diff --git a/meson.build b/meson.build
index 3423166..8fdafc6 100644
--- a/meson.build
+++ b/meson.build
@@ -3,7 +3,8 @@
 project('bmr', 'c',
   version: '0.1.0',
   default_options: [
-    'warning_level=3',
+    'warning_level=everything',
+#   'werror=true',
     'c_std=c2x'
   ]
 )
diff --git a/src/capability_cmd.c b/src/capability_cmd.c
index efe7f4e..704b03e 100644
--- a/src/capability_cmd.c
+++ b/src/capability_cmd.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "capability_cmd.h"
 #include "util_json.h"
 
 #include <jansson.h>
diff --git a/src/fault_cmd.c b/src/fault_cmd.c
index b5e87ce..9756b27 100644
--- a/src/fault_cmd.c
+++ b/src/fault_cmd.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "fault_cmd.h"
 #include "util_json.h"
 
 #include <jansson.h>
@@ -49,6 +50,8 @@ resp_mode_name(uint8_t b) {
       return "disable-and-retry";
     case MODE_DISABLE_UNTIL_CLEAR:
       return "disable-until-clear";
+    default:
+      return "invalid resp mode";
     }
 
   return "unknown";
diff --git a/src/freq_cmd.c b/src/freq_cmd.c
index 7a9a637..8fc8aaf 100644
--- a/src/freq_cmd.c
+++ b/src/freq_cmd.c
@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "freq_cmd.h"
 #include "util_json.h"
+
 #include <jansson.h>
 #include <string.h>
 #include <stdio.h>
diff --git a/src/interleave_cmd.c b/src/interleave_cmd.c
index 1467db1..1372f61 100644
--- a/src/interleave_cmd.c
+++ b/src/interleave_cmd.c
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
+
 #include "pmbus_io.h"
+#include "interleave_cmd.h"
 #include "util_json.h"
 
 #include <jansson.h>
diff --git a/src/main.c b/src/main.c
index 777b878..04eee85 100644
--- a/src/main.c
+++ b/src/main.c
@@ -37,7 +37,7 @@
 #include <getopt.h>
 
 static const char *opt_bus = "/dev/i2c-1";
-static int opt_addr = 0x40;
+static uint8_t opt_addr = 0x40;
 static int opt_pretty = 1;
 
 static void
@@ -121,7 +121,7 @@ main(int argc, char *const *argv) {
         opt_bus = optarg;
         break;
       case 'a':
-        opt_addr = (int)strtol(optarg, NULL, 0);
+        opt_addr = (uint8_t)strtol(optarg, NULL, 0);
         break;
       case 'P':
         opt_pretty = 0;
diff --git a/src/mfr_addr_offset.c b/src/mfr_addr_offset.c
index c29f89e..9d31be2 100644
--- a/src/mfr_addr_offset.c
+++ b/src/mfr_addr_offset.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "mfr_addr_offset.h"
 #include "util_json.h"
 
 #include <jansson.h>
diff --git a/src/mfr_fwdata.c b/src/mfr_fwdata.c
index 46a3572..9f7bb85 100644
--- a/src/mfr_fwdata.c
+++ b/src/mfr_fwdata.c
@@ -1,7 +1,9 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "mfr_fwdata.h"
 #include "util_json.h"
+
 #include <jansson.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -22,8 +24,8 @@ cmd_fwdata(int fd, int pretty) {
 
   /* Extract printable runs >= 3 */
   json_t *runs = json_array();
-  int run = 0, start = 0;
-  for (int i = 0; i < n; i++) {
+  size_t run = 0, start = 0;
+  for (size_t i = 0; i < (size_t)n; i++) {
     if (b[i] >= 32 && b[i] <= 126) {
       if (run == 0)
         start = i;
diff --git a/src/mfr_hrr.c b/src/mfr_hrr.c
index 840dbd0..20b96f1 100644
--- a/src/mfr_hrr.c
+++ b/src/mfr_hrr.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "mfr_hrr.h"
 #include "util_json.h"
 
