Replace irq_of_parse_and_map() with platform_get_irq(), which resolves
the interrupt from pdev->dev.of_node directly and returns a positive IRQ
or a negative errno (it never returns 0). Propagate the error on failure
instead of the previous open-coded "IRQ missing or invalid" / -EINVAL
message, so -EPROBE_DEFER is handled correctly. The rtc->irq field is a
signed short, so the negative error code is preserved.

np is still used by of_property_read_u32() for "st,lpc-mode", so it is
not removed.

Built for ARM (multi_v7_defconfig + CONFIG_RTC_DRV_ST_LPC) with LLVM=1;
drivers/rtc/rtc-st-lpc.o compiles cleanly.

Assisted-by: opencode:hy3-free
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/rtc/rtc-st-lpc.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-st-lpc.c b/drivers/rtc/rtc-st-lpc.c
index c6d4522411b3..ae79ddf24f37 100644
--- a/drivers/rtc/rtc-st-lpc.c
+++ b/drivers/rtc/rtc-st-lpc.c
@@ -18,7 +18,6 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
-#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/rtc.h>
 
@@ -212,11 +211,9 @@ static int st_rtc_probe(struct platform_device *pdev)
 	if (IS_ERR(rtc->ioaddr))
 		return PTR_ERR(rtc->ioaddr);
 
-	rtc->irq = irq_of_parse_and_map(np, 0);
-	if (!rtc->irq) {
-		dev_err(&pdev->dev, "IRQ missing or invalid\n");
-		return -EINVAL;
-	}
+	rtc->irq = platform_get_irq(pdev, 0);
+	if (rtc->irq < 0)
+		return rtc->irq;
 
 	ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler,
 			       IRQF_NO_AUTOEN, pdev->name, rtc);
-- 
2.55.0