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7f3d53c8bf
Back when I added this driver in commit 2ac8490412, 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>
117 lines
2.3 KiB
C
117 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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#include <dm.h>
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#include <dm/device_compat.h>
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#include <wdt.h>
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#include <asm/gpio.h>
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#include <linux/delay.h>
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enum {
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HW_ALGO_TOGGLE,
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HW_ALGO_LEVEL,
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};
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struct gpio_wdt_priv {
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struct gpio_desc gpio;
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unsigned int hw_algo;
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bool always_running;
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int state;
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};
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static int gpio_wdt_reset(struct udevice *dev)
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{
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struct gpio_wdt_priv *priv = dev_get_priv(dev);
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switch (priv->hw_algo) {
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case HW_ALGO_TOGGLE:
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/* Toggle output pin */
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priv->state = !priv->state;
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dm_gpio_set_value(&priv->gpio, priv->state);
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break;
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case HW_ALGO_LEVEL:
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/* Pulse */
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dm_gpio_set_value(&priv->gpio, 1);
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__udelay(1);
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dm_gpio_set_value(&priv->gpio, 0);
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break;
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}
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return 0;
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}
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static int gpio_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
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{
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struct gpio_wdt_priv *priv = dev_get_priv(dev);
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if (priv->always_running)
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return 0;
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dm_gpio_set_dir_flags(&priv->gpio, GPIOD_IS_OUT);
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gpio_wdt_reset(dev);
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return 0;
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}
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static int gpio_wdt_stop(struct udevice *dev)
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{
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struct gpio_wdt_priv *priv = dev_get_priv(dev);
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if (priv->always_running)
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return -EOPNOTSUPP;
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if (priv->hw_algo == HW_ALGO_TOGGLE)
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dm_gpio_set_dir_flags(&priv->gpio, GPIOD_IS_IN);
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else
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dm_gpio_set_value(&priv->gpio, 1);
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return 0;
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}
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static int dm_probe(struct udevice *dev)
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{
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struct gpio_wdt_priv *priv = dev_get_priv(dev);
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const char *algo = dev_read_string(dev, "hw_algo");
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int ret, flags;
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if (!algo)
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return -EINVAL;
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if (!strcmp(algo, "toggle"))
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priv->hw_algo = HW_ALGO_TOGGLE;
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else if (!strcmp(algo, "level"))
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priv->hw_algo = HW_ALGO_LEVEL;
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else
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return -EINVAL;
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priv->always_running = dev_read_bool(dev, "always-running");
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flags = priv->always_running || priv->hw_algo == HW_ALGO_LEVEL ?
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GPIOD_IS_OUT : GPIOD_IS_IN;
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ret = gpio_request_by_name(dev, "gpios", 0, &priv->gpio, flags);
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if (ret < 0) {
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dev_err(dev, "Request for wdt gpio failed: %d\n", ret);
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return ret;
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}
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if (priv->always_running)
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ret = gpio_wdt_reset(dev);
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return ret;
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}
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static const struct wdt_ops gpio_wdt_ops = {
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.start = gpio_wdt_start,
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.stop = gpio_wdt_stop,
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.reset = gpio_wdt_reset,
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};
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static const struct udevice_id gpio_wdt_ids[] = {
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{ .compatible = "linux,wdt-gpio" },
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{}
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};
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U_BOOT_DRIVER(wdt_gpio) = {
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.name = "wdt_gpio",
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.id = UCLASS_WDT,
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.of_match = gpio_wdt_ids,
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.ops = &gpio_wdt_ops,
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.probe = dm_probe,
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.priv_auto = sizeof(struct gpio_wdt_priv),
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};
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