hwdriver.c - chromium.googlesource.com/chromiumos/third_party/libsigrok - Gitiles

 /*
  * This file is part of the libsigrok project.
  *
  * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include <stdlib.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <dirent.h>
 #include <string.h>
 #include <glib.h>
 #include "config.h" /* Needed for HAVE_LIBUSB_1_0 and others. */
 #include "libsigrok.h"
 #include "libsigrok-internal.h"

 /* Message logging helpers with subsystem-specific prefix string. */
 #define LOG_PREFIX "hwdriver: "
 #define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
 #define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
 #define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
 #define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
 #define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
 #define sr_err(s, args...) sr_err(LOG_PREFIX s, ## args)

 /**
  * @file
  *
  * Hardware driver handling in libsigrok.
  */

 /**
  * @defgroup grp_driver Hardware drivers
  *
  * Hardware driver handling in libsigrok.
  *
  * @{
  */

 static struct sr_config_info sr_config_info_data[] = {
 	{SR_CONF_CONN, SR_T_CHAR, "conn",
 		"Connection", NULL},
 	{SR_CONF_SERIALCOMM, SR_T_CHAR, "serialcomm",
 		"Serial communication", NULL},
 	{SR_CONF_SAMPLERATE, SR_T_UINT64, "samplerate",
 		"Sample rate", NULL},
     {SR_CONF_CLOCK_TYPE, SR_T_BOOL, "clocktype",
         "Using External Clock", NULL},
     {SR_CONF_CAPTURE_RATIO, SR_T_UINT64, "captureratio",
 		"Pre-trigger capture ratio", NULL},
     {SR_CONF_DEVICE_MODE, SR_T_CHAR, "device",
         "Device Mode", NULL},
     {SR_CONF_PATTERN_MODE, SR_T_CHAR, "pattern",
         "Pattern mode", NULL},
     {SR_CONF_TRIGGER_TYPE, SR_T_CHAR, "triggertype",
 		"Trigger types", NULL},
 	{SR_CONF_RLE, SR_T_BOOL, "rle",
 		"Run Length Encoding", NULL},
 	{SR_CONF_TRIGGER_SLOPE, SR_T_UINT64, "triggerslope",
 		"Trigger slope", NULL},
 	{SR_CONF_TRIGGER_SOURCE, SR_T_CHAR, "triggersource",
 		"Trigger source", NULL},
 	{SR_CONF_HORIZ_TRIGGERPOS, SR_T_FLOAT, "horiz_triggerpos",
 		"Horizontal trigger position", NULL},
 	{SR_CONF_BUFFERSIZE, SR_T_UINT64, "buffersize",
 		"Buffer size", NULL},
 	{SR_CONF_TIMEBASE, SR_T_RATIONAL_PERIOD, "timebase",
 		"Time base", NULL},
 	{SR_CONF_FILTER, SR_T_CHAR, "filter",
 		"Filter targets", NULL},
 	{SR_CONF_VDIV, SR_T_RATIONAL_VOLT, "vdiv",
 		"Volts/div", NULL},
 	{SR_CONF_COUPLING, SR_T_CHAR, "coupling",
 		"Coupling", NULL},
 	{SR_CONF_DATALOG, SR_T_BOOL, "datalog",
 		"Datalog", NULL},
 	{0, 0, NULL, NULL, NULL},
 };

 /** @cond PRIVATE */
 #ifdef HAVE_LA_DEMO
 extern SR_PRIV struct sr_dev_driver demo_driver_info;
 #endif
 #ifdef HAVE_LA_DSLOGIC
 extern SR_PRIV struct sr_dev_driver DSLogic_driver_info;
 #endif
 /** @endcond */

 static struct sr_dev_driver *drivers_list[] = {
 #ifdef HAVE_LA_DEMO
 	&demo_driver_info,
 #endif
 #ifdef HAVE_LA_DSLOGIC
     &DSLogic_driver_info,
 #endif
 	NULL,
 };

