fsl_i2c: Added a callpoint for i2c_board_late_init

This patch adds a callpoint in i2c_init that allows board specific
i2c board initialization (typically for i2c bus reset) that is called
after i2c_init operations, allowing the i2c_board_late_init function
to use the pre-configured i2c bus speed and slave address.

README

@@ -1509,6 +1509,17 @@ The following options need to be configured:
 		custom i2c_init_board() routine in boards/xxx/board.c
 		is run early in the boot sequence.
 
+		CONFIG_SYS_I2C_BOARD_LATE_INIT
+
+		An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
+		defined a custom i2c_board_late_init() routine in
+		boards/xxx/board.c is run AFTER the operations in i2c_init()
+		is completed. This callpoint can be used to unreset i2c bus
+		using CPU i2c controller register accesses for CPUs whose i2c
+		controller provide such a method. It is called at the end of
+		i2c_init() to allow i2c_init operations to setup the i2c bus
+		controller on the CPU (e.g. setting bus speed & slave address).
+
 		CONFIG_I2CFAST (PPC405GP|PPC405EP only)
 
 		This option enables configuration of bi_iic_fast[] flags

drivers/i2c/fsl_i2c.c

@@ -221,9 +221,10 @@ i2c_init(int speed, int slaveadd)
 	unsigned int temp;
 
 #ifdef CONFIG_SYS_I2C_INIT_BOARD
-	/* call board specific i2c bus reset routine before accessing the   */
-	/* environment, which might be in a chip on that bus. For details   */
-	/* about this problem see doc/I2C_Edge_Conditions.                  */
+	/* Call board specific i2c bus reset routine before accessing the
+	 * environment, which might be in a chip on that bus. For details
+	 * about this problem see doc/I2C_Edge_Conditions.
+	*/
 	i2c_init_board();
 #endif
 	dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C_OFFSET);
@@ -249,6 +250,15 @@ i2c_init(int speed, int slaveadd)
 	writeb(0x0, &dev->sr);			/* clear status register */
 	writeb(I2C_CR_MEN, &dev->cr);		/* start I2C controller */
 #endif
+
+#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
+	/* Call board specific i2c bus reset routine AFTER the bus has been
+	 * initialized. Use either this callpoint or i2c_init_board;
+	 * which is called before i2c_init operations.
+	 * For details about this problem see doc/I2C_Edge_Conditions.
+	*/
+	i2c_board_late_init();
+#endif
 }
 
 static int

include/i2c.h

@@ -111,6 +111,9 @@ void i2c_init(int speed, int slaveaddr);
 #ifdef CONFIG_SYS_I2C_INIT_BOARD
 void i2c_init_board(void);
 #endif
+#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
+void i2c_board_late_init(void);
+#endif
 
 #if defined(CONFIG_I2C_MUX)