[PATCH] tty: serial: samsung: Fix S5L on Apple A18 Pro
From: Yureka Lilian <hidden>
Date: 2026-09-04 09:13:46
Also in:
asahi, linux-samsung-soc, lkml
Subsystem:
arm/samsung s3c, s5p and exynos arm architectures, the rest · Maintainers:
Krzysztof Kozlowski, Peter Griffin, Linus Torvalds
The UCON BIT(10) is set on boot on the S5L serials on Apple Silicon Macs of all generations and old iPhones [1]. It's unknown what it does exactly, but on the MacBook Neo (A18 Pro / T8140 SoC) clearing this bit breaks the uart and leads to garbled data in both directions. Add it to the APPLE_S5L_UCON_MASK to prevent it being cleared. Link[1]: https://oftc.catirclogs.org/asahi-dev/2026-07-24#35537011 Signed-off-by: Yureka Lilian <redacted> --- include/linux/serial_s3c.h | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h
index f54cb6e23f85..1732bc9240ff 100644
--- a/include/linux/serial_s3c.h
+++ b/include/linux/serial_s3c.h@@ -247,10 +247,12 @@ S5PV210_UFCON_RXTRIG4) #define APPLE_S5L_UCON_RXTO_ENA 9 +#define APPLE_S5L_UCON_UNK 10 #define APPLE_S5L_UCON_RXTO_LEGACY_ENA 11 #define APPLE_S5L_UCON_RXTHRESH_ENA 12 #define APPLE_S5L_UCON_TXTHRESH_ENA 13 #define APPLE_S5L_UCON_RXTO_ENA_MSK BIT(APPLE_S5L_UCON_RXTO_ENA) +#define APPLE_S5L_UCON_UNK_MSK BIT(APPLE_S5L_UCON_UNK) #define APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK BIT(APPLE_S5L_UCON_RXTO_LEGACY_ENA) #define APPLE_S5L_UCON_RXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_RXTHRESH_ENA) #define APPLE_S5L_UCON_TXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_TXTHRESH_ENA)
@@ -259,6 +261,7 @@ S3C2410_UCON_RXIRQMODE | \ S3C2410_UCON_RXFIFO_TOI) #define APPLE_S5L_UCON_MASK (APPLE_S5L_UCON_RXTO_ENA_MSK | \ + APPLE_S5L_UCON_UNK_MSK | \ APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK | \ APPLE_S5L_UCON_RXTHRESH_ENA_MSK | \ APPLE_S5L_UCON_TXTHRESH_ENA_MSK)
--- base-commit: cee9395acd8043be0644b25c34bfa86623f2b935 change-id: 20260904-apple-s5l-a18-pro-5f2b3e1a4e4a Best regards, -- Yureka Lilian [off-list ref]