diff --git a/rigs/kenwood/elecraft.c b/rigs/kenwood/elecraft.c
index 16ef7c418..4849217b9 100644
--- a/rigs/kenwood/elecraft.c
+++ b/rigs/kenwood/elecraft.c
@@ -22,6 +22,7 @@
  *  the complete text of the GNU Lesser Public License version 2.1.
  *
  */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <string.h>
 #include <stdio.h>
@@ -77,9 +78,9 @@ const struct confparams elecraft_ext_levels[] =
 
 
 /* Private function declarations */
-int verify_kenwood_id(RIG *rig, char *id);
-int elecraft_get_extension_level(RIG *rig, const char *cmd, int *ext_level);
-int elecraft_get_firmware_revision_level(RIG *rig, const char *cmd,
+static int verify_kenwood_id(RIG *rig, char *id);
+static int elecraft_get_extension_level(RIG *rig, const char *cmd, int *ext_level);
+static int elecraft_get_firmware_revision_level(RIG *rig, const char *cmd,
         char *fw_rev, size_t fw_rev_sz);
 
 /* Shared backend function definitions */
@@ -419,10 +420,10 @@ int elecraft_close(RIG *rig)
 
 /* Tests for Kenwood ID string of "017" */
 
-int verify_kenwood_id(RIG *rig, char *id)
+static int verify_kenwood_id(RIG *rig, char *id)
 {
     int err;
-    char *idptr;
+    const char *idptr;
 
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
 
@@ -472,11 +473,11 @@ int verify_kenwood_id(RIG *rig, char *id)
 
 /* Determines K2 and K3 extension level */
 
-int elecraft_get_extension_level(RIG *rig, const char *cmd, int *ext_level)
+static int elecraft_get_extension_level(RIG *rig, const char *cmd, int *ext_level)
 {
     int err, i;
     char buf[KENWOOD_MAX_BUF_LEN];
-    char *bufptr;
+    const char *bufptr;
 
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
 
@@ -511,7 +512,7 @@ int elecraft_get_extension_level(RIG *rig, const char *cmd, int *ext_level)
 
 /* Determine firmware revision level */
 
-int elecraft_get_firmware_revision_level(RIG *rig, const char *cmd,
+static int elecraft_get_firmware_revision_level(RIG *rig, const char *cmd,
         char *fw_rev, size_t fw_rev_sz)
 {
     int err;
diff --git a/rigs/kenwood/flex.c b/rigs/kenwood/flex.c
index d1f66e483..f5181fc3c 100644
--- a/rigs/kenwood/flex.c
+++ b/rigs/kenwood/flex.c
@@ -23,6 +23,7 @@
  *  the complete text of the GNU Lesser Public License version 2.1.
  *
  */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <string.h>
 
@@ -31,10 +32,10 @@
 
 /* Private helper functions */
 
-int verify_flexradio_id(RIG *rig, char *id)
+static int verify_flexradio_id(RIG *rig, char *id)
 {
     int err;
-    char *idptr;
+    const char *idptr;
 
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
 
diff --git a/rigs/kenwood/flex6xxx.c b/rigs/kenwood/flex6xxx.c
index dd145a368..ae13e96d7 100644
--- a/rigs/kenwood/flex6xxx.c
+++ b/rigs/kenwood/flex6xxx.c
@@ -22,6 +22,7 @@
  *  the complete text of the GNU Lesser Public License version 2.1.
  *
  */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -321,7 +322,7 @@ static int powersdr_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode,
 
 static int flex6k_find_width(rmode_t mode, pbwidth_t width, int *ridx)
 {
-    int *w_a; // Width array, these are all ordered in descending order!
+    const int *w_a; // Width array, these are all ordered in descending order!
     int idx = 0;
 
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
@@ -372,7 +373,7 @@ static int flex6k_find_width(rmode_t mode, pbwidth_t width, int *ridx)
 
 static int powersdr_find_width(rmode_t mode, pbwidth_t width, int *ridx)
 {
-    int *w_a; // Width array, these are all ordered in descending order!
+    const int *w_a; // Width array, these are all ordered in descending order!
     int idx = 0;
 
