Move i2cread and i2cwrite functions to i2c_common

Also moves the handy i2cscan command to i2c_common.  The
platform-dependent interface is now i2c_xfer().

Still more to do in follow-up CLs; for example, i2c_read_string() has
platform-dependent implementation, and the i2c/i2cread console
commands aren't common yet.

BUG=chrome-os-partner:18969
BRANCH=none
TEST=i2cscan on link, spring

Change-Id: Ia53d57beaa157bece293a4262257e20b4107589e
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/49492
Reviewed-by: Simon Glass <sjg@chromium.org>
Commit-Queue: Daniel Erat <derat@chromium.org>
Commit-Queue: Simon Glass <sjg@chromium.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/include/i2c.h b/include/i2c.h
index d14008a2d0..86535c1fa8 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -20,6 +20,47 @@ struct i2c_port_t {
 	int kbps;          /* Speed in kbps */
 };
 
+/* Flags for i2c_xfer() */
+#define I2C_XFER_START (1 << 0)  /* Start smbus session from idle state */
+#define I2C_XFER_STOP (1 << 1)  /* Terminate smbus session with stop bit */
+#define I2C_XFER_SINGLE (I2C_XFER_START | I2C_XFER_STOP)  /* One transaction */
+
+/**
+ * Transmit one block of raw data, then receive one block of raw data.
+ *
+ * This is a low-level platform-dependent function used by the other functions
+ * below.  It must be called between i2c_lock(port, 1) and i2c_lock(port, 0).
+ *
+ * @param port		Port to access
+ * @param slave_addr	Slave device address
+ * @param out		Data to send
+ * @param out_size	Number of bytes to send
+ * @param in		Destination buffer for received data
+ * @param in_size	Number of bytes to receive
+ * @param flags		Flags (see I2C_XFER_* above)
+ * @return EC_SUCCESS, or non-zero if error.
+ */
+int i2c_xfer(int port, int slave_addr, const uint8_t *out, int out_size,
+	     uint8_t *in, int in_size, int flags);
+
+#define I2C_LINE_SCL_HIGH (1 << 0)
+#define I2C_LINE_SDA_HIGH (1 << 1)
+#define I2C_LINE_IDLE (I2C_LINE_SCL_HIGH | I2C_LINE_SDA_HIGH)
+
+/**
+ * Return raw I/O line levels (I2C_LINE_*) for a port.
+ *
+ * @param port		Port to check
+ */
+int i2c_get_line_levels(int port);
+
+/**
+ * Lock / unlock an I2C port.
+ * @param port		Port to lock
+ * @param lock		1 to lock, 0 to unlock
+ */
+void i2c_lock(int port, int lock);
+
 /* Read a 16-bit register from the slave at 8-bit slave address <slaveaddr>, at
  * the specified 8-bit <offset> in the slave's address space. */
 int i2c_read16(int port, int slave_addr, int offset, int* data);