ACPI: Introduce has_acpi_companion()

Now that the ACPI companions of devices are represented by pointers
to struct fwnode_handle, it is not quite efficient to check whether
or not an ACPI companion of a device is present by evaluating the
ACPI_COMPANION() macro.

For this reason, introduce a special static inline routine for that,
has_acpi_companion(), and update the code to use it where applicable.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/glue.c

@@ -168,7 +168,7 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
 	unsigned int node_id;
 	int retval = -EINVAL;
 
-	if (ACPI_COMPANION(dev)) {
+	if (has_acpi_companion(dev)) {
 		if (acpi_dev) {
 			dev_warn(dev, "ACPI companion already set\n");
 			return -EINVAL;
@@ -220,7 +220,7 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
 	list_add(&physical_node->node, physnode_list);
 	acpi_dev->physical_node_count++;
 
-	if (!ACPI_COMPANION(dev))
+	if (!has_acpi_companion(dev))
 		ACPI_COMPANION_SET(dev, acpi_dev);
 
 	acpi_physnode_link_name(physical_node_name, node_id);

drivers/i2c/busses/i2c-designware-platdrv.c

@@ -166,7 +166,7 @@ static int dw_i2c_probe(struct platform_device *pdev)
 	/* fast mode by default because of legacy reasons */
 	clk_freq = 400000;
 
-	if (ACPI_COMPANION(&pdev->dev)) {
+	if (has_acpi_companion(&pdev->dev)) {
 		dw_i2c_acpi_configure(pdev);
 	} else if (pdev->dev.of_node) {
 		of_property_read_u32(pdev->dev.of_node,
@@ -286,7 +286,7 @@ static int dw_i2c_remove(struct platform_device *pdev)
 	pm_runtime_put(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
-	if (ACPI_COMPANION(&pdev->dev))
+	if (has_acpi_companion(&pdev->dev))
 		dw_i2c_acpi_unconfigure(pdev);
 
 	return 0;

drivers/iommu/intel-iommu.c

@@ -684,7 +684,7 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
 	if (dev_is_pci(dev)) {
 		pdev = to_pci_dev(dev);
 		segment = pci_domain_nr(pdev->bus);
-	} else if (ACPI_COMPANION(dev))
+	} else if (has_acpi_companion(dev))
 		dev = &ACPI_COMPANION(dev)->dev;
 
 	rcu_read_lock();

include/linux/acpi.h

@@ -58,6 +58,11 @@ static inline acpi_handle acpi_device_handle(struct acpi_device *adev)
 	acpi_fwnode_handle(adev) : NULL
 #define ACPI_HANDLE(dev)		acpi_device_handle(ACPI_COMPANION(dev))
 
+static inline bool has_acpi_companion(struct device *dev)
+{
+	return is_acpi_node(dev->fwnode);
+}
+
 static inline void acpi_preset_companion(struct device *dev,
 					 struct acpi_device *parent, u64 addr)
 {
@@ -472,6 +477,11 @@ static inline struct fwnode_handle *acpi_fwnode_handle(struct acpi_device *adev)
 	return NULL;
 }
 
+static inline bool has_acpi_companion(struct device *dev)
+{
+	return false;
+}
+
 static inline const char *acpi_dev_name(struct acpi_device *adev)
 {
 	return NULL;