rtc: zynqmp: check calibration max value

Enable check to not overflow the calibration
max value.

Reviewed-by: Harini T <harini.t@amd.com>
Tested-by: Harini T <harini.t@amd.com>
Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Acked-by: Michal Simek <michal.simek@amd.com>
Link: https://patch.msgid.link/20260122-zynqmp-rtc-updates-v4-2-d4edb966b499@vaisala.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Author: vai-tomme

drivers/rtc/rtc-zynqmp.c

@@ -349,6 +349,11 @@ static int xlnx_rtc_probe(struct platform_device *pdev)
 		xrtcdev->freq--;
 	}
 
+	if (xrtcdev->freq > RTC_TICK_MASK) {
+		dev_err(&pdev->dev, "Invalid RTC calibration value\n");
+		return -EINVAL;
+	}
+
 	ret = readl(xrtcdev->reg_base + RTC_CALIB_RD);
 	if (!ret)
 		writel(xrtcdev->freq, (xrtcdev->reg_base + RTC_CALIB_WR));