device: Add i2c read/write register field API

i2c_read_field() - read the value from the specific register field
i2c_write_field() - write the value to the specific register field

BRANCH=none
BUG=none
TEST=none

Change-Id: I2098715b4583c1936c93b3ff45ec330910964304
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 0817fc76d07491b39c066f1393a6435f0831b50c
Original-Change-Id: I92c187a89d10cfcecf3dfd9291e0bc015459c393
Original-Signed-off-by: Yidi Lin <yidi.lin@mediatek.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/332712
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/14105
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/include/device/i2c.h b/src/include/device/i2c.h
index 8e59ba7..b152bb9 100644
--- a/src/include/device/i2c.h
+++ b/src/include/device/i2c.h
@@ -45,6 +45,11 @@
 void software_i2c_wedge_read(unsigned bus, u8 chip, u8 reg, int bit_count);
 void software_i2c_wedge_write(unsigned bus, u8 chip, u8 reg, int bit_count);
 
+int i2c_read_field(unsigned bus, uint8_t chip, uint8_t reg, uint8_t *data,
+		   uint8_t mask, uint8_t shift);
+int i2c_write_field(unsigned bus, uint8_t chip, uint8_t reg, uint8_t data,
+		    uint8_t mask, uint8_t shift);
+
 /*
  * software_i2c is supposed to be a debug feature. It's usually not compiled in,
  * but when it is it can be dynamically enabled at runtime for certain busses.