linux-kernel - [PATCH v2] pmdomain: ti_sci: Handle wakeup constraint if device has pinctrl wakeup state

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Message-ID: <20250910-uart-daisy-chain-pmdomain-v2-1-6d0215f4af32@ti.com>
Date: Wed, 10 Sep 2025 16:16:35 -0500
From: Kendall Willis <k-willis@...com>
To: Nishanth Menon <nm@...com>, Tero Kristo <kristo@...nel.org>,
        Santosh
 Shilimkar <ssantosh@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>
CC: <linux-arm-kernel@...ts.infradead.org>, <linux-pm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <d-gole@...com>, <vishalm@...com>,
        <sebin.francis@...com>, <msp@...libre.com>, <khilman@...libre.com>,
        <a-kaur@...com>, <k-willis@...com>
Subject: [PATCH v2] pmdomain: ti_sci: Handle wakeup constraint if device
 has pinctrl wakeup state

For TI K3 SoCs with IO daisy-chaining using pinctrl wakeup state, avoid
sending wakeup constraints to the PM co-processor. This allows the SoC to
enter deeper low power states while still maintaining wakeup capability
for peripherals using IO daisy-chain wakeup via pinctrl wakeup state,
similar to the existing wake IRQ mechanism added in commit b06bc47279919
("pmdomain: ti_sci: handle wake IRQs for IO daisy chain wakeups").

Detect the pinctrl wakeup state in the suspend path, and if it exists,
skip sending the constraint.

Signed-off-by: Kendall Willis <k-willis@...com>
---
Implementation
--------------
This patch is intended to be implemented along with the following
series. This patch has no dependencies on any of the other series:

1. "pmdomain: ti_sci: Handle wakeup constraint if device has pinctrl
   wakeup state": (this patch) skips setting constraints for wakeup
   sources that use pinctrl state 'wakeup'.

2. "serial: 8250: omap: Add wakeup support": Implements wakeup from
   the UARTs for TI K3 SoCs
   https://github.com/kwillis01/linux/tree/b4/uart-daisy-chain-8250-omap

3. "arm64: dts: ti: k3-am62: Support Main UART wakeup": Implements the
   functionality to wakeup the system from the Main UART
   https://github.com/kwillis01/linux/tree/b4/uart-daisy-chain-dts

Testing
-------
Tested on a AM62P SK EVM board with all series and dependencies
implemented. Suspend/resume verified with the Main UART wakeup source
by entering a keypress on the console.

This github branch has all the necessary patches to test the series
using linux-next:
https://github.com/kwillis01/linux/tree/uart-daisy-chain

Version History
---------------
Changes from v1 to v2:
 - Reworded commit message to be concise and to reference commit
   b06bc47279919

v1: https://lore.kernel.org/all/20250904211607.3725897-1-k-willis@ti.com/
---
 drivers/pmdomain/ti/ti_sci_pm_domains.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/pmdomain/ti/ti_sci_pm_domains.c b/drivers/pmdomain/ti/ti_sci_pm_domains.c
index 82df7e44250bb64f9c4a2108b5e97bd782a5976d..884905fd0686c1b94aba68c03da038e577428adf 100644
--- a/drivers/pmdomain/ti/ti_sci_pm_domains.c
+++ b/drivers/pmdomain/ti/ti_sci_pm_domains.c
@@ -10,6 +10,7 @@
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_qos.h>
@@ -84,9 +85,24 @@ static inline void ti_sci_pd_set_wkup_constraint(struct device *dev)
 	struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
 	struct ti_sci_pm_domain *pd = genpd_to_ti_sci_pd(genpd);
 	const struct ti_sci_handle *ti_sci = pd->parent->ti_sci;
+	struct pinctrl *pinctrl = devm_pinctrl_get(dev);
+	struct pinctrl_state *pinctrl_state_wakeup;
 	int ret;
 
 	if (device_may_wakeup(dev)) {
+		/*
+		 * If device can wakeup using pinctrl wakeup state,
+		 * we do not want to set a constraint
+		 */
+		if (!IS_ERR_OR_NULL(pinctrl)) {
+			pinctrl_state_wakeup = pinctrl_lookup_state(pinctrl, "wakeup");
+			if (!IS_ERR_OR_NULL(pinctrl_state_wakeup)) {
+				dev_dbg(dev, "%s: has wake pinctrl wakeup state, not setting " \
+						"constraints\n", __func__);
+				return;
+			}
+		}
+
 		/*
 		 * If device can wakeup using IO daisy chain wakeups,
 		 * we do not want to set a constraint.

---
base-commit: 5f540c4aade9f1d58fb7b9490b4b7d5214ec9746
change-id: 20250910-uart-daisy-chain-pmdomain-b83b2db2c3cc

Best regards,
-- 
Kendall Willis <k-willis@...com>