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From:   David Lechner <david@lechnology.com>
To:     linux-spi@vger.kernel.org, linux-iio@vger.kernel.org
Cc:     David Lechner <david@lechnology.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Hartmut Knaack <knaack.h@gmx.de>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        Mark Brown <broonie@kernel.org>, linux-kernel@vger.kernel.org
Subject: [PATCH v2 4/4] spi: spi-davinci: Add support for SPI_CS_WORD
Date:   Wed, 12 Sep 2018 19:39:20 -0500
Message-Id: <20180913003920.30600-5-david@lechnology.com>
In-Reply-To: <20180913003920.30600-1-david@lechnology.com>
References: <20180913003920.30600-1-david@lechnology.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This adds support for the SPI_CS_WORD flag to the TI DaVinci SPI
driver. This mode can be used as long as we are using the hardware
chip select and not a GPIO chip select.

Signed-off-by: David Lechner <david@lechnology.com>
---
 drivers/spi/spi-davinci.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index d502cf504deb..8f7dcbc53c57 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -230,7 +230,8 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value)
 				!(spi->mode & SPI_CS_HIGH));
 	} else {
 		if (value == BITBANG_CS_ACTIVE) {
-			spidat1 |= SPIDAT1_CSHOLD_MASK;
+			if (!(spi->mode & SPI_CS_WORD))
+				spidat1 |= SPIDAT1_CSHOLD_MASK;
 			spidat1 &= ~(0x1 << chip_sel);
 		}
 	}
@@ -440,8 +441,12 @@ static int davinci_spi_setup(struct spi_device *spi)
 			return retval;
 		}
 
-		if (internal_cs)
+		if (internal_cs) {
 			set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);
+		} else if (spi->mode & SPI_CS_WORD) {
+			dev_err(&spi->dev, "SPI_CS_WORD can't be use with GPIO CS\n");
+			return -EINVAL;
+		}
 	}
 
 	if (spi->mode & SPI_READY)
@@ -976,7 +981,7 @@ static int davinci_spi_probe(struct platform_device *pdev)
 	dspi->prescaler_limit = pdata->prescaler_limit;
 	dspi->version = pdata->version;
 
-	dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP;
+	dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP | SPI_CS_WORD;
 	if (dspi->version == SPI_VERSION_2)
 		dspi->bitbang.flags |= SPI_READY;
 
-- 
2.17.1