On Thu, Nov 03, 2022 at 11:03:56AM +0100, Andrej Picej wrote:
> Putting device into the "Suspend-To-Idle" mode causes watchdog to
> trigger and resets the board after set watchdog timeout period elapses.
>
> Introduce new device-tree property "fsl,suspend-in-wait" which suspends
> watchdog in WAIT mode. This is done by setting WDW bit in WCR
> (Watchdog Control Register). Watchdog operation is restored after
> exiting WAIT mode as expected. WAIT mode corresponds with Linux's
> "Suspend-To-Idle".
>
> Signed-off-by: Andrej Picej <andrej.picej@xxxxxxxxx>
> Reviewed-by: Fabio Estevam <festevam@xxxxxxxxx>
For my reference:
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
This will have to wait for dt approval.
Thanks,
Guenter
> ---
> Changes in v3:
> - fix spelling in commit message,
> - fix and simplify property handling in probe,
> - add a comment about unknown interaction between imx7d no-ping
> functionality and "fsl,suspend-in-wait",
> - property support handled by of_device_id data pointer.
>
> Changes in v2:
> - validate the property with compatible string, as this functionality
> is not supported by all devices.
> ---
> drivers/watchdog/imx2_wdt.c | 55 +++++++++++++++++++++++++++++++++++--
> 1 file changed, 52 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
> index d0c5d47ddede..19ab7b3d286b 100644
> --- a/drivers/watchdog/imx2_wdt.c
> +++ b/drivers/watchdog/imx2_wdt.c
> @@ -27,6 +27,7 @@
> #include <linux/module.h>
> #include <linux/moduleparam.h>
> #include <linux/of_address.h>
> +#include <linux/of_device.h>
> #include <linux/platform_device.h>
> #include <linux/regmap.h>
> #include <linux/watchdog.h>
> @@ -35,6 +36,7 @@
>
> #define IMX2_WDT_WCR 0x00 /* Control Register */
> #define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */
> +#define IMX2_WDT_WCR_WDW BIT(7) /* -> Watchdog disable for WAIT */
> #define IMX2_WDT_WCR_WDA BIT(5) /* -> External Reset WDOG_B */
> #define IMX2_WDT_WCR_SRS BIT(4) /* -> Software Reset Signal */
> #define IMX2_WDT_WCR_WRE BIT(3) /* -> WDOG Reset Enable */
> @@ -60,13 +62,19 @@
>
> #define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8)
>
> +struct imx2_wdt_data {
> + bool wdw_supported;
> +};
> +
> struct imx2_wdt_device {
> struct clk *clk;
> struct regmap *regmap;
> struct watchdog_device wdog;
> + const struct imx2_wdt_data *data;
> bool ext_reset;
> bool clk_is_on;
> bool no_ping;
> + bool sleep_wait;
> };
>
> static bool nowayout = WATCHDOG_NOWAYOUT;
> @@ -129,6 +137,9 @@ static inline void imx2_wdt_setup(struct watchdog_device *wdog)
>
> /* Suspend timer in low power mode, write once-only */
> val |= IMX2_WDT_WCR_WDZST;
> + /* Suspend timer in low power WAIT mode, write once-only */
> + if (wdev->sleep_wait)
> + val |= IMX2_WDT_WCR_WDW;
> /* Strip the old watchdog Time-Out value */
> val &= ~IMX2_WDT_WCR_WT;
> /* Generate internal chip-level reset if WDOG times out */
> @@ -292,6 +303,8 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
> wdog->max_hw_heartbeat_ms = IMX2_WDT_MAX_TIME * 1000;
> wdog->parent = dev;
>
> + wdev->data = of_device_get_match_data(dev);
> +
> ret = platform_get_irq(pdev, 0);
> if (ret > 0)
> if (!devm_request_irq(dev, ret, imx2_wdt_isr, 0,
> @@ -313,9 +326,18 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
>
> wdev->ext_reset = of_property_read_bool(dev->of_node,
> "fsl,ext-reset-output");
> +
> + if (of_property_read_bool(dev->of_node, "fsl,suspend-in-wait")) {
> + if (!wdev->data->wdw_supported) {
> + dev_err(dev, "suspend-in-wait not supported\n");
> + return -EINVAL;
> + }
> + wdev->sleep_wait = true;
> + }
> +
> /*
> * The i.MX7D doesn't support low power mode, so we need to ping the watchdog
> - * during suspend.
> + * during suspend. Interaction with "fsl,suspend-in-wait" is unknown!
> */
> wdev->no_ping = !of_device_is_compatible(dev->of_node, "fsl,imx7d-wdt");
> platform_set_drvdata(pdev, wdog);
> @@ -417,9 +439,36 @@ static int __maybe_unused imx2_wdt_resume(struct device *dev)
> static SIMPLE_DEV_PM_OPS(imx2_wdt_pm_ops, imx2_wdt_suspend,
> imx2_wdt_resume);
>
> +struct imx2_wdt_data imx_wdt = {
> + .wdw_supported = true,
> +};
> +
> +struct imx2_wdt_data imx_wdt_legacy = {
> + .wdw_supported = false,
> +};
> +
> static const struct of_device_id imx2_wdt_dt_ids[] = {
> - { .compatible = "fsl,imx21-wdt", },
> - { .compatible = "fsl,imx7d-wdt", },
> + { .compatible = "fsl,imx21-wdt", .data = &imx_wdt_legacy },
> + { .compatible = "fsl,imx25-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx27-wdt", .data = &imx_wdt_legacy },
> + { .compatible = "fsl,imx31-wdt", .data = &imx_wdt_legacy },
> + { .compatible = "fsl,imx35-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx50-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx51-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx53-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx6q-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx6sl-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx6sll-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx6sx-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx6ul-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx7d-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx8mm-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx8mn-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx8mp-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,imx8mq-wdt", .data = &imx_wdt },
> + { .compatible = "fsl,ls1012a-wdt", .data = &imx_wdt_legacy },
> + { .compatible = "fsl,ls1043a-wdt", .data = &imx_wdt_legacy },
> + { .compatible = "fsl,vf610-wdt", .data = &imx_wdt },
> { /* sentinel */ }
> };
> MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids);
> --
> 2.25.1
>