 #include <jansson.h>
@@ -15,6 +16,10 @@
 #define BIT_ARTDLC  (1u<<3)     /* Adaptive Ramp-up Time / Dynamic Loop Compensation enable */
 #define BIT_DBV     (1u<<2)     /* Dynamic Bus Voltage enable */
 
+#define FLAG_SET8(v, flag)  ((v) |= (uint8_t)(flag))
+#define FLAG_CLEAR8(v, flag) ((v) &= (uint8_t)~(uint8_t)(flag))
+#define FLAG_ISSET8(val, flag) (!!(((uint8_t)(val)) & (uint8_t)(flag)))
+
 static void
 usage_hrr_short(void) {
   fprintf(stderr,
@@ -110,11 +115,11 @@ cmd_hrr(int fd, int argc, char *const *argv, int pretty) {
 
     json_t *o = json_object();
     json_object_set_new(o, "MFR_SPECIAL_OPTIONS_raw", json_integer((unsigned) (uint8_t) v));
-    json_object_set_new(o, "require_pec", json_boolean(!!((uint8_t) v & BIT_PEC)));
-    json_object_set_new(o, "hrr_enabled", json_boolean(!!((uint8_t) v & BIT_HRR)));
-    json_object_set_new(o, "dls_mode", json_string(((uint8_t) v & BIT_DLS) ? "nonlinear" : "linear"));
-    json_object_set_new(o, "artdlc_enabled", json_boolean(!!((uint8_t) v & BIT_ARTDLC)));
-    json_object_set_new(o, "dbv_enabled", json_boolean(!!((uint8_t) v & BIT_DBV)));
+    json_object_set_new(o, "require_pec", json_boolean(FLAG_ISSET8(v, BIT_PEC)));
+    json_object_set_new(o, "hrr_enabled", json_boolean(FLAG_ISSET8(v, BIT_HRR)));
+    json_object_set_new(o, "dls_mode", json_string(FLAG_ISSET8(v, BIT_DLS) ? "nonlinear" : "linear"));
+    json_object_set_new(o, "artdlc_enabled", json_boolean(FLAG_ISSET8(v, BIT_ARTDLC)));
+    json_object_set_new(o, "dbv_enabled", json_boolean(FLAG_ISSET8(v, BIT_DBV)));
 
     json_print_or_pretty(o, pretty);
 
@@ -164,22 +169,22 @@ cmd_hrr(int fd, int argc, char *const *argv, int pretty) {
       int v;
       if ((v = parse_onoff(pec_s)) >= 0) {
         if (v)
-          nv |= BIT_PEC;
+          FLAG_SET8(nv, BIT_PEC);
         else
-          nv &= ~BIT_PEC;
+          FLAG_CLEAR8(nv, BIT_PEC);
       }
       if ((v = parse_onoff(hrr_s)) >= 0) {
         if (v)
-          nv |= BIT_HRR;
+          FLAG_SET8(nv, BIT_HRR);
         else
-          nv &= ~BIT_HRR;
+          FLAG_CLEAR8(nv, BIT_HRR);
       }
 
       if (dls_s) {
         if (!strcmp(dls_s, "linear"))
-          nv &= ~BIT_DLS;
+          FLAG_CLEAR8(nv, BIT_DLS);
         else if (!strcmp(dls_s, "nonlinear"))
-          nv |= BIT_DLS;
+          FLAG_SET8(nv, BIT_DLS);
         else {
           fprintf(stderr, "--dls linear|nonlinear\n");
           return 2;
@@ -188,15 +193,15 @@ cmd_hrr(int fd, int argc, char *const *argv, int pretty) {
 
       if ((v = parse_onoff(art_s)) >= 0) {
         if (v)
-          nv |= BIT_ARTDLC;
+          FLAG_SET8(nv, BIT_ARTDLC);
         else
-          nv &= ~BIT_ARTDLC;
+          FLAG_CLEAR8(nv, BIT_ARTDLC);
       }
       if ((v = parse_onoff(dbv_s)) >= 0) {
         if (v)
-          nv |= BIT_DBV;
+          FLAG_SET8(nv, BIT_DBV);
         else
-          nv &= ~BIT_DBV;
+          FLAG_CLEAR8(nv, BIT_DBV);
       }
     }
 
