diff options
| author | Mylène Josserand | 2016-03-29 08:56:05 +0200 |
|---|---|---|
| committer | Alexandre Belloni | 2016-05-20 12:33:51 +0200 |
| commit | 05a7f27a889f1635b7b7d5b051b17cacb25267fa (patch) | |
| tree | 4198df3102566ceec1e0d65052be1179aa610ba1 /drivers/rtc | |
| parent | 3726a21833c9c96255735bddb5dacc8eacbff3ef (diff) | |
rtc: m41t80: handle oscillator failure bit
Handle the Oscillator Failure (OF) bit on each read of date-time.
If the OF is set, an error is returned (-EINVAL) instead of the date-time.
The OF bit is cleared each time the date is set.
Signed-off-by: Mylène Josserand <mylene.josserand@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc')
| -rw-r--r-- | drivers/rtc/rtc-m41t80.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c index 5706e99853a3..d1bf93a87200 100644 --- a/drivers/rtc/rtc-m41t80.c +++ b/drivers/rtc/rtc-m41t80.c @@ -56,6 +56,7 @@ #define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */ #define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */ #define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */ +#define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */ #define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */ #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */ #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */ @@ -134,7 +135,16 @@ static int m41t80_get_datetime(struct i2c_client *client, struct rtc_time *tm) { unsigned char buf[8]; - int err; + int err, flags; + + flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); + if (flags < 0) + return flags; + + if (flags & M41T80_FLAGS_OF) { + dev_err(&client->dev, "Oscillator failure, data is invalid.\n"); + return -EINVAL; + } err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC, sizeof(buf), buf); @@ -159,7 +169,7 @@ static int m41t80_get_datetime(struct i2c_client *client, static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) { unsigned char buf[8]; - int err; + int err, flags; if (tm->tm_year < 100 || tm->tm_year > 199) return -EINVAL; @@ -180,6 +190,17 @@ static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) return err; } + /* Clear the OF bit of Flags Register */ + flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); + if (flags < 0) + return flags; + + if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, + flags & ~M41T80_FLAGS_OF)) { + dev_err(&client->dev, "Unable to write flags register\n"); + return -EIO; + } + return err; } |