dm: i2c: dts: Support an offset-len device tree property

Since U-Boot can support different offset lengths (0-4 bytes), add a device
tree property to specify this. This avoids hard-coding it in the driver.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/doc/device-tree-bindings/i2c/i2c.txt b/doc/device-tree-bindings/i2c/i2c.txt
new file mode 100644 (file)
index 0000000..ea918dd
--- /dev/null
+++ b/doc/device-tree-bindings/i2c/i2c.txt
@@ -0,0 +1,28 @@
+U-Boot I2C
+----------
+
+U-Boot's I2C model has the concept of an offset within a chip (I2C target
+device). The offset can be up to 4 bytes long, but is normally 1 byte,
+meaning that offsets from 0 to 255 are supported by the chip. This often
+corresponds to register numbers.
+
+Apart from the controller-specific I2C bindings, U-Boot supports a special
+property which allows the chip offset length to be selected.
+
+Optional properties:
+- u-boot,i2c-offset-len - length of chip offset in bytes. If omitted the
+    default value of 1 is used.
+
+
+Example
+-------
+
+i2c4: i2c@12ca0000 {
+       cros-ec@1e {
+               reg = <0x1e>;
+               compatible = "google,cros-ec";
+               i2c-max-frequency = <100000>;
+               u-boot,i2c-offset-len = <0>;
+               ec-interrupt = <&gpx1 6 GPIO_ACTIVE_LOW>;
+       };
+};

diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
index 393cd6f583aac9dfde86d63726e9e9e6ab0d4c2e..eafa457845df2371bff8a59ce8b20b7d2d32dd82 100644 (file)
--- a/drivers/i2c/i2c-uclass.c
+++ b/drivers/i2c/i2c-uclass.c
@@ -420,7 +420,8 @@ int i2c_deblock(struct udevice *bus)
 int i2c_chip_ofdata_to_platdata(const void *blob, int node,
                                struct dm_i2c_chip *chip)
 {
-       chip->offset_len = 1;   /* default */
+       chip->offset_len = fdtdec_get_int(gd->fdt_blob, node,
+                                         "u-boot,i2c-offset-len", 1);
        chip->flags = 0;
        chip->chip_addr = fdtdec_get_int(gd->fdt_blob, node, "reg", -1);
        if (chip->chip_addr == -1) {