rtc: ingenic: Enable clock in probe

It makes no sense to request a clock and not enable it even though the
hardware is being used. So the driver now enables the clock in the
probe. Besides, now we can properly handle errors.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20200505221336.222313-3-paul@crapouillou.netSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-jz4740.c

@@ -264,8 +264,6 @@ static void jz4740_rtc_power_off(void)
 	unsigned long wakeup_filter_ticks;
 	unsigned long reset_counter_ticks;
 
-	clk_prepare_enable(rtc->clk);
-
 	rtc_rate = clk_get_rate(rtc->clk);
 
 	/*
@@ -297,6 +295,11 @@ static void jz4740_rtc_power_off(void)
 	kernel_halt();
 }
 
+static void jz4740_rtc_clk_disable(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
 static const struct of_device_id jz4740_rtc_of_match[] = {
 	{ .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
 	{ .compatible = "ingenic,jz4760-rtc", .data = (void *)ID_JZ4760 },
@@ -332,6 +335,18 @@ static int jz4740_rtc_probe(struct platform_device *pdev)
 		return PTR_ERR(rtc->clk);
 	}
 
+	ret = clk_prepare_enable(rtc->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(dev, jz4740_rtc_clk_disable, rtc->clk);
+	if (ret) {
+		dev_err(dev, "Failed to register devm action\n");
+		return ret;
+	}
+
 	spin_lock_init(&rtc->lock);
 
 	platform_set_drvdata(pdev, rtc);