dm: rtc: Convert 'date' command to support driver model

Adjust this command so that it supports using driver model for I2C, i.e.
CONFIG_DM_I2C. This will permit it to be used in sandbox also.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/cmd_date.c b/common/cmd_date.c
index dfb9349..61727e3 100644
--- a/common/cmd_date.c
+++ b/common/cmd_date.c
@@ -10,6 +10,7 @@
  */
 #include <common.h>
 #include <command.h>
+#include <dm.h>
 #include <rtc.h>
 #include <i2c.h>
 
@@ -33,10 +34,18 @@
 {
 	struct rtc_time tm;
 	int rcode = 0;
-	int old_bus;
+	int old_bus __maybe_unused;
 
 	/* switch to correct I2C bus */
-#ifdef CONFIG_SYS_I2C
+#ifdef CONFIG_DM_I2C
+	struct udevice *dev;
+
+	rcode = uclass_get_device(UCLASS_RTC, 0, &dev);
+	if (rcode) {
+		printf("Cannot find RTC: err=%d\n", rcode);
+		return CMD_RET_FAILURE;
+	}
+#elif defined(CONFIG_SYS_I2C)
 	old_bus = i2c_get_bus_num();
 	i2c_set_bus_num(CONFIG_SYS_RTC_BUS_NUM);
 #else
@@ -48,32 +57,50 @@
 	case 2:			/* set date & time */
 		if (strcmp(argv[1],"reset") == 0) {
 			puts ("Reset RTC...\n");
-			rtc_reset ();
+#ifdef CONFIG_DM_I2C
+			rcode = dm_rtc_reset(dev);
+			if (!rcode)
+				rcode = dm_rtc_set(dev, &default_tm);
+#else
+			rtc_reset();
 			rcode = rtc_set(&default_tm);
+#endif
 			if (rcode)
 				puts("## Failed to set date after RTC reset\n");
 		} else {
 			/* initialize tm with current time */
-			rcode = rtc_get (&tm);
-
-			if(!rcode) {
+#ifdef CONFIG_DM_I2C
+			rcode = dm_rtc_get(dev, &tm);
+#else
+			rcode = rtc_get(&tm);
+#endif
+			if (!rcode) {
 				/* insert new date & time */
-				if (mk_date (argv[1], &tm) != 0) {
+				if (mk_date(argv[1], &tm) != 0) {
 					puts ("## Bad date format\n");
 					break;
 				}
 				/* and write to RTC */
-				rcode = rtc_set (&tm);
-				if(rcode)
-					puts("## Set date failed\n");
+#ifdef CONFIG_DM_I2C
+				rcode = dm_rtc_set(dev, &tm);
+#else
+				rcode = rtc_set(&tm);
+#endif
+				if (rcode) {
+					printf("## Set date failed: err=%d\n",
+					       rcode);
+				}
 			} else {
 				puts("## Get date failed\n");
 			}
 		}
 		/* FALL TROUGH */
 	case 1:			/* get date & time */
-		rcode = rtc_get (&tm);
-
+#ifdef CONFIG_DM_I2C
+		rcode = dm_rtc_get(dev, &tm);
+#else
+		rcode = rtc_get(&tm);
+#endif
 		if (rcode) {
 			puts("## Get date failed\n");
 			break;
@@ -93,11 +120,11 @@
 	/* switch back to original I2C bus */
 #ifdef CONFIG_SYS_I2C
 	i2c_set_bus_num(old_bus);
-#else
+#elif !defined(CONFIG_DM_I2C)
 	I2C_SET_BUS(old_bus);
 #endif
 
-	return rcode;
+	return rcode ? CMD_RET_FAILURE : 0;
 }
 
 /*