mfd: core: redo ACPI matching of the children devices

There is at least one board on the market, i.e. Intel Galileo Gen2, that uses
_ADR to distinguish the devices under one actual device. Due to this we have to
improve the quirk in the MFD core to handle that board.

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 36 insertions, 16 deletions

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index c17635d3e504..60b60dc63ddd 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -82,29 +82,49 @@ static int mfd_platform_add_cell(struct platform_device *pdev,
 static void mfd_acpi_add_device(const struct mfd_cell *cell,
 				struct platform_device *pdev)
 {
-	struct acpi_device *parent_adev;
+	const struct mfd_cell_acpi_match *match = cell->acpi_match;
+	struct acpi_device *parent, *child;
 	struct acpi_device *adev;
 
-	parent_adev = ACPI_COMPANION(pdev->dev.parent);
-	if (!parent_adev)
+	parent = ACPI_COMPANION(pdev->dev.parent);
+	if (!parent)
 		return;
 
 	/*
-	 * MFD child device gets its ACPI handle either from the ACPI
-	 * device directly under the parent that matches the acpi_pnpid or
-	 * it will use the parent handle if is no acpi_pnpid is given.
+	 * MFD child device gets its ACPI handle either from the ACPI device
+	 * directly under the parent that matches the either _HID or _CID, or
+	 * _ADR or it will use the parent handle if is no ID is given.
+	 *
+	 * Note that use of _ADR is a grey area in the ACPI specification,
+	 * though Intel Galileo Gen2 is using it to distinguish the children
+	 * devices.
 	 */
-	adev = parent_adev;
-	if (cell->acpi_pnpid) {
-		struct acpi_device_id ids[2] = {};
-		struct acpi_device *child_adev;
-
-		strlcpy(ids[0].id, cell->acpi_pnpid, sizeof(ids[0].id));
-		list_for_each_entry(child_adev, &parent_adev->children, node)
-			if (acpi_match_device_ids(child_adev, ids)) {
-				adev = child_adev;
-				break;
+	adev = parent;
+	if (match) {
+		if (match->pnpid) {
+			struct acpi_device_id ids[2] = {};
+
+			strlcpy(ids[0].id, match->pnpid, sizeof(ids[0].id));
+			list_for_each_entry(child, &parent->children, node) {
+				if (acpi_match_device_ids(child, ids)) {
+					adev = child;
+					break;
+				}
+			}
+		} else {
+			unsigned long long adr;
+			acpi_status status;
+
+			list_for_each_entry(child, &parent->children, node) {
+				status = acpi_evaluate_integer(child->handle,
+							       "_ADR", NULL,
+							       &adr);
+				if (ACPI_SUCCESS(status) && match->adr == adr) {
+					adev = child;
+					break;
+				}
 			}
+		}
 	}
 
 	ACPI_COMPANION_SET(&pdev->dev, adev);