[PATCH v1 1/1] mfd: core: Use acpi_find_child_device() for child devices lookup

[Andy Shevchenko]

Use acpi_find_child_device() for child devices lookup in mfd_acpi_add_device()
instead of open coded approach. No functional change intended.

While at it, amend a note comment, since usage of _ADR is found on other
platforms and tables than Intel Galileo Gen 2, in particular USB wired devices
are using it, according to Microsoft specifications for embedded platforms.

Signed-off-by: Andy Shevchenko <andriy.shevche...@linux.intel.com>
---
Validated on Intel Galileo Gen 2.
 drivers/mfd/mfd-core.c | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index 6dcff4b8e15e..6f02b8022c6d 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -65,7 +65,7 @@ static void mfd_acpi_add_device(const struct mfd_cell *cell,
 {
        const struct mfd_cell_acpi_match *match = cell->acpi_match;
        struct acpi_device *parent, *child;
-       struct acpi_device *adev;
+       struct acpi_device *adev = NULL;
 
        parent = ACPI_COMPANION(pdev->dev.parent);
        if (!parent)
@@ -77,10 +77,9 @@ static void mfd_acpi_add_device(const struct mfd_cell *cell,
         * _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.
+        * though at least Intel Galileo Gen 2 is using it to distinguish
+        * the children devices.
         */
-       adev = parent;
        if (match) {
                if (match->pnpid) {
                        struct acpi_device_id ids[2] = {};
@@ -93,22 +92,11 @@ static void mfd_acpi_add_device(const struct mfd_cell *cell,
                                }
                        }
                } 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;
-                               }
-                       }
+                       adev = acpi_find_child_device(parent, match->adr, 
false);
                }
        }
 
-       ACPI_COMPANION_SET(&pdev->dev, adev);
+       ACPI_COMPANION_SET(&pdev->dev, adev ?: parent);
 }
 #else
 static inline void mfd_acpi_add_device(const struct mfd_cell *cell,
-- 
2.30.2