From: Lars-Peter Clausen <lars@xxxxxxxxxx> 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 can not be used. Add support for such enums to the IIO enum helper functions. A reserved values is marked by setting its entry in the items array to NULL rather than the normal descriptive string value. Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> --- Nearly 1 year and a half since I last touched this: https://lore.kernel.org/linux-iio/20190508111913.7276-3-alexandru.ardelean@xxxxxxxxxx/ I tried a few shots at working with 'lib/string.c', and that went slow. The __sysfs_match_string_with_gaps() approach has stalled. https://lore.kernel.org/linux-iio/20190422140251.8960-1-alexandru.ardelean@xxxxxxxxxx/ I also tried to update the __sysfs_match_string() implementation based on what the docstring said, https://lore.kernel.org/lkml/20200212144723.21884-1-alexandru.ardelean@xxxxxxxxxx/ but then I just fixed the docstring to match what the behavior does: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next-history.git/commit/lib/string.c?id=c11d3fa0116a6bc832a9e387427caa16f8de5ef2 In the end, for this patch, it means expanding the __sysfs_match_string() helper. drivers/iio/industrialio-core.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index e9ee9363fed0..a88494066811 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -470,8 +470,11 @@ 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'; @@ -492,7 +495,7 @@ 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]); @@ -504,16 +507,21 @@ 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); -- 2.17.1
