diff options
Diffstat (limited to 'drivers/iio/industrialio-backend.c')
| -rw-r--r-- | drivers/iio/industrialio-backend.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c index 2fea2bbbe47f..f08ed6d70ae5 100644 --- a/drivers/iio/industrialio-backend.c +++ b/drivers/iio/industrialio-backend.c @@ -43,10 +43,12 @@ #include <linux/types.h> #include <linux/iio/backend.h> +#include <linux/iio/iio.h> struct iio_backend { struct list_head entry; const struct iio_backend_ops *ops; + struct device *frontend_dev; struct device *dev; struct module *owner; void *priv; @@ -186,6 +188,44 @@ int iio_backend_data_format_set(struct iio_backend *back, unsigned int chan, } EXPORT_SYMBOL_NS_GPL(iio_backend_data_format_set, IIO_BACKEND); +/** + * iio_backend_data_source_set - Select data source + * @back: Backend device + * @chan: Channel number + * @data: Data source + * + * A given backend may have different sources to stream/sync data. This allows + * to choose that source. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_data_source_set(struct iio_backend *back, unsigned int chan, + enum iio_backend_data_source data) +{ + if (data >= IIO_BACKEND_DATA_SOURCE_MAX) + return -EINVAL; + + return iio_backend_op_call(back, data_source_set, chan, data); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_data_source_set, IIO_BACKEND); + +/** + * iio_backend_set_sampling_freq - Set channel sampling rate + * @back: Backend device + * @chan: Channel number + * @sample_rate_hz: Sample rate + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_set_sampling_freq(struct iio_backend *back, unsigned int chan, + u64 sample_rate_hz) +{ + return iio_backend_op_call(back, set_sample_rate, chan, sample_rate_hz); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_set_sampling_freq, IIO_BACKEND); + static void iio_backend_free_buffer(void *arg) { struct iio_backend_buffer_pair *pair = arg; @@ -231,6 +271,143 @@ int devm_iio_backend_request_buffer(struct device *dev, } EXPORT_SYMBOL_NS_GPL(devm_iio_backend_request_buffer, IIO_BACKEND); +static struct iio_backend *iio_backend_from_indio_dev_parent(const struct device *dev) +{ + struct iio_backend *back = ERR_PTR(-ENODEV), *iter; + + /* + * We deliberately go through all backends even after finding a match. + * The reason is that we want to catch frontend devices which have more + * than one backend in which case returning the first we find is bogus. + * For those cases, frontends need to explicitly define + * get_iio_backend() in struct iio_info. + */ + guard(mutex)(&iio_back_lock); + list_for_each_entry(iter, &iio_back_list, entry) { + if (dev == iter->frontend_dev) { + if (!IS_ERR(back)) { + dev_warn(dev, + "Multiple backends! get_iio_backend() needs to be implemented"); + return ERR_PTR(-ENODEV); + } + + back = iter; + } + } + + return back; +} + +/** + * iio_backend_ext_info_get - IIO ext_info read callback + * @indio_dev: IIO device + * @private: Data private to the driver + * @chan: IIO channel + * @buf: Buffer where to place the attribute data + * + * This helper is intended to be used by backends that extend an IIO channel + * (through iio_backend_extend_chan_spec()) with extended info. In that case, + * backends are not supposed to give their own callbacks (as they would not have + * a way to get the backend from indio_dev). This is the getter. + * + * RETURNS: + * Number of bytes written to buf, negative error number on failure. + */ +ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private, + const struct iio_chan_spec *chan, char *buf) +{ + struct iio_backend *back; + + /* + * The below should work for the majority of the cases. It will not work + * when one frontend has multiple backends in which case we'll need a + * new callback in struct iio_info so we can directly request the proper + * backend from the frontend. Anyways, let's only introduce new options + * when really needed... + */ + back = iio_backend_from_indio_dev_parent(indio_dev->dev.parent); + if (IS_ERR(back)) + return PTR_ERR(back); + + return iio_backend_op_call(back, ext_info_get, private, chan, buf); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_ext_info_get, IIO_BACKEND); + +/** + * iio_backend_ext_info_set - IIO ext_info write callback + * @indio_dev: IIO device + * @private: Data private to the driver + * @chan: IIO channel + * @buf: Buffer holding the sysfs attribute + * @len: Buffer length + * + * This helper is intended to be used by backends that extend an IIO channel + * (trough iio_backend_extend_chan_spec()) with extended info. In that case, + * backends are not supposed to give their own callbacks (as they would not have + * a way to get the backend from indio_dev). This is the setter. + * + * RETURNS: + * Buffer length on success, negative error number on failure. + */ +ssize_t iio_backend_ext_info_set(struct iio_dev *indio_dev, uintptr_t private, + const struct iio_chan_spec *chan, + const char *buf, size_t len) +{ + struct iio_backend *back; + + back = iio_backend_from_indio_dev_parent(indio_dev->dev.parent); + if (IS_ERR(back)) + return PTR_ERR(back); + + return iio_backend_op_call(back, ext_info_set, private, chan, buf, len); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_ext_info_set, IIO_BACKEND); + +/** + * iio_backend_extend_chan_spec - Extend an IIO channel + * @indio_dev: IIO device + * @back: Backend device + * @chan: IIO channel + * + * Some backends may have their own functionalities and hence capable of + * extending a frontend's channel. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_extend_chan_spec(struct iio_dev *indio_dev, + struct iio_backend *back, + struct iio_chan_spec *chan) +{ + const struct iio_chan_spec_ext_info *frontend_ext_info = chan->ext_info; + const struct iio_chan_spec_ext_info *back_ext_info; + int ret; + + ret = iio_backend_op_call(back, extend_chan_spec, chan); + if (ret) + return ret; + /* + * Let's keep things simple for now. Don't allow to overwrite the + * frontend's extended info. If ever needed, we can support appending + * it. + */ + if (frontend_ext_info && chan->ext_info != frontend_ext_info) + return -EOPNOTSUPP; + if (!chan->ext_info) + return 0; + + /* Don't allow backends to get creative and force their own handlers */ + for (back_ext_info = chan->ext_info; back_ext_info->name; back_ext_info++) { + if (back_ext_info->read != iio_backend_ext_info_get) + return -EINVAL; + if (back_ext_info->write != iio_backend_ext_info_set) + return -EINVAL; + } + + return 0; +} +EXPORT_SYMBOL_NS_GPL(iio_backend_extend_chan_spec, IIO_BACKEND); + static void iio_backend_release(void *arg) { struct iio_backend *back = arg; @@ -263,6 +440,8 @@ static int __devm_iio_backend_get(struct device *dev, struct iio_backend *back) "Could not link to supplier(%s)\n", dev_name(back->dev)); + back->frontend_dev = dev; + dev_dbg(dev, "Found backend(%s) device\n", dev_name(back->dev)); return 0; |