@@ -216,11 +221,11 @@ cmd_hrr(int fd, int argc, char *const *argv, int pretty) {
     json_t *o = json_object();
     json_object_set_new(o, "changed", json_boolean(nv != (uint8_t) cur));
     json_object_set_new(o, "MFR_SPECIAL_OPTIONS_raw", json_integer((unsigned) (uint8_t) rb));
-    json_object_set_new(o, "require_pec", json_boolean(!!((uint8_t) rb & BIT_PEC)));
-    json_object_set_new(o, "hrr_enabled", json_boolean(!!((uint8_t) rb & BIT_HRR)));
-    json_object_set_new(o, "dls_mode", json_string(((uint8_t) rb & BIT_DLS) ? "nonlinear" : "linear"));
-    json_object_set_new(o, "artdlc_enabled", json_boolean(!!((uint8_t) rb & BIT_ARTDLC)));
-    json_object_set_new(o, "dbv_enabled", json_boolean(!!((uint8_t) rb & BIT_DBV)));
+    json_object_set_new(o, "require_pec", json_boolean(FLAG_ISSET8(rb,BIT_PEC)));
+    json_object_set_new(o, "hrr_enabled", json_boolean(FLAG_ISSET8(rb, BIT_HRR)));
+    json_object_set_new(o, "dls_mode", json_string(FLAG_ISSET8(rb, BIT_DLS) ? "nonlinear" : "linear"));
+    json_object_set_new(o, "artdlc_enabled", json_boolean(FLAG_ISSET8(rb, BIT_ARTDLC)));
+    json_object_set_new(o, "dbv_enabled", json_boolean(FLAG_ISSET8(rb, BIT_DBV)));
 
     json_print_or_pretty(o, pretty);
 
diff --git a/src/mfr_id.c b/src/mfr_id.c
index a964177..c1583ba 100644
--- a/src/mfr_id.c
+++ b/src/mfr_id.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "mfr_id.h"
 #include "util_json.h"
 #include <jansson.h>
 #include <stdint.h>
diff --git a/src/mfr_multipin.c b/src/mfr_multipin.c
index 42ce56c..096f26a 100644
--- a/src/mfr_multipin.c
+++ b/src/mfr_multipin.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "mfr_multipin.h"
 #include "util_json.h"
 
 #include <jansson.h>
diff --git a/src/mfr_ramp_data.c b/src/mfr_ramp_data.c
index 8ce6560..4c31c81 100644
--- a/src/mfr_ramp_data.c
+++ b/src/mfr_ramp_data.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "mfr_ramp_data.h"
 #include "util_json.h"
 
 #include <jansson.h>
diff --git a/src/mfr_restart.c b/src/mfr_restart.c
index db60a5a..48800b9 100644
--- a/src/mfr_restart.c
+++ b/src/mfr_restart.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "mfr_restart.h"
 #include <stdio.h>
 
 int
diff --git a/src/mfr_save_restore.c b/src/mfr_save_restore.c
index 2276e1d..951ae1d 100644
--- a/src/mfr_save_restore.c
+++ b/src/mfr_save_restore.c
@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "mfr_save_restore.h"
+
 #include <stdio.h>
 #include <string.h>
 
diff --git a/src/mfr_snapshot.c b/src/mfr_snapshot.c
index 2c28294..d9f7b3e 100644
--- a/src/mfr_snapshot.c
+++ b/src/mfr_snapshot.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "mfr_snapshot.h"
 #include "decoders.h"
 #include "util_json.h"
 
diff --git a/src/mfr_status_data.c b/src/mfr_status_data.c
index e04df45..ae04883 100644
--- a/src/mfr_status_data.c
+++ b/src/mfr_status_data.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "mfr_status_data.h"
 #include "util_json.h"
 
