ACPI: introduce ACPI int340x thermal scan handler

Newer laptops and tablets that use ACPI may have thermal sensors and
other devices with thermal control capabilities outside the core CPU/SOC,
for thermal safety reasons.
They are exposed for the OS to use via
1) INT3400 ACPI device object as the master.
2) INT3401 ~ INT340B ACPI device objects as the slaves.

This patch introduces a scan handler to enumerate the INT3400
ACPI device object to platform bus, and prevent its slaves
from being enumerated before the controller driver being probed.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>

4 files changed, 54 insertions, 0 deletions

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 505d4d79fe3e..c3b2fcb729f3 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -43,6 +43,7 @@ acpi-y				+= pci_root.o pci_link.o pci_irq.o
 acpi-y                          += acpi_lpss.o
 acpi-y                          += acpi_platform.o
 acpi-y                          += acpi_pnp.o
+acpi-y                          += int340x_thermal.o
 acpi-y                          += power.o
 acpi-y                          += event.o
 acpi-y                          += sysfs.o
diff --git a/drivers/acpi/int340x_thermal.c b/drivers/acpi/int340x_thermal.c
new file mode 100644
index 000000000000..2103bb6d9016
--- /dev/null
+++ b/drivers/acpi/int340x_thermal.c
@@ -0,0 +1,51 @@
+/*
+ * ACPI support for int340x thermal drivers
+ *
+ * Copyright (C) 2014, Intel Corporation
+ * Authors: Zhang Rui <rui.zhang@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/module.h>
+
+#include "internal.h"
+
+#define DO_ENUMERATION 0x01
+static const struct acpi_device_id int340x_thermal_device_ids[] = {
+        {"INT3400", DO_ENUMERATION },
+        {"INT3401"},
+        {"INT3402"},
+        {"INT3403"},
+        {"INT3404"},
+        {"INT3406"},
+        {"INT3407"},
+        {"INT3408"},
+        {"INT3409"},
+        {"INT340A"},
+        {"INT340B"},
+        {""},
+};
+
+static int int340x_thermal_handler_attach(struct acpi_device *adev,
+                                        const struct acpi_device_id *id)
+{
+#ifdef CONFIG_INT340X_THERMAL
+        if (id->driver_data == DO_ENUMERATION)
+                acpi_create_platform_device(adev);
+#endif
+        return 1;
+}
+
+static struct acpi_scan_handler int340x_thermal_handler = {
+        .ids = int340x_thermal_device_ids,
+        .attach = int340x_thermal_handler_attach,
+};
+
+void __init acpi_int340x_thermal_init(void)
+{
+        acpi_scan_add_handler(&int340x_thermal_handler);
+}
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 4c5cf77e7576..de47f9f746c9 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -31,6 +31,7 @@ void acpi_pci_link_init(void);
 void acpi_processor_init(void);
 void acpi_platform_init(void);
 void acpi_pnp_init(void);
+void acpi_int340x_thermal_init(void);
 int acpi_sysfs_init(void);
 void acpi_container_init(void);
 void acpi_memory_hotplug_init(void);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 0a817ad24f16..eed9740651f8 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2306,6 +2306,7 @@ int __init acpi_scan_init(void)
         acpi_container_init();
         acpi_memory_hotplug_init();
         acpi_pnp_init();
+        acpi_int340x_thermal_init();
 
         mutex_lock(&acpi_scan_lock);
         /*