1 // SPDX-License-Identifier: GPL-2.0-only
3  * Framework to handle complex IIO aggregate devices.
6  * can be "linked" against one or multiple backend devices. All the IIO and
11  *                                           -------------------------------------------------------
12  * ------------------                        | ------------         ------------      -------  FPGA|
13  * |     ADC        |------------------------| | ADC CORE |---------| DMA CORE |------| RAM |      |
14  * | (Frontend/IIO) | Serial Data (eg: LVDS) | |(backend) |---------|          |------|     |      |
15  * |                |------------------------| ------------         ------------      -------      |
16  * ------------------                        -------------------------------------------------------
19  *   - Backends should register themselves with devm_iio_backend_register()
20  *   - Frontend devices should get backends with devm_iio_backend_get()
24  * devices. On top of that, this is "generic" for all IIO which means any kind
27  * the industrialio-backend.c is only left with the really generic stuff. Then,
30  * Copyright (C) 2023-2024 Analog Devices Inc.
32 #define dev_fmt(fmt) "iio-backend: " fmt
47 #include <linux/iio/backend.h>
48 #include <linux/iio/iio.h>
62 	 * backend. Used for the debugfs directory name.
80  * Helper macros to call backend ops. Makes sure the option is supported.
86 	if (!____back->ops->op)						\
87 		____ret = -EOPNOTSUPP;					\
98 		__ret = __back->ops->op(__back, ##args);	\
112 		ptr_err = __back->ops->op(__back, ##args);	\
123 		__back->ops->op(__back, ##args);		\
125 		dev_dbg(__back->dev, "Op(%s) not implemented\n",\
133 	struct iio_backend *back = file->private_data;  in iio_backend_debugfs_read_reg()
139 				  back->cached_reg_addr, 0, &val);  in iio_backend_debugfs_read_reg()
152 	struct iio_backend *back = file->private_data;  in iio_backend_debugfs_write_reg()
159 		return -ENOSPC;  in iio_backend_debugfs_write_reg()
161 	rc = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, userbuf, count);  in iio_backend_debugfs_write_reg()
167 	ret = sscanf(buf, "%i %i", &back->cached_reg_addr, &val);  in iio_backend_debugfs_write_reg()
174 					  back->cached_reg_addr, val, NULL);  in iio_backend_debugfs_write_reg()
179 		return -EINVAL;  in iio_backend_debugfs_write_reg()
193 	struct iio_backend *back = file->private_data;  in iio_backend_debugfs_read_name()
197 	len = scnprintf(name, sizeof(name), "%s\n", back->name);  in iio_backend_debugfs_read_name()
208  * iio_backend_debugfs_add - Add debugfs interfaces for Backends
209  * @back: Backend device
210  * @indio_dev: IIO device
221 	if (!back->ops->debugfs_reg_access && !back->name)  in iio_backend_debugfs_add()
224 	snprintf(name, sizeof(name), "backend%d", back->idx);  in iio_backend_debugfs_add()
230 	if (back->ops->debugfs_reg_access)  in iio_backend_debugfs_add()
234 	if (back->name)  in iio_backend_debugfs_add()
241  * iio_backend_debugfs_print_chan_status - Print channel status
242  * @back: Backend device
248  * interface and "ask" the backend to dump more details on why a test tone might
259 		return -ENODEV;  in iio_backend_debugfs_print_chan_status()
267  * iio_backend_chan_enable - Enable a backend channel
268  * @back: Backend device
281  * iio_backend_chan_disable - Disable a backend channel
282  * @back: Backend device
300  * iio_backend_disable - Backend disable
301  * @back: Backend device
310  * iio_backend_enable - Backend enable
311  * @back: Backend device
323  * devm_iio_backend_enable - Device managed backend enable
324  * @dev: Consumer device for the backend
325  * @back: Backend device
343  * iio_backend_data_format_set - Configure the channel data format
344  * @back: Backend device
357 	if (!data || data->type >= IIO_BACKEND_DATA_TYPE_MAX)  in iio_backend_data_format_set()
358 		return -EINVAL;  in iio_backend_data_format_set()
365  * iio_backend_data_source_set - Select data source
366  * @back: Backend device
370  * A given backend may have different sources to stream/sync data. This allows
380 		return -EINVAL;  in iio_backend_data_source_set()
387  * iio_backend_data_source_get - Get current data source
388  * @back: Backend device
392  * A given backend may have different sources to stream/sync data. This allows
408 		return -EINVAL;  in iio_backend_data_source_get()
415  * iio_backend_set_sampling_freq - Set channel sampling rate
416  * @back: Backend device
431  * iio_backend_test_pattern_set - Configure a test pattern
432  * @back: Backend device
436  * Configure a test pattern on the backend. This is typically used for
447 		return -EINVAL;  in iio_backend_test_pattern_set()
454  * iio_backend_chan_status - Get the channel status
455  * @back: Backend device
459  * Get the current state of the backend channel. Typically used to check if
473  * iio_backend_iodelay_set - Set digital I/O delay
474  * @back: Backend device
481  * is very backend specific. Hence, frontend devices typically should go through
496  * iio_backend_data_sample_trigger - Control when to sample data
497  * @back: Backend device
500  * Mostly useful for input backends. Configures the backend for when to sample
510 		return -EINVAL;  in iio_backend_data_sample_trigger()
520 	iio_backend_void_op_call(pair->back, free_buffer, pair->buffer);  in iio_backend_free_buffer()
524  * devm_iio_backend_request_buffer - Device managed buffer request
525  * @dev: Consumer device for the backend
526  * @back: Backend device
527  * @indio_dev: IIO device
529  * Request an IIO buffer from the backend. The type of the buffer (typically
530  * INDIO_BUFFER_HARDWARE) is up to the backend to decide. This is because,
531  * normally, the backend dictates what kind of buffering we can get.
