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> --- Changelog v7 -> v8: * https://lore.kernel.org/linux-iio/20210107084434.35283-1-alexandru.ardelean@xxxxxxxxxx/ * dropped patch 'lib/string.c: add __sysfs_match_string_with_gaps() helper' * merged __sysfs_match_string_with_gaps into drivers/iio/industrial-core.c as iio_sysfs_match_string_with_gaps() drivers/iio/industrialio-core.c | 39 ++++++++++++++++++++++++++++++--- 1 file changed, 36 insertions(+), 3 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index e9ee9363fed0..db20e2ab437d 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -169,6 +169,36 @@ static const char * const iio_chan_info_postfix[] = { [IIO_CHAN_INFO_CALIBAMBIENT] = "calibambient", }; +/** + * iio_sysfs_match_string_with_gaps - matches given string in an array with gaps + * @array: array of strings + * @n: number of strings in the array + * @str: string to match with + * + * Returns index of @str in the @array or -EINVAL, similar to match_string(). + * Uses sysfs_streq instead of strcmp for matching. + * + * This routine will look for a string in an array of strings. + * The search will continue until the element is found or the n-th element + * is reached, regardless of any NULL elements in the array. + */ +static int iio_sysfs_match_string_with_gaps(const char * const *array, size_t n, + const char *str) +{ + const char *item; + int index; + + for (index = 0; index < n; index++) { + item = array[index]; + if (!item) + continue; + if (sysfs_streq(item, str)) + return index; + } + + return -EINVAL; +} + #if defined(CONFIG_DEBUG_FS) /* * There's also a CONFIG_DEBUG_FS guard in include/linux/iio/iio.h for @@ -470,8 +500,11 @@ 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 +525,7 @@ 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]); @@ -509,7 +542,7 @@ ssize_t iio_enum_write(struct iio_dev *indio_dev, if (!e->set) return -EINVAL; - ret = __sysfs_match_string(e->items, e->num_items, buf); + ret = iio_sysfs_match_string_with_gaps(e->items, e->num_items, buf); if (ret < 0) return ret; -- 2.17.1