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
@@ -576,7 +577,7 @@ static int powersdr_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
 /*
  * flex6k_get_ptt
  */
-int flex6k_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt)
+static int flex6k_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt)
 {
     const char *ptt_cmd;
     int err;
@@ -604,7 +605,7 @@ int flex6k_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt)
     return RIG_OK;
 }
 
-int flex6k_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt)
+static int flex6k_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt)
 {
     const char *ptt_cmd;
     char response[16] = "";
@@ -642,7 +643,7 @@ int flex6k_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt)
 /*
  * powersdr_set_level
  */
-int powersdr_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
+static int powersdr_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
 {
     char cmd[KENWOOD_MAX_BUF_LEN];
     int retval;
@@ -741,7 +742,7 @@ int powersdr_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
 /*
  * flek6k_set_level
  */
-int flex6k_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
+static int flex6k_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
 {
     char cmd[KENWOOD_MAX_BUF_LEN];
     int retval;
@@ -778,10 +779,10 @@ int flex6k_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
 /*
  * flex6k_get_level
  */
-int flex6k_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
+static int flex6k_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 {
     char lvlbuf[KENWOOD_MAX_BUF_LEN];
-    char *cmd;
+    const char *cmd;
     int retval;
     int len, ans;
 
@@ -840,10 +841,10 @@ int flex6k_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 /*
  * powersdr_get_level
  */
-int powersdr_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
+static int powersdr_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 {
     char lvlbuf[KENWOOD_MAX_BUF_LEN];
-    char *cmd;
+    const char *cmd;
     int retval;
     int len, ans;
     rmode_t mode;
@@ -1143,7 +1144,7 @@ int powersdr_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
     return RIG_OK;
 }
 
-int powersdr_set_func(RIG *rig, vfo_t vfo, setting_t func, int status)
+static int powersdr_set_func(RIG *rig, vfo_t vfo, setting_t func, int status)
 {
     char cmd[KENWOOD_MAX_BUF_LEN];
 
@@ -1174,10 +1175,10 @@ int powersdr_set_func(RIG *rig, vfo_t vfo, setting_t func, int status)
     return kenwood_transaction(rig, cmd, NULL, 0);
 }
 
-int powersdr_get_func(RIG *rig, vfo_t vfo, setting_t func, int *status)
+static int powersdr_get_func(RIG *rig, vfo_t vfo, setting_t func, int *status)
 {
     char lvlbuf[KENWOOD_MAX_BUF_LEN];
-    char *cmd;
+    const char *cmd;
     int retval;
     int len, ans;
 
@@ -1234,7 +1235,7 @@ int powersdr_get_func(RIG *rig, vfo_t vfo, setting_t func, int *status)
     return RIG_OK;
 }
 
-int powersdr_set_parm(RIG *rig, setting_t parm, value_t val)
+static int powersdr_set_parm(RIG *rig, setting_t parm, value_t val)
 {
     ENTERFUNC;
     char cmd[KENWOOD_MAX_BUF_LEN];
@@ -1263,7 +1264,7 @@ int powersdr_set_parm(RIG *rig, setting_t parm, value_t val)
     RETURNFUNC(retval);
 }
 
-int powersdr_get_parm(RIG *rig, setting_t parm, value_t *val)
+static int powersdr_get_parm(RIG *rig, setting_t parm, value_t *val)
 {
     char cmd[KENWOOD_MAX_BUF_LEN];
     char buf[KENWOOD_MAX_BUF_LEN];
diff --git a/rigs/kenwood/k2.c b/rigs/kenwood/k2.c
index ba88c0028..904012efb 100644
--- a/rigs/kenwood/k2.c
+++ b/rigs/kenwood/k2.c
@@ -21,6 +21,7 @@
  *  the complete text of the GNU Lesser Public License version 2.1.
  *
  */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
 #include <string.h>
@@ -95,16 +96,16 @@ struct k2_filt_lst_s k2_fwmd_cw;
 struct k2_filt_lst_s k2_fwmd_rtty;
 