533  * The backend .free_buffer() hooks is automatically called on @dev detach.
547 		return -ENOMEM;  in devm_iio_backend_request_buffer()
554 	pair->back = back;  in devm_iio_backend_request_buffer()
555 	pair->buffer = buffer;  in devm_iio_backend_request_buffer()
562  * iio_backend_read_raw - Read a channel attribute from a backend device.
563  * @back:	Backend device
564  * @chan:	IIO channel reference
582 	struct iio_backend *back = ERR_PTR(-ENODEV), *iter;  in iio_backend_from_indio_dev_parent()
587 	 * than one backend in which case returning the first we find is bogus.  in iio_backend_from_indio_dev_parent()
593 		if (dev == iter->frontend_dev) {  in iio_backend_from_indio_dev_parent()
597 				return ERR_PTR(-ENODEV);  in iio_backend_from_indio_dev_parent()
608  * iio_backend_ext_info_get - IIO ext_info read callback
609  * @indio_dev: IIO device
611  * @chan: IIO channel
614  * This helper is intended to be used by backends that extend an IIO channel
617  * a way to get the backend from indio_dev). This is the getter.
631 	 * backend from the frontend. Anyways, let's only introduce new options  in iio_backend_ext_info_get()
634 	back = iio_backend_from_indio_dev_parent(indio_dev->dev.parent);  in iio_backend_ext_info_get()
643  * iio_backend_ext_info_set - IIO ext_info write callback
644  * @indio_dev: IIO device
646  * @chan: IIO channel
650  * This helper is intended to be used by backends that extend an IIO channel
653  * a way to get the backend from indio_dev). This is the setter.
664 	back = iio_backend_from_indio_dev_parent(indio_dev->dev.parent);  in iio_backend_ext_info_set()
673  * iio_backend_interface_type_get - get the interface type used.
674  * @back: Backend device
690 		return -EINVAL;  in iio_backend_interface_type_get()
697  * iio_backend_data_size_set - set the data width/size in the data bus.
698  * @back: Backend device
702  * interface/data bus. Hence, the backend device needs to be aware of it so
711 		return -EINVAL;  in iio_backend_data_size_set()
718  * iio_backend_oversampling_ratio_set - set the oversampling ratio
719  * @back: Backend device
720  * @ratio: The oversampling ratio - value 1 corresponds to no oversampling.
734  * iio_backend_extend_chan_spec - Extend an IIO channel
735  * @back: Backend device
736  * @chan: IIO channel
747 	const struct iio_chan_spec_ext_info *frontend_ext_info = chan->ext_info;  in iio_backend_extend_chan_spec()
759 	if (frontend_ext_info && chan->ext_info != frontend_ext_info)  in iio_backend_extend_chan_spec()
760 		return -EOPNOTSUPP;  in iio_backend_extend_chan_spec()
761 	if (!chan->ext_info)  in iio_backend_extend_chan_spec()
765 	for (back_ext_info = chan->ext_info; back_ext_info->name; back_ext_info++) {  in iio_backend_extend_chan_spec()
766 		if (back_ext_info->read != iio_backend_ext_info_get)  in iio_backend_extend_chan_spec()
767 			return -EINVAL;  in iio_backend_extend_chan_spec()
768 		if (back_ext_info->write != iio_backend_ext_info_set)  in iio_backend_extend_chan_spec()
769 			return -EINVAL;  in iio_backend_extend_chan_spec()
780 	module_put(back->owner);  in iio_backend_release()
794 	if (!try_module_get(back->owner))  in __devm_iio_backend_get()
795 		return dev_err_probe(dev, -ENODEV,  in __devm_iio_backend_get()
802 	link = device_link_add(dev, back->dev, DL_FLAG_AUTOREMOVE_CONSUMER);  in __devm_iio_backend_get()
804 		return dev_err_probe(dev, -EINVAL,  in __devm_iio_backend_get()
806 				     dev_name(back->dev));  in __devm_iio_backend_get()
808 	back->frontend_dev = dev;  in __devm_iio_backend_get()
810 	dev_dbg(dev, "Found backend(%s) device\n", dev_name(back->dev));  in __devm_iio_backend_get()
816  * iio_backend_filter_type_set - Set filter type
817  * @back: Backend device
827 		return -EINVAL;  in iio_backend_filter_type_set()
834  * iio_backend_interface_data_align - Perform the data alignment process.
