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>

2 files changed, 59 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/spi/spi-sc18is602.txt b/Documentation/devicetree/bindings/spi/spi-sc18is602.txt
new file mode 100644
index 000000000000..02f9033270a2
--- /dev/null
+++ 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
new file mode 100644
index 000000000000..a45702865a38
--- /dev/null
+++ 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.