CHAD-17426: Add stateless step capabilities to zigbee-switch

Author: wkhenon

drivers/SmartThings/zigbee-switch/src/stateless_handlers/can_handle.lua

@@ -0,0 +1,14 @@
+-- Copyright 2026 SmartThings, Inc.
+-- Licensed under the Apache License, Version 2.0
+
+local capabilities = require "st.capabilities"
+
+return function(opts, driver, device)
+    local can_handle = device:supports_capability(capabilities.statelessColorTemperatureStep)
+        or device:supports_capability(capabilities.statelessSwitchLevelStep)
+    if can_handle then
+        local subdriver = require("stateless_handlers")
+        return true, subdriver
+    end
+    return false
+end

drivers/SmartThings/zigbee-switch/src/stateless_handlers/init.lua

@@ -0,0 +1,54 @@
+-- Copyright 2026 SmartThings, Inc.
+-- Licensed under the Apache License, Version 2.0
+
+local capabilities = require "st.capabilities"
+local st_utils = require "st.utils"
+local clusters = require "st.zigbee.zcl.clusters"
+local log = require "log"
+
+-- The following definitions should be pulled from the `st.zigbee.constants` module once those changes land
+local KELVIN_MAX = "_max_kelvin"
+local KELVIN_MIN = "_min_kelvin"
+local MIREDS_CONVERSION_CONSTANT = 1000000
+local COLOR_TEMPERATURE_KELVIN_MAX = 15000
+local COLOR_TEMPERATURE_KELVIN_MIN = 1000
+local COLOR_TEMPERATURE_MIRED_MAX = st_utils.round(MIREDS_CONVERSION_CONSTANT/COLOR_TEMPERATURE_KELVIN_MIN) -- 1000
+local COLOR_TEMPERATURE_MIRED_MIN = st_utils.round(MIREDS_CONVERSION_CONSTANT/COLOR_TEMPERATURE_KELVIN_MAX) -- 67
+
+-- Transition Time: The time that shall be taken to perform the step change, in units of 1/10ths of a second.
+local TRANSITION_TIME = 3 -- default: 0.3 seconds
+-- Options Mask & Override: Indicates which options are being overriden by the Level/ColorControl cluster commands
+local OPTIONS_MASK = 0x01 -- default: The `ExecuteIfOff` option is overriden
+local IGNORE_COMMAND_IF_OFF = 0x00 -- default: the command will not be executed if the device is off
+
+local function step_color_temperature_by_percent_handler(driver, device, cmd)
+    local step_percent_change = cmd.args and cmd.args.stepSize or 0
+    if step_percent_change == 0 then return end
+    local step_mode = step_percent_change > 0 and (clusters.ColorControl.types.CcStepMode and clusters.ColorControl.types.CcStepMode.DOWN or 3) or (clusters.ColorControl.types.CcStepMode and clusters.ColorControl.types.CcStepMode.UP or 1)
+    local min_mireds = device:get_field(KELVIN_MIN) or COLOR_TEMPERATURE_MIRED_MIN -- default min mireds
+    local max_mireds = device:get_field(KELVIN_MAX) or COLOR_TEMPERATURE_MIRED_MAX -- default max mireds
+    local step_size_in_mireds = st_utils.round((max_mireds - min_mireds) * (math.abs(step_percent_change)/100.0))
+    device:send(clusters.ColorControl.server.commands.StepColorTemperature(device, step_mode, step_size_in_mireds, TRANSITION_TIME, min_mireds, max_mireds, OPTIONS_MASK, IGNORE_COMMAND_IF_OFF))
+end
+
+local function step_level_handler(driver, device, cmd)
+    local step_size = st_utils.round((cmd.args and cmd.args.stepSize or 0)/100.0 * 254)
+    if step_size == 0 then return end
+    local step_mode = step_size > 0 and clusters.Level.types.MoveStepMode.UP or clusters.Level.types.MoveStepMode.DOWN
+    device:send(clusters.Level.server.commands.Step(device, step_mode, math.abs(step_size), TRANSITION_TIME, OPTIONS_MASK, IGNORE_COMMAND_IF_OFF))
+end
+
+local stateless_handlers = {
+    Name = "Zigbee Stateless Step Handlers",
+    capability_handlers = {
+        [capabilities.statelessColorTemperatureStep.ID] = {
+            [capabilities.statelessColorTemperatureStep.commands.stepColorTemperatureByPercent.NAME] = step_color_temperature_by_percent_handler,
+        },
+        [capabilities.statelessSwitchLevelStep.ID] = {
+            [capabilities.statelessSwitchLevelStep.commands.stepLevel.NAME] = step_level_handler,
+        },
+    },
+    can_handle = require("stateless_handlers.can_handle")
+}
+
+return stateless_handlers

drivers/SmartThings/zigbee-switch/src/sub_drivers.lua

@@ -35,5 +35,6 @@ return {
     lazy_load_if_possible("tuya-multi"),
     lazy_load_if_possible("frient"),
     lazy_load_if_possible("frient-IO"),
-    lazy_load_if_possible("color_temp_range_handlers")
+    lazy_load_if_possible("color_temp_range_handlers"),
+    lazy_load_if_possible("stateless_handlers")
 }