 /**
  * Return the list of supported hardware drivers.
  *
  * @return Pointer to the NULL-terminated list of hardware driver pointers.
  */
 SR_API struct sr_dev_driver **sr_driver_list(void)
 {

 	return drivers_list;
 }

 /**
  * Initialize a hardware driver.
  *
  * This usually involves memory allocations and variable initializations
  * within the driver, but _not_ scanning for attached devices.
  * The API call sr_driver_scan() is used for that.
  *
  * @param ctx A libsigrok context object allocated by a previous call to
  *            sr_init(). Must not be NULL.
  * @param driver The driver to initialize. This must be a pointer to one of
  *               the entries returned by sr_driver_list(). Must not be NULL.
  *
  * @return SR_OK upon success, SR_ERR_ARG upon invalid parameters,
  *         SR_ERR_BUG upon internal errors, or another negative error code
  *         upon other errors.
  */
 SR_API int sr_driver_init(struct sr_context *ctx, struct sr_dev_driver *driver)
 {
 	int ret;

 	if (!ctx) {
 		sr_err("Invalid libsigrok context, can't initialize.");
 		return SR_ERR_ARG;
 	}

 	if (!driver) {
 		sr_err("Invalid driver, can't initialize.");
 		return SR_ERR_ARG;
 	}

 	sr_spew("Initializing driver '%s'.", driver->name);
 	if ((ret = driver->init(ctx)) < 0)
 		sr_err("Failed to initialize the driver: %d.", ret);

 	return ret;
 }

 /**
  * Tell a hardware driver to scan for devices.
  *
  * In addition to the detection, the devices that are found are also
  * initialized automatically. On some devices, this involves a firmware upload,
  * or other such measures.
  *
  * The order in which the system is scanned for devices is not specified. The
  * caller should not assume or rely on any specific order.
  *
  * Before calling sr_driver_scan(), the user must have previously initialized
  * the driver by calling sr_driver_init().
  *
  * @param driver The driver that should scan. This must be a pointer to one of
  *               the entries returned by sr_driver_list(). Must not be NULL.
  * @param options A list of 'struct sr_hwopt' options to pass to the driver's
  *                scanner. Can be NULL/empty.
  *
  * @return A GSList * of 'struct sr_dev_inst', or NULL if no devices were
  *         found (or errors were encountered). This list must be freed by the
  *         caller using g_slist_free(), but without freeing the data pointed
  *         to in the list.
  */
 SR_API GSList *sr_driver_scan(struct sr_dev_driver *driver, GSList *options)
 {
 	GSList *l;

 	if (!driver) {
 		sr_err("Invalid driver, can't scan for devices.");
 		return NULL;
 	}

 	if (!driver->priv) {
 		sr_err("Driver not initialized, can't scan for devices.");
 		return NULL;
 	}

 	l = driver->scan(options);

 	sr_spew("Scan of '%s' found %d devices.", driver->name,
 		g_slist_length(l));

 	return l;
 }

 /** @private */
 SR_PRIV void sr_hw_cleanup_all(void)
 {
 	int i;
 	struct sr_dev_driver **drivers;

 	drivers = sr_driver_list();
 	for (i = 0; drivers[i]; i++) {
 		if (drivers[i]->cleanup)
 			drivers[i]->cleanup();
 	}
 }

 /** A floating reference can be passed in for data. */
 SR_PRIV struct sr_config *sr_config_new(int key, GVariant *data)
 {
 	struct sr_config *src;

 	if (!(src = g_try_malloc(sizeof(struct sr_config))))
 		return NULL;
 	src->key = key;
 	src->data = g_variant_ref_sink(data);

 	return src;
 }

 SR_PRIV void sr_config_free(struct sr_config *src)
 {

 	if (!src || !src->data) {
 		sr_err("%s: invalid data!", __func__);
 		return;
 	}

 	g_variant_unref(src->data);
 	g_free(src);

 }

 /**
  * Returns information about the given driver or device instance.
  *
  * @param driver The sr_dev_driver struct to query.
  * @param key The configuration key (SR_CONF_*).
  * @param data Pointer to a GVariant where the value will be stored. Must
  *             not be NULL. The caller is given ownership of the GVariant
  *             and must thus decrease the refcount after use. However if
  *             this function returns an error code, the field should be
  *             considered unused, and should not be unreferenced.
  * @param sdi (optional) If the key is specific to a device, this must
  *            contain a pointer to the struct sr_dev_inst to be checked.
  *            Otherwise it must be NULL.
  *
  * @return SR_OK upon success or SR_ERR in case of error. Note SR_ERR_ARG
  *         may be returned by the driver indicating it doesn't know that key,
  *         but this is not to be flagged as an error by the caller; merely
  *         as an indication that it's not applicable.
  */
 SR_API int sr_config_get(const struct sr_dev_driver *driver, int key,
 		GVariant **data, const struct sr_dev_inst *sdi)
 {
 	int ret;

