linux-kernel - [Patch v2 1/3] spi: qup: Remove chip select function

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Message-Id: <1402601652-24641-2-git-send-email-agross@codeaurora.org>
Date:	Thu, 12 Jun 2014 14:34:10 -0500
From:	Andy Gross <agross@...eaurora.org>
To:	Mark Brown <broonie@...nel.org>
Cc:	linux-spi@...r.kernel.org, Sagar Dharia <sdharia@...eaurora.org>,
	Daniel Sneddon <dsneddon@...eaurora.org>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-arm-msm@...r.kernel.org,
	"Ivan T. Ivanov" <iivanov@...sol.com>,
	Bjorn Andersson <bjorn.andersson@...ymobile.com>,
	Andy Gross <agross@...eaurora.org>
Subject: [Patch v2 1/3] spi: qup: Remove chip select function

This patch removes the chip select function.  Chip select should instead be
supported using GPIOs, defining the DT entry "cs-gpios", and letting the SPI
core assert/deassert the chip select as it sees fit.

Signed-off-by: Andy Gross <agross@...eaurora.org>
---
 .../devicetree/bindings/spi/qcom,spi-qup.txt       |    6 ++++
 drivers/spi/spi-qup.c                              |   33 ++++----------------
 2 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt b/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
index b82a268..bee6ff2 100644
--- a/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
+++ b/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
@@ -23,6 +23,12 @@ Optional properties:
 - spi-max-frequency: Specifies maximum SPI clock frequency,
                      Units - Hz. Definition as per
                      Documentation/devicetree/bindings/spi/spi-bus.txt
+- num-cs:	total number of chipselects
+- cs-gpios:	should specify GPIOs used for chipselects.
+		The gpios will be referred to as reg = <index> in the SPI child
+		nodes.  If unspecified, a single SPI device without a chip
+		select can be used.
+
 
 SPI slave nodes must be children of the SPI master node and can contain
 properties described in Documentation/devicetree/bindings/spi/spi-bus.txt
diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index fc1de86..3938c62 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -424,31 +424,6 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
 	return 0;
 }
 
-static void spi_qup_set_cs(struct spi_device *spi, bool enable)
-{
-	struct spi_qup *controller = spi_master_get_devdata(spi->master);
-
-	u32 iocontol, mask;
-
-	iocontol = readl_relaxed(controller->base + SPI_IO_CONTROL);
-
-	/* Disable auto CS toggle and use manual */
-	iocontol &= ~SPI_IO_C_MX_CS_MODE;
-	iocontol |= SPI_IO_C_FORCE_CS;
-
-	iocontol &= ~SPI_IO_C_CS_SELECT_MASK;
-	iocontol |= SPI_IO_C_CS_SELECT(spi->chip_select);
-
-	mask = SPI_IO_C_CS_N_POLARITY_0 << spi->chip_select;
-
-	if (enable)
-		iocontol |= mask;
-	else
-		iocontol &= ~mask;
-
-	writel_relaxed(iocontol, controller->base + SPI_IO_CONTROL);
-}
-
 static int spi_qup_transfer_one(struct spi_master *master,
 			      struct spi_device *spi,
 			      struct spi_transfer *xfer)
@@ -571,12 +546,16 @@ static int spi_qup_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
+	/* use num-cs unless not present or out of range */
+	if (of_property_read_u16(dev->of_node, "num-cs",
+			&master->num_chipselect) ||
+			(master->num_chipselect > SPI_NUM_CHIPSELECTS))
+		master->num_chipselect = SPI_NUM_CHIPSELECTS;
+
 	master->bus_num = pdev->id;
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
-	master->num_chipselect = SPI_NUM_CHIPSELECTS;
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
 	master->max_speed_hz = max_freq;
-	master->set_cs = spi_qup_set_cs;
 	master->transfer_one = spi_qup_transfer_one;
 	master->dev.of_node = pdev->dev.of_node;
 	master->auto_runtime_pm = true;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

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