tty: serial: samsung: add gs101 earlycon support

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.

Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/20240119104526.1221243-6-tudor.ambarus@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 7a1b1ca82511c10f333f15ede41334b1e5047363..80b8fcf9e0259c3b6e0459710c519c913173704a 100644 (file)
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -2809,6 +2809,17 @@ 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)