linux-kernel - [PATCH v2] power: domain: handle power supplies that need interrupts

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Date:   Tue, 12 Jul 2022 14:18:32 +0200
From:   Martin Kepplinger <martin.kepplinger@...i.sm>
To:     rafael@...nel.org, khilman@...nel.org, ulf.hansson@...aro.org,
        robh@...nel.org, krzysztof.kozlowski@...aro.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de, festevam@...il.com,
        pavel@....cz
Cc:     kernel@...i.sm, linux-imx@....com, broonie@...nel.org,
        l.stach@...gutronix.de, aford173@...il.com,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Martin Kepplinger <martin.kepplinger@...i.sm>
Subject: [PATCH v2] power: domain: handle power supplies that need interrupts

If the power-domains' power-supply node (regulator) needs
interrupts to work, the current setup with noirq callbacks cannot
work; for example a pmic regulator on i2c, when suspending, usually already
times out during suspend_noirq:

[   41.024193] buck4: failed to disable: -ETIMEDOUT

So fix system suspend and resume for these power-domains by using the
"outer" suspend/resume callbacks instead. Tested on the imx8mq-librem5
board, but by looking at the dts, this will fix imx8mq-evk and possibly
other boards too.

Possibly one can find more changes than suspend/resume for this case. They
can be added later when testing them.

Initially system suspend problems had been discussed at
https://lore.kernel.org/linux-arm-kernel/20211002005954.1367653-8-l.stach@pengutronix.de/
which led to discussing the pmic that contains the regulators which
serve as power-domain power-supplies:
https://lore.kernel.org/linux-pm/573166b75e524517782471c2b7f96e03fd93d175.camel@puri.sm/T/

Signed-off-by: Martin Kepplinger <martin.kepplinger@...i.sm>
---

revision history
----------------
v2: (thank you Krzysztof)
* rewrite: find possible regulators' interrupts property in parents
  instead of inventing a new property.

v1: (initial idea)
https://lore.kernel.org/linux-arm-kernel/20220711094549.3445566-1-martin.kepplinger@puri.sm/T/#t


 drivers/base/power/domain.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 3e86772d5fac..ca3e3500939d 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2298,6 +2298,28 @@ static bool genpd_present(const struct generic_pm_domain *genpd)
 	return ret;
 }
 
+/**
+ * of_genpd_get_power_supply_irq() - Adjust if power-supply needs interrupts
+ * @genpd: Pointer to PM domain associated with the PM domain provider.
+ */
+static void of_genpd_get_power_supply_irq(struct generic_pm_domain *pd)
+{
+	struct device_node *dn;
+
+	dn = of_parse_phandle(pd->dev.of_node, "power-supply", 0);
+	if (!dn)
+		return;
+
+	while ((dn = of_get_next_parent(dn))) {
+		if (of_get_property(dn, "interrupts", NULL)) {
+			pd->domain.ops.suspend = genpd_suspend_noirq;
+			pd->domain.ops.resume = genpd_resume_noirq;
+			pd->domain.ops.suspend_noirq = NULL;
+			pd->domain.ops.resume_noirq = NULL;
+		}
+	}
+}
+
 /**
  * of_genpd_add_provider_simple() - Register a simple PM domain provider
  * @np: Device node pointer associated with the PM domain provider.
@@ -2343,6 +2365,8 @@ int of_genpd_add_provider_simple(struct device_node *np,
 	genpd->provider = &np->fwnode;
 	genpd->has_provider = true;
 
+	of_genpd_get_power_supply_irq(genpd);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_genpd_add_provider_simple);
@@ -2394,6 +2418,8 @@ int of_genpd_add_provider_onecell(struct device_node *np,
 
 		genpd->provider = &np->fwnode;
 		genpd->has_provider = true;
+
+		of_genpd_get_power_supply_irq(genpd);
 	}
 
 	ret = genpd_add_provider(np, data->xlate, data);
-- 
2.30.2