From 7f3d53c8bf3b851837dc2f5dd85e0c6a0d0116a1 Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <ravi@prevas.dk>
Date: Wed, 2 Oct 2024 21:23:23 +0200
Subject: [PATCH] watchdog: gpio_wdt: add support for stoppable devices
Back when I added this driver in commit 2ac8490412c9, I wrote
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;
That has changed now; I have a board with just such a watchdog on my
desk currently. Add support for that.
- For a hw_algo="toggle" device, the gpio is requested as output if the
always-running flag is set, otherwise as input.
- The ->start() method is updated to change the direction to output when
required (i.e. it is not always-running).
- The ->stop() method is implemented, but of course reports failure if
always-running.
As I still haven't met any hw_algo="level" devices, I'm not entirely
sure how they fit in, but I'm borrowing logic from the corresponding
linux driver:
- In ->probe(), such devices always request the gpio as GPIOD_IS_OUT.
- In ->stop(), the linux driver has an "eternal ping" comment and sets
the gpio to (logic) high.
Stefan:
Added necessary changes in test/dm/wdt.c to fix CI build breakage, as
suggested by Rasmus.
Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
Reviewed-by: Stefan Roese <sr@denx.de>
---
drivers/watchdog/gpio_wdt.c | 27 ++++++++++++++++++++++++---
test/dm/wdt.c | 4 ++--
2 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c
index 2920c2c751..e889861e91 100644
--- a/drivers/watchdog/gpio_wdt.c
+++ b/drivers/watchdog/gpio_wdt.c
@@ -45,14 +45,32 @@ static int gpio_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
if (priv->always_running)
return 0;
- return -ENOSYS;
+ dm_gpio_set_dir_flags(&priv->gpio, GPIOD_IS_OUT);
+ gpio_wdt_reset(dev);
+
+ return 0;
+}
+
+static int gpio_wdt_stop(struct udevice *dev)
+{
+ struct gpio_wdt_priv *priv = dev_get_priv(dev);
+
+ if (priv->always_running)
+ return -EOPNOTSUPP;
+
+ if (priv->hw_algo == HW_ALGO_TOGGLE)
+ dm_gpio_set_dir_flags(&priv->gpio, GPIOD_IS_IN);
+ else
+ dm_gpio_set_value(&priv->gpio, 1);
+
+ return 0;
}
static int dm_probe(struct udevice *dev)
{
struct gpio_wdt_priv *priv = dev_get_priv(dev);
- int ret;
const char *algo = dev_read_string(dev, "hw_algo");
+ int ret, flags;
if (!algo)
return -EINVAL;
@@ -64,7 +82,9 @@ static int dm_probe(struct udevice *dev)
return -EINVAL;
priv->always_running = dev_read_bool(dev, "always-running");
- ret = gpio_request_by_name(dev, "gpios", 0, &priv->gpio, GPIOD_IS_OUT);
+ flags = priv->always_running || priv->hw_algo == HW_ALGO_LEVEL ?
+ GPIOD_IS_OUT : GPIOD_IS_IN;
+ ret = gpio_request_by_name(dev, "gpios", 0, &priv->gpio, flags);
if (ret < 0) {
dev_err(dev, "Request for wdt gpio failed: %d\n", ret);
return ret;
@@ -78,6 +98,7 @@ static int dm_probe(struct udevice *dev)
static const struct wdt_ops gpio_wdt_ops = {
.start = gpio_wdt_start,
+ .stop = gpio_wdt_stop,
.reset = gpio_wdt_reset,
};
diff --git a/test/dm/wdt.c b/test/dm/wdt.c
index 541bcba1b5..710414881f 100644
--- a/test/dm/wdt.c
+++ b/test/dm/wdt.c
@@ -71,7 +71,7 @@ static int dm_test_wdt_gpio_toggle(struct unit_test_state *uts)
ut_assertok(wdt_reset(wdt));
ut_asserteq(val, sandbox_gpio_get_value(gpio, offset));
- ut_asserteq(-ENOSYS, wdt_stop(wdt));
+ ut_asserteq(-EOPNOTSUPP, wdt_stop(wdt));
return 0;
}
@@ -103,7 +103,7 @@ static int dm_test_wdt_gpio_level(struct unit_test_state *uts)
ut_assertok(wdt_reset(wdt));
ut_asserteq(val, sandbox_gpio_get_value(gpio, offset));
- ut_asserteq(-ENOSYS, wdt_stop(wdt));
+ ut_asserteq(-EOPNOTSUPP, wdt_stop(wdt));
return 0;
}
--
2.39.5