diff options
| author | Andrey Smirnov <andrew.smirnov@gmail.com> | 2016-04-03 18:06:33 -0700 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2016-04-05 08:42:54 +0200 |
| commit | 750f53c399143d35b4cf2b460cdead72d6f7cf9f (patch) | |
| tree | aa8b901512d3636dd81296188b10563148cc8905 | |
| parent | 6587b56678354f69f9b90edbe7b0dec2f6de5349 (diff) | |
| download | barebox-750f53c399143d35b4cf2b460cdead72d6f7cf9f.tar.gz barebox-750f53c399143d35b4cf2b460cdead72d6f7cf9f.tar.xz | |
ds1307: Configure ds1341 for lowest power mode
Empirical observations show that configuring INTCN=1, ECLK=0, EGFIL=0,
DOSF=1 on DS1341 put the chip in the mode where it draws the least
amount fo current.
Add code to configure DS1341 in such a way in case Barebox is the last
code that runs on the processor before being shut down.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
| -rw-r--r-- | drivers/rtc/rtc-ds1307.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index a1cfed6795..726586af4a 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -68,6 +68,7 @@ enum ds_type { #define DS1337_REG_CONTROL 0x0e # define DS1337_BIT_nEOSC 0x80 # define DS1339_BIT_BBSQI 0x20 +# define DS1341_BIT_EGFIL 0x20 # define DS3231_BIT_BBSQW 0x40 /* same as BBSQI */ # define DS1337_BIT_RS2 0x10 # define DS1337_BIT_RS1 0x08 @@ -83,6 +84,7 @@ enum ds_type { # define DS1340_BIT_OSF 0x80 #define DS1337_REG_STATUS 0x0f # define DS1337_BIT_OSF 0x80 +# define DS1341_BIT_DOSF 0x40 # define DS1341_BIT_ECLK 0x04 # define DS1337_BIT_A2I 0x02 # define DS1337_BIT_A1I 0x01 @@ -333,12 +335,22 @@ static int ds1307_probe(struct device_d *dev) i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ds1307->regs[0]); - /* - For the above to be true, DS1341 also has to have - ECLK bit set to 0 - */ if (ds1307->type == ds_1341) { + /* + * For the above to be true, DS1341 also has to have + * ECLK bit set to 0 + */ ds1307->regs[1] &= ~DS1341_BIT_ECLK; + + /* + * Let's set additionale RTC bits to + * facilitate maximum power saving. + */ + ds1307->regs[0] |= DS1341_BIT_DOSF; + ds1307->regs[0] &= ~DS1341_BIT_EGFIL; + + i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, + ds1307->regs[0]); i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, ds1307->regs[1]); } |