On Mon, 2026-05-11 at 14:09 +0200, Alexander Feilke wrote: > From: Alexander Feilke <[email protected]> > > Use previously ignored quartz-load-femtofarads property from device tree > to set load capacitance. If missing, leave the device unconfigured > as a default might have been set. force_cap is left out for now but > can be retrofitted in the future as there may be different hardware > without the 12.500pF flag. > > Signed-off-by: Alexander Feilke <[email protected]>
Reviewed-by: Alexander Sverdlin <[email protected]> > --- > drivers/rtc/pcf85063.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/drivers/rtc/pcf85063.c b/drivers/rtc/pcf85063.c > index 0b336b8c5ee..107e8b4d4c8 100644 > --- a/drivers/rtc/pcf85063.c > +++ b/drivers/rtc/pcf85063.c > @@ -140,6 +140,30 @@ static int pcf85063_write(struct udevice *dev, unsigned > int offset, > return dm_i2c_write(dev, offset, buf, len); > } > > +static int pcf85063_load_capacitance(struct udevice *dev) > +{ > + u32 load = 7000; > + u8 reg = 0; > + > + if (ofnode_read_u32(dev_ofnode(dev), "quartz-load-femtofarads", &load)) > + return 0; > + > + switch (load) { > + default: > + dev_warn(dev, "Unknown quartz-load-femtofarads value: %d. > Assuming 7000", > + load); > + fallthrough; > + case 7000: > + break; > + case 12500: > + reg = PCF85063_REG_CTRL1_CAP_SEL; > + break; > + } > + > + return dm_i2c_reg_clrset(dev, PCF85063_REG_CTRL1, > + PCF85063_REG_CTRL1_CAP_SEL, reg); > +} > + > static const struct rtc_ops pcf85063_rtc_ops = { > .get = pcf85063_get_time, > .set = pcf85063_set_time, > @@ -150,8 +174,22 @@ static const struct rtc_ops pcf85063_rtc_ops = { > > static int pcf85063_probe(struct udevice *dev) > { > + u8 tmp; > + int err; > + > i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS | > DM_I2C_CHIP_WR_ADDRESS); > > + err = dm_i2c_read(dev, PCF85063_REG_SC, &tmp, sizeof(tmp)); > + if (err) { > + dev_err(dev, "RTC chip is not present\n"); > + return err; > + } > + > + err = pcf85063_load_capacitance(dev); > + if (err < 0) > + dev_warn(dev, "failed to set xtal load capacitance: %d", > + err); > + > return 0; > } > -- Alexander Sverdlin Siemens AG www.siemens.com
