[PATCH v1 1/1] Input: icn8505 - Utilize acpi_get_subsystem_id()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

Replace open coded variant of recently introduced acpi_get_subsystem_id().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/input/touchscreen/chipone_icn8505.c | 29 ++++++---------------
 1 file changed, 8 insertions(+), 21 deletions(-)

diff --git a/drivers/input/touchscreen/chipone_icn8505.c b/drivers/input/touchscreen/chipone_icn8505.c
index f9ca5502ac8c..bb5e63b87c5d 100644
--- a/drivers/input/touchscreen/chipone_icn8505.c
+++ b/drivers/input/touchscreen/chipone_icn8505.c
@@ -364,32 +364,19 @@ static irqreturn_t icn8505_irq(int irq, void *dev_id)
 
 static int icn8505_probe_acpi(struct icn8505_data *icn8505, struct device *dev)
 {
-	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
-	const char *subsys = "unknown";
-	struct acpi_device *adev;
-	union acpi_object *obj;
-	acpi_status status;
-
-	adev = ACPI_COMPANION(dev);
-	if (!adev)
-		return -ENODEV;
+	const char *subsys;
 
-	status = acpi_evaluate_object(adev->handle, "_SUB", NULL, &buffer);
-	if (ACPI_SUCCESS(status)) {
-		obj = buffer.pointer;
-		if (obj->type == ACPI_TYPE_STRING)
-			subsys = obj->string.pointer;
-		else
-			dev_warn(dev, "Warning ACPI _SUB did not return a string\n");
-	} else {
-		dev_warn(dev, "Warning ACPI _SUB failed: %#x\n", status);
-		buffer.pointer = NULL;
-	}
+	subsys = acpi_get_subsystem_id(ACPI_HANDLE(dev));
+	if (IS_ERR(subsys) && PTR_ERR(subsys) != -ENODATA)
+		return PTR_ERR(subsys);
+
+	if (IS_ERR(subsys) && PTR_ERR(subsys) == -ENODATA)
+		subsys = kstrdup_const("unknown", GFP_KERNEL);
 
 	snprintf(icn8505->firmware_name, sizeof(icn8505->firmware_name),
 		 "chipone/icn8505-%s.fw", subsys);
 
-	kfree(buffer.pointer);
+	kfree_const(subsys);
 	return 0;
 }
 
-- 
2.35.1