 /* K2 specific rig_caps API function declarations */
-int k2_open(RIG *rig);
-int k2_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width);
-int k2_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width);
-int k2_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val);
-int k2_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op);
+static int k2_open(RIG *rig);
+static int k2_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width);
+static int k2_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width);
+static int k2_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val);
+static int k2_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op);
 
 /* Private function declarations */
-int k2_probe_mdfw(RIG *rig, struct kenwood_priv_data *priv);
-int k2_mdfw_rest(RIG *rig, const char *mode, const char *fw);
-int k2_pop_fw_lst(RIG *rig, const char *cmd);
+static int k2_probe_mdfw(RIG *rig, struct kenwood_priv_data *priv);
+static int k2_mdfw_rest(RIG *rig, const char *mode, const char *fw);
+static int k2_pop_fw_lst(RIG *rig, const char *cmd);
 
 
 /*
@@ -258,7 +259,7 @@ struct rig_caps k2_caps =
 /* k2_open()
  *
  */
-int k2_open(RIG *rig)
+static int k2_open(RIG *rig)
 {
     int err;
     struct kenwood_priv_data *priv = STATE(rig)->priv;
@@ -289,7 +290,7 @@ int k2_open(RIG *rig)
  * wider than the passed value and sets the radio accordingly.
  */
 
-int k2_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
+static int k2_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
 {
 
     int err;
@@ -425,12 +426,12 @@ int k2_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
  * by the radio and returns it to the caller.
  */
 
-int k2_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width)
+static int k2_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width)
 {
     int err;
     char buf[KENWOOD_MAX_BUF_LEN];
     char tmp[16];
-    char *bufptr;
+    const char *bufptr;
     pbwidth_t temp_w;
 
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
@@ -491,7 +492,7 @@ int k2_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width)
  *      STRING: val.cs for set, val.s for get
  *      CHECKBUTTON: val.i 0/1
  */
-int k2_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val)
+static int k2_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val)
 {
     char buf[KENWOOD_MAX_BUF_LEN];
     int err;
@@ -544,7 +545,7 @@ int k2_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val)
 /* Probes for mode and filter settings, based on information
  * by Chris Bryant, G3WIE.
  */
-int k2_probe_mdfw(RIG *rig, struct kenwood_priv_data *priv)
+static int k2_probe_mdfw(RIG *rig, struct kenwood_priv_data *priv)
 {
     int err, i, c;
     char buf[KENWOOD_MAX_BUF_LEN];
@@ -678,7 +679,7 @@ int k2_probe_mdfw(RIG *rig, struct kenwood_priv_data *priv)
 
 
 /* Restore mode, filter, and ext_lvl to original values */
-int k2_mdfw_rest(RIG *rig, const char *mode, const char *fw)
+static int k2_mdfw_rest(RIG *rig, const char *mode, const char *fw)
 {
     int err;
 
@@ -720,7 +721,7 @@ int k2_mdfw_rest(RIG *rig, const char *mode, const char *fw)
 
 
 /* Populate k2_filt_lst_s structure for each mode */
-int k2_pop_fw_lst(RIG *rig, const char *cmd)
+static int k2_pop_fw_lst(RIG *rig, const char *cmd)
 {
     int err, f;
     char fcmd[16];
@@ -806,7 +807,7 @@ int k2_pop_fw_lst(RIG *rig, const char *cmd)
     return RIG_OK;
 }
 
-int k2_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op)
+static int k2_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op)
 {
     char buf[32];
 
diff --git a/rigs/kenwood/k3.c b/rigs/kenwood/k3.c
index da0541059..29423315b 100644
--- a/rigs/kenwood/k3.c
+++ b/rigs/kenwood/k3.c
@@ -21,6 +21,7 @@
  *  the complete text of the GNU Lesser Public License version 2.1.
  *
  */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -143,47 +144,43 @@ static struct kenwood_priv_caps k3_priv_caps  =
 
