linux-kernel - [PATCH 3/4] rtc: mpc5121: set range

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Date:   Fri,  6 Mar 2020 08:44:02 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] rtc: mpc5121: set range

The datasheet states that 4052 is the maximum value for year. However, the
mpc5121 read_time and set_time function abuse the target time register
instead of using the broken down time so it is limited to 2106.

Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
 drivers/rtc/rtc-mpc5121.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/rtc/rtc-mpc5121.c b/drivers/rtc/rtc-mpc5121.c
index 845212fd1e33..5507f1847f7c 100644
--- a/drivers/rtc/rtc-mpc5121.c
+++ b/drivers/rtc/rtc-mpc5121.c
@@ -352,6 +352,8 @@ static int mpc5121_rtc_probe(struct platform_device *op)
 
 	rtc->rtc->ops = &mpc5200_rtc_ops;
 	rtc->rtc->uie_unsupported = 1;
+	rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
+	rtc->rtc->range_max = 65733206399ULL; /* 4052-12-31 23:59:59 */
 
 	if (of_device_is_compatible(op->dev.of_node, "fsl,mpc5121-rtc")) {
 		u32 ka;
@@ -362,6 +364,13 @@ static int mpc5121_rtc_probe(struct platform_device *op)
 			out_be32(&rtc->regs->keep_alive, ka);
 		}
 		rtc->rtc->ops = &mpc5121_rtc_ops;
+		/*
+		 * This is a limitation of the driver that abuses the target
+		 * time register, the actual maximum year for the mpc5121 is
+		 * also 4052.
+		 */
+		rtc->rtc->range_min = 0;
+		rtc->rtc->range_max = U32_MAX;
 	}
 
 	err = rtc_register_device(rtc->rtc);
-- 
2.24.1