From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nuno Sa Date: Fri, 12 Apr 2024 15:36:15 +0200 Subject: [PATCH v3 08/10] iio: backend: add new functionality MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20240412-iio-backend-axi-dac-v3-8-3e9d4c5201fb@analog.com> References: <20240412-iio-backend-axi-dac-v3-0-3e9d4c5201fb@analog.com> In-Reply-To: <20240412-iio-backend-axi-dac-v3-0-3e9d4c5201fb@analog.com> To: linux-iio@vger.kernel.org, devicetree@vger.kernel.org Cc: Dragos Bogdan , Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Olivier Moysan , Nuno Sa X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1712928968; l=11939; i=nuno.sa@analog.com; s=20231116; h=from:subject:message-id; bh=JTce4VAzVRMIj8i1O5Q/CkJZnomMUJ28yaNvN40DHoY=; b=xSeYv+1hOMQPcjmEwfE4whSGz9LVOdRXdWQtgEmZheluQbf2zaCxz2PcFqE69XELGXkKeVmqE IgSt0rOB0L8D2i7+xB9xA6NBSQC8hDUXREloIcFH1rm89iRv003xpLD X-Developer-Key: i=nuno.sa@analog.com; a=ed25519; pk=3NQwYA013OUYZsmDFBf8rmyyr5iQlxV/9H4/Df83o1E= X-Endpoint-Received: by B4 Relay for nuno.sa@analog.com/20231116 with auth_id=100 List-Id: B4 Relay Submissions This adds the needed backend ops for supporting a backend inerfacing with an high speed dac. The new ops are: * data_source_set(); * set_sampling_freq(); * extend_chan_spec(); * ext_info_set(); * ext_info_get(). Also to note the new helpers that are meant to be used by the backends when extending an IIO channel (adding extended info): * iio_backend_ext_info_set(); * iio_backend_ext_info_get(). Signed-off-by: Nuno Sa --- drivers/iio/industrialio-backend.c | 179 +++++++++++++++++++++++++++++++++++++ include/linux/iio/backend.h | 49 ++++++++++ 2 files changed, 228 insertions(+) diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c index 2fea2bbbe47fd..f08ed6d70ae59 100644 --- a/drivers/iio/industrialio-backend.c +++ b/drivers/iio/industrialio-backend.c @@ -43,10 +43,12 @@ #include #include +#include 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; diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h index a6d79381866ec..9d144631134db 100644 --- a/include/linux/iio/backend.h +++ b/include/linux/iio/backend.h @@ -4,6 +4,7 @@ #include +struct iio_chan_spec; struct fwnode_handle; struct iio_backend; struct device; @@ -15,6 +16,26 @@ enum iio_backend_data_type { IIO_BACKEND_DATA_TYPE_MAX }; +enum iio_backend_data_source { + IIO_BACKEND_INTERNAL_CONTINUOS_WAVE, + IIO_BACKEND_EXTERNAL, + IIO_BACKEND_DATA_SOURCE_MAX +}; + +/** + * IIO_BACKEND_EX_INFO - Helper for an IIO extended channel attribute + * @_name: Attribute name + * @_shared: Whether the attribute is shared between all channels + * @_what: Data private to the driver + */ +#define IIO_BACKEND_EX_INFO(_name, _shared, _what) { \ + .name = (_name), \ + .shared = (_shared), \ + .read = iio_backend_ext_info_get, \ + .write = iio_backend_ext_info_set, \ + .private = (_what), \ +} + /** * struct iio_backend_data_fmt - Backend data format * @type: Data type. @@ -35,8 +56,13 @@ struct iio_backend_data_fmt { * @chan_enable: Enable one channel. * @chan_disable: Disable one channel. * @data_format_set: Configure the data format for a specific channel. + * @data_source_set: Configure the data source for a specific channel. + * @set_sample_rate: Configure the sampling rate for a specific channel. * @request_buffer: Request an IIO buffer. * @free_buffer: Free an IIO buffer. + * @extend_chan_spec: Extend an IIO channel. + * @ext_info_set: Extended info setter. + * @ext_info_get: Extended info getter. **/ struct iio_backend_ops { int (*enable)(struct iio_backend *back); @@ -45,10 +71,21 @@ struct iio_backend_ops { int (*chan_disable)(struct iio_backend *back, unsigned int chan); int (*data_format_set)(struct iio_backend *back, unsigned int chan, const struct iio_backend_data_fmt *data); + int (*data_source_set)(struct iio_backend *back, unsigned int chan, + enum iio_backend_data_source data); + int (*set_sample_rate)(struct iio_backend *back, unsigned int chan, + u64 sample_rate_hz); struct iio_buffer *(*request_buffer)(struct iio_backend *back, struct iio_dev *indio_dev); void (*free_buffer)(struct iio_backend *back, struct iio_buffer *buffer); + int (*extend_chan_spec)(struct iio_backend *back, + struct iio_chan_spec *chan); + int (*ext_info_set)(struct iio_backend *back, uintptr_t private, + const struct iio_chan_spec *chan, + const char *buf, size_t len); + int (*ext_info_get)(struct iio_backend *back, uintptr_t private, + const struct iio_chan_spec *chan, char *buf); }; int iio_backend_chan_enable(struct iio_backend *back, unsigned int chan); @@ -56,10 +93,22 @@ int iio_backend_chan_disable(struct iio_backend *back, unsigned int chan); int devm_iio_backend_enable(struct device *dev, struct iio_backend *back); int iio_backend_data_format_set(struct iio_backend *back, unsigned int chan, const struct iio_backend_data_fmt *data); +int iio_backend_data_source_set(struct iio_backend *back, unsigned int chan, + enum iio_backend_data_source data); +int iio_backend_set_sampling_freq(struct iio_backend *back, unsigned int chan, + u64 sample_rate_hz); int devm_iio_backend_request_buffer(struct device *dev, struct iio_backend *back, struct iio_dev *indio_dev); +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); +ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private, + const struct iio_chan_spec *chan, char *buf); +int iio_backend_extend_chan_spec(struct iio_dev *indio_dev, + struct iio_backend *back, + struct iio_chan_spec *chan); void *iio_backend_get_priv(const struct iio_backend *conv); struct iio_backend *devm_iio_backend_get(struct device *dev, const char *name); struct iio_backend * -- 2.44.0