 	if (!driver || !data)
 		return SR_ERR;

 	if (!driver->config_get)
 		return SR_ERR_ARG;

 	if ((ret = driver->config_get(key, data, sdi)) == SR_OK) {
 		/* Got a floating reference from the driver. Sink it here,
 		 * caller will need to unref when done with it. */
 		g_variant_ref_sink(*data);
 	}

 	return ret;
 }

 /**
  * Set a configuration key in a device instance.
  *
  * @param sdi The device instance.
  * @param key The configuration key (SR_CONF_*).
  * @param data The new value for the key, as a GVariant with GVariantType
  *        appropriate to that key. A floating reference can be passed
  *        in; its refcount will be sunk and unreferenced after use.
  *
  * @return SR_OK upon success or SR_ERR in case of error. Note SR_ERR_ARG
  *         may be returned by the driver indicating it doesn't know that key,
  *         but this is not to be flagged as an error by the caller; merely
  *         as an indication that it's not applicable.
  */
 SR_API int sr_config_set(const struct sr_dev_inst *sdi, int key, GVariant *data)
 {
 	int ret;

 	g_variant_ref_sink(data);

 	if (!sdi || !sdi->driver || !data)
 		ret = SR_ERR;
 	else if (!sdi->driver->config_set)
 		ret = SR_ERR_ARG;
 	else
 		ret = sdi->driver->config_set(key, data, sdi);

 	g_variant_unref(data);

 	return ret;
 }

 /**
  * List all possible values for a configuration key.
  *
  * @param driver The sr_dev_driver struct to query.
  * @param key The configuration key (SR_CONF_*).
  * @param data A pointer to a GVariant where the list will be stored. The
  *             caller is given ownership of the GVariant and must thus
  *             unref the GVariant after use. However if this function
  *             returns an error code, the field should be considered
  *             unused, and should not be unreferenced.
  * @param sdi (optional) If the key is specific to a device, this must
  *            contain a pointer to the struct sr_dev_inst to be checked.
  *
  * @return SR_OK upon success or SR_ERR in case of error. Note SR_ERR_ARG
  *         may be returned by the driver indicating it doesn't know that key,
  *         but this is not to be flagged as an error by the caller; merely
  *         as an indication that it's not applicable.
  */
 SR_API int sr_config_list(const struct sr_dev_driver *driver, int key,
 		GVariant **data, const struct sr_dev_inst *sdi)
 {
 	int ret;

 	if (!driver || !data)
 		ret = SR_ERR;
 	else if (!driver->config_list)
 		ret = SR_ERR_ARG;
 	else if ((ret = driver->config_list(key, data, sdi)) == SR_OK)
 		g_variant_ref_sink(*data);

 	return ret;
 }

 /**
  * Get information about a configuration key.
  *
  * @param key The configuration key.
  *
  * @return A pointer to a struct sr_config_info, or NULL if the key
  *         was not found.
  */
 SR_API const struct sr_config_info *sr_config_info_get(int key)
 {
 	int i;

 	for (i = 0; sr_config_info_data[i].key; i++) {
 		if (sr_config_info_data[i].key == key)
 			return &sr_config_info_data[i];
 	}

 	return NULL;
 }

 /**
  * Get information about an configuration key, by name.
  *
  * @param optname The configuration key.
  *
  * @return A pointer to a struct sr_config_info, or NULL if the key
  *         was not found.
  */
 SR_API const struct sr_config_info *sr_config_info_name_get(const char *optname)
 {
 	int i;

 	for (i = 0; sr_config_info_data[i].key; i++) {
 		if (!strcmp(sr_config_info_data[i].id, optname))
 			return &sr_config_info_data[i];
 	}

 	return NULL;
 }

 /* Unnecessary level of indirection follows. */

 /** @private */
 SR_PRIV int sr_source_remove(int fd)
 {
 	return sr_session_source_remove(fd);
 }

