On 07/28/2011 05:54 PM, Jonathan Cameron wrote:
On 07/28/11 16:19, Michael Hennerich wrote:
On 07/28/2011 04:03 PM, Jonathan Cameron wrote:
On 07/28/11 12:32, michael.hennerich@xxxxxxxxxx wrote:
From: Michael Hennerich<michael.hennerich@xxxxxxxxxx>
The AD5933 is a high precision impedance converter system solution
that combines an on-board frequency generator with a 12-bit, 1 MSPS,
analog-to-digital converter (ADC). The frequency generator allows an
external complex impedance to be excited with a known frequency.
The response signal from the impedance is sampled by the on-board ADC
and a discrete Fourier transform (DFT) is processed by an on-chip DSP engine.
The DFT algorithm returns a real (R) and imaginary (I) data-word at each
output frequency.
Mostly looks good. Couple of nitpicks / queries in line. I'm particularly
bothered about the SCALE info elements in chan_spec that aren't matched
in the read_raw (or a write_raw if relevant).
in0_real_raw and in0_imag_raw only exist as scan elements.
They aren't present in indio_dev->channels. I therefore couldn't use
scale info elements from channel spec.
Ah. I hadn't noticed that (obviously). Why is this the case? Does it just
not make sense to read them directly? If so, set their channel number to -1
and they won't appear. Hmm. Perhaps we need to make that test a little
more refined to make this work. iio_device_add_channel_sysfs drops the channel
immediately if it's number is negative. Maybe move the magic value into channel2?
That way the only uggliness will come if we have a differential channel that only exists
for scans. Or use a negative index (rather than just -1). That's probably the cleanest
option, but will require a few abs() insertions in the code and some testing
to make sure we got them all.
Well this works well for channels abs(chan->channel) > 0.
But how about the case where I need no channel sysfs but the scale
attributes of channel# 0?
Unfortunately there is no -0 :-)
Since the AD5933 is a corner case - I suggest we leave it as is - and I
add some comments to the source... ?
Something like:
diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
index b49db92..aeeb5e6 100644
--- a/drivers/staging/iio/industrialio-core.c
+++ b/drivers/staging/iio/industrialio-core.c
@@ -480,7 +480,7 @@ int __iio_device_attr_init(struct device_attribute *dev_attr,
= kasprintf(GFP_KERNEL, "%s_%s%d_%s",
iio_direction[chan->output],
iio_chan_type_name_spec_shared[chan->type],
- chan->channel,
+ (int)abs(chan->channel),
full_postfix);
if (name_format == NULL) {
@@ -489,7 +489,7 @@ int __iio_device_attr_init(struct device_attribute *dev_attr,
}
dev_attr->attr.name = kasprintf(GFP_KERNEL,
name_format,
- chan->channel,
+ (int)abs(chan->channel),
chan->channel2);
if (dev_attr->attr.name == NULL) {
ret = -ENOMEM;
@@ -585,27 +585,27 @@ static int iio_device_add_channel_sysfs(struct iio_dev *dev_info,
{
int ret, i;
- if (chan->channel< 0)
- return 0;
- if (chan->processed_val)
- ret = __iio_add_chan_devattr("input", NULL, chan,
-&iio_read_channel_info,
- NULL,
- 0,
- 0,
-&dev_info->dev,
-&dev_info->channel_attr_list);
- else
- ret = __iio_add_chan_devattr("raw", NULL, chan,
-&iio_read_channel_info,
- (chan->output ?
-&iio_write_channel_info : NULL),
- 0,
- 0,
-&dev_info->dev,
-&dev_info->channel_attr_list);
- if (ret)
- goto error_ret;
+ if (chan->channel>= 0) {
+ if (chan->processed_val)
+ ret = __iio_add_chan_devattr("input", NULL, chan,
+&iio_read_channel_info,
+ NULL,
+ 0,
+ 0,
+&dev_info->dev,
+&dev_info->channel_attr_list);
+ else
+ ret = __iio_add_chan_devattr("raw", NULL, chan,
+&iio_read_channel_info,
+ (chan->output ?
+&iio_write_channel_info : NULL),
+ 0,
+ 0,
+&dev_info->dev,
+&dev_info->channel_attr_list);
+ if (ret)
+ goto error_ret;
+ }
for_each_set_bit(i,&chan->info_mask, sizeof(long)*8) {
ret = __iio_add_chan_devattr(iio_chan_info_postfix[i/2],
--
Greetings,
Michael
--
Analog Devices GmbH Wilhelm-Wagenfeld-Str. 6 80807 Muenchen
Sitz der Gesellschaft: Muenchen; Registergericht: Muenchen HRB 40368;
Geschaeftsfuehrer:Dr.Carsten Suckrow, Thomas Wessel, William A. Martin,
Margaret Seif
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
