On 08/01/2019 19:54:13+0100, Sam Ravnborg wrote: > Add support for specifying the xtal load capacitance in the DT node. > The pcf8523 supports xtal load capacitance of 7pF or 12.5pF. > If the rtc has the wrong configuration the time will > drift several hours/week. > > The driver use the default value 12.5pF. > > The DT may specify either 7000fF or 12500fF. > (The DT uses femto Farad to avoid decimal numbers). > Other values are warned and the driver uses the default value. > > Signed-off-by: Sam Ravnborg <[email protected]> > Cc: Alessandro Zummo <[email protected]> > Cc: Alexandre Belloni <[email protected]> > --- > drivers/rtc/rtc-pcf8523.c | 28 ++++++++++++++++++++-------- > 1 file changed, 20 insertions(+), 8 deletions(-) > > diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c > index 3fcd2cbafc84..dbbc00b53b50 100644 > --- a/drivers/rtc/rtc-pcf8523.c > +++ b/drivers/rtc/rtc-pcf8523.c > @@ -97,8 +97,9 @@ static int pcf8523_voltage_low(struct i2c_client *client) > return !!(value & REG_CONTROL3_BLF); > } > > -static int pcf8523_select_capacitance(struct i2c_client *client, bool high) > +static int pcf8523_load_capacitance(struct i2c_client *client) > { > + u32 load; > u8 value; > int err; > > @@ -106,14 +107,24 @@ static int pcf8523_select_capacitance(struct i2c_client > *client, bool high) > if (err < 0) > return err; > > - if (!high) > - value &= ~REG_CONTROL1_CAP_SEL; > - else > + load = 12500; > + of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads", > + &load); > + > + switch (load) { > + default: > + dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: > %d. Assuming 12500", > + load);
This alignment is not correct, as you will be respinning for the DT doc, please fix ;) > + /* fall through */ > + case 12500: > value |= REG_CONTROL1_CAP_SEL; > + break; > + case 7000: > + value &= ~REG_CONTROL1_CAP_SEL; > + break; > + } > > err = pcf8523_write(client, REG_CONTROL1, value); > - if (err < 0) > - return err; > > return err; > } > @@ -347,9 +358,10 @@ static int pcf8523_probe(struct i2c_client *client, > if (!pcf) > return -ENOMEM; > > - err = pcf8523_select_capacitance(client, true); > + err = pcf8523_load_capacitance(client); > if (err < 0) > - return err; > + dev_warn(&client->dev, "failed to set xtal load capacitance: > %d", > + err); Ditto > > err = pcf8523_set_pm(client, 0); > if (err < 0) > -- > 2.12.0 > -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
