linux-kernel - [PATCH] spi: spi-omap2-mcspi.c: Add dts for slave device configuration.

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Message-Id: <1364252415-3613-1-git-send-email-matthias.bgg@gmail.com>
Date:	Tue, 26 Mar 2013 00:00:15 +0100
From:	Matthias Brugger <matthias.bgg@...il.com>
To:	Grant Likely <grant.likely@...retlab.ca>,
	Rob Herring <rob.herring@...xeda.com>,
	Rob Landley <rob@...dley.net>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Daniel Mack <zonque@...il.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	"Enric Balletbo Serra" <eballetbo@...il.com>,
	"Javier Martinez Canillas" <martinez.javier@...il.com>,
	devicetree-discuss@...ts.ozlabs.org, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	spi-devel-general@...ts.sourceforge.net,
	linux-omap@...r.kernel.org, ezequiel.garcia@...e-electrons.com
Subject: [PATCH] spi: spi-omap2-mcspi.c: Add dts for slave device configuration.

TI omap2 mcspi allows the slave devices to configure the behavior of
the SPI master. This patch adds device tree support to the existing
options.

Signed-off-by: Matthias Brugger <matthias.bgg@...il.com>
---
 Documentation/devicetree/bindings/spi/omap-spi.txt | 23 ++++++++++++
 drivers/spi/spi-omap2-mcspi.c                      | 41 ++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/Documentation/devicetree/bindings/spi/omap-spi.txt b/Documentation/devicetree/bindings/spi/omap-spi.txt
index 938809c..fef16bf 100644
--- a/Documentation/devicetree/bindings/spi/omap-spi.txt
+++ b/Documentation/devicetree/bindings/spi/omap-spi.txt
@@ -10,8 +10,20 @@ Required properties:
 			  input. The default is D0 as input and
 			  D1 as output.
 
+SPI Controller specific data in SPI slave nodes:
+
+- The spi slave nodes can provide the following information which is used
+  by the spi controller.
+
+- ti,spi-cs-per-word: Set chipselect to be toggled on every word send.
+
+- ti,spi-turbo-mode: Set turbo mode for this device.
+
+
 Example:
 
+- SoC Specific Portion:
+
 mcspi1: mcspi@1 {
     #address-cells = <1>;
     #size-cells = <0>;
@@ -20,3 +32,14 @@ mcspi1: mcspi@1 {
     ti,spi-num-cs = <4>;
 };
 
+- Board Specific Portion:
+
+	spi-device@0 {
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		controller-data {
+			ti,spi-cs-per-word = <1>;
+			ti,spi-turbo-mode = <0>;
+		};
+	};
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 893c3d7..1ae5009 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -731,11 +731,47 @@ static u32 omap2_mcspi_calc_divisor(u32 speed_hz)
 	return 15;
 }
 
+static struct omap2_mcspi_device_config *omap2_mcspi_get_slave_ctrldata(
+			struct spi_device *spi)
+{
+	struct omap2_mcspi_device_config *cd;
+	struct device_node *slave_np, *data_np = NULL;
+
+	slave_np = spi->dev.of_node;
+	if (!slave_np) {
+		dev_err(&spi->dev, "device node not found\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	data_np = of_get_child_by_name(slave_np, "controller-data");
+	if (!data_np) {
+		dev_err(&spi->dev, "child node 'controller-data' not found\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
+	if (!cd) {
+		dev_err(&spi->dev, "could not allocate memory for controller data\n");
+		of_node_put(data_np);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	if (of_get_property(data_np, "ti,spi-cs-per-word", NULL))
+		cd->cs_per_word = 1;
+
+	if (of_get_property(data_np, "ti,spi-turbo-mode", NULL))
+		cd->turbo_mode = 1;
+
+	of_node_put(data_np);
+	return cd;
+}
+
 /* called only when no transfer is active to this device */
 static int omap2_mcspi_setup_transfer(struct spi_device *spi,
 		struct spi_transfer *t)
 {
 	struct omap2_mcspi_cs *cs = spi->controller_state;
+	struct omap2_mcspi_device_config *cd = spi->controller_data;
 	struct omap2_mcspi *mcspi;
 	struct spi_master *spi_cntrl;
 	u32 l = 0, div = 0;
@@ -745,6 +781,11 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
 	mcspi = spi_master_get_devdata(spi->master);
 	spi_cntrl = mcspi->master;
 
+	if (!cd && spi->dev.of_node) {
+		cd = omap2_mcspi_get_slave_ctrldata(spi);
+		spi->controller_data = cd;
+	}
+
 	if (t != NULL && t->bits_per_word)
 		word_len = t->bits_per_word;
 
-- 
1.7.11.7

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