Constify a lot more items.

This fixes various compiler warnings when -Wdiscarded-qualifiers is used.

include/libsigrok/libsigrok.h

@@ -546,11 +546,11 @@ struct sr_analog_spec {
 /** Generic option struct used by various subsystems. */
 struct sr_option {
 	/* Short name suitable for commandline usage, [a-z0-9-]. */
-	char *id;
+	const char *id;
 	/* Short name suitable for GUI usage, can contain UTF-8. */
-	char *name;
+	const char *name;
 	/* Description of the option, in a sentence. */
-	char *desc;
+	const char *desc;
 	/* Default value for this option. */
 	GVariant *def;
 	/* List of possible values, if this is an option with few values. */
@@ -645,11 +645,11 @@ struct sr_key_info {
 	/** Data type like SR_T_STRING, etc if applicable. */
 	int datatype;
 	/** Short, lowercase ID string, e.g. "serialcomm", "voltage". */
-	char *id;
+	const char *id;
 	/** Full capitalized name, e.g. "Serial communication". */
-	char *name;
+	const char *name;
 	/** Verbose description (unused currently). */
-	char *description;
+	const char *description;
 };
 
 #define SR_CONF_GET  (1 << 31)

src/analog.c

@@ -45,7 +45,7 @@
 
 struct unit_mq_string {
 	uint64_t value;
-	char *str;
+	const char *str;
 };
 
 /* Please use the same order as in enum sr_unit (libsigrok.h). */

src/hardware/atten-pps3xxx/protocol.c

@@ -21,7 +21,7 @@
 #include <string.h>
 #include "protocol.h"
 
-static void dump_packet(char *msg, uint8_t *packet)
+static void dump_packet(const char *msg, uint8_t *packet)
 {
 	int i;
 	char str[128];

src/hardware/atten-pps3xxx/protocol.h

@@ -54,7 +54,7 @@ struct channel_spec {
 
 struct pps_model {
 	int modelid;
-	char *name;
+	const char *name;
 	int channel_modes;
 	int num_channels;
 	struct channel_spec channels[MAX_CHANNELS];

src/hardware/baylibre-acme/protocol.c

@@ -651,7 +651,8 @@ static float read_sample(struct sr_channel *ch)
 SR_PRIV int bl_acme_open_channel(struct sr_channel *ch)
 {
 	struct channel_priv *chp;
-	char path[64], *file;
+	char path[64];
+	const char *file;
 	int fd;
 
 	chp = ch->priv;

src/hardware/center-3xx/protocol.h

@@ -37,9 +37,9 @@ enum {
 };
 
 struct center_dev_info {
-	char *vendor;
-	char *device;
-	char *conn;
+	const char *vendor;
+	const char *device;
+	const char *conn;
 	int num_channels;
 	uint32_t max_sample_points;
 	uint8_t packet_size;

src/hardware/fx2lafw/api.c

@@ -374,7 +374,7 @@ static int dev_open(struct sr_dev_inst *sdi)
 	struct sr_dev_driver *di = sdi->driver;
 	struct sr_usb_dev_inst *usb;
 	struct dev_context *devc;
-	char *fpga_firmware = NULL;
+	const char *fpga_firmware = NULL;
 	int ret;
 	int64_t timediff_us, timediff_ms;
 

src/hardware/hantek-dso/api.c

@@ -428,7 +428,8 @@ static int config_get(uint32_t key, GVariant **data, const struct sr_dev_inst *s
 {
 	struct dev_context *devc;
 	struct sr_usb_dev_inst *usb;
-	char str[128], *s;
+	char str[128];
+	const char *s;
 	const uint64_t *vdiv;
 	int ch_idx;
 

src/hardware/hantek-dso/dso.h

@@ -154,10 +154,10 @@ struct dso_profile {
 	/* VID/PID after firmware upload */
 	uint16_t fw_vid;
 	uint16_t fw_pid;
-	char *vendor;
-	char *model;
+	const char *vendor;
+	const char *model;
 	const uint64_t *buffersizes;
-	char *firmware;
+	const char *firmware;
 };
 
 struct dev_context {

src/hardware/kern-scale/protocol.h

@@ -27,11 +27,11 @@ struct scale_info {
 	/** libsigrok driver info struct. */
 	struct sr_dev_driver di;
 	/** Manufacturer/brand. */
-	char *vendor;
+	const char *vendor;
 	/** Model. */
-	char *device;
+	const char *device;
 	/** serialconn string. */
-	char *conn;
+	const char *conn;
 	/** Baud rate. */
 	uint32_t baudrate;
 	/** Packet size in bytes. */