 #include <jansson.h>
diff --git a/src/mfr_user_data.c b/src/mfr_user_data.c
index 293d7c9..18f3d7c 100644
--- a/src/mfr_user_data.c
+++ b/src/mfr_user_data.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "mfr_user_data.h"
 #include "util_json.h"
 
 #include <jansson.h>
@@ -27,7 +28,7 @@ cmd_user_data(int fd, int argc, char *const *argv, int pretty) {
 
     json_t *o = json_object();
     json_object_set_new(o, "len", json_integer(n));
-    json_object_set_new(o, "ascii", json_stringn((char *) b, n));
+    json_object_set_new(o, "ascii", json_stringn((char *) b, (size_t)n));
     json_add_hex_ascii(o, "hex", b, (size_t)n);
 
     json_print_or_pretty(o, pretty);
@@ -45,7 +46,7 @@ cmd_user_data(int fd, int argc, char *const *argv, int pretty) {
         ascii = argv[++i];
     }
 
-    int n = 0;
+    size_t n = 0;
 
     if (hex) {
       size_t L = strlen(hex);
@@ -62,9 +63,9 @@ cmd_user_data(int fd, int argc, char *const *argv, int pretty) {
         sscanf(hex + 2 * i, "%2x", &v);
         b[i] = (uint8_t) v;
       }
-      n = (int) (L / 2);
+      n = L / 2;
     } else if (ascii) {
-      n = (int) strlen(ascii);
+      n = strlen(ascii);
       if (n > 32)
         n = 32;
       memcpy(b, ascii, n);
@@ -74,7 +75,11 @@ cmd_user_data(int fd, int argc, char *const *argv, int pretty) {
       return 2;
     }
 
-    if (pmbus_wr_block(fd, MFR_USER_DATA_00, b, n) < 0) {
+    if (n > 255) {
+      fprintf(stderr, "USER_DATA_00 write: len %zu > 255", n);
+      return 1;
+    }
+    if (pmbus_wr_block(fd, MFR_USER_DATA_00, b, (uint8_t)n) < 0) {
       perror("USER_DATA_00 write");
 
       return 1;
diff --git a/src/onoff_cmd.c b/src/onoff_cmd.c
index d7f8199..4e4716b 100644
--- a/src/onoff_cmd.c
+++ b/src/onoff_cmd.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "onoff_cmd.h"
 #include "util_json.h"
 
 #include <jansson.h>
diff --git a/src/operation_cmd.c b/src/operation_cmd.c
index 11ad090..1f8b893 100644
--- a/src/operation_cmd.c
+++ b/src/operation_cmd.c
@@ -1,7 +1,9 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "operation_cmd.h"
 #include "util_json.h"
+
 #include <jansson.h>
 #include <string.h>
 #include <stdio.h>
@@ -162,6 +164,9 @@ cmd_operation(int fd, int argc, char *const *argv, int pretty) {
       case 3:
         m = "reserved";
         break;
+      default:
+        fprintf(stderr, "invalid pmbus operation\n");
+	return 2;
       }
 
       json_object_set_new(delta, "margin", json_string(m));
diff --git a/src/pgood_cmd.c b/src/pgood_cmd.c
index 9319cf3..5581bd9 100644
--- a/src/pgood_cmd.c
+++ b/src/pgood_cmd.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "pgood_cmd.h"
 #include "util_json.h"
 #include "util_lin.h"
 
diff --git a/src/pmbus_io.c b/src/pmbus_io.c
index d2361e6..f1169d4 100644
--- a/src/pmbus_io.c
+++ b/src/pmbus_io.c
@@ -63,7 +63,7 @@ pmbus_wr_word(int fd, uint8_t cmd, uint16_t val) {
 }
 
 int
-pmbus_wr_block(int fd, uint8_t cmd, const uint8_t *buf, int len) {
+pmbus_wr_block(int fd, uint8_t cmd, const uint8_t *buf, uint8_t len) {
   return i2c_smbus_write_block_data(fd, cmd, len, buf);
 }
 
