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Diffstat (limited to 'drivers/iio/industrialio-backend.c')
| -rw-r--r-- | drivers/iio/industrialio-backend.c | 973 |
1 files changed, 973 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c new file mode 100644 index 000000000000..363281272035 --- /dev/null +++ b/drivers/iio/industrialio-backend.c @@ -0,0 +1,973 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Framework to handle complex IIO aggregate devices. + * + * The typical architecture is to have one device as the frontend device which + * can be "linked" against one or multiple backend devices. All the IIO and + * userspace interface is expected to be registers/managed by the frontend + * device which will callback into the backends when needed (to get/set some + * configuration that it does not directly control). + * + * ------------------------------------------------------- + * ------------------ | ------------ ------------ ------- FPGA| + * | ADC |------------------------| | ADC CORE |---------| DMA CORE |------| RAM | | + * | (Frontend/IIO) | Serial Data (eg: LVDS) | |(backend) |---------| |------| | | + * | |------------------------| ------------ ------------ ------- | + * ------------------ ------------------------------------------------------- + * + * The framework interface is pretty simple: + * - Backends should register themselves with devm_iio_backend_register() + * - Frontend devices should get backends with devm_iio_backend_get() + * + * Also to note that the primary target for this framework are converters like + * ADC/DACs so iio_backend_ops will have some operations typical of converter + * devices. On top of that, this is "generic" for all IIO which means any kind + * of device can make use of the framework. That said, If the iio_backend_ops + * struct begins to grow out of control, we can always refactor things so that + * the industrialio-backend.c is only left with the really generic stuff. Then, + * we can build on top of it depending on the needs. + * + * Copyright (C) 2023-2024 Analog Devices Inc. + */ +#define dev_fmt(fmt) "iio-backend: " fmt + +#include <linux/cleanup.h> +#include <linux/debugfs.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/property.h> +#include <linux/slab.h> +#include <linux/stringify.h> +#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; + const char *name; + unsigned int cached_reg_addr; + /* + * This index is relative to the frontend. Meaning that for + * frontends with multiple backends, this will be the index of this + * backend. Used for the debugfs directory name. + */ + u8 idx; +}; + +/* + * Helper struct for requesting buffers. This ensures that we have all data + * that we need to free the buffer in a device managed action. + */ +struct iio_backend_buffer_pair { + struct iio_backend *back; + struct iio_buffer *buffer; +}; + +static LIST_HEAD(iio_back_list); +static DEFINE_MUTEX(iio_back_lock); + +/* + * Helper macros to call backend ops. Makes sure the option is supported. + */ +#define iio_backend_check_op(back, op) ({ \ + struct iio_backend *____back = back; \ + int ____ret = 0; \ + \ + if (!____back->ops->op) \ + ____ret = -EOPNOTSUPP; \ + \ + ____ret; \ +}) + +#define iio_backend_op_call(back, op, args...) ({ \ + struct iio_backend *__back = back; \ + int __ret; \ + \ + __ret = iio_backend_check_op(__back, op); \ + if (!__ret) \ + __ret = __back->ops->op(__back, ##args); \ + \ + __ret; \ +}) + +#define iio_backend_ptr_op_call(back, op, args...) ({ \ + struct iio_backend *__back = back; \ + void *ptr_err; \ + int __ret; \ + \ + __ret = iio_backend_check_op(__back, op); \ + if (__ret) \ + ptr_err = ERR_PTR(__ret); \ + else \ + ptr_err = __back->ops->op(__back, ##args); \ + \ + ptr_err; \ +}) + +#define iio_backend_void_op_call(back, op, args...) { \ + struct iio_backend *__back = back; \ + int __ret; \ + \ + __ret = iio_backend_check_op(__back, op); \ + if (!