| Message ID | 20210830145934.11024-1-florian.boor@kernelconcepts.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | iio: adc: ad799x: Implement selecting external reference voltage input on AD7991, AD7995 and AD7999. | expand |
On Mon, 30 Aug 2021 16:59:34 +0200 Florian Boor <florian.boor@kernelconcepts.de> wrote: > Make use of the AD7991_REF_SEL bit and support using the external > reference voltage by setting the 'vref-external' property in devicetree. > > Signed-off-by: Florian Boor <florian.boor@kernelconcepts.de> Normal convention on this (not helped here by the complete lack of a binding document for this device) would be that the driver would use the external vref is vref-supply is present. Currently the driver uses devm_regulator_get(). In this case it should be using devm_regulator_get_optional() as that will avoid a 'fake' regulator being provided. The driver will need a few changes to handle the possible error return from that call, but it shouldn't be too complicated. If you are willing it would be great to have a binding description for this driver. I'm no sure how it has slipped through the net for so long! Jonathan > --- > drivers/iio/adc/ad799x.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/adc/ad799x.c b/drivers/iio/adc/ad799x.c > index 18bf8386d50a..3ae7ec72caa3 100644 > --- a/drivers/iio/adc/ad799x.c > +++ b/drivers/iio/adc/ad799x.c > @@ -770,6 +770,7 @@ static int ad799x_probe(struct i2c_client *client, > const struct i2c_device_id *id) > { > int ret; > + int extra_config = 0; > struct ad799x_state *st; > struct iio_dev *indio_dev; > const struct ad799x_chip_info *chip_info = > @@ -806,6 +807,17 @@ static int ad799x_probe(struct i2c_client *client, > if (ret) > goto error_disable_reg; > > + > + /* allow to use external reference voltage */ > + if ((st->id == ad7991) || (st->id == ad7995) || (st->id == ad7999)) { > + unsigned int vref_external = 0; > + of_property_read_u32(client->dev.of_node, "vref-external", > + &vref_external); > + > + if (vref_external) > + extra_config |= AD7991_REF_SEL; > + } > + > st->client = client; > > indio_dev->name = id->name; > @@ -815,7 +827,7 @@ static int ad799x_probe(struct i2c_client *client, > indio_dev->channels = st->chip_config->channel; > indio_dev->num_channels = chip_info->num_channels; > > - ret = ad799x_update_config(st, st->chip_config->default_config); > + ret = ad799x_update_config(st, st->chip_config->default_config | extra_config); > if (ret) > goto error_disable_vref; >
On Mon, Aug 30, 2021 at 6:38 PM Florian Boor <florian.boor@kernelconcepts.de> wrote: > > Make use of the AD7991_REF_SEL bit and support using the external > reference voltage by setting the 'vref-external' property in devicetree. ... > + of_property_read_u32(client->dev.of_node, "vref-external", > + &vref_external); Please, use device property API instead in the code you are submitting to IIO.
Hi, On 05.09.21 13:26, Jonathan Cameron wrote: > On Mon, 30 Aug 2021 16:59:34 +0200 > Normal convention on this (not helped here by the complete lack of > a binding document for this device) would be that the driver would > use the external vref is vref-supply is present. > > Currently the driver uses devm_regulator_get(). In this case it > should be using devm_regulator_get_optional() as that will avoid a > 'fake' regulator being provided. okay right - in this case we could get rid of the additional setting and only if there is no vref-supply provided we need to get a dummy. > The driver will need a few changes to handle the possible error return > from that call, but it shouldn't be too complicated. I'll send an updated patch... > If you are willing it would be great to have a binding description for > this driver. I'm no sure how it has slipped through the net for so long! I'll add this as well. Greetings Florian
diff --git a/drivers/iio/adc/ad799x.c b/drivers/iio/adc/ad799x.c index 18bf8386d50a..3ae7ec72caa3 100644 --- a/drivers/iio/adc/ad799x.c +++ b/drivers/iio/adc/ad799x.c @@ -770,6 +770,7 @@ static int ad799x_probe(struct i2c_client *client, const struct i2c_device_id *id) { int ret; + int extra_config = 0; struct ad799x_state *st; struct iio_dev *indio_dev; const struct ad799x_chip_info *chip_info = @@ -806,6 +807,17 @@ static int ad799x_probe(struct i2c_client *client, if (ret) goto error_disable_reg; + + /* allow to use external reference voltage */ + if ((st->id == ad7991) || (st->id == ad7995) || (st->id == ad7999)) { + unsigned int vref_external = 0; + of_property_read_u32(client->dev.of_node, "vref-external", + &vref_external); + + if (vref_external) + extra_config |= AD7991_REF_SEL; + } + st->client = client; indio_dev->name = id->name; @@ -815,7 +827,7 @@ static int ad799x_probe(struct i2c_client *client, indio_dev->channels = st->chip_config->channel; indio_dev->num_channels = chip_info->num_channels; - ret = ad799x_update_config(st, st->chip_config->default_config); + ret = ad799x_update_config(st, st->chip_config->default_config | extra_config); if (ret) goto error_disable_vref;
Make use of the AD7991_REF_SEL bit and support using the external reference voltage by setting the 'vref-external' property in devicetree. Signed-off-by: Florian Boor <florian.boor@kernelconcepts.de> --- drivers/iio/adc/ad799x.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)