From 9b34845ee3620ddf1329932edde00bd5b4b9d466 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Thu, 17 Sep 2015 17:19:17 +0100 Subject: [PATCH] staging: comedi: drivers.c: document exported functions Add missing kernel-doc to the low-level COMEDI driver API functions exported from "drivers.c" and tart up some of the existing kernel-doc comments for consistency. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers.c | 327 ++++++++++++++++++++++++------- 1 file changed, 258 insertions(+), 69 deletions(-) diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c index 711811771bfc..aae94815b593 100644 --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -34,6 +34,28 @@ struct comedi_driver *comedi_drivers; /* protects access to comedi_drivers */ DEFINE_MUTEX(comedi_drivers_list_lock); +/** + * comedi_set_hw_dev() - Set hardware device associated with COMEDI device + * @dev: COMEDI device. + * @hw_dev: Hardware device. + * + * For automatically configured COMEDI devices (resulting from a call to + * comedi_auto_config() or one of its wrappers from the low-level COMEDI + * driver), comedi_set_hw_dev() is called automatically by the COMEDI core + * to associate the COMEDI device with the hardware device. It can also be + * called directly by "legacy" low-level COMEDI drivers that rely on the + * %COMEDI_DEVCONFIG ioctl to configure the hardware as long as the hardware + * has a &struct device. + * + * If @dev->hw_dev is NULL, it gets a reference to @hw_dev and sets + * @dev->hw_dev, otherwise, it does nothing. Calling it multiple times + * with the same hardware device is not considered an error. If it gets + * a reference to the hardware device, it will be automatically 'put' when + * the device is detached from COMEDI. + * + * Returns 0 if @dev->hw_dev was NULL or the same as @hw_dev, otherwise + * returns -EEXIST. + */ int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev) { if (hw_dev == dev->hw_dev) @@ -52,9 +74,15 @@ static void comedi_clear_hw_dev(struct comedi_device *dev) } /** - * comedi_alloc_devpriv() - Allocate memory for the device private data. - * @dev: comedi_device struct - * @size: size of the memory to allocate + * comedi_alloc_devpriv() - Allocate memory for the device private data + * @dev: COMEDI device. + * @size: Size of the memory to allocate. + * + * The allocated memory is zero-filled. @dev->private points to it on + * return. The memory will be automatically freed when the COMEDI device is + * "detached". + * + * Returns a pointer to the allocated memory, or NULL on failure. */ void *comedi_alloc_devpriv(struct comedi_device *dev, size_t size) { @@ -63,6 +91,18 @@ void *comedi_alloc_devpriv(struct comedi_device *dev, size_t size) } EXPORT_SYMBOL_GPL(comedi_alloc_devpriv); +/** + * comedi_alloc_subdevices() - Allocate subdevices for COMEDI device + * @dev: COMEDI device. + * @num_subdevices: Number of subdevices to allocate. + * + * Allocates and initializes an array of &struct comedi_subdevice for the + * COMEDI device. If successful, sets @dev->subdevices to point to the + * first one and @dev->n_subdevices to the number. + * + * Returns 0 on success, -EINVAL if @num_subdevices is < 1, or -ENOMEM if + * failed to allocate the memory. + */ int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices) { struct comedi_subdevice *s; @@ -90,8 +130,22 @@ int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices) EXPORT_SYMBOL_GPL(comedi_alloc_subdevices); /** - * comedi_alloc_subdev_readback() - Allocate memory for the subdevice readback. - * @s: comedi_subdevice struct + * comedi_alloc_subdev_readback() - Allocate memory for the subdevice readback + * @s: COMEDI subdevice. + * + * This is called by low-level COMEDI drivers to allocate an array to record + * the last values written to a subdevice's analog output channels (at least + * by the %INSN_WRITE instruction), to allow them to be read back by an + * %INSN_READ instruction. It also provides a default handler for the + * %INSN_READ instruction unless one has already been set. + * + * On success, @s->readback points to the first element of the array, which + * is zero-filled. The low-level driver is responsible for updating its + * contents. @s->insn_read will be set to comedi_readback_insn_read() + * unless