linux-kernel - [PATCH v9 4/4] can: m_can: Support pinctrl wakeup state

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Message-Id: <20250820-topic-mcan-wakeup-source-v6-12-v9-4-0ac13f2ddd67@baylibre.com>
Date: Wed, 20 Aug 2025 14:42:28 +0200
From: Markus Schneider-Pargmann <msp@...libre.com>
To: Chandrasekar Ramakrishnan <rcsekar@...sung.com>, 
 Marc Kleine-Budde <mkl@...gutronix.de>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>
Cc: Vishal Mahaveer <vishalm@...com>, Kevin Hilman <khilman@...libre.com>, 
 Dhruva Gole <d-gole@...com>, Sebin Francis <sebin.francis@...com>, 
 Kendall Willis <k-willis@...com>, Akashdeep Kaur <a-kaur@...com>, 
 Simon Horman <horms@...nel.org>, 
 Vincent MAILHOL <mailhol.vincent@...adoo.fr>, linux-can@...r.kernel.org, 
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Markus Schneider-Pargmann <msp@...libre.com>
Subject: [PATCH v9 4/4] can: m_can: Support pinctrl wakeup state

am62 requires a wakeup flag being set in pinctrl when mcan pins acts as
a wakeup source. Add support to select the wakeup state if WOL is
enabled.

Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
---
 drivers/net/can/m_can/m_can.c | 69 +++++++++++++++++++++++++++++++++++++++++--
 drivers/net/can/m_can/m_can.h |  3 ++
 2 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index e08fae5ddf5efa8345670dd50d50954ec5d52b29..a1fa4b2f6b6cc94e5e10259cca53bd931ab238c8 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -2249,7 +2249,26 @@ static int m_can_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
 		return ret;
 	}
 
+	if (!IS_ERR_OR_NULL(cdev->pinctrl_state_wakeup)) {
+		if (wol_enable)
+			ret = pinctrl_select_state(cdev->pinctrl, cdev->pinctrl_state_wakeup);
+		else
+			ret = pinctrl_pm_select_default_state(cdev->dev);
+
+		if (ret) {
+			netdev_err(cdev->net, "Failed to select pinctrl state %pE\n",
+				   ERR_PTR(ret));
+			goto err_wakeup_enable;
+		}
+	}
+
 	return 0;
+
+err_wakeup_enable:
+	/* Revert wakeup enable */
+	device_set_wakeup_enable(cdev->dev, !wol_enable);
+
+	return ret;
 }
 
 static const struct ethtool_ops m_can_ethtool_ops_coalescing = {
@@ -2377,6 +2396,42 @@ int m_can_class_get_clocks(struct m_can_classdev *cdev)
 }
 EXPORT_SYMBOL_GPL(m_can_class_get_clocks);
 
+static bool m_can_class_wakeup_pinctrl_enabled(struct m_can_classdev *class_dev)
+{
+	return device_may_wakeup(class_dev->dev) && class_dev->pinctrl_state_wakeup;
+}
+
+static int m_can_class_setup_optional_pinctrl(struct m_can_classdev *class_dev)
+{
+	struct device *dev = class_dev->dev;
+	int ret;
+
+	class_dev->pinctrl = devm_pinctrl_get(dev);
+	if (IS_ERR(class_dev->pinctrl)) {
+		ret = PTR_ERR(class_dev->pinctrl);
+		class_dev->pinctrl = NULL;
+
+		if (ret == -ENODEV)
+			return 0;
+
+		return dev_err_probe(dev, ret, "Failed to get pinctrl\n");
+	}
+
+	class_dev->pinctrl_state_wakeup =
+		pinctrl_lookup_state(class_dev->pinctrl, "wakeup");
+	if (IS_ERR(class_dev->pinctrl_state_wakeup)) {
+		ret = PTR_ERR(class_dev->pinctrl_state_wakeup);
+		class_dev->pinctrl_state_wakeup = NULL;
+
+		if (ret == -ENODEV)
+			return 0;
+
+		return dev_err_probe(dev, ret, "Failed to lookup pinctrl wakeup state\n");
+	}
+
+	return 0;
+}
+
 struct m_can_classdev *m_can_class_allocate_dev(struct device *dev,
 						int sizeof_priv)
 {
@@ -2418,7 +2473,15 @@ struct m_can_classdev *m_can_class_allocate_dev(struct device *dev,
 	m_can_of_parse_mram(class_dev, mram_config_vals);
 	spin_lock_init(&class_dev->tx_handling_spinlock);
 
+	ret = m_can_class_setup_optional_pinctrl(class_dev);
+	if (ret)
+		goto err_free_candev;
+
 	return class_dev;
+
+err_free_candev:
+	free_candev(net_dev);
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(m_can_class_allocate_dev);
 
@@ -2533,7 +2596,8 @@ int m_can_class_suspend(struct device *dev)
 		m_can_clk_stop(cdev);
 	}
 
-	pinctrl_pm_select_sleep_state(dev);
+	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
+		pinctrl_pm_select_sleep_state(dev);
 
 	cdev->can.state = CAN_STATE_SLEEPING;
 
@@ -2547,7 +2611,8 @@ int m_can_class_resume(struct device *dev)
 	struct net_device *ndev = cdev->net;
 	int ret = 0;
 
-	pinctrl_pm_select_default_state(dev);
+	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
+		pinctrl_pm_select_default_state(dev);
 
 	cdev->can.state = CAN_STATE_ERROR_ACTIVE;
 
diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
index bd4746c63af3f0a032910644dfd48a9ebb3a6168..583c7f1d005d61b3fc8587697388522993ff11a8 100644
--- a/drivers/net/can/m_can/m_can.h
+++ b/drivers/net/can/m_can/m_can.h
@@ -128,6 +128,9 @@ struct m_can_classdev {
 	struct mram_cfg mcfg[MRAM_CFG_NUM];
 
 	struct hrtimer hrtimer;
+
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pinctrl_state_wakeup;
 };
 
 struct m_can_classdev *m_can_class_allocate_dev(struct device *dev, int sizeof_priv);

-- 
2.50.1