On Sun, 10 Mar 2019 12:31:16 +0100 (CET) Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx> wrote: > > +Cc Peter. > > > > When issuing the write DAC register and write eeprom command, the two > > > powerdown bits (PD0 and PD1) are assumed by the chip to be present in > > > the bytes sent. Leaving them at 0 implies "powerdown disabled" which is > > > a different state that the current one. By adding the current state of > > > the powerdown in the i2c write, the chip will correctly power-on exactly > > > like as it is at the moment of store_eeprom call. > > > > > > This is documented in MCP4725's datasheet, FIGURE 6-2: "Write Commands > > > for DAC Input Register and EEPROM" and MCP4726's datasheet, FIGURE 6-3: > > > "Write All Memory Command". > > > > > > Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@xxxxxxxxx> > > > sounds fine to me, but I'd like to give Peter a chance to comment. > > Give me a poke if it turns out Peter is busy and doesn't get back > > to us in a week or two. > > I'd suggest whitespace around the + operator, otherwise > Good point, added... > Acked-by: Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx> Applied to the fixes-togreg branch of iio.git and marked for stable. It's not super critical as fixes go but things are currently not quite doing what someone might expect. Thanks, Jonathan > > > > --- > > > drivers/iio/dac/mcp4725.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c > > > index 6ab1f23e5a79..97bb350d1e77 100644 > > > --- a/drivers/iio/dac/mcp4725.c > > > +++ b/drivers/iio/dac/mcp4725.c > > > @@ -98,6 +98,7 @@ static ssize_t mcp4725_store_eeprom(struct device *dev, > > > > > > inoutbuf[0] = 0x60; /* write EEPROM */ > > > inoutbuf[0] |= data->ref_mode << 3; > > > + inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode+1) << 1) : 0; > > > inoutbuf[1] = data->dac_value >> 4; > > > inoutbuf[2] = (data->dac_value & 0xf) << 4; > > > > > >
