On 06/07/2011 03:04 PM, Jonathan Cameron wrote:
On 06/07/11 12:21, michael.hennerich@xxxxxxxxxx wrote:
From: Michael Hennerich<michael.hennerich@xxxxxxxxxx>
Allow iio_write_channel_info() to accept IIO_VAL_INT_PLUS_NANO
Hmm. I wonder if this is the right way around to do it. This puts a hard
requirement on the number of digits being what the driver expects.
Well - this requirement was there before - it was just limited to 6 digits.
Extra digits were simply cut off.
Alternative would be an optional callback (not needed if everything is int_plus_micro)
that allows the driver to be queried for what it wants and then reads data under
the assumption that is what it has.
Ideally write_raw would take an additional argument. Just like read_raw
returns what it has!
Which do people think would work better?
The approach here has the flaw that if someone writes a 9 decimal digit value
to something expect 6 decimal digits the core will pass it on whereas it should
have ignored the last 3 digits.
I don't think it's getting a big problem.
The driver itself knows the format what he expects.
If someone writes more digits than allowed it's simply not a match or fault.
In order to avoid faults - we could also say 6-8 digits are treated as
mirco while 9 and more are treated as nano.
switch (fract_digits) {
case 6..8: /* IIO_VAL_INT_PLUS_MICRO */
fract_mult = 100000;
break;
case 9..12: /* IIO_VAL_INT_PLUS_NANO */
fract_mult = 100000000;
break;
default:
return -EINVAL;
}
Signed-off-by: Michael Hennerich<michael.hennerich@xxxxxxxxxx>
---
drivers/staging/iio/industrialio-core.c | 27 +++++++++++++++++++++------
1 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
index e5a7663..74158c1 100644
--- a/drivers/staging/iio/industrialio-core.c
+++ b/drivers/staging/iio/industrialio-core.c
@@ -412,25 +412,40 @@ static ssize_t iio_write_channel_info(struct device *dev,
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
- int ret, integer = 0, micro = 0, micro_mult = 100000;
+ int ret, fract_digits, integer = 0, fract = 0, fract_mult;
bool integer_part = true, negative = false;
/* Assumes decimal - precision based on number of digits */
if (!indio_dev->info->write_raw)
return -EINVAL;
+
+ fract_digits = strnchr(buf, len, '\n') - strnchr(buf, len, '.') - 1;
+
+ switch (fract_digits) {
+ case 6: /* IIO_VAL_INT_PLUS_MICRO */
+ fract_mult = 100000;
+ break;
+ case 9: /* IIO_VAL_INT_PLUS_NANO */
+ fract_mult = 100000000;
+ break;
+ default:
+ return -EINVAL;
+ }
+
if (buf[0] == '-') {
negative = true;
buf++;
}
+
while (*buf) {
if ('0'<= *buf&& *buf<= '9') {
if (integer_part)
integer = integer*10 + *buf - '0';
else {
- micro += micro_mult*(*buf - '0');
- if (micro_mult == 1)
+ fract += fract_mult*(*buf - '0');
+ if (fract_mult == 1)
break;
- micro_mult /= 10;
+ fract_mult /= 10;
}
} else if (*buf == '\n') {
if (*(buf + 1) == '\0')
@@ -448,11 +463,11 @@ static ssize_t iio_write_channel_info(struct device *dev,
if (integer)
integer = -integer;
else
- micro = -micro;
+ fract = -fract;
}
ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
- integer, micro, this_attr->address);
+ integer, fract, this_attr->address);
if (ret)
return ret;
--
Greetings,
Michael
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