hwmon: Provide dtt_init()

Our boards rely on dtt for initialization of fan hardware.
dtt_init() was implemented to be called form board specific code.

Signed-off-by: Dirk Eibach <eibach@gdsys.de>
Acked-by: Heiko Schocher <hs@denx.de>
Tested-by: Heiko Schocher <hs@denx.de>

common/cmd_dtt.c

@@ -30,6 +30,36 @@
 
 static unsigned long sensor_initialized;
 
+static void _initialize_dtt(void)
+{
+	int i;
+	unsigned char sensors[] = CONFIG_DTT_SENSORS;
+
+	for (i = 0; i < sizeof(sensors); i++) {
+		if ((sensor_initialized & (1 << i)) == 0) {
+			if (dtt_init_one(sensors[i]) != 0) {
+				printf("DTT%d: Failed init!\n", i);
+				continue;
+			}
+			sensor_initialized |= (1 << i);
+		}
+	}
+}
+
+void dtt_init(void)
+{
+	int old_bus;
+
+	/* switch to correct I2C bus */
+	old_bus = I2C_GET_BUS();
+	I2C_SET_BUS(CONFIG_SYS_DTT_BUS_NUM);
+
+	_initialize_dtt();
+
+	/* switch back to original I2C bus */
+	I2C_SET_BUS(old_bus);
+}
+
 int do_dtt (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	int i;
@@ -42,20 +72,14 @@ int do_dtt (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 	old_bus = I2C_GET_BUS();
 	I2C_SET_BUS(CONFIG_SYS_DTT_BUS_NUM);
 
+	_initialize_dtt();
+
 	/*
 	 * Loop through sensors, read
 	 * temperature, and output it.
 	 */
-	for (i = 0; i < sizeof(sensors); i++) {
-		if ((sensor_initialized & (1 << i)) == 0) {
-			if (dtt_init_one(sensors[i]) != 0) {
-				printf("DTT%d: Failed init!\n", i);
-				continue;
-			}
-			sensor_initialized |= (1 << i);
-		}
+	for (i = 0; i < sizeof(sensors); i++)
 		printf("DTT%d: %i C\n", i + 1, dtt_get_temp(sensors[i]));
-	}
 
 	/* switch back to original I2C bus */
 	I2C_SET_BUS(old_bus);

include/dtt.h

@@ -52,6 +52,7 @@
 #endif
 #endif /* CONFIG_DTT_ADM1021 */
 
+extern void dtt_init(void);
 extern int dtt_init_one(int);
 extern int dtt_read(int sensor, int reg);
 extern int dtt_write(int sensor, int reg, int val);