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[213.113.123.174]) by smtp.gmail.com with ESMTPSA id d13-v6sm441020lfi.74.2018.09.25.07.32.25 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 25 Sep 2018 07:32:25 -0700 (PDT) From: Linus Walleij To: Mark Brown , linux-spi@vger.kernel.org, Andrzej Hajda , Lorenzo Bianconi Cc: linux-gpio@vger.kernel.org, Linus Walleij , devicetree@vger.kernel.org Subject: [PATCH 1/2] spi: Add a DT binding for high-impedance turn-around Date: Tue, 25 Sep 2018 16:32:19 +0200 Message-Id: <20180925143220.19007-1-linus.walleij@linaro.org> X-Mailer: git-send-email 2.17.1 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org Some 3WIRE SPI devices require the host to insert a "high-impedance turn-around" essentially a clock pulse after switching the one line from output to input. This is needed to support the TPO TPG110 panel to use the 3WIRE SPI bindings. Cc: devicetree@vger.kernel.org Cc: Andrzej Hajda Cc: Lorenzo Bianconi Signed-off-by: Linus Walleij --- ChangeLog v1->v2: - Change some spelling, instert dash in high-impedance use turn-around instead of turnaround. --- Documentation/devicetree/bindings/spi/spi-bus.txt | 4 ++++ 1 file changed, 4 insertions(+) -- 2.17.1 diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index 1f6e86f787ef..d0b2d88a20ee 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -70,6 +70,10 @@ All slave nodes can contain the following optional properties: - spi-cs-high - Empty property indicating device requires chip select active high. - spi-3wire - Empty property indicating device requires 3-wire mode. +- spi-3wire-high-impedance-turn-around - Empty property indicating that a + 3wire host need to insert a high-impedance turn-around + clock cycle after turning the one output line into an + input line. - spi-lsb-first - Empty property indicating device requires LSB first mode. - spi-tx-bus-width - The bus width (number of data wires) that is used for MOSI. Defaults to 1 if not present.