rtc: mxc: set range

Let the core handle the range, and in particular the imx1 offsetting. This
has the benefit of extending the range of the RTC further than 365 days and
making .read_time useful again on imx1.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-mxc.c

@@ -256,19 +256,6 @@ static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
  */
 static int mxc_rtc_set_mmss(struct device *dev, time64_t time)
 {
-	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
-
-	/*
-	 * TTC_DAYR register is 9-bit in MX1 SoC, save time and day of year only
-	 */
-	if (is_imx1_rtc(pdata)) {
-		struct rtc_time tm;
-
-		rtc_time64_to_tm(time, &tm);
-		tm.tm_year = 70;
-		time = rtc_tm_to_time64(&tm);
-	}
-
 	/* Avoid roll-over from reading the different registers */
 	do {
 		set_alarm_or_time(dev, MXC_RTC_TIME, time);
@@ -346,6 +333,23 @@ static int mxc_rtc_probe(struct platform_device *pdev)
 
 	pdata->rtc = rtc;
 	rtc->ops = &mxc_rtc_ops;
+	if (is_imx1_rtc(pdata)) {
+		struct rtc_time tm;
+
+		/* 9bit days + hours minutes seconds */
+		rtc->range_max = (1 << 9) * 86400 - 1;
+
+		/*
+		 * Set the start date as beginning of the current year. This can
+		 * be overridden using device tree.
+		 */
+		rtc_time64_to_tm(ktime_get_real_seconds(), &tm);
+		rtc->start_secs =  mktime64(tm.tm_year, 1, 1, 0, 0, 0);
+		rtc->set_start_time = true;
+	} else {
+		/* 16bit days + hours minutes seconds */
+		rtc->range_max = (1 << 16) * 86400ULL - 1;
+	}
 
 	pdata->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
 	if (IS_ERR(pdata->clk_ipg)) {