 /** @private */
 SR_PRIV int sr_source_add(int fd, int events, int timeout,
 			  sr_receive_data_callback_t cb, void *cb_data)
 {
     return sr_session_source_add(fd, events, timeout, cb, cb_data);
 }

 /** @} */
	/*
	* This file is part of the libsigrok project.
	*
	* Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
	*
	* This program is free software: you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 3 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <stdlib.h>
	#include <stdio.h>
	#include <sys/types.h>
	#include <dirent.h>
	#include <string.h>
	#include <glib.h>
	#include "config.h" /* Needed for HAVE_LIBUSB_1_0 and others. */
	#include "libsigrok.h"
	#include "libsigrok-internal.h"

	/* Message logging helpers with subsystem-specific prefix string. */
	#define LOG_PREFIX "hwdriver: "
	#define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
	#define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
	#define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
	#define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
	#define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
	#define sr_err(s, args...) sr_err(LOG_PREFIX s, ## args)

	/**
	* @file
	*
	* Hardware driver handling in libsigrok.
	*/

	/**
	* @defgroup grp_driver Hardware drivers
	*
	* Hardware driver handling in libsigrok.
	*
	* @{
	*/

	static struct sr_config_info sr_config_info_data[] = {
	{SR_CONF_CONN, SR_T_CHAR, "conn",
	"Connection", NULL},
	{SR_CONF_SERIALCOMM, SR_T_CHAR, "serialcomm",
	"Serial communication", NULL},
	{SR_CONF_SAMPLERATE, SR_T_UINT64, "samplerate",
	"Sample rate", NULL},
	{SR_CONF_CLOCK_TYPE, SR_T_BOOL, "clocktype",
	"Using External Clock", NULL},
	{SR_CONF_CAPTURE_RATIO, SR_T_UINT64, "captureratio",
	"Pre-trigger capture ratio", NULL},
	{SR_CONF_DEVICE_MODE, SR_T_CHAR, "device",
	"Device Mode", NULL},
	{SR_CONF_PATTERN_MODE, SR_T_CHAR, "pattern",
	"Pattern mode", NULL},
	{SR_CONF_TRIGGER_TYPE, SR_T_CHAR, "triggertype",
	"Trigger types", NULL},
	{SR_CONF_RLE, SR_T_BOOL, "rle",
	"Run Length Encoding", NULL},
	{SR_CONF_TRIGGER_SLOPE, SR_T_UINT64, "triggerslope",
	"Trigger slope", NULL},
	{SR_CONF_TRIGGER_SOURCE, SR_T_CHAR, "triggersource",
	"Trigger source", NULL},
	{SR_CONF_HORIZ_TRIGGERPOS, SR_T_FLOAT, "horiz_triggerpos",
	"Horizontal trigger position", NULL},
	{SR_CONF_BUFFERSIZE, SR_T_UINT64, "buffersize",
	"Buffer size", NULL},
	{SR_CONF_TIMEBASE, SR_T_RATIONAL_PERIOD, "timebase",
	"Time base", NULL},
	{SR_CONF_FILTER, SR_T_CHAR, "filter",
	"Filter targets", NULL},
	{SR_CONF_VDIV, SR_T_RATIONAL_VOLT, "vdiv",
	"Volts/div", NULL},
	{SR_CONF_COUPLING, SR_T_CHAR, "coupling",
	"Coupling", NULL},
	{SR_CONF_DATALOG, SR_T_BOOL, "datalog",
	"Datalog", NULL},
	{0, 0, NULL, NULL, NULL},
	};

	/** @cond PRIVATE */
	#ifdef HAVE_LA_DEMO
	extern SR_PRIV struct sr_dev_driver demo_driver_info;
	#endif
	#ifdef HAVE_LA_DSLOGIC
	extern SR_PRIV struct sr_dev_driver DSLogic_driver_info;
	#endif
	/** @endcond */

	static struct sr_dev_driver *drivers_list[] = {
	#ifdef HAVE_LA_DEMO
	&demo_driver_info,
	#endif
	#ifdef HAVE_LA_DSLOGIC
	&DSLogic_driver_info,
	#endif
	NULL,
	};

