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- To: Herve Codina <herve.codina@xxxxxxxxxxx>, Liam Girdwood <lgirdwood@xxxxxxxxx>, Mark Brown <broonie@xxxxxxxxxx>, Rob Herring <robh+dt@xxxxxxxxxx>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx>, Jonathan Cameron <jic23@xxxxxxxxxx>, Lars-Peter Clausen <lars@xxxxxxxxxx>, Jaroslav Kysela <perex@xxxxxxxx>, Takashi Iwai <tiwai@xxxxxxxx>
- Subject: [PATCH 2/4] iio: inkern: Add a helper to query an available minimum raw value
- From: Herve Codina <herve.codina@xxxxxxxxxxx>
- Date: Fri, 21 Apr 2023 14:41:20 +0200
- Cc: alsa-devel@xxxxxxxxxxxxxxxx, devicetree@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, linux-iio@xxxxxxxxxxxxxxx, Christophe Leroy <christophe.leroy@xxxxxxxxxx>, Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxx>
- In-reply-to: <20230421124122.324820-1-herve.codina@bootlin.com>
- References: <20230421124122.324820-1-herve.codina@bootlin.com>
A helper, iio_read_max_channel_raw() exists to read the available maximum raw value of a channel but nothing similar exists to read the available minimum raw value. This new helper, iio_read_min_channel_raw(), fills the hole and can be used for reading the available minimum raw value of a channel. It is fully based on the existing iio_read_max_channel_raw(). Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx> --- drivers/iio/inkern.c | 67 ++++++++++++++++++++++++++++++++++++ include/linux/iio/consumer.h | 11 ++++++ 2 files changed, 78 insertions(+) diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index 872fd5c24147..914fc69c718a 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -912,6 +912,73 @@ int iio_read_max_channel_raw(struct iio_channel *chan, int *val) } EXPORT_SYMBOL_GPL(iio_read_max_channel_raw); +static int iio_channel_read_min(struct iio_channel *chan, + int *val, int *val2, int *type, + enum iio_chan_info_enum info) +{ + int unused; + const int *vals; + int length; + int ret; + + if (!val2) + val2 = &unused; + + ret = iio_channel_read_avail(chan, &vals, type, &length, info); + switch (ret) { + case IIO_AVAIL_RANGE: + switch (*type) { + case IIO_VAL_INT: + *val = vals[0]; + break; + default: + *val = vals[0]; + *val2 = vals[1]; + } + return 0; + + case IIO_AVAIL_LIST: + if (length <= 0) + return -EINVAL; + switch (*type) { + case IIO_VAL_INT: + *val = vals[--length]; + while (length) { + if (vals[--length] < *val) + *val = vals[length]; + } + break; + default: + /* FIXME: learn about min for other iio values */ + return -EINVAL; + } + return 0; + + default: + return ret; + } +} + +int iio_read_min_channel_raw(struct iio_channel *chan, int *val) +{ + struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(chan->indio_dev); + int ret; + int type; + + mutex_lock(&iio_dev_opaque->info_exist_lock); + if (!chan->indio_dev->info) { + ret = -ENODEV; + goto err_unlock; + } + + ret = iio_channel_read_min(chan, val, NULL, &type, IIO_CHAN_INFO_RAW); +err_unlock: + mutex_unlock(&iio_dev_opaque->info_exist_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(iio_read_min_channel_raw); + int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type) { struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(chan->indio_dev); diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h index 6802596b017c..956120d8b5a3 100644 --- a/include/linux/iio/consumer.h +++ b/include/linux/iio/consumer.h @@ -297,6 +297,17 @@ int iio_write_channel_raw(struct iio_channel *chan, int val); */ int iio_read_max_channel_raw(struct iio_channel *chan, int *val); +/** + * iio_read_min_channel_raw() - read minimum available raw value from a given + * channel, i.e. the minimum possible value. + * @chan: The channel being queried. + * @val: Value read back. + * + * Note raw reads from iio channels are in adc counts and hence + * scale will need to be applied if standard units are required. + */ +int iio_read_min_channel_raw(struct iio_channel *chan, int *val); + /** * iio_read_avail_channel_raw() - read available raw values from a given channel * @chan: The channel being queried. -- 2.39.2
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