diff options
Diffstat (limited to 'drivers/rtc')
| -rw-r--r-- | drivers/rtc/rtc-pcf85063.c | 47 |
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, ®s[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; } |