From: Grant Likely [EMAIL PROTECTED]
Add documentation about how to describe SPI busses in the device tree.
Signed-off-by: Grant Likely [EMAIL PROTECTED]
---
Documentation/powerpc/booting-without-of.txt | 60 ++
1 files changed, 60 insertions(+), 0 deletions(-)
diff --git a/Documentation/powerpc/booting-without-of.txt
b/Documentation/powerpc/booting-without-of.txt
index 1d2a772..7d3564f 100644
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -58,6 +58,7 @@ Table of Contents
o) Xilinx IP cores
p) Freescale Synchronous Serial Interface
q) USB EHCI controllers
+ t) SPI busses
VII - Marvell Discovery mv64[345]6x System Controller chips
1) The /system-controller node
@@ -2870,6 +2871,65 @@ platforms are moved over to use the
flattened-device-tree model.
reg = 0xe800 32;
};
+t) SPI (Serial Peripheral Interface) busses
+
+SPI busses can be described with a node for the SPI master device
+and a set of child nodes for each SPI slave on the bus. For this
+discussion, it is assumed that the system's SPI controller is in
+SPI master mode. This binding does not describe SPI controllers
+in slave mode.
+
+The SPI master node requires the following properties:
+- #address-cells - number of cells required to define a chip select
+ address on the SPI bus.
+- #size-cells - should be zero.
+- compatible - name of SPI bus controller following generic names
+ recommended practice.
+No other properties are required in the SPI bus node. It is assumed
+that a driver for an SPI bus device will understand that it is an SPI bus.
+However, the binding does not attempt to define the specific method for
+assigning chip select numbers. Since SPI chip select configuration is
+flexible and non-standardized, it is left out of this binding with the
+assumption that board specific platform code will be used to manage
+chip selects. Individual drivers can define additional properties to
+support describing the chip select layout.
+
+SPI slave nodes must be children of the SPI master node and can
+contain the following properties.
+- reg - (required) chip select address of device.
+- compatible - (required) name of SPI device following generic names
+ recommended practice
+- max-speed - (required) Maximum SPI clocking speed of device in Hz
+- spi,cpol- (optional) Device requires inverse clock polarity
+- spi,cpha- (optional) Device requires shifted clock phase
+- linux,modalias - (optional, Linux specific) Force binding of SPI device
+ to a particular spi_device driver. Useful for changing
+ driver binding between spidev and a kernel SPI driver.
+
+SPI example for an MPC5200 SPI bus:
+ [EMAIL PROTECTED] {
+ #address-cells = 1;
+ #size-cells = 0;
+ compatible = fsl,mpc5200b-spi,fsl,mpc5200-spi;
+ reg = 0xf00 0x20;
+ interrupts = 2 13 0 2 14 0;
+ interrupt-parent = mpc5200_pic;
+
+ [EMAIL PROTECTED] {
+ compatible = micrel,ks8995m;
+ linux,modalias = ks8995;
+ max-speed = 100;
+ reg = 0;
+ };
+
+ [EMAIL PROTECTED] {
+ compatible = ti,tlv320aic26;
+ max-speed = 10;
+ reg = 1;
+ };
+ };
+
+
VII - Marvell Discovery mv64[345]6x System Controller chips
===
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