Fixes from draft PR

Author: gamblor21

shared-bindings/adafruit_bus_device/I2CDevice.c

@@ -135,9 +135,10 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_readinto(size_t n_args, const mp_o
     mp_load_method(self->i2c, MP_QSTR_readfrom_into, dest);
     dest[2] = mp_obj_new_int_from_ull(self->device_address);
     dest[3] = args[ARG_buffer].u_obj;
-    dest[4] = mp_obj_new_str("start", 5);
+    //dest[4] = mp_obj_new_str("start", 5);
+    dest[4] = MP_OBJ_NEW_QSTR(MP_QSTR_start);
     dest[5] = mp_obj_new_int(args[ARG_start].u_int);
-    dest[6] = mp_obj_new_str("end", 3);
+    dest[6] = MP_OBJ_NEW_QSTR(MP_QSTR_end);
     dest[7] = mp_obj_new_int(args[ARG_end].u_int);
     mp_call_method_n_kw(2, 2, dest);
 
@@ -172,9 +173,9 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_write(size_t n_args, const mp_obj_
     mp_load_method(self->i2c, MP_QSTR_writeto, dest);
     dest[2] = mp_obj_new_int_from_ull(self->device_address);
     dest[3] = args[ARG_buffer].u_obj;
-    dest[4] = mp_obj_new_str("start", 5);
+    dest[4] = MP_OBJ_NEW_QSTR(MP_QSTR_start);
     dest[5] = mp_obj_new_int(args[ARG_start].u_int);
-    dest[6] = mp_obj_new_str("end", 3);
+    dest[6] = MP_OBJ_NEW_QSTR(MP_QSTR_end);
     dest[7] = mp_obj_new_int(args[ARG_end].u_int);
     mp_call_method_n_kw(2, 2, dest);
 
@@ -224,13 +225,13 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_write_then_readinto(size_t n_args,
     dest[2] = mp_obj_new_int_from_ull(self->device_address);
     dest[3] = args[ARG_out_buffer].u_obj;
     dest[4] = args[ARG_in_buffer].u_obj;
-    dest[5] = mp_obj_new_str("out_start", 9);
+    dest[5] = MP_OBJ_NEW_QSTR(MP_QSTR_out_start);
     dest[6] = mp_obj_new_int(args[ARG_out_start].u_int);
-    dest[7] = mp_obj_new_str("out_end", 7);
+    dest[7] = MP_OBJ_NEW_QSTR(MP_QSTR_out_end);
     dest[8] = mp_obj_new_int(args[ARG_out_end].u_int);
-    dest[9] = mp_obj_new_str("in_start", 8);
+    dest[9] = MP_OBJ_NEW_QSTR(MP_QSTR_in_start);
     dest[10] = mp_obj_new_int(args[ARG_in_start].u_int);
-    dest[11] = mp_obj_new_str("in_end", 6);
+    dest[11] = MP_OBJ_NEW_QSTR(MP_QSTR_in_end);
     dest[12] = mp_obj_new_int(args[ARG_in_end].u_int);
 
     mp_call_method_n_kw(3, 4, dest);

shared-module/adafruit_bus_device/I2CDevice.c

@@ -68,37 +68,22 @@ void common_hal_adafruit_bus_device_i2cdevice_probe_for_device(adafruit_bus_devi
     mp_obj_t dest[4];
 
     /* catch exceptions that may be thrown while probing for the device */
-    nlr_buf_t write_nlr;
-    if (nlr_push(&write_nlr) == 0) {
+    nlr_buf_t nlr;
+    if (nlr_push(&nlr) == 0) {
         mp_load_method(self->i2c, MP_QSTR_writeto, dest);
         dest[2] = mp_obj_new_int_from_ull(self->device_address);
         dest[3] = write_buffer;
         mp_call_method_n_kw(2, 0, dest);
         nlr_pop();
     } else {
-        /* some OS's don't like writing an empty bytestring... retry by reading a byte */
-        mp_buffer_info_t read_bufinfo;
-        mp_obj_t read_buffer = mp_obj_new_bytearray_of_zeros(1);
-        mp_get_buffer_raise(read_buffer, &read_bufinfo, MP_BUFFER_WRITE);
+        common_hal_adafruit_bus_device_i2cdevice_unlock(self);
 
-        mp_load_method(self->i2c, MP_QSTR_readfrom_into, dest);
-        dest[2] = mp_obj_new_int_from_ull(self->device_address);
-        dest[3] = read_buffer;
-
-        nlr_buf_t read_nlr;
-        if (nlr_push(&read_nlr) == 0) {
-            mp_call_method_n_kw(2, 0, dest);
-            nlr_pop();
-        } else {
-            /* At this point we tried two methods and only got exceptions */
-            if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(((mp_obj_base_t*)read_nlr.ret_val)->type), MP_OBJ_FROM_PTR(&mp_type_OSError))) {
-                common_hal_adafruit_bus_device_i2cdevice_unlock(self);
-                mp_raise_ValueError_varg(translate("No I2C device at address: %x"), self->device_address);
-            }
-            else {
-                /* In case we receive an unrelated exception pass it up */
-                nlr_raise(MP_OBJ_FROM_PTR(read_nlr.ret_val));
-            }
+        if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(((mp_obj_base_t*)nlr.ret_val)->type), MP_OBJ_FROM_PTR(&mp_type_OSError))) {
+            mp_raise_ValueError_varg(translate("No I2C device at address: %x"), self->device_address);
+        }
+        else {
+            /* In case we receive an unrelated exception pass it up */
+            nlr_raise(MP_OBJ_FROM_PTR(nlr.ret_val));
         }
     }