libftdi Archives

Subject: [PATCH 1/4] ftdi_eeprom: expose all EEPROM I/O drive settings for Hi-Speed chips

From: Vincent Jardin <vjardin@xxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Cc: thomas.jarosch@xxxxxxxxxxxxx, Vincent Jardin <vjardin@xxxxxxx>
Date: Sat, 7 Mar 2026 00:15:46 +0100
Since ae9aea3 ("Add group 0 & 1 options to ftdi_eeprom, and fix group1
eeprom offset for ft232h"), only group0_drive was accessible from the
ftdi_eeprom config file. The remaining I/O group settings supported by
the libftdi API (schmitt, slew, drive for groups 0-3) and several
per-chip boolean options were not wired through the config parser.

Add the missing config file options:

  I/O groups (all Hi-Speed chips):
    group0-3_drive=4MA/8MA/12MA/16MA  - pin drive strength
    group0-3_schmitt=true/false       - Schmitt trigger input
    group0-3_slew=slow/fast           - output slew rate

  FT232H:    power_save, clock_polarity, data_order, flow_control
  FT2232H:   high_current_a/b, suspend_dbus7, external_oscillator
  FT4232H:   external_oscillator
  All chips: is_not_pnp

Boolean options are always written to the EEPROM (not skipped when
false), so that read-modify-write workflows can explicitly clear bits.

Per-chip group count follows the hardware:
  FT232H:  2 groups (group0=ACBUS, group1=ADBUS)
  FT2232H: 4 groups (group0=AL, group1=AH, group2=BL, group3=BH)
  FT4232H: 4 groups (group0=A, group1=B, group2=C, group3=D)
---
 ftdi_eeprom/main.c | 102 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)

diff --git a/ftdi_eeprom/main.c b/ftdi_eeprom/main.c
index 614d51e..7d589c1 100644
--- a/ftdi_eeprom/main.c
+++ b/ftdi_eeprom/main.c
@@ -87,6 +87,23 @@ static int parse_group0_drive(cfg_t *cfg, cfg_opt_t *opt, 
const char *value, voi
     return -1;
 }
 
+static int parse_slew(cfg_t *cfg, cfg_opt_t *opt, const char *value, void 
*result)
+{
+    if (!(strcasecmp(value, "slow")))
+    {
+        *(int *)result = 1;
+        return 0;
+    }
+    if (!(strcasecmp(value, "fast")))
+    {
+        *(int *)result = 0;
+        return 0;
+    }
+
+    cfg_error(cfg, "Invalid %s option '%s'", cfg_opt_name(opt), value);
+    return -1;
+}
+
 static int parse_cbush(cfg_t *cfg, cfg_opt_t *opt, const char *value, void 
*result)
 {
     static const char* options[] =
@@ -261,6 +278,26 @@ int main(int argc, char *argv[])
         CFG_INT_CB("cbusx2", -1, 0, parse_cbusx),
         CFG_INT_CB("cbusx3", -1, 0, parse_cbusx),
         CFG_INT_CB("group0_drive", -1, 0, parse_group0_drive),
+        CFG_BOOL("group0_schmitt", cfg_false, 0),
+        CFG_INT_CB("group0_slew", -1, 0, parse_slew),
+        CFG_INT_CB("group1_drive", -1, 0, parse_group0_drive),
+        CFG_BOOL("group1_schmitt", cfg_false, 0),
+        CFG_INT_CB("group1_slew", -1, 0, parse_slew),
+        CFG_INT_CB("group2_drive", -1, 0, parse_group0_drive),
+        CFG_BOOL("group2_schmitt", cfg_false, 0),
+        CFG_INT_CB("group2_slew", -1, 0, parse_slew),
+        CFG_INT_CB("group3_drive", -1, 0, parse_group0_drive),
+        CFG_BOOL("group3_schmitt", cfg_false, 0),
+        CFG_INT_CB("group3_slew", -1, 0, parse_slew),
+        CFG_BOOL("high_current_a", cfg_false, 0),
+        CFG_BOOL("high_current_b", cfg_false, 0),
+        CFG_BOOL("suspend_dbus7", cfg_false, 0),
+        CFG_BOOL("external_oscillator", cfg_false, 0),
+        CFG_BOOL("power_save", cfg_false, 0),
+        CFG_BOOL("clock_polarity", cfg_false, 0),
+        CFG_BOOL("data_order", cfg_false, 0),
+        CFG_BOOL("flow_control", cfg_false, 0),
+        CFG_BOOL("is_not_pnp", cfg_false, 0),
         CFG_BOOL("invert_txd", cfg_false, 0),
         CFG_BOOL("invert_rxd", cfg_false, 0),
         CFG_BOOL("invert_rts", cfg_false, 0),
@@ -478,6 +515,8 @@ int main(int argc, char *argv[])
     eeprom_set_value(ftdi, CHIP_TYPE, cfg_getint(cfg, "eeprom_type"));
 