 
 /* K3 specific function declarations */
-int k3_set_freq(RIG *rig, vfo_t vfo, freq_t freq);
-int k3_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width);
-int k3_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width);
-int k3_get_vfo(RIG *rig, vfo_t *vfo);
-int k3_set_vfo(RIG *rig, vfo_t vfo);
-int k3_set_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t val);
-int k3_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val);
-int k3_set_rit(RIG *rig, vfo_t vfo, shortfreq_t rit);
-int k3_set_xit(RIG *rig, vfo_t vfo, shortfreq_t rit);
-int k3_set_split_mode(RIG *rig, vfo_t vfo, rmode_t tx_mode, pbwidth_t tx_width);
-int k3_get_split_mode(RIG *rig, vfo_t vfo, rmode_t *tx_mode,
+static int k3_set_freq(RIG *rig, vfo_t vfo, freq_t freq);
+static int k3_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width);
+static int k3_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width);
+static int k3_get_vfo(RIG *rig, vfo_t *vfo);
+static int k3_set_vfo(RIG *rig, vfo_t vfo);
+static int k3_set_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t val);
+static int k3_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val);
+static int k3_set_rit(RIG *rig, vfo_t vfo, shortfreq_t rit);
+static int k3_set_xit(RIG *rig, vfo_t vfo, shortfreq_t rit);
+static int k3_set_split_mode(RIG *rig, vfo_t vfo, rmode_t tx_mode, pbwidth_t tx_width);
+static int k3_get_split_mode(RIG *rig, vfo_t vfo, rmode_t *tx_mode,
                       pbwidth_t *tx_width);
-int k3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val);
-int k3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val);
-int kx3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val);
-int kx3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val);
-int k3_set_func(RIG *rig, vfo_t vfo, setting_t func, int status);
-int k3_get_func(RIG *rig, vfo_t vfo, setting_t func, int *status);
-int k3_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op);
-int k3_power2mW(RIG *rig, unsigned int *mwpower, float power, freq_t freq,
+static int k3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val);
+static int k3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val);
+static int kx3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val);
+static int kx3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val);
+static int k3_set_func(RIG *rig, vfo_t vfo, setting_t func, int status);
+static int k3_get_func(RIG *rig, vfo_t vfo, setting_t func, int *status);
+static int k3_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op);
+static int k3_power2mW(RIG *rig, unsigned int *mwpower, float power, freq_t freq,
                 rmode_t mode);
 
 /* Private helper functions */
 int set_rit_xit(RIG *rig, shortfreq_t rit);
-int k3_set_nb_level(RIG *rig, float dsp_nb, float if_nb);
-int k3_get_nb_level(RIG *rig, float *dsp_nb, float *if_nb);
-int k3_get_bar_graph_level(RIG *rig, float *smeter, float *pwr, float *alc,
+static int k3_set_nb_level(RIG *rig, float dsp_nb, float if_nb);
+static int k3_get_nb_level(RIG *rig, float *dsp_nb, float *if_nb);
+static int k3_get_bar_graph_level(RIG *rig, float *smeter, float *pwr, float *alc,
                            int *mode_tx);
-int k4_get_bar_graph_level(RIG *rig, float *swr, float *pwr, float *alc,
+static int k4_get_bar_graph_level(RIG *rig, float *swr, float *pwr, float *alc,
                            int *mode_tx);
-int kx3_get_bar_graph_level(RIG *rig, float *level);
-int k3_send_voice_mem(RIG *rig, vfo_t vfo, int ch);
-int k3_stop_voice_mem(RIG *rig, vfo_t vfo);
-int k3_stop_morse(RIG *rig, vfo_t vfo);
 
 /* K4 functions */
-int k4_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt);
-int k4_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt);
-int k4_send_voice_mem(RIG *rig, vfo_t vfo, int ch);
-int k4_stop_voice_mem(RIG *rig, vfo_t vfo);
-int k4_stop_morse(RIG *rig, vfo_t vfo);
+static int k4_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt);
+static int k4_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt);
+static int k4_send_voice_mem(RIG *rig, vfo_t vfo, int ch);
+static int k4_stop_voice_mem(RIG *rig, vfo_t vfo);
+static int k4_stop_morse(RIG *rig, vfo_t vfo);
 