@@ -111,14 +111,16 @@ pmbus_lin16u_to_double(uint16_t raw, int exp5) {
 }
 
 uint16_t
-le16(const uint8_t *p) {
-  return (uint16_t) p[0]
-      | ((uint16_t) p[1] << 8)
-      ;
+BMR_PURE le16(const uint8_t *p) {
+  return (uint16_t)(
+        (uint16_t)p[0]
+      | ((uint16_t)p[1] << 8)
+      );
+
 }
 
 uint32_t
-le32(const uint8_t *p) {
+BMR_PURE le32(const uint8_t *p) {
   return (uint32_t)  p[0]
        | ((uint32_t) p[1] << 8)
        | ((uint32_t) p[2] << 16)
diff --git a/src/pmbus_io.h b/src/pmbus_io.h
index 0349e2e..b4c73b1 100644
--- a/src/pmbus_io.h
+++ b/src/pmbus_io.h
@@ -5,6 +5,15 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+#define D(xf) (double)((xf))
+
+#if defined(__GNUC__) || defined(__clang__)
+#  define BMR_PURE __attribute__((pure))
+#else
+#  define BMR_PURE
+#endif
+
+/* TODO: align with PMBus-Specification-Rev-1-3-1-Part-II-20150313.pdf */
 /*
  * PMBus standard (generic):
  *   - Control:            0x01, 0x02, 0x03, 0x10, 0x11, 0x12, 0x15, 0x16, 0x19
@@ -177,7 +186,7 @@ int pmbus_rd_word(int fd, uint8_t cmd);
 int pmbus_rd_block(int fd, uint8_t cmd, uint8_t * buf, int max);
 int pmbus_wr_byte(int fd, uint8_t cmd, uint8_t val);
 int pmbus_wr_word(int fd, uint8_t cmd, uint16_t val);
-int pmbus_wr_block(int fd, uint8_t cmd, const uint8_t * buf, int len);
+int pmbus_wr_block(int fd, uint8_t cmd, const uint8_t * buf, uint8_t len);
 int pmbus_send_byte(int fd, uint8_t cmd);
 
 /* returns 0 if linear mode */
diff --git a/src/read_cmd.c b/src/read_cmd.c
index f5424de..ad04d62 100644
--- a/src/read_cmd.c
+++ b/src/read_cmd.c
@@ -1,7 +1,9 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "read_cmd.h"
 #include "util_json.h"
+
 #include <jansson.h>
 #include <string.h>
 #include <stdio.h>
@@ -31,6 +33,9 @@ add_read_field(json_t *o, const char *key, int fd, uint8_t reg, enum enc_t enc,
   case ENC_RAW_INT:
     json_object_set_new(o, key, json_integer(w));
     break;
+  default:
+    __builtin_unreachable();
+    break;
   }
 }
 
diff --git a/src/rw_cmd.c b/src/rw_cmd.c
index 2eb9518..3a5ea9a 100644
--- a/src/rw_cmd.c
+++ b/src/rw_cmd.c
@@ -1,7 +1,9 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "rw_cmd.h"
 #include "util_json.h"
+
 #include <jansson.h>
 #include <string.h>
 #include <stdio.h>
diff --git a/src/salert_cmd.c b/src/salert_cmd.c
index 58bc128..b883b87 100644
--- a/src/salert_cmd.c
+++ b/src/salert_cmd.c
@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "salert_cmd.h"
 #include "util_json.h"
+
 #include <jansson.h>
 #include <string.h>
 #include <stdio.h>
diff --git a/src/status_cmd.c b/src/status_cmd.c
index 9f38dc1..7163a4e 100644
--- a/src/status_cmd.c
+++ b/src/status_cmd.c
@@ -1,7 +1,9 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "status_cmd.h"
 #include "decoders.h"
+
 #include "util_json.h"
 #include <jansson.h>
 
diff --git a/src/temp_cmd.c b/src/temp_cmd.c
index dcc82a8..fc1a55b 100644
--- a/src/temp_cmd.c
+++ b/src/temp_cmd.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "temp_cmd.h"
 #include "util_json.h"
 
