The new devm_iio_adc_device_alloc_chaninfo() -helper is intended to help
drivers avoid open-coding the for_each_node -loop for getting the
channel IDs. The helper provides standard way to detect the ADC channel
nodes (by the node name), and a standard way to convert the "reg",
"diff-channels", "single-channel" and the "common-mode-channel" to
channel identification numbers used in the struct iio_chan_spec.
Furthermore, the helper checks the ID is in range of 0 ... num-channels.
The original driver treated all found child nodes as channel nodes. The
new helper requires channel nodes to be named channel[@N]. This should
help avoid problems with devices which may contain also other but ADC
child nodes. Quick grep from arch/* with the rzg2l_adc's compatible
string didn't reveal any in-tree .dts with channel nodes named
othervice. Also, same grep shows all the .dts seem to have channel IDs
between 0..num of channels.
Use the new helper.
Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
---
Revision history:
v2 => v3:
- New patch
I picked the rzg2l_adc in this series because it has a straightforward
approach for populating the struct iio_chan_spec. Only other member
in the stuct besides the .channel, which can't use a 'template' -data,
is the .datasheet_name. This makes the rzg2l_adc well suited for example
user of this new helper. I hope this patch helps to evaluate whether these
helpers are worth the hassle.
The change is compile tested only!! Testing before applying is highly
appreciated (as always!).
---
drivers/iio/adc/rzg2l_adc.c | 41 ++++++++++++++++++-------------------
1 file changed, 20 insertions(+), 21 deletions(-)
diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
index cd3a7e46ea53..3e1c74019785 100644
--- a/drivers/iio/adc/rzg2l_adc.c
+++ b/drivers/iio/adc/rzg2l_adc.c
@@ -11,6 +11,7 @@
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
+#include <linux/iio/adc-helpers.h>
#include <linux/iio/iio.h>
#include <linux/interrupt.h>
#include <linux/io.h>
@@ -299,20 +300,34 @@ static irqreturn_t rzg2l_adc_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static const struct iio_chan_spec rzg2l_adc_chan_template = {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+};
+
+static const struct iio_adc_props rzg2l_adc_chan_props = {
+ .required = IIO_ADC_CHAN_PROP_TYPE_REG,
+};
+
static int rzg2l_adc_parse_properties(struct platform_device *pdev, struct rzg2l_adc *adc)
{
struct iio_chan_spec *chan_array;
struct rzg2l_adc_data *data;
- unsigned int channel;
int num_channels;
- int ret;
u8 i;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
- num_channels = device_get_child_node_count(&pdev->dev);
+ num_channels = devm_iio_adc_device_alloc_chaninfo(&pdev->dev,
+ &rzg2l_adc_chan_template, &chan_array,
+ &rzg2l_adc_chan_props);
+
+ if (num_channels < 0)
+ return num_channels;
+
if (!num_channels) {
dev_err(&pdev->dev, "no channel children\n");
return -ENODEV;
@@ -323,26 +338,10 @@ static int rzg2l_adc_parse_properties(struct platform_device *pdev, struct rzg2l
return -EINVAL;
}
- chan_array = devm_kcalloc(&pdev->dev, num_channels, sizeof(*chan_array),
- GFP_KERNEL);
- if (!chan_array)
- return -ENOMEM;
-
- i = 0;
- device_for_each_child_node_scoped(&pdev->dev, fwnode) {
- ret = fwnode_property_read_u32(fwnode, "reg", &channel);
- if (ret)
- return ret;
-
- if (channel >= RZG2L_ADC_MAX_CHANNELS)
- return -EINVAL;
+ for (i = 0; i < num_channels; i++) {
+ int channel = chan_array[i].channel;
- chan_array[i].type = IIO_VOLTAGE;
- chan_array[i].indexed = 1;
- chan_array[i].channel = channel;
- chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
chan_array[i].datasheet_name = rzg2l_adc_channel_name[channel];
- i++;
}
data->num_channels = num_channels;
--
2.48.1
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