     eeprom_set_value(ftdi, HIGH_CURRENT, cfg_getbool(cfg, "high_current"));
+    if (cfg_getbool(cfg, "is_not_pnp"))
+        eeprom_set_value(ftdi, IS_NOT_PNP, 1);
 
     if (ftdi->type == TYPE_R)
     {
@@ -516,6 +555,69 @@ int main(int argc, char *argv[])
             eeprom_set_value(ftdi, CBUS_FUNCTION_9, cfg_getint(cfg, "cbush9"));
         if (cfg_getint(cfg, "group0_drive") != -1)
             eeprom_set_value(ftdi, GROUP0_DRIVE, cfg_getint(cfg, 
"group0_drive"));
+        eeprom_set_value(ftdi, GROUP0_SCHMITT, cfg_getbool(cfg, 
"group0_schmitt"));
+        if (cfg_getint(cfg, "group0_slew") != -1)
+            eeprom_set_value(ftdi, GROUP0_SLEW, cfg_getint(cfg, 
"group0_slew"));
+        if (cfg_getint(cfg, "group1_drive") != -1)
+            eeprom_set_value(ftdi, GROUP1_DRIVE, cfg_getint(cfg, 
"group1_drive"));
+        eeprom_set_value(ftdi, GROUP1_SCHMITT, cfg_getbool(cfg, 
"group1_schmitt"));
+        if (cfg_getint(cfg, "group1_slew") != -1)
+            eeprom_set_value(ftdi, GROUP1_SLEW, cfg_getint(cfg, 
"group1_slew"));
+        eeprom_set_value(ftdi, POWER_SAVE, cfg_getbool(cfg, "power_save"));
+        eeprom_set_value(ftdi, CLOCK_POLARITY, cfg_getbool(cfg, 
"clock_polarity"));
+        eeprom_set_value(ftdi, DATA_ORDER, cfg_getbool(cfg, "data_order"));
+        eeprom_set_value(ftdi, FLOW_CONTROL, cfg_getbool(cfg, "flow_control"));
+    }
+    else if (ftdi->type == TYPE_2232H)
+    {
+        eeprom_set_value(ftdi, HIGH_CURRENT_A, cfg_getbool(cfg, 
"high_current_a"));
+        eeprom_set_value(ftdi, HIGH_CURRENT_B, cfg_getbool(cfg, 
"high_current_b"));
+        eeprom_set_value(ftdi, SUSPEND_DBUS7, cfg_getbool(cfg, 
"suspend_dbus7"));
+        eeprom_set_value(ftdi, EXTERNAL_OSCILLATOR, cfg_getbool(cfg, 
"external_oscillator"));
+        if (cfg_getint(cfg, "group0_drive") != -1)
+            eeprom_set_value(ftdi, GROUP0_DRIVE, cfg_getint(cfg, 
"group0_drive"));
+        eeprom_set_value(ftdi, GROUP0_SCHMITT, cfg_getbool(cfg, 
"group0_schmitt"));
+        if (cfg_getint(cfg, "group0_slew") != -1)
+            eeprom_set_value(ftdi, GROUP0_SLEW, cfg_getint(cfg, 
"group0_slew"));
+        if (cfg_getint(cfg, "group1_drive") != -1)
+            eeprom_set_value(ftdi, GROUP1_DRIVE, cfg_getint(cfg, 
"group1_drive"));
+        eeprom_set_value(ftdi, GROUP1_SCHMITT, cfg_getbool(cfg, 
"group1_schmitt"));
+        if (cfg_getint(cfg, "group1_slew") != -1)
+            eeprom_set_value(ftdi, GROUP1_SLEW, cfg_getint(cfg, 
