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-rw-r--r--drivers/rtc/rtc-pcf85063.c47
1 files changed, 38 insertions, 9 deletions
diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index 437638eb68a7..efb0a08ac117 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
@@ -55,6 +65,22 @@ static int pcf85063_stop_clock(struct i2c_client *client, u8 *ctrl1)
return 0;
}
+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;
@@ -94,7 +120,8 @@ 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;
@@ -103,7 +130,7 @@ static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
* 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;
@@ -125,13 +152,6 @@ static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
/* 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;
-
/* write all registers at once */
rc = i2c_smbus_write_i2c_block_data(client, PCF85063_REG_SC,
sizeof(regs), regs);
@@ -140,6 +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;
}