	/**
	* Return the list of supported hardware drivers.
	*
	* @return Pointer to the NULL-terminated list of hardware driver pointers.
	*/
	SR_API struct sr_dev_driver **sr_driver_list(void)
	{

	return drivers_list;
	}

	/**
	* Initialize a hardware driver.
	*
	* This usually involves memory allocations and variable initializations
	* within the driver, but _not_ scanning for attached devices.
	* The API call sr_driver_scan() is used for that.
	*
	* @param ctx A libsigrok context object allocated by a previous call to
	* sr_init(). Must not be NULL.
	* @param driver The driver to initialize. This must be a pointer to one of
	* the entries returned by sr_driver_list(). Must not be NULL.
	*
	* @return SR_OK upon success, SR_ERR_ARG upon invalid parameters,
	* SR_ERR_BUG upon internal errors, or another negative error code
	* upon other errors.
	*/
	SR_API int sr_driver_init(struct sr_context ctx, struct sr_dev_driver driver)
	{
	int ret;

	if (!ctx) {
	sr_err("Invalid libsigrok context, can't initialize.");
	return SR_ERR_ARG;
	}

	if (!driver) {
	sr_err("Invalid driver, can't initialize.");
	return SR_ERR_ARG;
	}

	sr_spew("Initializing driver '%s'.", driver->name);
	if ((ret = driver->init(ctx)) < 0)
	sr_err("Failed to initialize the driver: %d.", ret);

	return ret;
	}

	/**
	* Tell a hardware driver to scan for devices.
	*
	* In addition to the detection, the devices that are found are also
	* initialized automatically. On some devices, this involves a firmware upload,
	* or other such measures.
	*
	* The order in which the system is scanned for devices is not specified. The
	* caller should not assume or rely on any specific order.
	*
	* Before calling sr_driver_scan(), the user must have previously initialized
	* the driver by calling sr_driver_init().
	*
	* @param driver The driver that should scan. This must be a pointer to one of
	* the entries returned by sr_driver_list(). Must not be NULL.
	* @param options A list of 'struct sr_hwopt' options to pass to the driver's
	* scanner. Can be NULL/empty.
	*
	* @return A GSList * of 'struct sr_dev_inst', or NULL if no devices were
	* found (or errors were encountered). This list must be freed by the
	* caller using g_slist_free(), but without freeing the data pointed
	* to in the list.
	*/
	SR_API GSList sr_driver_scan(struct sr_dev_driver driver, GSList *options)
	{
	GSList *l;

	if (!driver) {
	sr_err("Invalid driver, can't scan for devices.");
	return NULL;
	}

	if (!driver->priv) {
	sr_err("Driver not initialized, can't scan for devices.");
	return NULL;
	}

	l = driver->scan(options);

	sr_spew("Scan of '%s' found %d devices.", driver->name,
	g_slist_length(l));

	return l;
	}

	/** @private */
	SR_PRIV void sr_hw_cleanup_all(void)
	{
	int i;
	struct sr_dev_driver **drivers;

	drivers = sr_driver_list();
	for (i = 0; drivers[i]; i++) {
	if (drivers[i]->cleanup)
	drivers[i]->cleanup();
	}
	}

	/** A floating reference can be passed in for data. */
	SR_PRIV struct sr_config sr_config_new(int key, GVariant data)
	{
	struct sr_config *src;

	if (!(src = g_try_malloc(sizeof(struct sr_config))))
	return NULL;
	src->key = key;
	src->data = g_variant_ref_sink(data);

	return src;
	}

	SR_PRIV void sr_config_free(struct sr_config *src)
	{

	if (!src \|\| !src->data) {
	sr_err("%s: invalid data!", __func__);
	return;
	}

	g_variant_unref(src->data);
	g_free(src);

	}

	/**
	* Returns information about the given driver or device instance.
	*
	* @param driver The sr_dev_driver struct to query.
	* @param key The configuration key (SR_CONF_*).
	* @param data Pointer to a GVariant where the value will be stored. Must
	* not be NULL. The caller is given ownership of the GVariant
	* and must thus decrease the refcount after use. However if
	* this function returns an error code, the field should be
	* considered unused, and should not be unreferenced.
	* @param sdi (optional) If the key is specific to a device, this must
	* contain a pointer to the struct sr_dev_inst to be checked.
	* Otherwise it must be NULL.
	*
	* @return SR_OK upon success or SR_ERR in case of error. Note SR_ERR_ARG
	* may be returned by the driver indicating it doesn't know that key,
	* but this is not to be flagged as an error by the caller; merely
	* as an indication that it's not applicable.
	*/
	SR_API int sr_config_get(const struct sr_dev_driver *driver, int key,
	GVariant *data, const struct sr_dev_inst sdi)
	{
	int ret;

