dm: i2c: Add a function to transfer messages

Sometimes it is useful to be able to transfer a raw I2C message. This
happens when the chip address needs to be set manually, or when the data to
be sent/received is in another buffer.

Add a function to provide access to this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>

diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
index 42d6e89e9dd5997b884a07aa5576d4912597fa3c..50b99ead3d9fb4179940d2c6566a698d954028f5 100644 (file)
--- a/drivers/i2c/i2c-uclass.c
+++ b/drivers/i2c/i2c-uclass.c
@@ -202,6 +202,17 @@ int dm_i2c_write(struct udevice *dev, uint offset, const uint8_t *buffer,
        }
 }
 
+int dm_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
+{
+       struct udevice *bus = dev_get_parent(dev);
+       struct dm_i2c_ops *ops = i2c_get_ops(bus);
+
+       if (!ops->xfer)
+               return -ENOSYS;
+
+       return ops->xfer(bus, msg, nmsgs);
+}
+
 int dm_i2c_reg_read(struct udevice *dev, uint offset)
 {
        uint8_t val;

diff --git a/include/i2c.h b/include/i2c.h
index 4c0e263b9338f5e214591a061869c2a560e62911..d19182931c57a328981721ceaf8dbf8edabeb998 100644 (file)
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -190,6 +190,19 @@ int dm_i2c_reg_read(struct udevice *dev, uint offset);
  */
 int dm_i2c_reg_write(struct udevice *dev, uint offset, unsigned int val);
 
+/**
+ * dm_i2c_xfer() - Transfer messages over I2C
+ *
+ * This transfers a raw message. It is best to use dm_i2c_reg_read/write()
+ * instead.
+ *
+ * @dev:       Device to use for transfer
+ * @msg:       List of messages to transfer
+ * @nmsgs:     Number of messages to transfer
+ * @return 0 on success, -ve on error
+ */
+int dm_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs);
+
 /**
  * dm_i2c_set_bus_speed() - set the speed of a bus
  *