On Sat, 19 Sep 2020 16:14:40 +0100
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> On Fri, 18 Sep 2020 12:33:56 +0300
> Cristian Pop <cristian.pop@xxxxxxxxxx> wrote:
>
> > This is a demo usage of new "label" attribute for channel.
> While I can see this is a demo in someways, I assume we also have
> a valid usecase for doing this beyond as a demo!
>
> So perhaps rephrase that intro.
I also forgot to say that you also need to update the dt-bindings
for this driver. I've just committed a patch converting them to yaml
so work on top of that.
Thanks
Jonathan
>
> >
> > Signed-off-by: Cristian Pop <cristian.pop@xxxxxxxxxx>
> > ---
> > Changes in V5:
> > Create a separate patch file for this commit
> > drivers/iio/adc/ad7768-1.c | 49 ++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 49 insertions(+)
> >
> > diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
> > index 0d132708c429..5ca9f9febb5a 100644
> > --- a/drivers/iio/adc/ad7768-1.c
> > +++ b/drivers/iio/adc/ad7768-1.c
> > @@ -161,6 +161,7 @@ struct ad7768_state {
> > struct completion completion;
> > struct iio_trigger *trig;
> > struct gpio_desc *gpio_sync_in;
> > + const char **labels;
> > /*
> > * DMA (thus cache coherency maintenance) requires the
> > * transfer buffers to live in their own cache lines.
> > @@ -407,6 +408,14 @@ static int ad7768_write_raw(struct iio_dev *indio_dev,
> > }
> > }
> >
> > +static int ad7768_read_label(struct iio_dev *indio_dev,
> > + const struct iio_chan_spec *chan, char *label)
> > +{
> > + struct ad7768_state *st = iio_priv(indio_dev);
> > +
> > + return sprintf(label, "%s\n", st->labels[chan->channel]);
> > +}
> > +
> > static struct attribute *ad7768_attributes[] = {
> > &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
> > NULL
> > @@ -420,6 +429,7 @@ static const struct iio_info ad7768_info = {
> > .attrs = &ad7768_group,
> > .read_raw = &ad7768_read_raw,
> > .write_raw = &ad7768_write_raw,
> > + .read_label = ad7768_read_label,
> > .debugfs_reg_access = &ad7768_reg_access,
> > };
> >
> > @@ -538,6 +548,41 @@ static void ad7768_clk_disable(void *data)
> > clk_disable_unprepare(st->mclk);
> > }
> >
> > +static int ad7768_set_channel_label(struct iio_dev *indio_dev,
> > + int num_channels)
> > +{
> > + struct ad7768_state *st = iio_priv(indio_dev);
> > + struct device *device = indio_dev->dev.parent;
> > + struct fwnode_handle *fwnode;
> > + struct fwnode_handle *child;
> > + const char *label;
> > + int crt_ch = 0;
> > +
> > + st->labels = devm_kcalloc(indio_dev->dev.parent,
> > + num_channels,
> > + sizeof(**st->labels),
>
> I think that ends up being the size of a single character which isn't
> the intent. I assume aim is a suitable sized array of pointers to
> strings which we will fill in later?
>
> If so we can probably just use a static sized array as the maximum
> number of channels is well constrained. In this particular driver
> that is 1 I think!
>
> > + GFP_KERNEL);
> > +
> > + if (!st->labels)
> > + return -ENOMEM;
> > +
> > + fwnode = dev_fwnode(device);
> > + fwnode_for_each_child_node(fwnode, child) {
> > + if (fwnode_property_read_u32(child, "reg", &crt_ch))
> > + continue;
> > +
> > + if (crt_ch >= num_channels)
> > + continue;
> > +
> > + if (fwnode_property_read_string(child, "label", &label))
> > + continue;
> > +
> > + st->labels[crt_ch] = label;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static int ad7768_probe(struct spi_device *spi)
> > {
> > struct ad7768_state *st;
> > @@ -611,6 +656,10 @@ static int ad7768_probe(struct spi_device *spi)
> >
> > init_completion(&st->completion);
> >
> > + ret = ad7768_set_channel_label(indio_dev, ARRAY_SIZE(ad7768_channels));
> > + if (ret)
> > + return ret;
> > +
> > ret = devm_request_irq(&spi->dev, spi->irq,
> > &ad7768_interrupt,
> > IRQF_TRIGGER_RISING | IRQF_ONESHOT,
>
