Some enums might have gaps or reserved values in the middle of their value
range. E.g. consider a 2-bit enum where the values 0, 1 and 3 have a
meaning, but 2 is a reserved value and must not be used.
Add support for such enums to the IIO enum helper functions. A reserved
value is marked by setting its entry in the items array to NULL rather
than the normal descriptive string value.
Unfortunately that means we can no longer use __sysfs_match_string() since
it treats a NULL entry as the array terminator. But the amount of
boilerplate is manageable.
Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
---
Open for suggestions on how to massage __sysfs_match_string() into handling
this use-case.
---
drivers/iio/industrialio-core.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 2e8e36f9da61..e69bef13d005 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -446,8 +446,12 @@ ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
if (!e->num_items)
return 0;
- for (i = 0; i < e->num_items; ++i)
+ for (i = 0; i < e->num_items; ++i) {
+ if (!e->items[i])
+ continue;
+
len += scnprintf(buf + len, PAGE_SIZE - len, "%s ", e->items[i]);
+ }
/* replace last space with a newline */
buf[len - 1] = '\n';
@@ -468,7 +472,7 @@ ssize_t iio_enum_read(struct iio_dev *indio_dev,
i = e->get(indio_dev, chan);
if (i < 0)
return i;
- else if (i >= e->num_items)
+ else if (i >= e->num_items || !e->items[i])
return -EINVAL;
return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
@@ -480,16 +484,21 @@ ssize_t iio_enum_write(struct iio_dev *indio_dev,
size_t len)
{
const struct iio_enum *e = (const struct iio_enum *)priv;
+ unsigned int i;
int ret;
if (!e->set)
return -EINVAL;
- ret = __sysfs_match_string(e->items, e->num_items, buf);
- if (ret < 0)
- return ret;
+ for (i = 0; i < e->num_items; i++) {
+ if (e->items[i] && sysfs_streq(buf, e->items[i]))
+ break;
+ }
+
+ if (i == e->num_items)
+ return -EINVAL;
- ret = e->set(indio_dev, chan, ret);
+ ret = e->set(indio_dev, chan, i);
return ret ? ret : len;
}
EXPORT_SYMBOL_GPL(iio_enum_write);
--
2.11.0
--
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
