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Mon, 16 Oct 2023 14:33:05 +1300 Received: from richardl-dl.ws.atlnz.lc (richardl-dl.ws.atlnz.lc [10.33.23.23]) by pat.atlnz.lc (Postfix) with ESMTP id 9808813EDA9; Mon, 16 Oct 2023 14:33:05 +1300 (NZDT) Received: by richardl-dl.ws.atlnz.lc (Postfix, from userid 1481) id 959D6520158; Mon, 16 Oct 2023 14:33:05 +1300 (NZDT) From: Richard Laing To: gregkh@linuxfoundation.org, jirislaby@kernel.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, ilpo.jarvinen@linux.intel.com, andriy.shevchenko@linux.intel.com Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, devicetree@vger.kernel.org, Richard Laing Subject: [PATCH] dt-bindings: serial: snps-dw-apb-uart: Add property to drain TX FIFO Date: Mon, 16 Oct 2023 14:32:07 +1300 Message-ID: <20231016013207.2249946-3-richard.laing@alliedtelesis.co.nz> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231016013207.2249946-1-richard.laing@alliedtelesis.co.nz> References: <20231016013207.2249946-1-richard.laing@alliedtelesis.co.nz> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SEG-SpamProfiler-Analysis: v=2.3 cv=L6ZjvNb8 c=1 sm=1 tr=0 a=KLBiSEs5mFS1a/PbTCJxuA==:117 a=bhdUkHdE2iEA:10 a=yJYUBcXGP3-BVwV7yiEA:9 X-SEG-SpamProfiler-Score: 0 x-atlnz-ls: pat X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_PASS,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net An issue has been observed on the Broadcom BCM56160 serial port which appears closely related to a similar issue on the Marvell Armada 38x serial port. Add a new property to force the TX FIFO to be drained before changing the UART_LCR. Signed-off-by: Richard Laing --- .../devicetree/bindings/serial/snps-dw-apb-uart.yaml | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml index 17c553123f96..4266ef96832c 100644 --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml @@ -114,6 +114,12 @@ properties: register. Define this if your serial port does not use this pin. type: boolean + drain-before-lcr-change: + description: Force TX buffer flush before LCR change. Make sure all + characters in the buffer are sent before reconfiguring. Define this if + the UART drops its FIFO when reconfiguring. + type: boolean + required: - compatible - reg