__ret) \ + __back->ops->op(__back, ##args); \ + else \ + dev_dbg(__back->dev, "Op(%s) not implemented\n",\ + __stringify(op)); \ +} + +static ssize_t iio_backend_debugfs_read_reg(struct file *file, + char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct iio_backend *back = file->private_data; + char read_buf[20]; + unsigned int val; + int ret, len; + + ret = iio_backend_op_call(back, debugfs_reg_access, + back->cached_reg_addr, 0, &val); + if (ret) + return ret; + + len = scnprintf(read_buf, sizeof(read_buf), "0x%X\n", val); + + return simple_read_from_buffer(userbuf, count, ppos, read_buf, len); +} + +static ssize_t iio_backend_debugfs_write_reg(struct file *file, + const char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct iio_backend *back = file->private_data; + unsigned int val; + char buf[80]; + ssize_t rc; + int ret; + + rc = simple_write_to_buffer(buf, sizeof(buf), ppos, userbuf, count); + if (rc < 0) + return rc; + + ret = sscanf(buf, "%i %i", &back->cached_reg_addr, &val); + + switch (ret) { + case 1: + return count; + case 2: + ret = iio_backend_op_call(back, debugfs_reg_access, + back->cached_reg_addr, val, NULL); + if (ret) + return ret; + return count; + default: + return -EINVAL; + } +} + +static const struct file_operations iio_backend_debugfs_reg_fops = { + .open = simple_open, + .read = iio_backend_debugfs_read_reg, + .write = iio_backend_debugfs_write_reg, +}; + +static ssize_t iio_backend_debugfs_read_name(struct file *file, + char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct iio_backend *back = file->private_data; + char name[128]; + int len; + + len = scnprintf(name, sizeof(name), "%s\n", back->name); + + return simple_read_from_buffer(userbuf, count, ppos, name, len); +} + +static const struct file_operations iio_backend_debugfs_name_fops = { + .open = simple_open, + .read = iio_backend_debugfs_read_name, +}; + +/** + * iio_backend_debugfs_add - Add debugfs interfaces for Backends + * @back: Backend device + * @indio_dev: IIO device + */ +void iio_backend_debugfs_add(struct iio_backend *back, + struct iio_dev *indio_dev) +{ + struct dentry *d = iio_get_debugfs_dentry(indio_dev); + struct dentry *back_d; + char name[128]; + + if (!IS_ENABLED(CONFIG_DEBUG_FS) || !d) + return; + if (!back->ops->debugfs_reg_access && !back->name) + return; + + snprintf(name, sizeof(name), "backend%d", back->idx); + + back_d = debugfs_create_dir(name, d); + if (IS_ERR(back_d)) + return; + + if (back->ops->debugfs_reg_access) + debugfs_create_file("direct_reg_access", 0600, back_d, back, + &iio_backend_debugfs_reg_fops); + + if (back->name) + debugfs_create_file("name", 0400, back_d, back, + &iio_backend_debugfs_name_fops); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_debugfs_add, "IIO_BACKEND"); + +/** + * iio_backend_debugfs_print_chan_status - Print channel status + * @back: Backend device + * @chan: Channel number + * @buf: Buffer where to print the status + * @len: Available space + * + * One usecase where this is useful is for testing test tones in a digital + * interface and "ask" the backend to dump more details on why a test tone might + * have errors. + * + * RETURNS: + * Number of copied bytes on success, negative error code on failure. + */ +ssize_t iio_backend_debugfs_print_chan_status(struct iio_backend *back, + unsigned int chan, char *buf, + size_t len) +{ + if (!IS_ENABLED(CONFIG_DEBUG_FS)) + return -ENODEV; + + return iio_backend_op_call(back, debugfs_print_chan_status, chan, buf, + len); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_debugfs_print_chan_status, "IIO_BACKEND"); + +/** + * iio_backend_chan_enable - Enable a backend channel + * @back: Backend device + * @chan: Channel number + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_chan_enable(struct iio_backend *back, unsigned int chan) +{ + return iio_backend_op_call(back, chan_enable, chan); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_chan_enable, "IIO_BACKEND"); + +/** + * iio_backend_chan_disable - Disable a backend channel + * @back: Backend device + * @chan: Channel number + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_chan_disable(struct iio_backend *back, unsigned int chan) +{ + return iio_backend_op_call(back, chan_disable, chan); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_chan_disable, "IIO_BACKEND"); + +static void __iio_backend_disable(void *back) +{ + iio_backend_void_op_call(back, disable); +} + +/** + * iio_backend_disable - Backend disable + * @back: Backend device + */ +void iio_backend_disable(struct iio_backend *back) +{ + __iio_backend_disable(back); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_disable, "IIO_BACKEND"); + +/** + * iio_backend_enable - Backend enable + * @back: Backend device + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_enable(struct iio_backend *back) +{ + return iio_backend_op_call(back, enable); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_enable, "IIO_BACKEND"); + +/** + * devm_iio_backend_enable - Device managed backend enable + * @dev: Consumer device for the backend + * @back: Backend device + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int devm_iio_backend_enable(struct device *dev, struct iio_backend *back) +{ + int ret; + + ret = iio_backend_enable(back); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, __iio_backend_disable, back); +} +EXPORT_SYMBOL_NS_GPL(devm_iio_backend_enable, "IIO_BACKEND"); + +/** + * iio_backend_data_format_set - Configure the channel data format + * @back: Backend device + * @chan: Channel number + * @data: Data format + * + * Properly configure a channel with respect to the expected data format. A + * @struct iio_backend_data_fmt must be passed with the settings. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_data_format_set(struct iio_backend *back, unsigned int chan, + const struct iio_backend_data_fmt *data) +{ + if (!data || data->type >= IIO_BACKEND_DATA_TYPE_MAX) + return -EINVAL; + + return iio_backend_op_call(back, data_format_set, chan, data); +} +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"); + +/** + * iio_backend_test_pattern_set - Configure a test pattern + * @back: Backend device + * @chan: Channel number + * @pattern: Test pattern + * + * Configure a test pattern on the backend. This is typically used for + * calibrating the timings on the data digital interface. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_test_pattern_set(struct iio_backend *back, + unsigned int chan, + enum iio_backend_test_pattern pattern) +{ + if (pattern >= IIO_BACKEND_TEST_PATTERN_MAX) + return -EINVAL; + + return iio_backend_op_call(back, test_pattern_set, chan, pattern); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_test_pattern_set, "IIO_BACKEND"); + +/** + * iio_backend_chan_status - Get the channel status + * @back: Backend device + * @chan: Channel number + * @error: Error indication + * + * Get the current state of the backend channel. Typically used to check if + * there were any errors sending/receiving data. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_chan_status(struct iio_backend *back, unsigned int chan, + bool *error) +{ + return iio_backend_op_call(back, chan_status, chan, error); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_chan_status, "IIO_BACKEND"); + +/** + * iio_backend_iodelay_set - Set digital I/O delay + * @back: Backend device + * @lane: Lane number + * @taps: Number of taps + * + * Controls delays on sending/receiving data. One usecase for this is to + * calibrate the data digital interface so we get the best results when + * transferring data. Note that @taps has no unit since the actual delay per tap + * is very backend specific. Hence, frontend devices typically should go through + * an array of @taps (the size of that array should typically match the size of + * calibration points on the frontend device) and call this API. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_iodelay_set(struct iio_backend *back, unsigned int lane, + unsigned int taps) +{ + return iio_backend_op_call(back, iodelay_set, lane, taps); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_iodelay_set, "IIO_BACKEND"); + +/** + * iio_backend_data_sample_trigger - Control when to sample data + * @back: Backend device + * @trigger: Data trigger + * + * Mostly useful for input backends. Configures the backend for when to sample + * data (eg: rising vs falling edge). + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_data_sample_trigger(struct iio_backend *back, + enum iio_backend_sample_trigger trigger) +{ + if (trigger >= IIO_BACKEND_SAMPLE_TRIGGER_MAX) + return -EINVAL; + + return iio_backend_op_call(back, data_sample_trigger, trigger); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_data_sample_trigger, "IIO_BACKEND"); + +static void iio_backend_free_buffer(void *arg) +{ + struct iio_backend_buffer_pair *pair = arg; + + iio_backend_void_op_call(pair->back, free_buffer, pair->buffer); +} + +/** + * devm_iio_backend_request_buffer - Device managed buffer request + * @dev: Consumer device for the backend + * @back: Backend device + * @indio_dev: IIO device + * + * Request an IIO buffer from the backend. The type of the buffer (typically + * INDIO_BUFFER_HARDWARE) is up to the backend to decide. This is because, + * normally, the backend dictates what kind of buffering we can get. + * + * The backend .free_buffer() hooks is automatically called on @dev detach. