ACPI: ibm-acpi: store embedded controller firmware version for matching

This patch changes the ThinkPad Embedded Controller DMI matching
code to store the firmware version of the EC for later usage, e.g.
for quirks.

It also prints the firmware version when starting up.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>

drivers/acpi/ibm_acpi.c

@@ -77,6 +77,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/string.h>
 #include <linux/proc_fs.h>
 #include <linux/backlight.h>
 #include <asm/uaccess.h>
@@ -361,7 +362,7 @@ enum {					/* Fan control constants */
 						 * control */
 };
 
-static int ibm_thinkpad_ec_found;
+static char* ibm_thinkpad_ec_found = NULL;
 
 struct ibm_struct {
 	char *name;
@@ -2540,11 +2541,15 @@ static void acpi_ibm_exit(void)
 		ibm_exit(&ibms[i]);
 
 	remove_proc_entry(IBM_DIR, acpi_root_dir);
+
+	if (ibm_thinkpad_ec_found)
+		kfree(ibm_thinkpad_ec_found);
 }
 
-static int __init check_dmi_for_ec(void)
+static char* __init check_dmi_for_ec(void)
 {
 	struct dmi_device *dev = NULL;
+	char ec_fw_string[18];
 
 	/*
 	 * ThinkPad T23 or newer, A31 or newer, R50e or newer,
@@ -2554,10 +2559,15 @@ static int __init check_dmi_for_ec(void)
 	 * See http://thinkwiki.org/wiki/List_of_DMI_IDs
 	 */
 	while ((dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, dev))) {
-		if (strstr(dev->name, "IBM ThinkPad Embedded Controller"))
-			return 1;
+		if (sscanf(dev->name,
+			   "IBM ThinkPad Embedded Controller -[%17c",
+			   ec_fw_string) == 1) {
+			ec_fw_string[sizeof(ec_fw_string) - 1] = 0;
+			ec_fw_string[strcspn(ec_fw_string, " ]")] = 0;
+			return kstrdup(ec_fw_string, GFP_KERNEL);
 		}
-	return 0;
+	}
+	return NULL;
 }
 
 static int __init acpi_ibm_init(void)
@@ -2581,6 +2591,9 @@ static int __init acpi_ibm_init(void)
 
 	/* Models with newer firmware report the EC in DMI */
 	ibm_thinkpad_ec_found = check_dmi_for_ec();
+	if (ibm_thinkpad_ec_found)
+		printk(IBM_INFO "ThinkPad EC firmware %s\n",
+		       ibm_thinkpad_ec_found);
 
 	/* these handles are not required */
 	IBM_HANDLE_INIT(vid);