platform/chrome: use sysfs_emit_at() instead of scnprintf()

Follow the advice in Documentation/filesystems/sysfs.rst:
show() should only use sysfs_emit() or sysfs_emit_at() when formatting
the value to be returned to user space.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221205061042.1774769-1-tzungbi@kernel.org

drivers/platform/chrome/cros_ec_sysfs.c

@@ -27,10 +27,9 @@ static ssize_t reboot_show(struct device *dev,
 {
 	int count = 0;
 
-	count += scnprintf(buf + count, PAGE_SIZE - count,
-			   "ro|rw|cancel|cold|disable-jump|hibernate|cold-ap-off");
-	count += scnprintf(buf + count, PAGE_SIZE - count,
-			   " [at-shutdown]\n");
+	count += sysfs_emit_at(buf, count,
+			       "ro|rw|cancel|cold|disable-jump|hibernate|cold-ap-off");
+	count += sysfs_emit_at(buf, count, " [at-shutdown]\n");
 	return count;
 }
 
@@ -138,12 +137,9 @@ static ssize_t version_show(struct device *dev,
 	/* Strings should be null-terminated, but let's be sure. */
 	r_ver->version_string_ro[sizeof(r_ver->version_string_ro) - 1] = '\0';
 	r_ver->version_string_rw[sizeof(r_ver->version_string_rw) - 1] = '\0';
-	count += scnprintf(buf + count, PAGE_SIZE - count,
-			   "RO version:    %s\n", r_ver->version_string_ro);
-	count += scnprintf(buf + count, PAGE_SIZE - count,
-			   "RW version:    %s\n", r_ver->version_string_rw);
-	count += scnprintf(buf + count, PAGE_SIZE - count,
-			   "Firmware copy: %s\n",
+	count += sysfs_emit_at(buf, count, "RO version:    %s\n", r_ver->version_string_ro);
+	count += sysfs_emit_at(buf, count, "RW version:    %s\n", r_ver->version_string_rw);
+	count += sysfs_emit_at(buf, count, "Firmware copy: %s\n",
 			   (r_ver->current_image < ARRAY_SIZE(image_names) ?
 			    image_names[r_ver->current_image] : "?"));
 
@@ -152,21 +148,20 @@ static ssize_t version_show(struct device *dev,
 	msg->insize = EC_HOST_PARAM_SIZE;
 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0) {
-		count += scnprintf(buf + count, PAGE_SIZE - count,
+		count += sysfs_emit_at(buf, count,
 				   "Build info:    XFER / EC ERROR %d / %d\n",
 				   ret, msg->result);
 	} else {
 		msg->data[EC_HOST_PARAM_SIZE - 1] = '\0';
-		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Build info:    %s\n", msg->data);
+		count += sysfs_emit_at(buf, count, "Build info:    %s\n", msg->data);
 	}
 
 	/* Get chip info. */
 	msg->command = EC_CMD_GET_CHIP_INFO + ec->cmd_offset;
 	msg->insize = sizeof(*r_chip);
 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0) {
-		count += scnprintf(buf + count, PAGE_SIZE - count,
+		count += sysfs_emit_at(buf, count,
 				   "Chip info:     XFER / EC ERROR %d / %d\n",
 				   ret, msg->result);
 	} else {
@@ -175,26 +170,23 @@ static ssize_t version_show(struct device *dev,
 		r_chip->vendor[sizeof(r_chip->vendor) - 1] = '\0';
 		r_chip->name[sizeof(r_chip->name) - 1] = '\0';
 		r_chip->revision[sizeof(r_chip->revision) - 1] = '\0';
-		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Chip vendor:   %s\n", r_chip->vendor);
-		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Chip name:     %s\n", r_chip->name);
-		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Chip revision: %s\n", r_chip->revision);
+		count += sysfs_emit_at(buf, count, "Chip vendor:   %s\n", r_chip->vendor);
+		count += sysfs_emit_at(buf, count, "Chip name:     %s\n", r_chip->name);
+		count += sysfs_emit_at(buf, count, "Chip revision: %s\n", r_chip->revision);
 	}
 
 	/* Get board version */
 	msg->command = EC_CMD_GET_BOARD_VERSION + ec->cmd_offset;
 	msg->insize = sizeof(*r_board);
 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0) {
-		count += scnprintf(buf + count, PAGE_SIZE - count,
+		count += sysfs_emit_at(buf, count,
 				   "Board version: XFER / EC ERROR %d / %d\n",
 				   ret, msg->result);
 	} else {
 		r_board = (struct ec_response_board_version *)msg->data;
 
-		count += scnprintf(buf + count, PAGE_SIZE - count,
+		count += sysfs_emit_at(buf, count,
 				   "Board version: %d\n",
 				   r_board->board_version);
 	}