platform/x86: thinkpad_acpi: fixed warning and incorporated review comments

The previous commit adding new sysfs for keyboard language has warning and
few code correction has to be done as per new review comments.

Below changes has been addressed in this version:
 - corrected warning. Many thanks to kernel test robot <lkp@intel.com> for
   reporting and determining this warning.
 - used sysfs_emit_at() API instead of strcat.
 - sorted keyboard language array.
 - removed unwanted space and corrected sentences.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nitin Joshi <njoshi1@lenovo.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210202003210.91773-1-njoshi1@lenovo.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

Documentation/admin-guide/laptops/thinkpad-acpi.rst

@@ -1476,18 +1476,19 @@ sysfs: keyboard_lang
 This feature is used to set keyboard language to ECFW using ASL interface.
 Fewer thinkpads models like T580 , T590 , T15 Gen 1 etc.. has "=", "(',
 ")" numeric keys, which are not displaying correctly, when keyboard language
-is other than "english". This is because of default keyboard language in ECFW
-is set as "english". Hence using this sysfs, user can set correct keyboard
-language to ECFW and then these key's will work correctly .
+is other than "english". This is because the default keyboard language in ECFW
+is set as "english". Hence using this sysfs, user can set the correct keyboard
+language to ECFW and then these key's will work correctly.
 
 Example of command to set keyboard language is mentioned below::
 
         echo jp > /sys/devices/platform/thinkpad_acpi/keyboard_lang
 
-Text corresponding to keyboard layout to be set in sysfs are : jp (Japan), be(Belgian),
-cz(Czech), en(English), da(Danish), de(German), es(Spain) , et(Estonian),
-fr(French) , fr-ch (French(Switzerland)), pl(Polish), sl(Slovenian), hu
-(Hungarian), nl(Dutch), tr(Turkey), it(Italy), sv(Sweden), pt(portugese)
+Text corresponding to keyboard layout to be set in sysfs are: be(Belgian),
+cz(Czech), da(Danish), de(German), en(English), es(Spain), et(Estonian),
+fr(French), fr-ch(French(Switzerland)), hu(Hungarian), it(Italy), jp (Japan),
+nl(Dutch), nn(Norway), pl(Polish), pt(portugese), sl(Slovenian), sv(Sweden),
+tr(Turkey)
 
 
 Adaptive keyboard

drivers/platform/x86/thinkpad_acpi.c

@@ -9992,16 +9992,12 @@ struct keyboard_lang_data {
 	int lang_code;
 };
 
-/*
- * When adding new entries to keyboard_lang_data, please check that
- * the select_lang[] buffer in keyboard_lang_show() is still large enough.
- */
-struct keyboard_lang_data keyboard_lang_data[] = {
-	{"en", 0},
+static const struct keyboard_lang_data keyboard_lang_data[] = {
 	{"be", 0x080c},
 	{"cz", 0x0405},
 	{"da", 0x0406},
 	{"de", 0x0c07},
+	{"en", 0x0000},
 	{"es", 0x2c0a},
 	{"et", 0x0425},
 	{"fr", 0x040c},
@@ -10064,9 +10060,7 @@ static ssize_t keyboard_lang_show(struct device *dev,
 				struct device_attribute *attr,
 				char *buf)
 {
-	int output, err, i;
-	char select_lang[80] = "";
-	char lang[8] = "";
+	int output, err, i, len = 0;
 
 	err = get_keyboard_lang(&output);
 	if (err)
@@ -10074,19 +10068,17 @@ static ssize_t keyboard_lang_show(struct device *dev,
 
 	for (i = 0; i < ARRAY_SIZE(keyboard_lang_data); i++) {
 		if (i)
-			strcat(select_lang, " ");
+			len += sysfs_emit_at(buf, len, "%s", " ");
 
 		if (output == keyboard_lang_data[i].lang_code) {
-			strcat(lang, "[");
-			strcat(lang, keyboard_lang_data[i].lang_str);
-			strcat(lang, "]");
-			strcat(select_lang, lang);
+			len += sysfs_emit_at(buf, len, "[%s]", keyboard_lang_data[i].lang_str);
 		} else {
-			strcat(select_lang, keyboard_lang_data[i].lang_str);
+			len += sysfs_emit_at(buf, len, "%s", keyboard_lang_data[i].lang_str);
 		}
 	}
+	len += sysfs_emit_at(buf, len, "\n");
 
-	return sysfs_emit(buf, "%s\n", select_lang);
+	return len;
 }
 
 static ssize_t keyboard_lang_store(struct device *dev,
@@ -10113,7 +10105,7 @@ static ssize_t keyboard_lang_store(struct device *dev,
 		if (err)
 			return err;
 	} else {
-		pr_err("Unknown Keyboard language. Ignoring\n");
+		dev_err(&tpacpi_pdev->dev, "Unknown Keyboard language. Ignoring\n");
 		return -EINVAL;
 	}
 
@@ -10124,7 +10116,6 @@ static ssize_t keyboard_lang_store(struct device *dev,
 
 	return count;
 }
-
 static DEVICE_ATTR_RW(keyboard_lang);
 
 static struct attribute *kbdlang_attributes[] = {
@@ -10143,7 +10134,7 @@ static int tpacpi_kbdlang_init(struct ibm_init_struct *iibm)
 	err = get_keyboard_lang(&output);
 	/*
 	 * If support isn't available (ENODEV) then don't return an error
-	 * just don't create the sysfs group
+	 * just don't create the sysfs group.
 	 */
 	if (err == -ENODEV)
 		return 0;
@@ -10152,9 +10143,7 @@ static int tpacpi_kbdlang_init(struct ibm_init_struct *iibm)
 		return err;
 
 	/* Platform supports this feature - create the sysfs file */
-	err = sysfs_create_group(&tpacpi_pdev->dev.kobj, &kbdlang_attr_group);
-
-	return err;
+	return sysfs_create_group(&tpacpi_pdev->dev.kobj, &kbdlang_attr_group);
 }
 
 static void kbdlang_exit(void)