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([179.179.237.181]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-677c1b1b585sm3449969d50.5.2026.10.05.10.25.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Oct 2026 10:25:57 -0700 (PDT) From: Vinicius Pedrosa To: linux-serial@vger.kernel.org Cc: gregkh@linuxfoundation.org, jirislaby@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, andriy.shevchenko@linux.intel.com, ilpo.jarvinen@linux.intel.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sunxi@lists.linux.dev, Enzo Adriano Subject: [PATCH 0/3] serial: 8250_dw: Allwinner A733 UART support Date: Mon, 5 Oct 2026 14:25:35 -0300 Message-ID: <20261005172538.398522-1-vinicius.eduardo.pedrosa@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit I'm bringing up mainline on the Radxa Cubie A7Z (Allwinner A733). The console worked until the first termios change from userspace, then stopped taking interrupts. Patch 1 fixes that in the generic driver: with a DLF register present, dw8250_setup_port() replaces the BUSY-safe divisor hook, and the LCR retry path then restores IER into DLH. It's tagged for stable. Patches 2-3 add an A733 compatible with two quirks: no clk_set_rate() around termios (the baud clock is a fixed bus gate), and no DLF probe (offset 0xc0 is an RS485 control register). Tested on a Cubie A7Z, with local DT and clock changes that aren't part of this series. The console worked in both directions and a termios stress loop ran without stalls or corrupted bytes. The no-DLF check in patch 3 was reworked after that run (an if block in place of a goto), and this exact revision hasn't been booted yet. The A733 DTSI isn't in linux-next yet. Enzo Adriano's posted version uses plain "snps,dw-apb-uart" for uart0, so it would need the new compatible once this lands. Based on tty-next. Vinicius Pedrosa (3): serial: 8250_dw: Keep the BUSY-safe divisor hook when DLF is present dt-bindings: serial: snps-dw-apb-uart: Add Allwinner A733 serial: 8250_dw: Add Allwinner A733 UART .../bindings/serial/snps-dw-apb-uart.yaml | 1 + drivers/tty/serial/8250/8250_dw.c | 25 ++++++++++++++++++- drivers/tty/serial/8250/8250_dwlib.c | 22 ++++++++-------- drivers/tty/serial/8250/8250_dwlib.h | 1 + 4 files changed, 38 insertions(+), 11 deletions(-) base-commit: 36844ea19656fb41278799ef3d5cd52120d89149 -- 2.43.0