spi: Add API to count spi acpi resources

Some ACPI nodes may have more than one Spi Resource.
To be able to handle these case, its necessary to have
a way of counting these resources.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-5-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 06c0a30..ec9f2ed 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2324,6 +2324,46 @@ struct acpi_spi_lookup {
        int                     index;
 };
 
+static int acpi_spi_count(struct acpi_resource *ares, void *data)
+{
+       struct acpi_resource_spi_serialbus *sb;
+       int *count = data;
+
+       if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+               return 1;
+
+       sb = &ares->data.spi_serial_bus;
+       if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
+               return 1;
+
+       *count = *count + 1;
+
+       return 1;
+}
+
+/**
+ * acpi_spi_count_resources - Count the number of SpiSerialBus resources
+ * @adev:      ACPI device
+ *
+ * Returns the number of SpiSerialBus resources in the ACPI-device's
+ * resource-list; or a negative error code.
+ */
+int acpi_spi_count_resources(struct acpi_device *adev)
+{
+       LIST_HEAD(r);
+       int count = 0;
+       int ret;
+
+       ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count);
+       if (ret < 0)
+               return ret;
+
+       acpi_dev_free_resource_list(&r);
+
+       return count;
+}
+EXPORT_SYMBOL_GPL(acpi_spi_count_resources);
+
 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
                                            struct acpi_spi_lookup *lookup)
 {

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index e5bbb9c..394b424 100644 (file)
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -764,6 +764,7 @@ extern void spi_unregister_controller(struct spi_controller *ctlr);
 extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
                                                struct acpi_device *adev,
                                                int index);
+int acpi_spi_count_resources(struct acpi_device *adev);
 #endif
 
 /*