thinkpad-acpi: detect EC node using its HID (v2)

Use the EC HID (PNP0C09) to locate its main node, instead of a static
list.

Suggested-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Matthew Garrett <mjg@redhat.com>

1 files changed, 41 insertions, 12 deletions

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index b03cb3e04582..877a7802e830 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -129,6 +129,7 @@ enum {
 
 /* ACPI HIDs */
 #define TPACPI_ACPI_HKEY_HID            "IBM0068"
+#define TPACPI_ACPI_EC_HID              "PNP0C09"
 
 /* Input IDs */
 #define TPACPI_HKEY_INPUT_PRODUCT       0x5054 /* "TP" */
@@ -511,6 +512,7 @@ static inline bool __pure __init tpacpi_is_ibm(void)
  */
 
 static acpi_handle root_handle;
+static acpi_handle ec_handle;
 
 #define TPACPI_HANDLE(object, parent, paths...)                 \
         static acpi_handle  object##_handle;                    \
@@ -518,16 +520,6 @@ static acpi_handle root_handle;
         static char        *object##_path;                      \
         static char        *object##_paths[] = { paths }
 
-TPACPI_HANDLE(ec, root, "\\_SB.PCI0.ISA.EC0",   /* 240, 240x */
-           "\\_SB.PCI.ISA.EC",  /* 570 */
-           "\\_SB.PCI0.ISA0.EC0",       /* 600e/x, 770e, 770x */
-           "\\_SB.PCI0.ISA.EC", /* A21e, A2xm/p, T20-22, X20-21 */
-           "\\_SB.PCI0.AD4S.EC0",       /* i1400, R30 */
-           "\\_SB.PCI0.ICH3.EC0",       /* R31 */
-           "\\_SB.PCI0.LPC0.EC",        /* X100e and a few others */
-           "\\_SB.PCI0.LPC.EC", /* all others */
-           );
-
 TPACPI_HANDLE(ecrd, ec, "ECRD");        /* 570 */
 TPACPI_HANDLE(ecwr, ec, "ECWR");        /* 570 */
 
@@ -708,6 +700,43 @@ static void drv_acpi_handle_init(char *name,
         *handle = NULL;
 }
 
+static acpi_status __init tpacpi_acpi_handle_locate_callback(acpi_handle handle,
+                        u32 level, void *context, void **return_value)
+{
+        *(acpi_handle *)return_value = handle;
+
+        return AE_CTRL_TERMINATE;
+}
+
+static void __init tpacpi_acpi_handle_locate(const char *name,
+                const char *hid,
+                acpi_handle *handle)
+{
+        acpi_status status;
+        acpi_handle device_found;
+
+        BUG_ON(!name || !hid || !handle);
+        vdbg_printk(TPACPI_DBG_INIT,
+                        "trying to locate ACPI handle for %s, using HID %s\n",
+                        name, hid);
+
+        memset(&device_found, 0, sizeof(device_found));
+        status = acpi_get_devices(hid, tpacpi_acpi_handle_locate_callback,
+                                  (void *)name, &device_found);
+
+        *handle = NULL;
+
+        if (ACPI_SUCCESS(status)) {
+                *handle = device_found;
+                dbg_printk(TPACPI_DBG_INIT,
+                           "Found ACPI handle for %s\n", name);
+        } else {
+                vdbg_printk(TPACPI_DBG_INIT,
+                            "Could not locate an ACPI handle for %s: %s\n",
+                            name, acpi_format_exception(status));
+        }
+}
+
 static void dispatch_acpi_notify(acpi_handle handle, u32 event, void *data)
 {
         struct ibm_struct *ibm = data;
@@ -8752,8 +8781,8 @@ static int __init probe_for_thinkpad(void)
                       (thinkpad_id.ec_model != 0) ||
                       tpacpi_is_fw_known();
 
-        /* ec is required because many other handles are relative to it */
-        TPACPI_ACPIHANDLE_INIT(ec);
+        /* The EC handler is required */
+        tpacpi_acpi_handle_locate("ec", TPACPI_ACPI_EC_HID, &ec_handle);
         if (!ec_handle) {
                 if (is_thinkpad)
                         printk(TPACPI_ERR