 /*
  * K3 rig capabilities.
@@ -194,28 +191,11 @@ int k4_stop_morse(RIG *rig, vfo_t vfo);
  * Part of info comes from http://www.elecraft.com/K2_Manual_Download_Page.htm#K3
  * look for K3 Programmer's Reference PDF
  */
-int kx3_get_bar_graph_level(RIG *rig, float *level);
-int k3_send_voice_mem(RIG *rig, vfo_t vfo, int ch);
-int k3_stop_voice_mem(RIG *rig, vfo_t vfo);
-int k3_stop_morse(RIG *rig, vfo_t vfo);
+static int kx3_get_bar_graph_level(RIG *rig, float *level);
+static int k3_send_voice_mem(RIG *rig, vfo_t vfo, int ch);
+static int k3_stop_voice_mem(RIG *rig, vfo_t vfo);
+static int k3_stop_morse(RIG *rig, vfo_t vfo);
 
-/* K4 functions */
-int k4_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt);
-int k4_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt);
-int k4_send_voice_mem(RIG *rig, vfo_t vfo, int ch);
-int k4_stop_voice_mem(RIG *rig, vfo_t vfo);
-int k4_stop_morse(RIG *rig, vfo_t vfo);
-
-/*
- * K3 rig capabilities.
- * This kit can recognize a large subset of TS-570/K2 commands and has many
- * extensions of its own.  Extension backend functions to standard Kenwood
- * command are defined in elecraft.c (shared with K2) and in this file.
- *
- * Part of info comes from http://www.elecraft.com/K2_Manual_Download_Page.htm#K3
- * look for K3 Programmer's Reference PDF
- *
- */
 struct rig_caps k3_caps =
 {
     RIG_MODEL(RIG_MODEL_K3),
@@ -1037,14 +1017,14 @@ struct rig_caps kx2_caps =
  * RIG_MODE_PKTUSB and RIG_MODE_PKTLSB can be supported.
  */
 
-int k3_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width)
+static int k3_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width)
 {
     char buf[KENWOOD_MAX_BUF_LEN];
     int err;
     rmode_t temp_m;
     pbwidth_t temp_w;
-    char *cmd_data = "DT";
-    char *cmd_bw = "BW";
+    const char *cmd_data = "DT";
+    const char *cmd_bw = "BW";
     int cmd_bw_len = 6;
     const struct kenwood_priv_data *priv = STATE(rig)->priv;
 
@@ -1191,7 +1171,7 @@ int k3_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width)
  * mapping seems most likely to cover the user requirements.
  */
 
-int k3_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
+static int k3_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
 {
     int err, err2;
     char cmd_m[5];
@@ -1396,7 +1376,7 @@ int k3_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
  * We just emulate them so rigctl can work correctly.
  */
 
-int k3_set_vfo(RIG *rig, vfo_t vfo)
+static int k3_set_vfo(RIG *rig, vfo_t vfo)
 {
     ENTERFUNC;
 
@@ -1406,7 +1386,7 @@ int k3_set_vfo(RIG *rig, vfo_t vfo)
     RETURNFUNC(RIG_OK);
 }
 
-int k3_get_vfo(RIG *rig, vfo_t *vfo)
+static int k3_get_vfo(RIG *rig, vfo_t *vfo)
 {
     ENTERFUNC;
 
@@ -1427,7 +1407,7 @@ int k3_get_vfo(RIG *rig, vfo_t *vfo)
  * See Private Elecraft extra levels definitions in elecraft.c and
  * private token #define in elecraft.h
  */
-int k3_set_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t val)
+static int k3_set_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t val)
 {
     char buf[10];
 
