The entire bus (PERIC) on which the GS101 serial resides only allows 32-bit register accesses. The reg-io-width dt property is disallowed for the "google,gs101-uart" compatible and instead the iotype is inferred from the compatible. Always set UPIO_MEM32 iotype for the gs101 earlycon. Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxx> --- v2: update commit message drivers/tty/serial/samsung_tty.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c index 938127179acf..2fbaaf0e756b 100644 --- a/drivers/tty/serial/samsung_tty.c +++ b/drivers/tty/serial/samsung_tty.c @@ -2812,6 +2812,17 @@ OF_EARLYCON_DECLARE(exynos4210, "samsung,exynos4210-uart", OF_EARLYCON_DECLARE(artpec8, "axis,artpec8-uart", s5pv210_early_console_setup); +static int __init gs101_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + /* gs101 always expects MMIO32 register accesses. */ + device->port.iotype = UPIO_MEM32; + + return s5pv210_early_console_setup(device, opt); +} + +OF_EARLYCON_DECLARE(gs101, "google,gs101-uart", gs101_early_console_setup); + /* Apple S5L */ static int __init apple_s5l_early_console_setup(struct earlycon_device *device, const char *opt) -- 2.43.0.472.g3155946c3a-goog