835  * @back: Backend device
850 		return -EINVAL;  in iio_backend_interface_data_align()
857  * iio_backend_num_lanes_set - Number of lanes enabled.
858  * @back: Backend device
867 		return -EINVAL;  in iio_backend_num_lanes_set()
874  * iio_backend_ddr_enable - Enable interface DDR (Double Data Rate) mode
875  * @back: Backend device
890  * iio_backend_ddr_disable - Disable interface DDR (Double Data Rate) mode
891  * @back: Backend device
905  * iio_backend_data_stream_enable - Enable data stream
906  * @back: Backend device
920  * iio_backend_data_stream_disable - Disable data stream
921  * @back: Backend device
935  * iio_backend_data_transfer_addr - Set data address.
936  * @back: Backend device
939  * Some devices may need to inform the backend about an address
960 		ret = device_property_match_string(dev, "io-backend-names",  in __devm_iio_backend_fwnode_get()
969 	fwnode_back = fwnode_find_reference(fwnode, "io-backends", index);  in __devm_iio_backend_fwnode_get()
976 		if (!device_match_fwnode(back->dev, fwnode_back))  in __devm_iio_backend_fwnode_get()
985 			back->idx = index;  in __devm_iio_backend_fwnode_get()
991 	return ERR_PTR(-EPROBE_DEFER);  in __devm_iio_backend_fwnode_get()
995  * devm_iio_backend_get - Device managed backend device get
996  * @dev: Consumer device for the backend
997  * @name: Backend name
999  * Get's the backend associated with @dev.
1002  * A backend pointer, negative error pointer otherwise.
1011  * devm_iio_backend_fwnode_get - Device managed backend firmware node get
1012  * @dev: Consumer device for the backend
1013  * @name: Backend name
1014  * @fwnode: Firmware node of the backend consumer
1016  * Get's the backend associated with a firmware node.
1019  * A backend pointer, negative error pointer otherwise.
1030  * __devm_iio_backend_get_from_fwnode_lookup - Device managed fwnode backend device get
1031  * @dev: Consumer device for the backend
1032  * @fwnode: Firmware node of the backend device
1034  * Search the backend list for a device matching @fwnode.
1039  * A backend pointer, negative error pointer otherwise.
1050 		if (!device_match_fwnode(back->dev, fwnode))  in __devm_iio_backend_get_from_fwnode_lookup()
1060 	return ERR_PTR(-EPROBE_DEFER);  in __devm_iio_backend_get_from_fwnode_lookup()
1065  * iio_backend_get_priv - Get driver private data
1066  * @back: Backend device
1070 	return back->priv;  in iio_backend_get_priv()
1079 	list_del(&back->entry);  in iio_backend_unregister()
1083  * devm_iio_backend_register - Device managed backend device register
1084  * @dev: Backend device being registered
1085  * @info: Backend info
1088  * @info is mandatory. Not providing it results in -EINVAL.
1098 	if (!info || !info->ops)  in devm_iio_backend_register()
1099 		return dev_err_probe(dev, -EINVAL, "No backend ops given\n");  in devm_iio_backend_register()
1103 	 * bound/exist if the backend driver is not around. Hence, we can bind  in devm_iio_backend_register()
1104 	 * the backend object lifetime with the device being passed since  in devm_iio_backend_register()
1109 		return -ENOMEM;  in devm_iio_backend_register()
1111 	back->ops = info->ops;  in devm_iio_backend_register()
1112 	back->name = info->name;  in devm_iio_backend_register()
1113 	back->owner = dev->driver->owner;  in devm_iio_backend_register()
1114 	back->dev = dev;  in devm_iio_backend_register()
1115 	back->priv = priv;  in devm_iio_backend_register()
1117 		list_add(&back->entry, &iio_back_list);  in devm_iio_backend_register()
1124 MODULE_DESCRIPTION("Framework to handle complex IIO aggregate devices");