Re: [PATCH v4 2/8] iio: inkern: add helpers to query available values from channels

Jonathan Cameron
2016-11-12T17:18:02Z

On 08/11/16 11:58, Peter Rosin wrote:
> Specifically a helper for reading the available maximum raw value of a
> channel and a helper for forwarding read_avail requests for raw values
> from one iio driver to an iio channel that is consumed.
>
> These rather specific helpers are in turn built with generic helpers
> making it easy to build more helpers for available values as needed.
>
> Signed-off-by: Peter Rosin <peda@axentia.se>
Applied.
> ---
> drivers/iio/inkern.c | 104 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/iio/consumer.h | 28 ++++++++++++
> include/linux/iio/iio.h | 17 +++++++
> 3 files changed, 149 insertions(+)
>
> diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
> index c4757e6367e7..cfca17ba2535 100644
> --- a/drivers/iio/inkern.c
> +++ b/drivers/iio/inkern.c
> @@ -703,6 +703,110 @@ int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
> }
> EXPORT_SYMBOL_GPL(iio_read_channel_scale);
>
> +static int iio_channel_read_avail(struct iio_channel *chan,
> + const int **vals, int *type, int *length,
> + enum iio_chan_info_enum info)
> +{
> + if (!iio_channel_has_available(chan->channel, info))
> + return -EINVAL;
> +
> + return chan->indio_dev->info->read_avail(chan->indio_dev, chan->channel,
> + vals, type, length, info);
> +}
> +
> +int iio_read_avail_channel_raw(struct iio_channel *chan,
> + const int **vals, int *length)
> +{
> + int ret;
> + int type;
> +
> + mutex_lock(&chan->indio_dev->info_exist_lock);
> + if (!chan->indio_dev->info) {
> + ret = -ENODEV;
> + goto err_unlock;
> + }
> +
> + ret = iio_channel_read_avail(chan,
> + vals, &type, length, IIO_CHAN_INFO_RAW);
> +err_unlock:
> + mutex_unlock(&chan->indio_dev->info_exist_lock);
> +
> + if (ret >= 0 && type != IIO_VAL_INT) {
> + /* raw values are assumed to be IIO_VAL_INT */
> + ret = -EINVAL;
> + goto err_unlock;
> + }
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(iio_read_avail_channel_raw);
> +
> +static int iio_channel_read_max(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[2];
> + break;
> + default:
> + *val = vals[4];
> + *val2 = vals[5];
> + }
> + 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 max for other iio values */
> + return -EINVAL;
> + }
> + return 0;
> +
> + default:
> + return ret;
> + }
> +}
> +
> +int iio_read_max_channel_raw(struct iio_channel *chan, int *val)
> +{
> + int ret;
> + int type;
> +
> + mutex_lock(&chan->indio_dev->info_exist_lock);
> + if (!chan->indio_dev->info) {
> + ret = -ENODEV;
> + goto err_unlock;
> + }
> +
> + ret = iio_channel_read_max(chan, val, NULL, &type, IIO_CHAN_INFO_RAW);
> +err_unlock:
> + mutex_unlock(&chan->indio_dev->info_exist_lock);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(iio_read_max_channel_raw);
> +
> int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
> {
> int ret = 0;
> diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
> index 9edccfba1ffb..9a4f336d8b4a 100644
> --- a/include/linux/iio/consumer.h
> +++ b/include/linux/iio/consumer.h
> @@ -226,6 +226,34 @@ int iio_read_channel_processed(struct iio_channel *chan, int *val);
> int iio_write_channel_raw(struct iio_channel *chan, int val);
>
> /**
> + * iio_read_max_channel_raw() - read maximum available raw value from a given
> + * channel, i.e. the maximum 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_max_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.
> + * @vals: Available values read back.
> + * @length: Number of entries in vals.
> + *
> + * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
> + *
> + * For ranges, three vals are always returned; min, step and max.
> + * For lists, all the possible values are enumerated.
> + *
> + * Note raw available values from iio channels are in adc counts and
> + * hence scale will need to be applied if standard units are required.
> + */
> +int iio_read_avail_channel_raw(struct iio_channel *chan,
> + const int **vals, int *length);
> +
> +/**
> * iio_get_channel_type() - get the type of a channel
> * @channel: The channel being queried.
> * @type: The type of the channel.
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index 45b781084a4b..f9be8836ef23 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -315,6 +315,23 @@ static inline bool iio_channel_has_info(const struct iio_chan_spec *chan,
> (chan->info_mask_shared_by_all & BIT(type));
> }
>
> +/**
> + * iio_channel_has_available() - Checks if a channel has an available attribute
> + * @chan: The channel to be queried
> + * @type: Type of the available attribute to be checked
> + *
> + * Returns true if the channel supports reporting available values for the
> + * given attribute type, false otherwise.
> + */
> +static inline bool iio_channel_has_available(const struct iio_chan_spec *chan,
> + enum iio_chan_info_enum type)
> +{
> + return (chan->info_mask_separate_available & BIT(type)) |
> + (chan->info_mask_shared_by_type_available & BIT(type)) |
> + (chan->info_mask_shared_by_dir_available & BIT(type)) |
> + (chan->info_mask_shared_by_all_available & BIT(type));
> +}
> +
> #define IIO_CHAN_SOFT_TIMESTAMP(_si) { \
> .type = IIO_TIMESTAMP, \
> .channel = -1, \
>