spi: Master driver for NXP SC18IS602/603

This driver adds support for NXP SC18IS602/603 I2C to SPI bus bridge. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
git-mirror · Aug 22, 2012 · 3ce8859 · 3ce8859
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diff --git a/Documentation/devicetree/bindings/spi/spi-sc18is602.txt b/Documentation/devicetree/bindings/spi/spi-sc18is602.txt
@@ -0,0 +1,23 @@
+NXP SC18IS602/SCIS603
+
+Required properties:
+	- compatible : Should be one of
+		"nxp,sc18is602"
+		"nxp,sc18is602b"
+		"nxp,sc18is603"
+	- reg: I2C bus address
+
+Optional properties:
+	- clock-frequency : external oscillator clock frequency. If not
+	  specified, the SC18IS602 default frequency (7372000) will be used.
+
+The clock-frequency property is relevant and needed only if the chip has an
+external oscillator (SC18IS603).
+
+Example:
+
+	sc18is603@28 {
+		compatible = "nxp,sc18is603";
+		reg = <0x28>;
+		clock-frequency = <14744000>;
+	}
diff --git a/Documentation/spi/spi-sc18is602 b/Documentation/spi/spi-sc18is602
@@ -0,0 +1,36 @@
+Kernel driver spi-sc18is602
+===========================
+
+Supported chips:
+  * NXP SI18IS602/602B/603
+    Datasheet: http://www.nxp.com/documents/data_sheet/SC18IS602_602B_603.pdf
+
+Author:
+        Guenter Roeck <linux@roeck-us.net>
+
+
+Description
+-----------
+
+This driver provides connects a NXP SC18IS602/603 I2C-bus to SPI bridge to the
+kernel's SPI core subsystem.
+
+The driver does not probe for supported chips, since the SI18IS602/603 does not
+support Chip ID registers. You will have to instantiate the devices explicitly.
+Please see Documentation/i2c/instantiating-devices for details.
+
+
+Usage Notes
+-----------
+
+This driver requires the I2C adapter driver to support raw I2C messages. I2C
+adapter drivers which can only handle the SMBus protocol are not supported.
+
+The maximum SPI message size supported by SC18IS602/603 is 200 bytes. Attempts
+to initiate longer transfers will fail with -EINVAL. EEPROM read operations and
+similar large accesses have to be split into multiple chunks of no more than
+200 bytes per SPI message (128 bytes of data per message is recommended). This
+means that programs such as "cp" or "od", which automatically use large block
+sizes to access a device, can not be used directly to read data from EEPROM.
+Programs such as dd, where the block size can be specified, should be used
+instead.
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
@@ -325,6 +325,12 @@ config SPI_S3C64XX
 	help
 	  SPI driver for Samsung S3C64XX and newer SoCs.
 
+config SPI_SC18IS602
+	tristate "NXP SC18IS602/602B/603 I2C to SPI bridge"
+	depends on I2C
+	help
+	  SPI driver for NXP SC18IS602/602B/603 I2C to SPI bridge.
+
 config SPI_SH_MSIOF
 	tristate "SuperH MSIOF SPI controller"
 	depends on SUPERH && HAVE_CLK

diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_SPI_S3C24XX)		+= spi-s3c24xx-hw.o
 spi-s3c24xx-hw-y			:= spi-s3c24xx.o
 spi-s3c24xx-hw-$(CONFIG_SPI_S3C24XX_FIQ) += spi-s3c24xx-fiq.o
 obj-$(CONFIG_SPI_S3C64XX)		+= spi-s3c64xx.o
+obj-$(CONFIG_SPI_SC18IS602)		+= spi-sc18is602.o
 obj-$(CONFIG_SPI_SH)			+= spi-sh.o
 obj-$(CONFIG_SPI_SH_HSPI)		+= spi-sh-hspi.o
 obj-$(CONFIG_SPI_SH_MSIOF)		+= spi-sh-msiof.o