If a label is defined in the device tree for this channel add that
to the channel specific attributes. This is useful for userspace to
be able to identify an individual channel.
Signed-off-by: Cristian Pop <[email protected]>
---
Changes in V6:
- Fix indentation
- Check for "read_label callback" inside "iio_device_add_channel_label"
drivers/iio/industrialio-core.c | 40 +++++++++++++++++++++++++++++++++
include/linux/iio/iio.h | 6 +++++
2 files changed, 46 insertions(+)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 6e388293c828..b577fff35641 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -669,6 +669,19 @@ ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
}
EXPORT_SYMBOL_GPL(iio_format_value);
+static ssize_t iio_read_channel_label(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+ if (!indio_dev->info->read_label)
+ return -EINVAL;
+
+ return indio_dev->info->read_label(indio_dev, this_attr->c, buf);
+}
+
static ssize_t iio_read_channel_info(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -1137,6 +1150,28 @@ int __iio_add_chan_devattr(const char *postfix,
return ret;
}
+static int iio_device_add_channel_label(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan)
+{
+ int ret;
+
+ if (!indio_dev->info->read_label)
+ return 0;
+
+ ret = __iio_add_chan_devattr("label",
+ chan,
+ &iio_read_channel_label,
+ NULL,
+ 0,
+ IIO_SEPARATE,
+ &indio_dev->dev,
+ &indio_dev->channel_attr_list);
+ if (ret < 0)
+ return ret;
+
+ return 1;
+}
+
static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
enum iio_shared_by shared_by,
@@ -1270,6 +1305,11 @@ static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
return ret;
attrcount += ret;
+ ret = iio_device_add_channel_label(indio_dev, chan);
+ if (ret < 0)
+ return ret;
+ attrcount += ret;
+
if (chan->ext_info) {
unsigned int i = 0;
for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 2e45b3ceafa7..9a3cf4815148 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -362,6 +362,8 @@ struct iio_trigger; /* forward declaration */
* and max. For lists, all possible values are enumerated.
* @write_raw: function to write a value to the device.
* Parameters are the same as for read_raw.
+ * @read_label: function to request label name for a specified label,
+ * for better channel identification.
* @write_raw_get_fmt: callback function to query the expected
* format/precision. If not set by the driver, write_raw
* returns IIO_VAL_INT_PLUS_MICRO.
@@ -420,6 +422,10 @@ struct iio_info {
int val2,
long mask);
+ int (*read_label)(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ char *label);
+
int (*write_raw_get_fmt)(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
long mask);
--
2.17.1
For better identification of the channels.
Signed-off-by: Cristian Pop <[email protected]>
---
Changes in v6:
- Use static variable for labels
drivers/iio/adc/ad7768-1.c | 41 ++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index 0e93b0766eb4..5c0cbee03230 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[ARRAY_SIZE(ad7768_channels)];
/*
* 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,
};
@@ -532,6 +542,33 @@ 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;
+
+ 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;
@@ -604,6 +641,10 @@ 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,
--
2.17.1
On Mon, 21 Sep 2020 16:30:17 +0300
Cristian Pop <[email protected]> wrote:
> If a label is defined in the device tree for this channel add that
> to the channel specific attributes. This is useful for userspace to
> be able to identify an individual channel.
>
> Signed-off-by: Cristian Pop <[email protected]>
Hi Cristian,
Looks good to me as does patch 3. Just the docs and DT to tidy up now.
Thanks,
Jonathan
> ---
> Changes in V6:
> - Fix indentation
> - Check for "read_label callback" inside "iio_device_add_channel_label"
>
> drivers/iio/industrialio-core.c | 40 +++++++++++++++++++++++++++++++++
> include/linux/iio/iio.h | 6 +++++
> 2 files changed, 46 insertions(+)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 6e388293c828..b577fff35641 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -669,6 +669,19 @@ ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
> }
> EXPORT_SYMBOL_GPL(iio_format_value);
>
> +static ssize_t iio_read_channel_label(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +
> + if (!indio_dev->info->read_label)
> + return -EINVAL;
> +
> + return indio_dev->info->read_label(indio_dev, this_attr->c, buf);
> +}
> +
> static ssize_t iio_read_channel_info(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> @@ -1137,6 +1150,28 @@ int __iio_add_chan_devattr(const char *postfix,
> return ret;
> }
>
> +static int iio_device_add_channel_label(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan)
> +{
> + int ret;
> +
> + if (!indio_dev->info->read_label)
> + return 0;
> +
> + ret = __iio_add_chan_devattr("label",
> + chan,
> + &iio_read_channel_label,
> + NULL,
> + 0,
> + IIO_SEPARATE,
> + &indio_dev->dev,
> + &indio_dev->channel_attr_list);
> + if (ret < 0)
> + return ret;
> +
> + return 1;
> +}
> +
> static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan,
> enum iio_shared_by shared_by,
> @@ -1270,6 +1305,11 @@ static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
> return ret;
> attrcount += ret;
>
> + ret = iio_device_add_channel_label(indio_dev, chan);
> + if (ret < 0)
> + return ret;
> + attrcount += ret;
> +
> if (chan->ext_info) {
> unsigned int i = 0;
> for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index 2e45b3ceafa7..9a3cf4815148 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -362,6 +362,8 @@ struct iio_trigger; /* forward declaration */
> * and max. For lists, all possible values are enumerated.
> * @write_raw: function to write a value to the device.
> * Parameters are the same as for read_raw.
> + * @read_label: function to request label name for a specified label,
> + * for better channel identification.
> * @write_raw_get_fmt: callback function to query the expected
> * format/precision. If not set by the driver, write_raw
> * returns IIO_VAL_INT_PLUS_MICRO.
> @@ -420,6 +422,10 @@ struct iio_info {
> int val2,
> long mask);
>
> + int (*read_label)(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + char *label);
> +
> int (*write_raw_get_fmt)(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan,
> long mask);