i2c: acpi: Add an i2c_acpi_client_count() helper function

We have 3 files now which have the need to count the number of
I2cSerialBus resources in an ACPI-device's resource-list.

Currently all implement their own helper function for this,
add a generic helper function to replace the 3 implementations.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210803160044.158802-2-hdegoede@redhat.com
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Wolfram Sang <wsa@kernel.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 6f0aa0ed3241..aaeeacc12121 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -69,6 +69,38 @@ bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
 }
 EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
 
+static int i2c_acpi_resource_count(struct acpi_resource *ares, void *data)
+{
+	struct acpi_resource_i2c_serialbus *sb;
+	int *count = data;
+
+	if (i2c_acpi_get_i2c_resource(ares, &sb))
+		*count = *count + 1;
+
+	return 1;
+}
+
+/**
+ * i2c_acpi_client_count - Count the number of I2cSerialBus resources
+ * @adev:	ACPI device
+ *
+ * Returns the number of I2cSerialBus resources in the ACPI-device's
+ * resource-list; or a negative error code.
+ */
+int i2c_acpi_client_count(struct acpi_device *adev)
+{
+	int ret, count = 0;
+	LIST_HEAD(r);
+
+	ret = acpi_dev_get_resources(adev, &r, i2c_acpi_resource_count, &count);
+	if (ret < 0)
+		return ret;
+
+	acpi_dev_free_resource_list(&r);
+	return count;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_client_count);
+
 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
 {
 	struct i2c_acpi_lookup *lookup = data;