[PATCH v4 2/8] platform/x86: think-lmi: Enable opcode support on BIOS settings

[Mark Pearson <mpearson-lenovo@squebb.ca>]

Whilst reviewing some documentation from the FW team on using WMI on
Lenovo system I noticed that we weren't using Opcode support when
changing BIOS settings in the thinkLMI driver.

We should be doing this to ensure we're future proof as the old
non-opcode mechanism has been deprecated.

Tested on X1 Carbon G10 and G11.

Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca>
---
Changes in v2:
 - Update comment for clearer explanation of what the driver is doing.
Changes in v3:
 - None. Version bump with rest of series.
Changes in v4:
 - Fixed code alignment as requested.
 - changed 'non opcode' to 'non-opcode'.
 - Missing space added at end of comment.
 - This patch was previously #1 and is now #2 in series.

 drivers/platform/x86/think-lmi.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index 6cf77bc26b05..80a5c989db03 100644
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -1010,7 +1010,33 @@ static ssize_t current_value_store(struct kobject *kobj,
 				tlmi_priv.pwd_admin->save_signature);
 		if (ret)
 			goto out;
-	} else { /* Non certiifcate based authentication */
+	} else if (tlmi_priv.opcode_support) {
+		/*
+		 * If opcode support is present use that interface.
+		 * Note - this sets the variable and then the password as separate
+		 * WMI calls. Function tlmi_save_bios_settings will error if the
+		 * password is incorrect.
+		 */
+		set_str = kasprintf(GFP_KERNEL, "%s,%s;", setting->display_name,
+				    new_setting);
+		if (!set_str) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		ret = tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID, set_str);
+		if (ret)
+			goto out;
+
+		if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) {
+			ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin",
+						  tlmi_priv.pwd_admin->password);
+			if (ret)
+				goto out;
+		}
+
+		ret = tlmi_save_bios_settings("");
+	} else { /* old non-opcode based authentication method (deprecated) */
 		if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) {
 			auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s;",
 					tlmi_priv.pwd_admin->password,
-- 
2.40.1