it is already non-NULL. + * + * Returns 0 on success, -EINVAL if the subdevice has no channels, or + * -ENOMEM on allocation failure. */ int comedi_alloc_subdev_readback(struct comedi_subdevice *s) { @@ -174,10 +228,20 @@ int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s, /** * comedi_readback_insn_read() - A generic (*insn_read) for subdevice readback. - * @dev: comedi_device struct - * @s: comedi_subdevice struct - * @insn: comedi_insn struct - * @data: pointer to return the readback data + * @dev: COMEDI device. + * @s: COMEDI subdevice. + * @insn: COMEDI instruction. + * @data: Pointer to return the readback data. + * + * Handles the %INSN_READ instruction for subdevices that use the readback + * array allocated by comedi_alloc_subdev_readback(). It may be used + * directly as the subdevice's handler (@s->insn_read) or called via a + * wrapper. + * + * @insn->n is normally 1, which will read a single value. If higher, the + * same element of the readback array will be read multiple times. + * + * Returns @insn->n on success, or -EINVAL if @s->readback is NULL. */ int comedi_readback_insn_read(struct comedi_device *dev, struct comedi_subdevice *s, @@ -198,12 +262,21 @@ int comedi_readback_insn_read(struct comedi_device *dev, EXPORT_SYMBOL_GPL(comedi_readback_insn_read); /** - * comedi_timeout() - busy-wait for a driver condition to occur. - * @dev: comedi_device struct - * @s: comedi_subdevice struct - * @insn: comedi_insn struct - * @cb: callback to check for the condition - * @context: private context from the driver + * comedi_timeout() - Busy-wait for a driver condition to occur + * @dev: COMEDI device. + * @s: COMEDI subdevice. + * @insn: COMEDI instruction. + * @cb: Callback to check for the condition. + * @context: Private context from the driver. + * + * Busy-waits for up to a second (%COMEDI_TIMEOUT_MS) for the condition or + * some error (other than -EBUSY) to occur. The parameters @dev, @s, @insn, + * and @context are passed to the callback function, which returns -EBUSY to + * continue waiting or some other value to stop waiting (generally 0 if the + * condition occurred, or some error value). + * + * Returns -ETIMEDOUT if timed out, otherwise the return value from the + * callback function. */ int comedi_timeout(struct comedi_device *dev, struct comedi_subdevice *s, @@ -228,12 +301,30 @@ int comedi_timeout(struct comedi_device *dev, EXPORT_SYMBOL_GPL(comedi_timeout); /** - * comedi_dio_insn_config() - boilerplate (*insn_config) for DIO subdevices. - * @dev: comedi_device struct - * @s: comedi_subdevice struct - * @insn: comedi_insn struct - * @data: parameters for the @insn - * @mask: io_bits mask for grouped channels + * comedi_dio_insn_config() - Boilerplate (*insn_config) for DIO subdevices + * @dev: COMEDI device. + * @s: COMEDI subdevice. + * @insn: COMEDI instruction. + * @data: Instruction parameters and return data. + * @mask: io_bits mask for grouped channels, or 0 for single channel. + * + * If @mask is 0, it is replaced with a single-bit mask corresponding to the + * channel number specified by @insn->chanspec. Otherwise, @mask + * corresponds to a group of channels (which should include the specified + * channel) that are always configured together as inputs or outputs. + * + * Partially handles the %INSN_CONFIG_DIO_INPUT, %INSN_CONFIG_DIO_OUTPUTS, + * and %INSN_CONFIG_DIO_QUERY instructions. The first two update + * @s->io_bits to record the directions of the masked channels. The last + * one sets @data[1] to the current direction of the group of channels + * (%COMEDI_INPUT) or %COMEDI_OUTPUT) as recorded in @s->io_bits. + * + * The caller is responsible for updating the DIO direction in the hardware + * registers if this function returns 0. + * + * Returns 0 for a %INSN_CONFIG_DIO_INPUT or %INSN_CONFIG_DIO_OUTPUT + * instruction, @insn->n (> 0) for a %INSN_CONFIG_DIO_QUERY instruction, or + * -EINVAL for some other instruction. */ int comedi_dio_insn_config(struct comedi_device *dev, struct comedi_subdevice *s, @@ -268,9 +359,18 @@ int comedi_dio_insn_config(struct comedi_device *dev, EXPORT_SYMBOL_GPL(comedi_dio_insn_config); /** - * comedi_dio_update_state() - update the internal state of DIO subdevices. - * @s: comedi_subdevice