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int devm_iio_backend_request_buffer(struct device *dev, + struct iio_backend *back, + struct iio_dev *indio_dev) +{ + struct iio_backend_buffer_pair *pair; + struct iio_buffer *buffer; + + pair = devm_kzalloc(dev, sizeof(*pair), GFP_KERNEL); + if (!pair) + return -ENOMEM; + + buffer = iio_backend_ptr_op_call(back, request_buffer, indio_dev); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); + + /* weak reference should be all what we need */ + pair->back = back; + pair->buffer = buffer; + + return devm_add_action_or_reset(dev, iio_backend_free_buffer, pair); +} +EXPORT_SYMBOL_NS_GPL(devm_iio_backend_request_buffer, "IIO_BACKEND"); + +/** + * iio_backend_read_raw - Read a channel attribute from a backend device. + * @back: Backend device + * @chan: IIO channel reference + * @val: First returned value + * @val2: Second returned value + * @mask: Specify the attribute to return + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_read_raw(struct iio_backend *back, + struct iio_chan_spec const *chan, int *val, int *val2, + long mask) +{ + return iio_backend_op_call(back, read_raw, chan, val, val2, mask); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_read_raw, "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 + * @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_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; + + module_put(back->owner); +} + +static int __devm_iio_backend_get(struct device *dev, struct iio_backend *back) +{ + struct device_link *link; + int ret; + + /* + * Make sure the provider cannot be unloaded before the consumer module. + * Note that device_links would still guarantee that nothing is + * accessible (and breaks) but this makes it explicit that the consumer + * module must be also unloaded. + */ + if (!try_module_get(back->owner)) + return dev_err_probe(dev, -ENODEV, + "Cannot get module reference\n"); + + ret = devm_add_action_or_reset(dev, iio_backend_release, back); + if (ret) + return ret; + + link = device_link_add(dev, back->dev, DL_FLAG_AUTOREMOVE_CONSUMER); + if (!link) + return dev_err_probe(dev, -EINVAL, + "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; +} + +/** + * iio_backend_ddr_enable - Enable interface DDR (Double Data Rate) mode + * @back: Backend device + * + * Enable DDR, data is generated by the IP at each front (raising and falling) + * of the bus clock signal. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_ddr_enable(struct iio_backend *back) +{ + return iio_backend_op_call(back, ddr_enable); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_ddr_enable, "IIO_BACKEND"); + +/** + * iio_backend_ddr_disable - Disable interface DDR (Double Data Rate) mode + * @back: Backend device + * + * Disable DDR, setting into SDR mode (Single Data Rate). + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_ddr_disable(struct iio_backend *back) +{ + return iio_backend_op_call(back, ddr_disable); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_ddr_disable, "IIO_BACKEND"); + +/** + * iio_backend_data_stream_enable - Enable data stream + * @back: Backend device + * + * Enable data stream over the bus interface. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_data_stream_enable(struct iio_backend *back) +{ + return iio_backend_op_call(back, data_stream_enable); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_data_stream_enable, "IIO_BACKEND"); + +/** + * iio_backend_data_stream_disable - Disable data stream + * @back: Backend device + * + * Disable data stream over the bus interface. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_data_stream_disable(struct iio_backend *back) +{ + return iio_backend_op_call(back, data_stream_disable); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_data_stream_disable, "IIO_BACKEND"); + +/** + * iio_backend_data_transfer_addr - Set data address. + * @back: Backend device + * @address: Data register address + * + * Some devices may need to inform the backend about an address + * where to read or write the data. