tmc2660: Use bus.py helper code for spi

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example-extras.cfg

@@ -745,14 +745,14 @@
 #   The pin corresponding to the TMC2660 chip select line. This pin
 #   will be set to low at the start of SPI messages and set to high
 #   after the message transfer completes. This parameter must be provided.
-#bus:
-#   Select the SPI bus the TMC2660 stepper driver is connected to. This
-#   depends on the physical connections on your board, as well as the
-#   SPI implementation of your particular microcontroller. This parameter
-#   must be provided.
-#freq: 2000000
+#spi_bus:
+#   Select the SPI bus the TMC2660 stepper driver is connected to.
+#   This depends on the physical connections on your board, as well as
+#   the SPI implementation of your particular micro-controller. The
+#   default is bus 0.
+#spi_speed: 2000000
 #   SPI bus frequency used to communicate with the TMC2660 stepper
-#   driver. the default is 2000000.
+#   driver. The default is 2000000.
 #microsteps:
 #   The number of microsteps to configure the driver to use. Valid
 #   values are 1, 2, 4, 8, 16, 32, 64, 128, 256. This parameter must

config/generic-duet2.cfg

@@ -94,7 +94,7 @@ position_max: 250
 
 [tmc2660 stepper_x]
 cs_pin: PD14 # X_SPI_EN Required for communication
-bus: 1 # All TMC2660 drivers are connected to USART1, which is bus 1 on the sam4e port
+spi_bus: 1 # All TMC2660 drivers are connected to USART1, which is bus 1 on the sam4e port
 microsteps: 16
 interpolate: True # 1/16 micro-steps interpolated to 1/256
 run_current: 1.000
@@ -111,7 +111,7 @@ position_max: 210
 
 [tmc2660 stepper_y]
 cs_pin: PC9
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000
@@ -128,7 +128,7 @@ position_max: 200
 
 [tmc2660 stepper_z]
 cs_pin: PC10
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000
@@ -142,7 +142,7 @@ step_distance: .0025
 
 [tmc2660 stepper_z1]
 cs_pin: PD25
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000
@@ -156,7 +156,7 @@ step_distance: .0025
 
 [tmc2660 stepper_z2]
 cs_pin: PD26
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000
@@ -170,7 +170,7 @@ step_distance: .0025
 
 [tmc2660 stepper_z3]
 cs_pin: PC28
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000
@@ -195,7 +195,7 @@ max_temp: 250
 
 [tmc2660 extruder0]
 cs_pin: PC17
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000
@@ -220,7 +220,7 @@ max_temp: 250
 
 [tmc2660 extruder1]
 cs_pin: PC25
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000
@@ -245,7 +245,7 @@ max_temp: 250
 
 [tmc2660 extruder2]
 cs_pin: PD23
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000
@@ -270,7 +270,7 @@ max_temp: 250
 
 [tmc2660 extruder3]
 cs_pin: PD24
-bus: 1
+spi_bus: 1
 microsteps: 16
 interpolate: True
 run_current: 1.000