struct - * @data: the channel mask and bits to update + * comedi_dio_update_state() - Update the internal state of DIO subdevices + * @s: COMEDI subdevice. + * @data: The channel mask and bits to update. + * + * Updates @s->state which holds the internal state of the outputs for DIO + * or DO subdevices (up to 32 channels). @data[0] contains a bit-mask of + * the channels to be updated. @data[1] contains a bit-mask of those + * channels to be set to '1'. The caller is responsible for updating the + * outputs in hardware according to @s->state. As a minimum, the channels + * in the returned bit-mask need to be updated. + * + * Returns @mask with non-existent channels removed. */ unsigned int comedi_dio_update_state(struct comedi_subdevice *s, unsigned int *data) @@ -290,17 +390,17 @@ unsigned int comedi_dio_update_state(struct comedi_subdevice *s, EXPORT_SYMBOL_GPL(comedi_dio_update_state); /** - * comedi_bytes_per_scan - get length of asynchronous command "scan" in bytes - * @s: comedi_subdevice struct + * comedi_bytes_per_scan() - Get length of asynchronous command "scan" in bytes + * @s: COMEDI subdevice. * * Determines the overall scan length according to the subdevice type and the * number of channels in the scan. * - * For digital input, output or input/output subdevices, samples for multiple - * channels are assumed to be packed into one or more unsigned short or - * unsigned int values according to the subdevice's SDF_LSAMPL flag. For other - * types of subdevice, samples are assumed to occupy a whole unsigned short or - * unsigned int according to the SDF_LSAMPL flag. + * For digital input, output or input/output subdevices, samples for + * multiple channels are assumed to be packed into one or more unsigned + * short or unsigned int values according to the subdevice's %SDF_LSAMPL + * flag. For other types of subdevice, samples are assumed to occupy a + * whole unsigned short or unsigned int according to the %SDF_LSAMPL flag. * * Returns the overall scan length in bytes. */ @@ -326,18 +426,18 @@ unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s) EXPORT_SYMBOL_GPL(comedi_bytes_per_scan); /** - * comedi_nscans_left - return the number of scans left in the command - * @s: comedi_subdevice struct - * @nscans: the expected number of scans + * comedi_nscans_left() - Return the number of scans left in the command + * @s: COMEDI subdevice. + * @nscans: The expected number of scans or 0 for all available scans. * - * If nscans is 0, the number of scans available in the async buffer will be - * used. Otherwise the expected number of scans will be used. + * If @nscans is 0, it is set to the number of scans available in the + * async buffer. * - * If the async command has a stop_src of TRIG_COUNT, the nscans will be - * checked against the number of scans left in the command. + * If the async command has a stop_src of %TRIG_COUNT, the @nscans will be + * checked against the number of scans remaining to complete the command. * * The return value will then be either the expected number of scans or the - * number of scans remaining in the command. + * number of scans remaining to complete the command, whichever is fewer. */ unsigned int comedi_nscans_left(struct comedi_subdevice *s, unsigned int nscans) @@ -365,12 +465,12 @@ unsigned int comedi_nscans_left(struct comedi_subdevice *s, EXPORT_SYMBOL_GPL(comedi_nscans_left); /** - * comedi_nsamples_left - return the number of samples left in the command - * @s: comedi_subdevice struct - * @nsamples: the expected number of samples + * comedi_nsamples_left() - Return the number of samples left in the command + * @s: COMEDI subdevice. + * @nsamples: The expected number of samples. * - * Returns the expected number of samples of the number of samples remaining - * in the command. + * Returns the number of samples remaining to complete the command, or the + * specified expected number of samples (@nsamples), whichever is fewer. */ unsigned int comedi_nsamples_left(struct comedi_subdevice *s, unsigned int nsamples) @@ -399,14 +499,14 @@ unsigned int comedi_nsamples_left(struct comedi_subdevice *s, EXPORT_SYMBOL_GPL(comedi_nsamples_left); /** - * comedi_inc_scan_progress - update scan progress in asynchronous command - * @s: comedi_subdevice struct - * @num_bytes: amount of data in bytes to increment scan progress + * comedi_inc_scan_progress() - Update scan progress in asynchronous command + * @s: COMEDI subdevice. + * @num_bytes: Amount of data in bytes to increment scan progress. * - * Increments the scan progress by the number of bytes specified by num_bytes. + * Increments the scan progress by the number of bytes specified by @num_bytes. * If the scan progress reaches or exceeds the scan length in bytes, reduce * it modulo the scan length in bytes and set the "end of scan" asynchronous - * event flag to be processed later. + * event flag (%COMEDI_CB_EOS) to be processed later. */ void comedi_inc_scan_progress(struct comedi_subdevice *s, unsigned int num_bytes) @@ -437,12 +537,12 @@ void comedi_inc_scan_progress(struct comedi_subdevice *s, EXPORT_SYMBOL_GPL(comedi_inc_scan_progress); /** - * comedi_handle_events - handle events and possibly stop acquisition - * @dev: comedi_device struct - * @s: comedi_subdevice struct + * comedi_handle_events() - Handle events and possibly stop acquisition + * @dev: COMEDI device. + * @s: COMEDI subdevice. * * Handles outstanding asynchronous acquisition event flags associated - * with the subdevice. Call the subdevice's "->cancel()" handler if the + * with the subdevice. Call the subdevice's @s->cancel() handler if the * "end of acquisition", "error" or "overflow" event flags are set in order * to stop the acquisition at the driver level. * @@ -677,12 +777,19 @@ static void comedi_report_boards(struct comedi_driver *driv) } /** - * comedi_load_firmware() - Request and load firmware for a device. - * @dev: comedi_device struct - * @hw_device: device struct for the comedi_device - * @name: the name of the firmware image - * @cb: callback to the upload the firmware image - * @context: private context from the driver + * comedi_load_firmware() - Request and load firmware for a device + * @dev: COMEDI device. + * @device: Hardware device. + * @name: The name of the firmware image. + * @cb: Callback to the upload the firmware image. + * @context: Private context from the driver. + * + * Sends a firmware request for the hardware device and waits for it. Calls + * the callback function to upload the firmware to the device, them releases + * the firmware. + * + * Returns 0 on success, -EINVAL if @cb is NULL, or a negative error number + * from the firmware request or the callback function. */ int comedi_load_firmware(struct comedi_device *dev, struct device *device, @@ -709,10 +816,16 @@ int comedi_load_firmware(struct comedi_device *dev, EXPORT_SYMBOL_GPL(comedi_load_firmware); /** - * __comedi_request_region() - Request an I/O reqion for a legacy driver. - * @dev: comedi_device struct - * @start: base address of the I/O reqion - * @len: length of the I/O region + * __comedi_request_region() - Request an I/O region for a legacy driver + * @dev: COMEDI device. + * @start: Base address of the I/O region. + * @len: Length of the I/O region. + * + * Requests the specified I/O port region which must start at a non-zero + * address. + * + * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request + * fails. */ int __comedi_request_region(struct comedi_device *dev, unsigned long start, unsigned long len) @@ -735,10 +848,19 @@ int __comedi_request_region(struct comedi_device *dev, EXPORT_SYMBOL_GPL(__comedi_request_region); /** - * comedi_request_region() - Request an I/O reqion for a legacy driver. - * @dev: comedi_device struct - * @start: base address of the I/O reqion - * @len: length of the I/O region + * comedi_request_region() - Request an I/O region for a legacy driver + * @dev: COMEDI device. + * @start: Base address of the I/O region. + * @len: Length of the I/O region. + * + * Requests the specified I/O port region which must start at a non-zero + * address. + * + * On success, @dev->iobase is set to the base address of the region and + * @dev->iolen is set to its length. + * + * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request + * fails. */ int comedi_request_region(struct comedi_device *dev, unsigned long start, unsigned long len) @@ -756,8 +878,16 @@ int comedi_request_region(struct comedi_device *dev, EXPORT_SYMBOL_GPL(comedi_request_region); /** - * comedi_legacy_detach() - A