[PATCH v3 3/4] ACPI: platform: Ignore SMB0001 only when it has resources

[Andy Shevchenko]

After switching i2c-scmi driver to be a platform one, it stopped
being enumerated on number of Kontron platforms, because it's
listed in the forbidden_id_list.

To resolve the situation, add a flag to driver data to allow devices
with no resources in _CRS to be enumerated via platform bus.

Fixes: 03d4287add6e ("i2c: scmi: Convert to be a platform driver")
Closes: https://lore.kernel.org/r/60c1756765b9a3f1eab0dcbd84f59f00fe1caf48.camel@xxxxxxxxxxx
Link: https://lore.kernel.org/r/20230621151652.79579-1-andriy.shevchenko@xxxxxxxxxxxxxxx
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
 drivers/acpi/acpi_platform.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
index fe00a5783f53..ee6ea1ee8396 100644
--- a/drivers/acpi/acpi_platform.c
+++ b/drivers/acpi/acpi_platform.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/bits.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
@@ -19,13 +20,16 @@
 
 #include "internal.h"
 
+/* Exclude devices that have no _CRS resources provided */
+#define ACPI_ALLOW_WO_RESOURCES		BIT(0)
+
 static const struct acpi_device_id forbidden_id_list[] = {
 	{"ACPI0009", 0},	/* IOxAPIC */
 	{"ACPI000A", 0},	/* IOAPIC */
 	{"PNP0000",  0},	/* PIC */
 	{"PNP0100",  0},	/* Timer */
 	{"PNP0200",  0},	/* AT DMA Controller */
-	{"SMB0001",  0},	/* ACPI SMBUS virtual device */
+	{"SMB0001",  ACPI_ALLOW_WO_RESOURCES},	/* ACPI SMBUS virtual device */
 	{ }
 };
 
@@ -83,6 +87,15 @@ static void acpi_platform_fill_resource(struct acpi_device *adev,
 		dest->parent = pci_find_resource(to_pci_dev(parent), dest);
 }
 
+static unsigned int acpi_platform_resource_count(struct acpi_resource *ares, void *data)
+{
+	int *count = data;
+
+	(*count)++;
+
+	return AE_OK;
+}
+
 /**
  * acpi_create_platform_device - Create platform device for ACPI device node
  * @adev: ACPI device node to create a platform device for.
@@ -100,17 +113,27 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
 	struct acpi_device *parent = acpi_dev_parent(adev);
 	struct platform_device *pdev = NULL;
 	struct platform_device_info pdevinfo;
+	const struct acpi_device_id *match;
 	struct resource_entry *rentry;
 	struct list_head resource_list;
 	struct resource *resources = NULL;
-	int count;
+	int count = 0;
 
 	/* If the ACPI node already has a physical device attached, skip it. */
 	if (adev->physical_node_count)
 		return NULL;
 
-	if (!acpi_match_device_ids(adev, forbidden_id_list))
-		return ERR_PTR(-EINVAL);
+	match = acpi_match_acpi_device(forbidden_id_list, adev);
+	if (match) {
+		if (match->driver_data & ACPI_ALLOW_WO_RESOURCES) {
+			acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
+					    acpi_platform_resource_count, &count);
+			if (count > 0)
+				return ERR_PTR(-EINVAL);
+		} else {
+			return ERR_PTR(-EINVAL);
+		}
+	}
 
 	INIT_LIST_HEAD(&resource_list);
 	count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
-- 
2.40.0.1.gaa8946217a0b