 #include <jansson.h>
@@ -11,6 +12,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <assert.h>
 
 /*
  * Linear11: 5-bit signed exponent (E), 11-bit signed mantissa (Y), value = Y * 2^E
@@ -19,15 +21,20 @@
 
 static inline long
 lround_compat(double d) {
-  return (long) ((d >= 0.0) ? (d + 0.5) : (d - 0.5));
+  return (long) ((d >= D(0.0f)) ? (d + D(0.5f)) : (d - D(0.5f)));
 }
 
 static inline int32_t
 sign_extend(int32_t v, unsigned bits) {
-  int32_t m = 1u << (bits - 1);
+  assert(bits > 0 && bits < 32);
 
-  v = v & ((1u << bits) - 1);
-  return (v ^ m) - m;
+  uint32_t uv = (uint32_t)v;
+  uint32_t m = (uint32_t)1u << (bits - 1);
+
+  uv &= (m << 1) - 1u;
+  uv = (uv ^ m) - m;
+
+  return (int32_t)uv;
 }
 
 static double
@@ -47,8 +54,17 @@ lin11_to_double(uint16_t raw) {
 
 static uint16_t
 double_to_lin11(double v) {
-  if (v == 0.0)
+
+#if 0
+  if (v == D(0.0f))
     return 0;
+#else
+  /* epsilon: smallest assume it is same than 0 */
+  const double lin11_eps = D(1.0f / (float)(1u << 16));
+
+  if ((v > -lin11_eps) && (v < lin11_eps))
+    return 0;
+#endif
 
   /* Choose E in [-16..15] so Y fits in [-1024..1023] with best resolution. */
   int bestE = 0;
@@ -121,9 +137,9 @@ parse_temp_celsius(const char *s, double *outC) {
     if (u == 'C') {
       C = v;
     } else if (u == 'K') {
-      C = v - 273.15;
+      C = v - D(273.15f);
     } else if (u == 'F') {
-      C = (v - 32.0) * (5.0 / 9.0);
+      C = (v - D(32.0f)) * (D(5.0f) / D(9.0f));
     } else {
       /* unknown */
       return -1;
@@ -231,7 +247,8 @@ usage_temp_long(void) {
 
 static int
 write_one_limit(int fd, const char *label, uint8_t cmd, const char *val_s, json_t *w, json_t *rb) {
-  double C = 0.0;
+  double C = D(0.0f);
+
   if (parse_temp_celsius(val_s, &C) < 0) {
     fprintf(stderr, "bad value for %s\n", label);
     return 2;
diff --git a/src/timing_cmd.c b/src/timing_cmd.c
index cd6e7b4..4047edf 100644
--- a/src/timing_cmd.c
+++ b/src/timing_cmd.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "timing_cmd.h"
 #include "util_json.h"
 
 #include <jansson.h>
@@ -99,6 +100,7 @@ struct timing_profile {
   uint16_t ton_rise;
   uint16_t ton_max_fault_limit;
   uint8_t ton_max_fault_response; /* packed byte */
+  uint8_t __pad1;
   uint16_t toff_delay;
   uint16_t toff_fall;
   uint16_t toff_max_warn_limit;
diff --git a/src/util_json.c b/src/util_json.c
index 2add90e..5e82cf4 100644
--- a/src/util_json.c
+++ b/src/util_json.c
@@ -7,13 +7,13 @@
 
 /* TODO: replace with json_add_len_and_hex() */
 static void
-add_hex_ascii(json_t *dst, const uint8_t *buf, int n) {
-  json_object_set_new(dst, "len", json_integer(n));
+add_hex_ascii(json_t *dst, const uint8_t *buf, size_t n) {
+  json_object_set_new(dst, "len", json_integer((int)n));
   json_object_set_new(dst, "ascii", json_stringn((const char *) buf, n));
 
-  char *hex = (char *) malloc((size_t) n * 2 + 1);
+  char *hex = (char *) malloc(n * 2 + 1);
 
