mimxrt/machine_i2c: Support the timeout keyword argument.

Set the default timeout to 50000 us.  The default used to be 0, causing the
NXP I2C driver to silently stop working in case of a non-responding device.

Signed-off-by: robert-hh <[email protected]>

Author: robert-hh

ports/mimxrt/machine_i2c.c

@@ -36,6 +36,7 @@
 
 #define DEFAULT_I2C_FREQ        (400000)
 #define DEFAULT_I2C_DRIVE       (6)
+#define DEFAULT_I2C_TIMEOUT     (50000)
 
 typedef struct _machine_i2c_obj_t {
     mp_obj_base_t base;
@@ -82,16 +83,18 @@ bool lpi2c_set_iomux(int8_t hw_i2c, uint8_t drive) {
 
 static void machine_i2c_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     machine_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_printf(print, "I2C(%u, freq=%u)",
-        self->i2c_id, self->master_config->baudRate_Hz);
+    mp_printf(print, "I2C(%u, freq=%u, timeout=%u)",
+        self->i2c_id, self->master_config->baudRate_Hz,
+        self->master_config->pinLowTimeout_ns / 1000);
 }
 
 mp_obj_t machine_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
-    enum { ARG_id, ARG_freq, ARG_drive};
+    enum { ARG_id, ARG_freq, ARG_drive, ARG_timeout};
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
         { MP_QSTR_freq, MP_ARG_INT, {.u_int = DEFAULT_I2C_FREQ} },
         { MP_QSTR_drive, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_I2C_DRIVE} },
+        { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_I2C_TIMEOUT} },
     };
 
     // Parse args.
@@ -121,6 +124,9 @@ mp_obj_t machine_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n
     LPI2C_MasterGetDefaultConfig(self->master_config);
     // Initialise the I2C peripheral.
     self->master_config->baudRate_Hz = args[ARG_freq].u_int;
+    if (args[ARG_timeout].u_int >= 0) {
+        self->master_config->pinLowTimeout_ns = args[ARG_timeout].u_int * 1000; // to be set as ns
+    }
     LPI2C_MasterInit(self->i2c_inst, self->master_config, BOARD_BOOTCLOCKRUN_LPI2C_CLK_ROOT);
 
     return MP_OBJ_FROM_PTR(self);