drivers: stepper: introduce step-dir api to facilitate implementing motion controllers as device drivers #91979

jilaypandya · 2025-06-21T22:30:40Z

This PR aims to facilitate implementation of stepper motion controllers as device drivers. Hence the low-level step-dir drivers now shall implement a step-dir-driver-api, effectively also signifying what the IC actually supports i.e enable, step-dir and in some cases fault detection

Stepper API as all of us know it, remains unchanged.
Step-Dir API which is just a wrapper as of now for some gpios, does all the low-level work.

Drivers	Stepper Step-Dir Driver (step-dir API)	Stepper Integrated Motion Control Driver ( stepper API)
adi,tmc22xx	x
allegro,a4979	x
ti,drv84xx	x
zephyr,gpio-stepper(h-bridge based driver)	x
adi,tmc50xx		x
adi,tmc51xx		x
zephyr,stepper-motion-controller (CPU Based)		x

Notes:

This is an intermediate step. Final Goal is having two APIs as follows,

	stepper driver api	stepper motion control api
enable / disable	impl
microstep_resolution	impl
step/dir	impl
move_to/move_by/run/stop		impl
set_reference_position		impl
*is_moving		impl
get_actual_position		impl
set_reference_position		impl

Teaser:

I am trying locally to implement both stepper-driver-api currently step-dir api and stepper-motion-control-api currently stepper api in tmc50xx using child-bindings.
This will be achieved by adding index to stepper_move_to

#define X_AXIS  0
#define Y_AXIS  1

stepper_move_to(tmc50xx_motion_controller, X_AXIS, 200);
stepper_stop(tmc50xx_motion_controller, Y_AXIS);
stepper_disable(tmc50xx_stepper_driver_x_axis@0);
stepper_disanle(tmc50xx_stepper_driver_y_axis@1);

spi {
    
      /* Implements stepper motion control api */
     tmc50xx_motion_controller {
        compatible = "adi,tmc50xx"

        /* Implements stepper driver api */
        tmc50xx_stepper_driver_x_axis@0 {
        };

        /* Implements stepper driver api */
        tmc50xx_stepper_driver_y_axis@1 {
        };
    };
};

Side effects:

A lot of common code is refactored out and the stepper step-dir or h-bridge based drivers only do what the ic supports. i.e. enable/disable, set/get ustep resolution, step/dir.
Drv84xx handles fault events as of now, which is good. However, handling of fault event has to be refactored out of stepper_api, as mentioned in the RFC Split Stepper Motion Controller <-> Stepper Driver #89786 .
Introduce set_fault_event_callback, remove fault_event from the current stepper_event enum and rename stepper_event_callback to stepper_motion_control_event_callback.

This PR should effectively resolve the PR drvers: stepper: Modular Step-Dir Implementations #91584, which also aims to be an intermediate step.
This PR is inspired by the presentation of the complexity of implementing a motion-controller behind an all-knowing stepper api in PR drivers: stepper: Stepper driver architectural refactoring #90748. Thanks @andre-stefanov.
PR drivers: stepper: ADI TMC2130 Stepper Driver #90677 will have rebase and implement step-dir api, since it's a step-dir driver instead of stepper api, if this PR gets merged before

faxe1008

Small little pass, will do some in depth review later on :^)

faxe1008 · 2025-06-22T12:59:59Z

drivers/stepper/adi_tmc/tmc22xx.c


 static int tmc22xx_stepper_enable(const struct device *dev)
 {
 	const struct tmc22xx_config *config = dev->config;

 	LOG_DBG("Enabling Stepper motor controller %s", dev->name);
-	return gpio_pin_set_dt(&config->enable_pin, 1);
+	return gpio_pin_set_dt(&config->enable_pin, 0);


Generally you would set this to 1 and change the actual output to be active low via devicetree

Yeah that makes sense :) Thanks :^)

Ping @andre-stefanov

yes this is exactly what i came up with in my implementation in the end. It is a bit inconvenient because the user of e.g. tmc2209 has to know this inverted EN logic during DTS definition instead of just saying "i define the pins, the driver knows which level has to be used for enable/disable". But unfortunately i could not provide gpio port/pin references without output level flag in DTS so i left it as faxe is proposing.

faxe1008 · 2025-06-22T13:00:13Z

drivers/stepper/adi_tmc/tmc22xx.c

 }

 static int tmc22xx_stepper_disable(const struct device *dev)
 {
 	const struct tmc22xx_config *config = dev->config;

