i2c: Replace the i2c API.

The new API is in use in depthcharge and is based around the "i2c_transfer"
function instead of i2c_read and i2c_write. The new function takes an array of
i2c_seg structures which represent each portion of the transfer after a start
bit and before the stop bit. If there's more than one segment, they're
seperated by repeated starts.

Some wrapper functions have also been added which make certain common
operations easy. These include reading or writing a byte from a register or
reading or writing a blob of raw data. The i2c device drivers generally use
these wrappers but can call the i2c_transfer function directly if the need
something different.

The tegra i2c driver was very similar to the one in depthcharge and was simple
to convert. The Exynos 5250 and 5420 drivers were ported from depthcharge and
replace the ones in coreboot. The Exynos 5420 driver was ported from the high
speed portion of the one in coreboot and was straightforward to port back. The
low speed portion and the Exynos 5250 drivers had been transplanted from U-Boot
and were replaced with the depthcharge implementation.

BUG=None
TEST=Built and booted on nyan with and without EFS. Built and booted on, pit
and daisy.
BRANCH=None

Original-Change-Id: I1e98c3fa2560be25444ab3d0394bb214b9d56e93
Original-Signed-off-by: Gabe Black <gabeblack@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/193561
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Reviewed-by: Jimmy Zhang <jimmzhang@nvidia.com>
Original-Tested-by: Jimmy Zhang <jimmzhang@nvidia.com>
Original-Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Original-Commit-Queue: Gabe Black <gabeblack@chromium.org>
Original-Tested-by: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit 00c423fb2c06c69d580ee3ec0a3892ebf164a5fe)

This cherry-pick required additional changes to the following:
src/cpu/allwinner/a10/twi.c
src/drivers/xpowers/axp209/axp209.c

Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I691959c66308eeeec219b1bec463b8b365a246d7
Reviewed-on: http://review.coreboot.org/7751
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

1 files changed, 78 insertions, 6 deletions

diff --git a/src/include/device/i2c.h b/src/include/device/i2c.h
index 997d201341..da9d1bcb3c 100644
--- a/src/include/device/i2c.h
+++ b/src/include/device/i2c.h
@@ -1,7 +1,7 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright (C) 2013 Google, Inc.
+ * Copyright (C) 2014 Google, Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -21,11 +21,83 @@
 #define _DEVICE_I2C_H_
 
 #include <stdint.h>
+#include <stdlib.h>
 
-/* note: chip is the 7-bit I2C address */
-int i2c_read(unsigned bus, unsigned chip, unsigned addr,
-		unsigned alen, uint8_t *buf, unsigned len);
-int i2c_write(unsigned bus, unsigned chip, unsigned addr,
-		unsigned alen, const uint8_t *buf, unsigned len);
+struct i2c_seg
+{
+	int read;
+	uint8_t chip;
+	uint8_t *buf;
+	int len;
+};
+
+int i2c_transfer(unsigned bus, struct i2c_seg *segments, int count);
+
+/*
+ * Read a raw chunk of data in one segment and one frame.
+ *
+ * [start][slave addr][r][data][stop]
+ */
+static inline int i2c_read_raw(unsigned bus, uint8_t chip, uint8_t *data,
+			       int len)
+{
+	struct i2c_seg seg =
+		{ .read = 1, .chip = chip, .buf = data, .len = len };
+	return i2c_transfer(bus, &seg, 1);
+}
+
+/*
+ * Write a raw chunk of data in one segment and one frame.
+ *
+ * [start][slave addr][w][data][stop]
+ */
+static inline int i2c_write_raw(unsigned bus, uint8_t chip, uint8_t *data,
+			        int len)
+{
+	struct i2c_seg seg =
+		{ .read = 0, .chip = chip, .buf = data, .len = len };
+	return i2c_transfer(bus, &seg, 1);
+}
+
+/**
+ * Read a byte with two segments in one frame
+ *
+ * [start][slave addr][w][register addr][start][slave addr][r][data][stop]
+ */
+static inline int i2c_readb(unsigned bus, uint8_t chip, uint8_t reg,
+			    uint8_t *data)
+{
+	struct i2c_seg seg[2];
+
+	seg[0].read = 0;
+	seg[0].chip = chip;
+	seg[0].buf = &reg;
+	seg[0].len = 1;
+	seg[1].read = 1;
+	seg[1].chip = chip;
+	seg[1].buf = data;
+	seg[1].len = 1;
+
+	return i2c_transfer(bus, seg, ARRAY_SIZE(seg));
+}
+
+/**
+ * Write a byte with one segment in one frame.
+ *
+ * [start][slave addr][w][register addr][data][stop]
+ */
+static inline int i2c_writeb(unsigned bus, uint8_t chip, uint8_t reg,
+			     uint8_t data)
+{
+	struct i2c_seg seg;
+	uint8_t buf[] = {reg, data};
+
+	seg.read = 0;
+	seg.chip = chip;
+	seg.buf = buf;
+	seg.len = ARRAY_SIZE(buf);
+
+	return i2c_transfer(bus, &seg, 1);
+}
 
 #endif	/* _DEVICE_I2C_H_ */