@@ -1476,7 +1456,7 @@ int k3_set_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t val)
  *      STRING: val.cs for set, val.s for get
  *      CHECKBUTTON: val.i 0/1
  */
-int k3_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val)
+static int k3_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val)
 {
     char buf[KENWOOD_MAX_BUF_LEN];
     int err;
@@ -1544,7 +1524,7 @@ int k3_get_ext_level(RIG *rig, vfo_t vfo, hamlib_token_t token, value_t *val)
  * k3_set_rit() -- Differs from from generic Kenwood function as K3 can set
  * RIT to an arbitrary offset.  When rit == 0, the RIT offset is cleared.
  */
-int k3_set_rit(RIG *rig, vfo_t vfo, shortfreq_t rit)
+static int k3_set_rit(RIG *rig, vfo_t vfo, shortfreq_t rit)
 {
     int err;
 
@@ -1565,7 +1545,7 @@ int k3_set_rit(RIG *rig, vfo_t vfo, shortfreq_t rit)
  * k3_set_xit() -- Differs from from generic Kenwood function as K3 can set
  * XIT to an arbitrary offset.  When rit == 0, the XIT offset is cleared.
  */
-int k3_set_xit(RIG *rig, vfo_t vfo, shortfreq_t rit)
+static int k3_set_xit(RIG *rig, vfo_t vfo, shortfreq_t rit)
 {
     int err;
 
@@ -1585,7 +1565,7 @@ int k3_set_xit(RIG *rig, vfo_t vfo, shortfreq_t rit)
 /*
  * The K3 *always* uses VFOB for TX.
  */
-int k3_set_split_mode(RIG *rig, vfo_t vfo, rmode_t tx_mode, pbwidth_t tx_width)
+static int k3_set_split_mode(RIG *rig, vfo_t vfo, rmode_t tx_mode, pbwidth_t tx_width)
 {
     struct kenwood_priv_caps *caps = kenwood_caps(rig);
     char buf[32];
@@ -1761,7 +1741,7 @@ int k3_set_split_mode(RIG *rig, vfo_t vfo, rmode_t tx_mode, pbwidth_t tx_width)
 
 /* The K3 *always* uses VFOB for TX.
  */
-int k3_get_split_mode(RIG *rig, vfo_t vfo, rmode_t *tx_mode,
+static int k3_get_split_mode(RIG *rig, vfo_t vfo, rmode_t *tx_mode,
                       pbwidth_t *tx_width)
 {
     char buf[KENWOOD_MAX_BUF_LEN];
@@ -1919,7 +1899,7 @@ static int k3_get_maxpower(RIG *rig)
     return maxpower;
 }
 
-int k3_power2mW(RIG *rig,
+static int k3_power2mW(RIG *rig,
                 unsigned int *mwpower,
                 float power,
                 freq_t freq,
@@ -1931,7 +1911,7 @@ int k3_power2mW(RIG *rig,
     return RIG_OK;
 }
 
-int k3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
+static int k3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
 {
     char levelbuf[16];
     int kenwood_val;
@@ -2050,7 +2030,7 @@ int k3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
 /*
  * Handle S-meter (SM, SMH) level locally and pass rest to kenwood_get_level()
  */
-int k3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
+static int k3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 {
     char levelbuf[16];
     int retval;
@@ -2395,7 +2375,7 @@ int k3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
     return RIG_OK;
 }
 
-int kx3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
+static int kx3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
 {
     int ival;
     char cmdbuf[32];
@@ -2425,7 +2405,7 @@ int kx3_set_level(RIG *rig, vfo_t vfo, setting_t level, value_t val)
     return k3_set_level(rig, vfo, level, val);
 }
 
-int kx3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
+static int kx3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 {
     int retval;
     float f;
@@ -2515,7 +2495,7 @@ int kx3_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 }
 
 
-int k3_set_func(RIG *rig, vfo_t vfo, setting_t func, int status)
+static int k3_set_func(RIG *rig, vfo_t vfo, setting_t func, int status)
 {
     char buf[10];
 
@@ -2555,7 +2535,7 @@ int k3_set_func(RIG *rig, vfo_t vfo, setting_t func, int status)
     return kenwood_transaction(rig, buf, NULL, 0);
 }
 