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int iio_backend_data_transfer_addr(struct iio_backend *back, u32 address) +{ + return iio_backend_op_call(back, data_transfer_addr, address); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_data_transfer_addr, "IIO_BACKEND"); + +static struct iio_backend *__devm_iio_backend_fwnode_get(struct device *dev, const char *name, + struct fwnode_handle *fwnode) +{ + struct fwnode_handle *fwnode_back; + struct iio_backend *back; + unsigned int index; + int ret; + + if (name) { + ret = device_property_match_string(dev, "io-backend-names", + name); + if (ret < 0) + return ERR_PTR(ret); + index = ret; + } else { + index = 0; + } + + fwnode_back = fwnode_find_reference(fwnode, "io-backends", index); + if (IS_ERR(fwnode_back)) + return dev_err_cast_probe(dev, fwnode_back, + "Cannot get Firmware reference\n"); + + guard(mutex)(&iio_back_lock); + list_for_each_entry(back, &iio_back_list, entry) { + if (!device_match_fwnode(back->dev, fwnode_back)) + continue; + + fwnode_handle_put(fwnode_back); + ret = __devm_iio_backend_get(dev, back); + if (ret) + return ERR_PTR(ret); + + if (name) + back->idx = index; + + return back; + } + + fwnode_handle_put(fwnode_back); + return ERR_PTR(-EPROBE_DEFER); +} + +/** + * devm_iio_backend_get - Device managed backend device get + * @dev: Consumer device for the backend + * @name: Backend name + * + * Get's the backend associated with @dev. + * + * RETURNS: + * A backend pointer, negative error pointer otherwise. + */ +struct iio_backend *devm_iio_backend_get(struct device *dev, const char *name) +{ + return __devm_iio_backend_fwnode_get(dev, name, dev_fwnode(dev)); +} +EXPORT_SYMBOL_NS_GPL(devm_iio_backend_get, "IIO_BACKEND"); + +/** + * devm_iio_backend_fwnode_get - Device managed backend firmware node get + * @dev: Consumer device for the backend + * @name: Backend name + * @fwnode: Firmware node of the backend consumer + * + * Get's the backend associated with a firmware node. + * + * RETURNS: + * A backend pointer, negative error pointer otherwise. + */ +struct iio_backend *devm_iio_backend_fwnode_get(struct device *dev, + const char *name, + struct fwnode_handle *fwnode) +{ + return __devm_iio_backend_fwnode_get(dev, name, fwnode); +} +EXPORT_SYMBOL_NS_GPL(devm_iio_backend_fwnode_get, "IIO_BACKEND"); + +/** + * __devm_iio_backend_get_from_fwnode_lookup - Device managed fwnode backend device get + * @dev: Consumer device for the backend + * @fwnode: Firmware node of the backend device + * + * Search the backend list for a device matching @fwnode. + * This API should not be used and it's only present for preventing the first + * user of this framework to break it's DT ABI. + * + * RETURNS: + * A backend pointer, negative error pointer otherwise. + */ +struct iio_backend * +__devm_iio_backend_get_from_fwnode_lookup(struct device *dev, + struct fwnode_handle *fwnode) +{ + struct iio_backend *back; + int ret; + + guard(mutex)(&iio_back_lock); + list_for_each_entry(back, &iio_back_list, entry) { + if (!device_match_fwnode(back->dev, fwnode)) + continue; + + ret = __devm_iio_backend_get(dev, back); + if (ret) + return ERR_PTR(ret); + + return back; + } + + return ERR_PTR(-EPROBE_DEFER); +} +EXPORT_SYMBOL_NS_GPL(__devm_iio_backend_get_from_fwnode_lookup, "IIO_BACKEND"); + +/** + * iio_backend_get_priv - Get driver private data + * @back: Backend device + */ +void *iio_backend_get_priv(const struct iio_backend *back) +{ + return back->priv; +} +EXPORT_SYMBOL_NS_GPL(iio_backend_get_priv, "IIO_BACKEND"); + +static void iio_backend_unregister(void *arg) +{ + struct iio_backend *back = arg; + + guard(mutex)(&iio_back_lock); + list_del(&back->entry); +} + +/** + * devm_iio_backend_register - Device managed backend device register + * @dev: Backend device being registered + * @info: Backend info + * @priv: Device private data + * + * @info is mandatory. Not providing it results in -EINVAL. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int devm_iio_backend_register(struct device *dev, + const struct iio_backend_info *info, void *priv) +{ + struct iio_backend *back; + + if (!info || !info->ops) + return dev_err_probe(dev, -EINVAL, "No backend ops given\n"); + + /* + * Through device_links, we guarantee that a frontend device cannot be + * bound/exist if the backend driver is not around. Hence, we can bind + * the backend object lifetime with the device being passed since + * removing it will tear the frontend/consumer down. + */ + back = devm_kzalloc(dev, sizeof(*back), GFP_KERNEL); + if (!back) + return -ENOMEM; + + back->ops = info->ops; + back->name = info->name; + back->owner = dev->driver->owner; + back->dev = dev; + back->priv = priv; + scoped_guard(mutex, &iio_back_lock) + list_add(&back->entry, &iio_back_list); + + return devm_add_action_or_reset(dev, iio_backend_unregister, back); +} +EXPORT_SYMBOL_NS_GPL(devm_iio_backend_register, "IIO_BACKEND"); + +MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>"); +MODULE_DESCRIPTION("Framework to handle complex IIO aggregate devices"); +MODULE_LICENSE("GPL"); |