linux-kernel - [PATCH 4/8] i2c: acpi: Use ACPI GPIO wake capability bit to set wake

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Message-Id: <20220830171332.4.I8af4282adc72eb9f247adcd03676a43893a020a6@changeid>
Date:   Tue, 30 Aug 2022 17:15:37 -0600
From:   Raul E Rangel <rrangel@...omium.org>
To:     linux-acpi@...r.kernel.org, linux-input@...r.kernel.org
Cc:     hdegoede@...hat.com, mario.limonciello@....com, timvp@...gle.com,
        rafael@...nel.org, Raul E Rangel <rrangel@...omium.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Wolfram Sang <wsa@...nel.org>, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 4/8] i2c: acpi: Use ACPI GPIO wake capability bit to set wake_irq

Device tree already has a mechanism to pass the wake_irq. It does this
by looking for the wakeup-source property and setting the
I2C_CLIENT_WAKE flag. This CL adds the ACPI equivalent. It uses at the
ACPI GpioInt wake flag to determine if the interrupt can be used to wake
the system. Previously the i2c drivers had to make assumptions and
blindly enable the wake IRQ. This can cause spurious wake events. e.g.,
If there is a device with an Active Low interrupt and the device gets
powered off while suspending, the interrupt line will go low since it's
no longer powered and wake the system. For this reason we should respect
the board designers wishes and honor the wake bit defined on the
GpioInt.

This change does not cover the ACPI Interrupt or IRQ resources.

Signed-off-by: Raul E Rangel <rrangel@...omium.org>
---

 drivers/i2c/i2c-core-acpi.c |  8 ++++++--
 drivers/i2c/i2c-core-base.c | 17 +++++++++++------
 drivers/i2c/i2c-core.h      |  4 ++--
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index c762a879c4cc6b..cfe82a6ba3ef28 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -182,12 +182,13 @@ static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
 /**
  * i2c_acpi_get_irq - get device IRQ number from ACPI
  * @client: Pointer to the I2C client device
+ * @wake_capable: Set to 1 if the IRQ is wake capable
  *
  * Find the IRQ number used by a specific client device.
  *
  * Return: The IRQ number or an error code.
  */
-int i2c_acpi_get_irq(struct i2c_client *client)
+int i2c_acpi_get_irq(struct i2c_client *client, int *wake_capable)
 {
 	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 	struct list_head resource_list;
@@ -196,6 +197,9 @@ int i2c_acpi_get_irq(struct i2c_client *client)
 
 	INIT_LIST_HEAD(&resource_list);
 
+	if (wake_capable)
+		*wake_capable = 0;
+
 	ret = acpi_dev_get_resources(adev, &resource_list,
 				     i2c_acpi_add_resource, &irq);
 	if (ret < 0)
@@ -204,7 +208,7 @@ int i2c_acpi_get_irq(struct i2c_client *client)
 	acpi_dev_free_resource_list(&resource_list);
 
 	if (irq == -ENOENT)
-		irq = acpi_dev_gpio_irq_get(adev, 0);
+		irq = acpi_dev_gpio_irq_get_wake(adev, 0, wake_capable);
 
 	return irq;
 }
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 91007558bcb260..88f4ef76235f4e 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -468,6 +468,7 @@ static int i2c_device_probe(struct device *dev)
 	struct i2c_client	*client = i2c_verify_client(dev);
 	struct i2c_driver	*driver;
 	int status;
+	int acpi_wake_capable = 0;
 
 	if (!client)
 		return 0;
@@ -487,7 +488,7 @@ static int i2c_device_probe(struct device *dev)
 			if (irq == -EINVAL || irq == -ENODATA)
 				irq = of_irq_get(dev->of_node, 0);
 		} else if (ACPI_COMPANION(dev)) {
-			irq = i2c_acpi_get_irq(client);
+			irq = i2c_acpi_get_irq(client, &acpi_wake_capable);
 		}
 		if (irq == -EPROBE_DEFER) {
 			status = irq;
@@ -513,13 +514,17 @@ static int i2c_device_probe(struct device *dev)
 		goto put_sync_adapter;
 	}
 
-	if (client->flags & I2C_CLIENT_WAKE) {
+	if (client->flags & I2C_CLIENT_WAKE || acpi_wake_capable) {
 		int wakeirq;
 
-		wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
-		if (wakeirq == -EPROBE_DEFER) {
-			status = wakeirq;
-			goto put_sync_adapter;
+		if (acpi_wake_capable) {
+			wakeirq = client->irq;
+		} else {
+			wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
+			if (wakeirq == -EPROBE_DEFER) {
+				status = wakeirq;
+				goto put_sync_adapter;
+			}
 		}
 
 		device_init_wakeup(&client->dev, true);
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
index 87e2c914f1c57b..8e336638a0cd2e 100644
--- a/drivers/i2c/i2c-core.h
+++ b/drivers/i2c/i2c-core.h
@@ -61,11 +61,11 @@ static inline int __i2c_check_suspended(struct i2c_adapter *adap)
 #ifdef CONFIG_ACPI
 void i2c_acpi_register_devices(struct i2c_adapter *adap);
 
-int i2c_acpi_get_irq(struct i2c_client *client);
+int i2c_acpi_get_irq(struct i2c_client *client, int *wake_capable);
 #else /* CONFIG_ACPI */
 static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
 
-static inline int i2c_acpi_get_irq(struct i2c_client *client)
+static inline int i2c_acpi_get_irq(struct i2c_client *client, int *wake_capable)
 {
 	return 0;
 }
-- 
2.37.2.672.g94769d06f0-goog