	if (!driver \|\| !data)
	return SR_ERR;

	if (!driver->config_get)
	return SR_ERR_ARG;

	if ((ret = driver->config_get(key, data, sdi)) == SR_OK) {
	/* Got a floating reference from the driver. Sink it here,
	* caller will need to unref when done with it. */
	g_variant_ref_sink(*data);
	}

	return ret;
	}

	/**
	* Set a configuration key in a device instance.
	*
	* @param sdi The device instance.
	* @param key The configuration key (SR_CONF_*).
	* @param data The new value for the key, as a GVariant with GVariantType
	* appropriate to that key. A floating reference can be passed
	* in; its refcount will be sunk and unreferenced after use.
	*
	* @return SR_OK upon success or SR_ERR in case of error. Note SR_ERR_ARG
	* may be returned by the driver indicating it doesn't know that key,
	* but this is not to be flagged as an error by the caller; merely
	* as an indication that it's not applicable.
	*/
	SR_API int sr_config_set(const struct sr_dev_inst sdi, int key, GVariant data)
	{
	int ret;

	g_variant_ref_sink(data);

	if (!sdi \|\| !sdi->driver \|\| !data)
	ret = SR_ERR;
	else if (!sdi->driver->config_set)
	ret = SR_ERR_ARG;
	else
	ret = sdi->driver->config_set(key, data, sdi);

	g_variant_unref(data);

	return ret;
	}

	/**
	* List all possible values for a configuration key.
	*
	* @param driver The sr_dev_driver struct to query.
	* @param key The configuration key (SR_CONF_*).
	* @param data A pointer to a GVariant where the list will be stored. The
	* caller is given ownership of the GVariant and must thus
	* unref the GVariant after use. However if this function
	* returns an error code, the field should be considered
	* unused, and should not be unreferenced.
	* @param sdi (optional) If the key is specific to a device, this must
	* contain a pointer to the struct sr_dev_inst to be checked.
	*
	* @return SR_OK upon success or SR_ERR in case of error. Note SR_ERR_ARG
	* may be returned by the driver indicating it doesn't know that key,
	* but this is not to be flagged as an error by the caller; merely
	* as an indication that it's not applicable.
	*/
	SR_API int sr_config_list(const struct sr_dev_driver *driver, int key,
	GVariant *data, const struct sr_dev_inst sdi)
	{
	int ret;

	if (!driver \|\| !data)
	ret = SR_ERR;
	else if (!driver->config_list)
	ret = SR_ERR_ARG;
	else if ((ret = driver->config_list(key, data, sdi)) == SR_OK)
	g_variant_ref_sink(*data);

	return ret;
	}

	/**
	* Get information about a configuration key.
	*
	* @param key The configuration key.
	*
	* @return A pointer to a struct sr_config_info, or NULL if the key
	* was not found.
	*/
	SR_API const struct sr_config_info *sr_config_info_get(int key)
	{
	int i;

	for (i = 0; sr_config_info_data[i].key; i++) {
	if (sr_config_info_data[i].key == key)
	return &sr_config_info_data[i];
	}

	return NULL;
	}

	/**
	* Get information about an configuration key, by name.
	*
	* @param optname The configuration key.
	*
	* @return A pointer to a struct sr_config_info, or NULL if the key
	* was not found.
	*/
	SR_API const struct sr_config_info sr_config_info_name_get(const char optname)
	{
	int i;

	for (i = 0; sr_config_info_data[i].key; i++) {
	if (!strcmp(sr_config_info_data[i].id, optname))
	return &sr_config_info_data[i];
	}

	return NULL;
	}

	/* Unnecessary level of indirection follows. */

	/** @private */
	SR_PRIV int sr_source_remove(int fd)
	{
	return sr_session_source_remove(fd);
	}

	/** @private */
	SR_PRIV int sr_source_add(int fd, int events, int timeout,
	sr_receive_data_callback_t cb, void *cb_data)
	{
	return sr_session_source_add(fd, events, timeout, cb, cb_data);
	}

	/** @} */