generic (*detach) function for legacy drivers. - * @dev: comedi_device struct + * comedi_legacy_detach() - A generic (*detach) function for legacy drivers + * @dev: COMEDI device. + * + * This is a simple, generic 'detach' handler for legacy COMEDI devices that + * just use a single I/O port region and possibly an IRQ and that don't need + * any special clean-up for their private device or subdevice storage. It + * can also be called by a driver-specific 'detach' handler. + * + * If @dev->irq is non-zero, the IRQ will be freed. If @dev->iobase and + * @dev->iolen are both non-zero, the I/O port region will be released. */ void comedi_legacy_detach(struct comedi_device *dev) { @@ -831,6 +961,29 @@ out: return ret; } +/** + * comedi_auto_config() - Create a COMEDI device for a hardware device + * @hardware_device: Hardware device. + * @driver: COMEDI low-level driver for the hardware device. + * @context: Driver context for the auto_attach handler. + * + * Allocates a new COMEDI device for the hardware device and calls the + * low-level driver's 'auto_attach' handler to set-up the hardware and + * allocate the COMEDI subdevices. Additional "post-configuration" setting + * up is performed on successful return from the 'auto_attach' handler. + * If the 'auto_attach' handler fails, the low-level driver's 'detach' + * handler will be called as part of the clean-up. + * + * This is usually called from a wrapper function in a bus-specific COMEDI + * module, which in turn is usually called from a bus device 'probe' + * function in the low-level driver. + * + * Returns 0 on success, -EINVAL if the parameters are invalid or the + * post-configuration determines the driver has set the COMEDI device up + * incorrectly, -ENOMEM if failed to allocate memory, -EBUSY if run out of + * COMEDI minor device numbers, or some negative error number returned by + * the driver's 'auto_attach' handler. + */ int comedi_auto_config(struct device *hardware_device, struct comedi_driver *driver, unsigned long context) { @@ -888,6 +1041,22 @@ int comedi_auto_config(struct device *hardware_device, } EXPORT_SYMBOL_GPL(comedi_auto_config); +/** + * comedi_auto_unconfig() - Unconfigure auto-allocated COMEDI device + * @hardware_device: Hardware device previously passed to + * comedi_auto_config(). + * + * Cleans up and eventually destroys the COMEDI device allocated by + * comedi_auto_config() for the same hardware device. As part of this + * clean-up, the low-level COMEDI driver's 'detach' handler will be called. + * (The COMEDI device itself will persist in an unattached state if it is + * still open, until it is released, and any mmapped buffers will persist + * until they are munmapped.) + * + * This is usually called from a wrapper module in a bus-specific COMEDI + * module, which in turn is usually set as the bus device 'remove' function + * in the low-level COMEDI driver. + */ void comedi_auto_unconfig(struct device *hardware_device) { if (!hardware_device) @@ -896,6 +1065,17 @@ void comedi_auto_unconfig(struct device *hardware_device) } EXPORT_SYMBOL_GPL(comedi_auto_unconfig); +/** + * comedi_driver_register() - Register a low-level COMEDI driver + * @driver: Low-level COMEDI driver. + * + * The low-level COMEDI driver is added to the list of registered COMEDI + * drivers. This is used by the handler for the "/proc/comedi" file and is + * also used by the handler for the %COMEDI_DEVCONFIG ioctl to configure + * "legacy" COMEDI devices (for those low-level drivers that support it). + * + * Returns 0. + */ int comedi_driver_register(struct comedi_driver *driver) { mutex_lock(&comedi_drivers_list_lock); @@ -907,6 +1087,15 @@ int comedi_driver_register(struct comedi_driver *driver) } EXPORT_SYMBOL_GPL(comedi_driver_register); +/** + * comedi_driver_unregister() - Unregister a low-level COMEDI driver + * @driver: Low-level COMEDI driver. + * + * The low-level COMEDI driver is removed from the list of registered COMEDI + * drivers. Detaches any COMEDI devices attached to the driver, which will + * result in the low-level driver's 'detach' handler being called for those + * devices before this function returns. + */ void comedi_driver_unregister(struct comedi_driver *driver) { struct comedi_driver *prev; -- 2.34.1