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path: root/drivers/rtc/rtc-pcf85063.c
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Diffstat (limited to 'drivers/rtc/rtc-pcf85063.c')
-rw-r--r--drivers/rtc/rtc-pcf85063.c59
1 files changed, 43 insertions, 16 deletions
diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index e8ddbb359..efb0a08ac 100644
--- a/drivers/rtc/rtc-pcf85063.c
+++ b/drivers/rtc/rtc-pcf85063.c
@@ -16,6 +16,16 @@
#include <linux/rtc.h>
#include <linux/module.h>
+/*
+ * Information for this driver was pulled from the following datasheets.
+ *
+ * http://www.nxp.com/documents/data_sheet/PCF85063A.pdf
+ * http://www.nxp.com/documents/data_sheet/PCF85063TP.pdf
+ *
+ * PCF85063A -- Rev. 6 — 18 November 2015
+ * PCF85063TP -- Rev. 4 — 6 May 2015
+*/
+
#define PCF85063_REG_CTRL1 0x00 /* status */
#define PCF85063_REG_CTRL1_STOP BIT(5)
#define PCF85063_REG_CTRL2 0x01
@@ -55,10 +65,22 @@ static int pcf85063_stop_clock(struct i2c_client *client, u8 *ctrl1)
return 0;
}
-/*
- * In the routines that deal directly with the pcf85063 hardware, we use
- * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
- */
+static int pcf85063_start_clock(struct i2c_client *client, u8 ctrl1)
+{
+ s32 ret;
+
+ /* start the clock */
+ ctrl1 &= PCF85063_REG_CTRL1_STOP;
+
+ ret = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, ctrl1);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failing to start the clock\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
int rc;
@@ -90,8 +112,7 @@ static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm)
tm->tm_wday = regs[4] & 0x07;
tm->tm_mon = bcd2bin(regs[5] & 0x1F) - 1; /* rtc mn 1-12 */
tm->tm_year = bcd2bin(regs[6]);
- if (tm->tm_year < 70)
- tm->tm_year += 100; /* assume we are in 1970...2069 */
+ tm->tm_year += 100;
return rtc_valid_tm(tm);
}
@@ -99,13 +120,17 @@ static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm)
static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
int rc;
- u8 regs[8];
+ u8 regs[7];
+ u8 ctrl1;
+
+ if ((tm->tm_year < 100) || (tm->tm_year > 199))
+ return -EINVAL;
/*
* to accurately set the time, reset the divider chain and keep it in
* reset state until all time/date registers are written
*/
- rc = pcf85063_stop_clock(client, &regs[7]);
+ rc = pcf85063_stop_clock(client, &ctrl1);
if (rc != 0)
return rc;
@@ -125,14 +150,7 @@ static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
regs[5] = bin2bcd(tm->tm_mon + 1);
/* year and century */
- regs[6] = bin2bcd(tm->tm_year % 100);
-
- /*
- * after all time/date registers are written, let the 'address auto
- * increment' feature wrap around and write register CTRL1 to re-enable
- * the clock divider chain again
- */
- regs[7] &= ~PCF85063_REG_CTRL1_STOP;
+ regs[6] = bin2bcd(tm->tm_year - 100);
/* write all registers at once */
rc = i2c_smbus_write_i2c_block_data(client, PCF85063_REG_SC,
@@ -142,6 +160,15 @@ static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
return rc;
}
+ /*
+ * Write the control register as a separate action since the size of
+ * the register space is different between the PCF85063TP and
+ * PCF85063A devices. The rollover point can not be used.
+ */
+ rc = pcf85063_start_clock(client, ctrl1);
+ if (rc != 0)
+ return rc;
+
return 0;
}