leds: leds-lp5562 allow firmware files up to the maximum length

BugLink: https://bugs.launchpad.net/bugs/1848589

[ Upstream commit ed2abfeb ]

Firmware files are in ASCII, using 2 hex characters per byte. The
maximum length of a firmware string is therefore

16 (commands) * 2 (bytes per command) * 2 (characters per byte) = 64

Fixes: ff45262a ("leds: add new LP5562 LED driver")
Signed-off-by: Nick Stoughton <nstoughton@logitech.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/leds/leds-lp5562.c

@@ -263,7 +263,11 @@ static void lp5562_firmware_loaded(struct lp55xx_chip *chip)
 {
 	const struct firmware *fw = chip->fw;
 
-	if (fw->size > LP5562_PROGRAM_LENGTH) {
+	/*
+	 * the firmware is encoded in ascii hex character, with 2 chars
+	 * per byte
+	 */
+	if (fw->size > (LP5562_PROGRAM_LENGTH * 2)) {
 		dev_err(&chip->cl->dev, "firmware data size overflow: %zu\n",
 			fw->size);
 		return;