diff options
| author | Ranjani Vaidyanathan <ranjani.vaidyanathan@nxp.com> | 2026-02-06 08:23:32 +0800 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2026-05-10 08:31:34 -0700 |
| commit | 1f5b29add64e7c1500530079bbbe359cad28cb63 (patch) | |
| tree | cf815d898384feed853e1ba137041ccefa30681b /drivers/watchdog | |
| parent | aed1abf31ea3f13b8ac8aa0f6c1078a9bc7b9564 (diff) | |
watchdog: imx7ulp_wdt: Keep WDOG running until A55 enters WFI on i.MX94
On i.MX94, watchdog sources clock from bus clock that will be always on
during the lifecycle of Linux. There is a Low Power Clock Gating(LPCG)
between the bus clock and watchdog, but the LPCG is not exported for
software to control, it is hardware automatically controlled. When
Cortex-A55 executes WFI during suspend flow, the LPCG will automatically
gate off the clock to stop watchdog and resume clock when Cortex-A55 is
woke up.
So watchdog could always be alive to protect Linux, except Cortex-A
platform WFI is executed in Linux suspend flow.
Introduce a new hardware feature flag to indicate CPU low-power-mode
auto clock gating support, and use it to avoid stopping the watchdog
during suspend when LPCG can safely keep it running.
Add i.MX94-specific watchdog hardware data and DT compatible entry to
enable this behavior.
Signed-off-by: Ranjani Vaidyanathan <ranjani.vaidyanathan@nxp.com>
[peng.fan@nxp.com: rewrite commit log for clarity]
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20260206-imx94-wdog-v2-1-4dd725faec1f@nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/watchdog')
| -rw-r--r-- | drivers/watchdog/imx7ulp_wdt.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/watchdog/imx7ulp_wdt.c b/drivers/watchdog/imx7ulp_wdt.c index 03479110453c..855dc9d5083a 100644 --- a/drivers/watchdog/imx7ulp_wdt.c +++ b/drivers/watchdog/imx7ulp_wdt.c @@ -56,6 +56,7 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" struct imx_wdt_hw_feature { bool prescaler_enable; bool post_rcs_wait; + bool cpu_lpm_auto_cg; u32 wdog_clock_rate; }; @@ -360,7 +361,7 @@ static int __maybe_unused imx7ulp_wdt_suspend_noirq(struct device *dev) { struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev); - if (watchdog_active(&imx7ulp_wdt->wdd)) + if (watchdog_active(&imx7ulp_wdt->wdd) && !imx7ulp_wdt->hw->cpu_lpm_auto_cg) imx7ulp_wdt_stop(&imx7ulp_wdt->wdd); clk_disable_unprepare(imx7ulp_wdt->clk); @@ -408,10 +409,17 @@ static const struct imx_wdt_hw_feature imx93_wdt_hw = { .wdog_clock_rate = 125, }; +static const struct imx_wdt_hw_feature imx94_wdt_hw = { + .prescaler_enable = true, + .wdog_clock_rate = 125, + .cpu_lpm_auto_cg = true, +}; + static const struct of_device_id imx7ulp_wdt_dt_ids[] = { { .compatible = "fsl,imx7ulp-wdt", .data = &imx7ulp_wdt_hw, }, { .compatible = "fsl,imx8ulp-wdt", .data = &imx8ulp_wdt_hw, }, { .compatible = "fsl,imx93-wdt", .data = &imx93_wdt_hw, }, + { .compatible = "fsl,imx94-wdt", .data = &imx94_wdt_hw, }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids); |