src/hardware/korad-kdxxxxp/protocol.c

@@ -80,7 +80,8 @@ static void give_device_time_to_process(struct dev_context *devc)
 SR_PRIV int korad_kdxxxxp_set_value(struct sr_serial_dev_inst *serial,
 				struct dev_context *devc)
 {
-	char msg[21], *cmd;
+	char msg[21];
+	const char *cmd;
 	float value;
 	int ret;
 

src/hardware/korad-kdxxxxp/protocol.h

@@ -44,9 +44,9 @@ enum {
 /* Information on single model */
 struct korad_kdxxxxp_model {
 	int model_id; /**< Model info */
-	char *vendor; /**< Vendor name */
-	char *name; /**< Model name */
-	char *id; /**< Model ID, as delivered by interface */
+	const char *vendor; /**< Vendor name */
+	const char *name; /**< Model name */
+	const char *id; /**< Model ID, as delivered by interface */
 	int channels; /**< Number of channels */
 	double voltage[3]; /**< Min, max, step */
 	double current[3]; /**< Min, max, step */

src/hardware/lascar-el-usb/protocol.h

@@ -68,7 +68,7 @@ enum {
 
 struct elusb_profile {
 	int modelid;
-	char *modelname;
+	const char *modelname;
 	int logformat;
 };
 

src/hardware/manson-hcs-3xxx/protocol.h

@@ -58,8 +58,8 @@ enum {
 /** Information on a single model. */
 struct hcs_model {
 	int model_id;      /**< Model info */
-	char *name;        /**< Model name */
-	char *id;          /**< Model ID, like delivered by interface */
+	const char *name;  /**< Model name */
+	const char *id;    /**< Model ID, like delivered by interface */
 	double voltage[3]; /**< Min, max, step */
 	double current[3]; /**< Min, max, step */
 };

src/hardware/mic-985xx/protocol.h

@@ -36,9 +36,9 @@ enum {
 };
 
 struct mic_dev_info {
-	char *vendor;
-	char *device;
-	char *conn;
+	const char *vendor;
+	const char *device;
+	const char *conn;
 	uint32_t max_sample_points;
 	gboolean has_temperature;
 	gboolean has_humidity;

src/hardware/serial-dmm/protocol.h

@@ -26,11 +26,11 @@ struct dmm_info {
 	/** libsigrok driver info struct. */
 	struct sr_dev_driver di;
 	/** Manufacturer/brand. */
-	char *vendor;
+	const char *vendor;
 	/** Model. */
-	char *device;
+	const char *device;
 	/** serialconn string. */
-	char *conn;
+	const char *conn;
 	/** Baud rate. */
 	uint32_t baudrate;
 	/** Packet size in bytes. */

src/hardware/testo/protocol.c

@@ -61,7 +61,7 @@ SR_PRIV int testo_probe_channels(struct sr_dev_inst *sdi)
 	struct sr_usb_dev_inst *usb;
 	int unit, packet_len, len, i;
 	unsigned char packet[MAX_REPLY_SIZE], buf[MAX_REPLY_SIZE];
-	char *probe_name;
+	const char *probe_name;
 
 	devc = sdi->priv;
 	usb = sdi->conn;

src/hardware/testo/protocol.h

@@ -46,7 +46,7 @@
 #define EP_OUT               2 | LIBUSB_ENDPOINT_OUT
 
 struct testo_model {
-	char *name;
+	const char *name;
 	int request_size;
 	const uint8_t *request;
 };

src/hardware/uni-t-dmm/protocol.h

@@ -31,8 +31,8 @@
 
 struct dmm_info {
 	struct sr_dev_driver di;
-	char *vendor;
-	char *device;
+	const char *vendor;
+	const char *device;
 	uint32_t baudrate;
 	int packet_size;
 	gboolean (*packet_valid)(const uint8_t *);

src/hardware/zeroplus-logic-cube/api.c

@@ -31,7 +31,7 @@
 struct zp_model {
 	uint16_t vid;
 	uint16_t pid;
-	char *model_name;
+	const char *model_name;
 	unsigned int channels;
 	unsigned int sample_depth;	/* In Ksamples/channel */
 	unsigned int max_sampling_freq;

src/hwdriver.c

@@ -569,7 +569,8 @@ static int check_key(const struct sr_dev_driver *driver,
 	GVariant *gvar_opts;
 	const uint32_t *opts;
 	uint32_t pub_opt;
-	char *suffix, *opstr;
+	const char *suffix;
+	const char *opstr;
 
 	if (sdi && cg)
 		suffix = " for this device and channel group";

src/input/binary.c

@@ -150,7 +150,7 @@ static struct sr_option options[] = {
 	ALL_ZERO
 };
 
