On Fri, 18 Sep 2020 12:33:56 +0300 Cristian Pop <[email protected]> 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. > > Signed-off-by: Cristian Pop <[email protected]> > --- > 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,
