i2c: add i2c deblock sequence before and after every mux config

To make sure that the mux can be configured a deblocking sequence
is done before the mux configuration. After the mux switch the new leaf
of, the i2c tree must be again deblocked.

Signed-off-by: Stefan Bigler <stefan.bigler@keymile.com>
Acked-by: Heiko Schocher <hs@denx.de>
cc: Wolfgang Denk <wd@denx.de>
cc: Detlev Zundel <dzu@denx.de>
cc: Prafulla Wadaskar <prafulla@marvell.com>
cc: Valentin Longchamp <valentin.longchamp@keymile.com>
cc: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
diff --git a/common/cmd_i2c.c b/common/cmd_i2c.c
index c272b0d..d913e13 100644
--- a/common/cmd_i2c.c
+++ b/common/cmd_i2c.c
@@ -132,6 +132,14 @@
 
 #define DISP_LINE_LEN	16
 
+/* implement possible board specific board init */
+void __def_i2c_init_board(void)
+{
+	return;
+}
+void i2c_init_board(void)
+	__attribute__((weak, alias("__def_i2c_init_board")));
+
 /* TODO: Implement architecture-specific get/set functions */
 unsigned int __def_i2c_get_bus_speed(void)
 {
@@ -1541,6 +1549,8 @@
 
 	mux = dev->mux;
 	while (mux != NULL) {
+		/* do deblocking on each level of mux, before mux config */
+		i2c_init_board();
 		if (i2c_write(mux->chip, 0, 0, &mux->channel, 1) != 0) {
 			printf ("Error setting Mux: chip:%x channel: \
 				%x\n", mux->chip, mux->channel);
@@ -1548,6 +1558,8 @@
 		}
 		mux = mux->next;
 	}
+	/* do deblocking on each level of mux and after mux config */
+	i2c_init_board();
 	return 0;
 }
 #endif /* CONFIG_I2C_MUX */