-int k3_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op)
+static int k3_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op)
 {
     char buf[32];
     ENTERFUNC;
@@ -2593,7 +2573,7 @@ int k3_vfo_op(RIG *rig, vfo_t vfo, vfo_op_t op)
  * on the K3.  Those functions are handled here and others are passed
  * through to kenwood_get_func().
  */
-int k3_get_func(RIG *rig, vfo_t vfo, setting_t func, int *status)
+static int k3_get_func(RIG *rig, vfo_t vfo, setting_t func, int *status)
 {
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
 
@@ -2674,7 +2654,7 @@ int set_rit_xit(RIG *rig, shortfreq_t rit)
     return RIG_OK;
 }
 
-int k3_set_nb_level(RIG *rig, float dsp_nb, float if_nb)
+static int k3_set_nb_level(RIG *rig, float dsp_nb, float if_nb)
 {
     char levelbuf[16];
     int dsp_nb_raw = 0;
@@ -2722,7 +2702,7 @@ int k3_set_nb_level(RIG *rig, float dsp_nb, float if_nb)
     return kenwood_transaction(rig, levelbuf, NULL, 0);
 }
 
-int k3_get_nb_level(RIG *rig, float *dsp_nb, float *if_nb)
+static int k3_get_nb_level(RIG *rig, float *dsp_nb, float *if_nb)
 {
     char levelbuf[16];
     int retval;
@@ -2780,7 +2760,7 @@ int k4_get_bar_graph_level(RIG *rig, float *swr, float *pwr, float *alc,
     return RIG_OK;
 }
 
-int k3_get_bar_graph_level(RIG *rig, float *smeter, float *pwr, float *alc,
+static int k3_get_bar_graph_level(RIG *rig, float *smeter, float *pwr, float *alc,
                            int *mode_tx)
 {
     char levelbuf[16];
@@ -2878,7 +2858,7 @@ int k3_get_bar_graph_level(RIG *rig, float *smeter, float *pwr, float *alc,
     return RIG_OK;
 }
 
-int kx3_get_bar_graph_level(RIG *rig, float *level)
+static int kx3_get_bar_graph_level(RIG *rig, float *level)
 {
     char levelbuf[16];
     int retval;
@@ -2992,7 +2972,7 @@ int k4_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt)
 // K3S band memory needs some time to do its thing after freq change
 // K3 probably does too
 // But what about the K4?
-int k3_set_freq(RIG *rig, vfo_t vfo, freq_t freq)
+static int k3_set_freq(RIG *rig, vfo_t vfo, freq_t freq)
 {
     int retval;
     freq_t tfreq;
@@ -3012,9 +2992,9 @@ int k3_set_freq(RIG *rig, vfo_t vfo, freq_t freq)
     return retval;
 }
 
-int k3_send_voice_mem(RIG *rig, vfo_t vfo, int ch)
+static int k3_send_voice_mem(RIG *rig, vfo_t vfo, int ch)
 {
-    char *cmd;
+    const char *cmd;
     int retval;
 
     if (ch < 1 || ch > 4)
@@ -3038,7 +3018,7 @@ int k3_send_voice_mem(RIG *rig, vfo_t vfo, int ch)
     return retval;
 }
 
-int k3_stop_voice_mem(RIG *rig, vfo_t vfo)
+static int k3_stop_voice_mem(RIG *rig, vfo_t vfo)
 {
     int retval;
     retval = kenwood_transaction(rig, "SWT37;", NULL, 0);
@@ -3075,7 +3055,7 @@ int k4_stop_morse(RIG *rig, vfo_t vfo)
     return retval;
 }
 
-int k3_stop_morse(RIG *rig, vfo_t vfo)
+static int k3_stop_morse(RIG *rig, vfo_t vfo)
 {
     int retval;
     char cmd[32];
diff --git a/rigs/kenwood/ts890s.c b/rigs/kenwood/ts890s.c
index 74f3c22b5..db9aa255a 100644
--- a/rigs/kenwood/ts890s.c
+++ b/rigs/kenwood/ts890s.c
@@ -44,7 +44,8 @@
 static int kenwood_ts890_set_level(RIG *rig, vfo_t vfo, setting_t level,
                                    value_t val)
 {
-    char levelbuf[16], *command_string;
+    char levelbuf[16];
+    const char *command_string;
     int kenwood_val, retval;
     gran_t *level_info;
 