-static struct sr_option *get_options(void)
+static const struct sr_option *get_options(void)
 {
 	if (!options[0].def) {
 		options[0].def = g_variant_ref_sink(g_variant_new_int32(DEFAULT_NUM_CHANNELS));

src/input/chronovu_la8.c

@@ -162,7 +162,7 @@ static struct sr_option options[] = {
 	ALL_ZERO
 };
 
-static struct sr_option *get_options(void)
+static const struct sr_option *get_options(void)
 {
 	if (!options[0].def) {
 		options[0].def = g_variant_ref_sink(g_variant_new_int32(DEFAULT_NUM_CHANNELS));

src/input/csv.c

@@ -784,7 +784,7 @@ static struct sr_option options[] = {
 	ALL_ZERO
 };
 
-static struct sr_option *get_options(void)
+static const struct sr_option *get_options(void)
 {
 	if (!options[0].def) {
 		options[0].def = g_variant_ref_sink(g_variant_new_int32(0));

src/input/input.c

@@ -242,7 +242,7 @@ SR_API struct sr_input *sr_input_new(const struct sr_input_module *imod,
 		GHashTable *options)
 {
 	struct sr_input *in;
-	struct sr_option *mod_opts;
+	const struct sr_option *mod_opts;
 	const GVariantType *gvt;
 	GHashTable *new_opts;
 	GHashTableIter iter;

src/input/vcd.c

@@ -551,7 +551,7 @@ static struct sr_option options[] = {
 	ALL_ZERO
 };
 
-static struct sr_option *get_options(void)
+static const struct sr_option *get_options(void)
 {
 	if (!options[0].def) {
 		options[0].def = g_variant_ref_sink(g_variant_new_int32(DEFAULT_NUM_CHANNELS));

src/libsigrok-internal.h

@@ -288,7 +288,7 @@ struct sr_input_module {
 	 * Returns a NULL-terminated list of options this module can take.
 	 * Can be NULL, if the module has no options.
 	 */
-	struct sr_option *(*options) (void);
+	const struct sr_option *(*options) (void);
 
 	/**
 	 * Check if this input module can load and parse the specified stream.
@@ -383,7 +383,7 @@ struct sr_output_module {
 	 * A unique ID for this output module, suitable for use in command-line
 	 * clients, [a-z0-9-]. Must not be NULL.
 	 */
-	char *id;
+	const char *id;
 
 	/**
 	 * A unique name for this output module, suitable for use in GUI
@@ -397,7 +397,7 @@ struct sr_output_module {
 	 * This can be displayed by frontends, e.g. when selecting the output
 	 * module for saving a file.
 	 */
-	char *desc;
+	const char *desc;
 
 	/**
 	 * A NULL terminated array of strings containing a list of file name
@@ -491,7 +491,7 @@ struct sr_transform_module {
 	 * A unique ID for this transform module, suitable for use in
 	 * command-line clients, [a-z0-9-]. Must not be NULL.
 	 */
-	char *id;
+	const char *id;
 
 	/**
 	 * A unique name for this transform module, suitable for use in GUI
@@ -505,7 +505,7 @@ struct sr_transform_module {
 	 * This can be displayed by frontends, e.g. when selecting
 	 * which transform module(s) to add.
 	 */
-	char *desc;
+	const char *desc;
 
 	/**
 	 * Returns a NULL-terminated list of options this transform module

src/output/analog.c

@@ -68,7 +68,7 @@ static int init(struct sr_output *o, GHashTable *options)
 	return SR_OK;
 }
 
-static void si_printf(float value, GString *out, char *unitstr)
+static void si_printf(float value, GString *out, const char *unitstr)
 {
 	float v;
 

src/scpi/scpi_vxi.c

@@ -76,7 +76,7 @@ static int scpi_vxi_open(struct sr_scpi_dev_inst *scpi)
 	link_parms.clientId = (long) vxi->client;
 	link_parms.lockDevice = 0;
 	link_parms.lock_timeout = VXI_DEFAULT_TIMEOUT_MS;
-	link_parms.device = "inst0";
+	link_parms.device = (char *)"inst0";
 
 	if (!(link_resp = create_link_1(&link_parms, vxi->client))) {
 		sr_err("Link creation failed for %s", vxi->address);