i2c-ocores: add some device tree documentation
This puts some documentation for the device tree configuration at the head
of the driver file. Hopefully this can get moved to a common area for this
type of documentation at a later date; unfortunately, there isn't really
such a place in the kernel tree at this time.
Furthermore, the regstep and clock-frequency parameters are really bus
parameters and should probably be passed to the driver in a better way.
Consider that a TODO.
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index dee0352..ef3bcb1 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -9,6 +9,41 @@
* kind, whether express or implied.
*/
+/*
+ * Device tree configuration:
+ *
+ * Required properties:
+ * - compatible : "opencores,i2c-ocores"
+ * - reg : bus address start and address range size of device
+ * - interrupts : interrupt number
+ * - regstep : size of device registers in bytes
+ * - clock-frequency : frequency of bus clock in Hz
+ *
+ * Example:
+ *
+ * i2c0: ocores@a0000000 {
+ * compatible = "opencores,i2c-ocores";
+ * reg = <0xa0000000 0x8>;
+ * interrupts = <10>;
+ *
+ * regstep = <1>;
+ * clock-frequency = <20000000>;
+ *
+ * -- Devices connected on this I2C bus get
+ * -- defined here; address- and size-cells
+ * -- apply to these child devices
+ *
+ * #address-cells = <1>;
+ * #size-cells = <0>;
+ *
+ * dummy@60 {
+ * compatible = "dummy";
+ * reg = <60>;
+ * };
+ * };
+ *
+ */
+
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>