@@ -117,7 +118,7 @@ static int kenwood_ts890_get_level(RIG *rig, vfo_t vfo, setting_t level,
     size_t ack_len, ack_len_expected, len;
     int levelint;
     int retval;
-    char *command_string;
+    const char *command_string;
     gran_t *level_info;
 
     level_info = &rig->caps->level_gran[rig_setting2idx(level)];
@@ -475,13 +476,13 @@ static int ts890s_get_split_vfo(RIG *rig, vfo_t rxvfo, split_t *split,
 {
     char buf[4];
     int retval;
-    vfo_t tvfo;
     struct rig_state *rs = STATE(rig);
     struct kenwood_priv_data *priv = rs->priv;
 
     if (RIG_OK == (retval = kenwood_safe_transaction(rig, "FT", buf, sizeof(buf),
                                 3)))
     {
+        vfo_t tvfo;
         if ('0' == buf[2])
         {
             tvfo = RIG_VFO_A;
diff --git a/src/misc.c b/src/misc.c
index 0a59f1499..8b3c0372c 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -17,6 +17,7 @@
  *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  *
  */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 /**
  * \addtogroup rig_internal
@@ -383,7 +384,7 @@ int millis_to_dot10ths(int millis, int wpm)
 int HAMLIB_API sprintf_freq(char *str, int str_len, freq_t freq)
 {
     double f;
-    char *hz;
+    const char *hz;
     int decplaces = 10;
     int retval;
 
@@ -2763,7 +2764,7 @@ void errmsg(int err, char *s, const char *func, const char *file, int line)
               rigerror(err));
 }
 
-uint32_t CRC32_function(uint8_t *buf, uint32_t len)
+uint32_t CRC32_function(const uint8_t *buf, uint32_t len)
 {
 
     uint32_t crc;
@@ -2893,7 +2894,7 @@ const char *rig_get_band_str(RIG *rig, hamlib_band_t band, int which)
         rig_debug(RIG_DEBUG_VERBOSE, "%s: bandlist=%s\n", __func__, bandlist);
         int n = 0;
         char *p = strchr(bandlist, '(') + 1;
-        char *token;
+        const char *token;
 
         if (p == NULL)
         {
@@ -2941,7 +2942,7 @@ hamlib_band_t rig_get_band(RIG *rig, freq_t freq, int band)
         rig_debug(RIG_DEBUG_VERBOSE, "%s: bandlist=%s\n", __func__, bandlist);
         // e.g. BANDSELECT(BAND160M,BAND80M,BANDUNUSED,BAND40M)
         char *p = strchr(bandlist, '(') + 1;
-        char *token;
+        const char *token;
 
         if (p == NULL)
         {
@@ -3000,7 +3001,7 @@ int rig_get_band_rig(RIG *rig, freq_t freq, const char *band)
         }
 
         char *p = strchr(bandlist, '(') + 1;
-        char *token;
+        const char *token;
 
         if (p == NULL)
         {
diff --git a/src/misc.h b/src/misc.h
index 31ff966ec..8e2e57001 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -18,6 +18,7 @@
  *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  *
  */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #ifndef _MISC_H
 #define _MISC_H 1
@@ -122,7 +123,7 @@ extern HAMLIB_EXPORT(vfo_t) vfo_fixup2a(RIG *rig, vfo_t vfo, split_t split, cons
 
 extern HAMLIB_EXPORT(int) parse_hoststr(char *hoststr, int hoststr_len, char host[256], char port[6]);
 
-extern HAMLIB_EXPORT(uint32_t) CRC32_function(uint8_t *buf, uint32_t len);
+extern HAMLIB_EXPORT(uint32_t) CRC32_function(const uint8_t *buf, uint32_t len);
 
 extern HAMLIB_EXPORT(char *)date_strget(char *buf, int buflen, int localtime);