"group1_slew"));
+        if (cfg_getint(cfg, "group2_drive") != -1)
+            eeprom_set_value(ftdi, GROUP2_DRIVE, cfg_getint(cfg, 
"group2_drive"));
+        eeprom_set_value(ftdi, GROUP2_SCHMITT, cfg_getbool(cfg, 
"group2_schmitt"));
+        if (cfg_getint(cfg, "group2_slew") != -1)
+            eeprom_set_value(ftdi, GROUP2_SLEW, cfg_getint(cfg, 
"group2_slew"));
+        if (cfg_getint(cfg, "group3_drive") != -1)
+            eeprom_set_value(ftdi, GROUP3_DRIVE, cfg_getint(cfg, 
"group3_drive"));
+        eeprom_set_value(ftdi, GROUP3_SCHMITT, cfg_getbool(cfg, 
"group3_schmitt"));
+        if (cfg_getint(cfg, "group3_slew") != -1)
+            eeprom_set_value(ftdi, GROUP3_SLEW, cfg_getint(cfg, 
"group3_slew"));
+    }
+    else if (ftdi->type == TYPE_4232H)
+    {
+        eeprom_set_value(ftdi, EXTERNAL_OSCILLATOR, cfg_getbool(cfg, 
"external_oscillator"));
+        if (cfg_getint(cfg, "group0_drive") != -1)
+            eeprom_set_value(ftdi, GROUP0_DRIVE, cfg_getint(cfg, 
"group0_drive"));
+        eeprom_set_value(ftdi, GROUP0_SCHMITT, cfg_getbool(cfg, 
"group0_schmitt"));
+        if (cfg_getint(cfg, "group0_slew") != -1)
+            eeprom_set_value(ftdi, GROUP0_SLEW, cfg_getint(cfg, 
"group0_slew"));
+        if (cfg_getint(cfg, "group1_drive") != -1)
+            eeprom_set_value(ftdi, GROUP1_DRIVE, cfg_getint(cfg, 
"group1_drive"));
+        eeprom_set_value(ftdi, GROUP1_SCHMITT, cfg_getbool(cfg, 
"group1_schmitt"));
+        if (cfg_getint(cfg, "group1_slew") != -1)
+            eeprom_set_value(ftdi, GROUP1_SLEW, cfg_getint(cfg, 
"group1_slew"));
+        if (cfg_getint(cfg, "group2_drive") != -1)
+            eeprom_set_value(ftdi, GROUP2_DRIVE, cfg_getint(cfg, 
"group2_drive"));
+        eeprom_set_value(ftdi, GROUP2_SCHMITT, cfg_getbool(cfg, 
"group2_schmitt"));
+        if (cfg_getint(cfg, "group2_slew") != -1)
+            eeprom_set_value(ftdi, GROUP2_SLEW, cfg_getint(cfg, 
"group2_slew"));
+        if (cfg_getint(cfg, "group3_drive") != -1)
+            eeprom_set_value(ftdi, GROUP3_DRIVE, cfg_getint(cfg, 
"group3_drive"));
+        eeprom_set_value(ftdi, GROUP3_SCHMITT, cfg_getbool(cfg, 
"group3_schmitt"));
+        if (cfg_getint(cfg, "group3_slew") != -1)
+            eeprom_set_value(ftdi, GROUP3_SLEW, cfg_getint(cfg, 
"group3_slew"));
     }
     else if (ftdi->type == TYPE_230X)
     {
-- 
2.51.0


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