 	LOG_DBG("Disabling Stepper motor controller %s", dev->name);
-	return gpio_pin_set_dt(&config->enable_pin, 0);
+	return gpio_pin_set_dt(&config->enable_pin, 1);


faxe1008 · 2025-06-22T13:01:56Z

drivers/stepper/allegro/a4979.c

@@ -121,7 +120,6 @@ static int a4979_stepper_set_micro_step_res(const struct device *dev,
 	case STEPPER_MICRO_STEP_4:
 		m0_value = 0;
 		m1_value = 1;
-		break;


I guess this was an accident

faxe1008 · 2025-06-22T13:05:07Z

drivers/stepper/gpio_stepper_driver.c

+	const struct gpio_stepper_config *config = dev->config;
+
+	LOG_DBG("Initializing %s gpio_stepper with %d pin", dev->name, NUM_CONTROL_PINS);
+	for (uint8_t n_pin = 0; n_pin < NUM_CONTROL_PINS; n_pin++) {


Checking readyness via gpio_ready_dt

dipakgmx · 2025-06-22T14:22:06Z

drivers/stepper/gpio_stepper_driver.c

+#include <zephyr/sys/__assert.h>
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(gpio_stepper_motor_controller, CONFIG_STEPPER_LOG_LEVEL);


Nit: gpio_stepper_motor_controller, just a bit too long :)

dts/bindings/stepper/stepper.yaml

drivers/stepper/stepper_motion_controllers/zephyr_stepper_motion_controller.c

dts/bindings/stepper/adi/adi,tmc50xx.yaml

include/zephyr/drivers/stepper.h

samples/drivers/stepper/generic/boards/nucleo_g071rb.overlay

jbehrensnx

Mostly minor stuff from me. Overall I am pretty happy with it and I think for an interim solution it is fine.

There are some aspects of the final intended architecture that I feel are worth discussing, but I also feel that they would be beyond the scope of this PR.
The one exception to this is the fault event, as I feel that motion-controllers should be able to raise fault events as well.

Personally, I would prefer if the stepper_motion_controller got renamed to indicate that it is for step-dir drivers, but that is not a hard requirement for me.

drivers/stepper/step_dir/step_dir_stepper_common.h

drivers/stepper/stepper_timing_sources/Kconfig

drivers/stepper/stepper_timing_sources/stepper_timing_source.h

include/zephyr/drivers/stepper.h

tests/drivers/build_all/stepper/gpio.dtsi

tests/drivers/stepper/drv84xx/api/src/main.c

dts/bindings/stepper/zephyr,stepper-motion-control.yaml

jilaypandya · 2025-06-24T19:49:54Z

Hey Everyone, here is the wip implementation of splitted stepper_api. stepper_api implements motion_control functions whereas step_dir_api implements stepper_driver functions.

MotionControl functions look highly similar to the ones now from the very first stepper_api #26221.

The tmc50xx sample shows how the combined use of the two apis would look like. Let me know of your opinions :)

introduce step_dir api which is to be implemented by the step_dir stepper drivers Add fault handling in drv84xx using a fault cb mechanism With the introduction of the step-dir api,different motion controllers to consume various step-dir drivers allowing for further upstream as well as downstream stepper motion controllers to be implemented Signed-off-by: Jilay Pandya <[email protected]>

sonarqubecloud · 2025-06-24T20:18:56Z

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

jilaypandya force-pushed the feature/introduce-step-dir-functions branch from 0429ffb to 5c9c369 Compare June 21, 2025 22:35

jilaypandya assigned faxe1008 Jun 21, 2025

jilaypandya changed the title ~~wip~~ drivers: stepper: introduce step-dir functions in stepper api to facilitate implementing motion controllers as device drivers Jun 21, 2025

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Split Stepper Motion Controller <-> Stepper Driver #89786

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jilaypandya requested review from dipakgmx, faxe1008 and andre-stefanov June 23, 2025 16:30

jilaypandya changed the title ~~drivers: stepper: introduce step-dir functions in stepper api to facilitate implementing motion controllers as device drivers~~ drivers: stepper: introduce step-dir api to facilitate implementing motion controllers as device drivers Jun 23, 2025

jilaypandya linked an issue Jun 23, 2025 that may be closed by this pull request

Split Stepper Motion Controller <-> Stepper Driver #89786

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Split Stepper Motion Controller <-> Stepper Driver #89786

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drivers: stepper: introduce step-dir api to facilitate implementing motion controllers as device drivers #91979

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drivers: stepper: introduce step-dir api to facilitate implementing motion controllers as device drivers #91979

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jilaypandya commented Jun 24, 2025

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sonarqubecloud bot commented Jun 24, 2025

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jilaypandya commented Jun 21, 2025 •

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