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SubjectRe: [PATCH] watchdog: max63xx_wdt: Add support for specifying WDI logic via GPIO
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On 4/28/22 02:16, Pali Rohár wrote:
> On some boards is WDI logic of max6370 chip connected via GPIO. So extend
> max63xx_wdt driver and DTS schema to allow specifying WDI logic via GPIO.
>
> Signed-off-by: Pali Rohár <pali@kernel.org>

How is that different to just using the gpio watchdog driver ?

Guenter

> ---
> .../bindings/watchdog/maxim,max63xx.yaml | 4 +++
> drivers/watchdog/max63xx_wdt.c | 28 +++++++++++++++++++
> 2 files changed, 32 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/watchdog/maxim,max63xx.yaml b/Documentation/devicetree/bindings/watchdog/maxim,max63xx.yaml
> index ab9641e845db..a97aa0135ef9 100644
> --- a/Documentation/devicetree/bindings/watchdog/maxim,max63xx.yaml
> +++ b/Documentation/devicetree/bindings/watchdog/maxim,max63xx.yaml
> @@ -27,6 +27,10 @@ properties:
> description: This is a 1-byte memory-mapped address
> maxItems: 1
>
> + gpios:
> + description: Optional GPIO used for controlling WDI when WDI bit is not mapped to memory
> + maxItems: 1
> +
> required:
> - compatible
> - reg
> diff --git a/drivers/watchdog/max63xx_wdt.c b/drivers/watchdog/max63xx_wdt.c
> index 9e1541cfae0d..eaf00c3f06a5 100644
> --- a/drivers/watchdog/max63xx_wdt.c
> +++ b/drivers/watchdog/max63xx_wdt.c
> @@ -27,6 +27,7 @@
> #include <linux/io.h>
> #include <linux/slab.h>
> #include <linux/property.h>
> +#include <linux/gpio/consumer.h>
>
> #define DEFAULT_HEARTBEAT 60
> #define MAX_HEARTBEAT 60
> @@ -53,6 +54,9 @@ struct max63xx_wdt {
> void __iomem *base;
> spinlock_t lock;
>
> + /* GPIOs */
> + struct gpio_desc *gpio_wdi;
> +
> /* WDI and WSET bits write access routines */
> void (*ping)(struct max63xx_wdt *wdt);
> void (*set)(struct max63xx_wdt *wdt, u8 set);
> @@ -158,6 +162,17 @@ static const struct watchdog_info max63xx_wdt_info = {
> .identity = "max63xx Watchdog",
> };
>
> +static void max63xx_gpio_ping(struct max63xx_wdt *wdt)
> +{
> + spin_lock(&wdt->lock);
> +
> + gpiod_set_value_cansleep(wdt->gpio_wdi, 1);
> + udelay(1);
> + gpiod_set_value_cansleep(wdt->gpio_wdi, 0);
> +
> + spin_unlock(&wdt->lock);
> +}
> +
> static void max63xx_mmap_ping(struct max63xx_wdt *wdt)
> {
> u8 val;
> @@ -225,6 +240,19 @@ static int max63xx_wdt_probe(struct platform_device *pdev)
> return -EINVAL;
> }
>
> + wdt->gpio_wdi = devm_gpiod_get(dev, NULL, GPIOD_FLAGS_BIT_DIR_OUT);
> + if (IS_ERR(wdt->gpio_wdi) && PTR_ERR(wdt->gpio_wdi) != -ENOENT) {
> + if (PTR_ERR(wdt->gpio_wdi) != -EPROBE_DEFER)
> + dev_err(dev, "unable to request gpio: %ld\n",
> + PTR_ERR(wdt->gpio_wdi));
> + return PTR_ERR(wdt->gpio_wdi);
> + }
> +
> + if (!IS_ERR(wdt->gpio_wdi))
> + wdt->ping = max63xx_gpio_ping;
> + else
> + wdt->gpio_wdi = NULL;
> +
> err = max63xx_mmap_init(pdev, wdt);
> if (err)
> return err;

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