin_ms",
                                                    4 * reset_period) / 4;
-               noautostart = dev_read_bool(dev, "u-boot,noautostart");
+               if (dev_read_bool(dev, "u-boot,noautostart"))
+                       autostart = false;
+               else if (dev_read_bool(dev, "u-boot,autostart"))
+                       autostart = true;
        }
        priv = dev_get_uclass_priv(dev);
        priv->timeout = timeout;
        priv->reset_period = reset_period;
-       priv->noautostart = noautostart;
+       priv->autostart = autostart;
        /*
         * Pretend this device was last reset "long" ago so the first
         * watchdog_reset will actually call its ->reset method.