linux-kernel - [PATCH] rtc: ds1307: check for oscillator fault on ds1388

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Message-Id: <20191107011245.26796-1-chris.packham@alliedtelesis.co.nz>
Date:   Thu,  7 Nov 2019 14:12:45 +1300
From:   Chris Packham <chris.packham@...iedtelesis.co.nz>
To:     a.zummo@...ertech.it, alexandre.belloni@...tlin.com
Cc:     linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org,
        John Collis <john.collis@...iedtelesis.co.nz>,
        Chris Packham <chris.packham@...iedtelesis.co.nz>
Subject: [PATCH] rtc: ds1307: check for oscillator fault on ds1388

Ensure that the oscillator is running and check the OSF bit for the
ds1388 variant. The FLAG and CONTROL registers are at a different
location to the other supported RTCs so this requires an extra case in
the existing switch statement.

Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
---
 drivers/rtc/rtc-ds1307.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 1f7e8aefc1eb..865c06347d0a 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -101,6 +101,10 @@ enum ds_type {
 #	define DS1337_BIT_A2I		0x02
 #	define DS1337_BIT_A1I		0x01
 #define DS1339_REG_ALARM1_SECS	0x07
+#define DS1388_REG_FLAG		0x0b
+#	define DS1388_BIT_OSF		0x80
+#define DS1388_REG_CONTROL	0x0c
+#	define DS1388_BIT_nEOSC		0x80
 
 #define DS13XX_TRICKLE_CHARGER_MAGIC	0xa0
 
@@ -1688,6 +1692,26 @@ static int ds1307_probe(struct i2c_client *client,
 		}
 		break;
 
+	case ds_1388:
+		err = regmap_bulk_read(ds1307->regmap, DS1388_REG_FLAG,
+				       regs, 2);
+		if (err) {
+			dev_dbg(ds1307->dev, "read error %d\n", err);
+			goto exit;
+		}
+
+		if (regs[1] & DS1388_BIT_nEOSC) {
+			regmap_write(ds1307->regmap, DS1388_REG_CONTROL,
+				     regs[1] & ~DS1388_BIT_nEOSC);
+		}
+
+		if (regs[0] & DS1388_BIT_OSF) {
+			regmap_write(ds1307->regmap, DS1388_REG_FLAG,
+				     regs[0]  & ~DS1388_BIT_OSF);
+			dev_warn(ds1307->dev, "SET TIME!\n");
+		}
+		break;
+
 	case rx_8025:
 		err = regmap_bulk_read(ds1307->regmap,
 				       RX8025_REG_CTRL1 << 4 | 0x08, regs, 2);
-- 
2.24.0