-  for (int i = 0; i < n; i++)
+  for (size_t i = 0; i < n; i++)
     sprintf(hex + 2 * i, "%02X", buf[i]);
   hex[n * 2] = '\0';
 
@@ -26,10 +26,12 @@ void
 rd_block_string(int fd, uint8_t cmd, const char *key, json_t *root) {
   uint8_t b[64];
   int n = pmbus_rd_block(fd, cmd, b, (int) sizeof b);
+
   if (n < 0)
     return;
+
   json_t *o = json_object();
-  add_hex_ascii(o, b, n);
+  add_hex_ascii(o, b, (size_t)n);
 
   json_object_set_new(root, key, o);
 }
diff --git a/src/util_lin.h b/src/util_lin.h
index 6081a61..e684e78 100644
--- a/src/util_lin.h
+++ b/src/util_lin.h
@@ -2,21 +2,21 @@
 
 #pragma once
 
+#include "pmbus_io.h"
+
 #include <stdint.h>
 #include <math.h> /* ldexp: no need of libm */
 
-/* TODO: align with PMBus-Specification-Rev-1-3-1-Part-II-20150313.pdf */
-
 /* Round-to-nearest and saturate into [0, 65535] for non-negative doubles. */
 static inline uint16_t
 u16_round_sat_pos(double x) {
-  if (isnan(x))
-    return 0;
+  if ((x <= D(0.0f)) || isnan(x))
+    return 0u;
 
-  if (x >= 65535.0)
-    return 65535;
+  if (x >= D(65535.0f))
+    return UINT16_MAX;
 
-  return (uint16_t)(x + 0.5);
+  return (uint16_t)(x + D(0.5f));
 }
 
 /* Linear16-Unsigned: units = y * 2^N */
diff --git a/src/vin_cmd.c b/src/vin_cmd.c
index 0596a22..80bc773 100644
--- a/src/vin_cmd.c
+++ b/src/vin_cmd.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "vin_cmd.h"
 #include "util_json.h"
 #include "util_lin.h"
 
diff --git a/src/vout_cmd.c b/src/vout_cmd.c
index e750ed2..64a15cf 100644
--- a/src/vout_cmd.c
+++ b/src/vout_cmd.c
@@ -1,7 +1,9 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 
 #include "pmbus_io.h"
+#include "vout_cmd.h"
 #include "util_json.h"
+
 #include "util_lin.h"
 #include <jansson.h>
 #include <string.h>
@@ -129,7 +131,7 @@ cmd_vout(int fd, int argc, char *const *argv, int pretty) {
     if (read_exp(fd, &exp5) < 0)
       return 1;
 
-    double v_nom = 0.0, pct = 0.0;
+    double v_nom = 0.0f, pct = 0.0f;
     if (s_all_nom) {
       if (parse_double(s_all_nom, &v_nom) != 0) {
         fprintf(stderr, "invalid --set-all NOM\n");
@@ -150,14 +152,14 @@ cmd_vout(int fd, int argc, char *const *argv, int pretty) {
 
       if (!s_high) {
         static char bufH[64];
-        double vH = v_nom * (1.0 + pct / 100.0);
+        double vH = v_nom * (D(1.0f) + pct / D(100.0f));
         snprintf(bufH, sizeof(bufH), "%.9g", vH);
         s_high = bufH;
       }
 
       if (!s_low) {
         static char bufL[64];
-        double vL = v_nom * (1.0 - pct / 100.0);
+        double vL = v_nom * (D(1.0f) - pct / D(100.0f));
         snprintf(bufL, sizeof(bufL), "%.9g", vL);
         s_low = bufL;
       }
diff --git a/src/write_protect_cmd.c b/src/write_protect_cmd.c
index 9dcf6cf..3a9656e 100644
--- a/src/write_protect_cmd.c
+++ b/src/write_protect_cmd.c
@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: AGPL-3.0-or-later */
 #include "pmbus_io.h"
+#include "write_protect_cmd.h"
 #include "util_json.h"
+
 #include <jansson.h>
 #include <string.h>
 #include <stdio.h>