[PATCH 2/9] i2c: Allow specifying irq-index to be used in i2c_device_probe()

[Hans de Goede <hdegoede@redhat.com>]

Some types of interrupts are retrieved in i2c_device_probe() because
getting them might fail with -EPROBE_DEFER.

So far we've always assumed the first IRQ (index 0) in the firmware-node
is the one we want.

At least with ACPI enumerated i2c-clients in some cases the firmware-node
is shared between multiple i2c-clients so we need to be able to specify
the index rather then hardcoding it at 0.

This commit adds a new fwnode_irq_index member to i2c_board_info and
i2c_client which allows specifying the index.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/i2c/i2c-core-base.c | 7 +++++--
 include/linux/i2c.h         | 5 +++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 1ba40bb2b966..ae3fda2c96a4 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -312,9 +312,11 @@ static int i2c_device_probe(struct device *dev)
 		} else if (dev->of_node) {
 			irq = of_irq_get_byname(dev->of_node, "irq");
 			if (irq == -EINVAL || irq == -ENODATA)
-				irq = of_irq_get(dev->of_node, 0);
+				irq = of_irq_get(dev->of_node,
+						 client->fwnode_irq_index);
 		} else if (ACPI_COMPANION(dev)) {
-			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
+			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev),
+						    client->fwnode_irq_index);
 		}
 		if (irq == -EPROBE_DEFER)
 			return irq;
@@ -724,6 +726,7 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 	client->flags = info->flags;
 	client->addr = info->addr;
 
+	client->fwnode_irq_index = info->fwnode_irq_index;
 	client->irq = info->irq;
 	if (!client->irq)
 		client->irq = i2c_dev_irq_from_resources(info->resources,
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 44ad14e016b5..7f9506714a5e 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -316,6 +316,8 @@ struct i2c_driver {
  *	generic enough to hide second-sourcing and compatible revisions.
  * @adapter: manages the bus segment hosting this I2C device
  * @dev: Driver model device node for the slave.
+ * @fwnode_irq_index: some devices share a single fwnode, this tells
+ *                    i2c_device_probe() to use the Nth irq from the fwnode
  * @irq: indicates the IRQ generated by this device (if any)
  * @detected: member of an i2c_driver.clients list or i2c-core's
  *	userspace_devices list
@@ -334,6 +336,7 @@ struct i2c_client {
 	char name[I2C_NAME_SIZE];
 	struct i2c_adapter *adapter;	/* the adapter we sit on	*/
 	struct device dev;		/* the device structure		*/
+	int fwnode_irq_index;		/* index for irq lookup		*/
 	int irq;			/* irq issued by device		*/
 	struct list_head detected;
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
@@ -400,6 +403,7 @@ static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
  * @properties: additional device properties for the device
  * @resources: resources associated with the device
  * @num_resources: number of resources in the @resources array
+ * @fwnode_irq_index: stored in i2c_client.fwnode_irq_index
  * @irq: stored in i2c_client.irq
  *
  * I2C doesn't actually support hardware probing, although controllers and
@@ -425,6 +429,7 @@ struct i2c_board_info {
 	const struct property_entry *properties;
 	const struct resource *resources;
 	unsigned int	num_resources;
+	int		fwnode_irq_index;
 	int		irq;
 };
 
-- 
2.17.0