Merge pull request #19891 from chrysn-pull-requests/ws2181x_timer

drivers/ws281x: Add gpio_ll and timer based driver

boards/common/e104-bt50xxa-tb/include/board.h

@@ -56,6 +56,14 @@ extern "C" {
 #define BTN1_MODE           GPIO_IN_PU
 /** @} */
 
+/**
+ * @name    WS281x RGB LED configuration
+ * @{
+ */
+#define WS281X_TIMER_DEV    TIMER_DEV(1)            /**< Timer device */
+#define WS281X_TIMER_MAX_VALUE TIMER_1_MAX_VALUE    /**< Timer max value */
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif

boards/common/nrf51/include/cfg_timer_01.h

@@ -49,6 +49,11 @@ static const timer_conf_t timer_config[] = {
 #define TIMER_0_ISR         isr_timer0
 #define TIMER_1_ISR         isr_timer1
 
+/** See @ref timer_init */
+#define TIMER_0_MAX_VALUE 0xffffffff
+/** See @ref timer_init */
+#define TIMER_1_MAX_VALUE 0xffffffff
+
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
 

boards/common/nrf51/include/cfg_timer_012.h

@@ -56,6 +56,13 @@ static const timer_conf_t timer_config[] = {
 #define TIMER_1_ISR         isr_timer1
 #define TIMER_2_ISR         isr_timer2
 
+/** See @ref timer_init */
+#define TIMER_0_MAX_VALUE 0xffffffff
+/** See @ref timer_init */
+#define TIMER_1_MAX_VALUE 0xffffffff
+/** See @ref timer_init */
+#define TIMER_2_MAX_VALUE 0xffffffff
+
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
 

boards/common/nrf52/include/cfg_timer_default.h

@@ -80,6 +80,21 @@ static const timer_conf_t timer_config[] = {
 #define TIMER_2_ISR         isr_timer3
 #define TIMER_3_ISR         isr_timer4
 
+/** See @ref timer_init */
+#define TIMER_0_MAX_VALUE 0xffffffff
+/** See @ref timer_init */
+#define TIMER_1_MAX_VALUE 0xffffffff
+#ifdef NRF_TIMER3
+/** See @ref timer_init */
+#define TIMER_2_MAX_VALUE 0xffffffff
+#endif
+/* If there is no NRF_TIMER3 this should be TIMER_2 because the index shifts
+ * up, but there is only a TIMER4 if there is a TIMER3 too. */
+#ifdef NRF_TIMER4
+/** See @ref timer_init */
+#define TIMER_3_MAX_VALUE 0xffffffff
+#endif
+
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
 

boards/nrf9160dk/include/board.h

@@ -87,6 +87,14 @@ extern "C" {
 #define BTN3_MODE           GPIO_IN         /**< BTN3 default mode */
 /** @} */
 
+/**
+ * @name    WS281x RGB LED configuration
+ * @{
+ */
+#define WS281X_TIMER_DEV    TIMER_DEV(1)            /**< Timer device */
+#define WS281X_TIMER_MAX_VALUE TIMER_1_MAX_VALUE    /**< Timer max value */
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif

boards/nrf9160dk/include/periph_conf.h

@@ -83,6 +83,11 @@ static const timer_conf_t timer_config[] = {
 #define TIMER_0_ISR         isr_timer0 /**< Timer0 IRQ*/
 #define TIMER_1_ISR         isr_timer1 /**< Timer1 IRQ */
 
+/** See @ref timer_init */
+#define TIMER_0_MAX_VALUE 0xffffffff
+/** See @ref timer_init */
+#define TIMER_1_MAX_VALUE 0xffffffff
+
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config) /**< Timer configuration NUMOF */
 /** @} */
 

cpu/nrf53/Kconfig

@@ -16,6 +16,7 @@ config CPU_FAM_NRF53
     select HAS_PERIPH_GPIO
     select HAS_PERIPH_GPIO_IRQ
     select HAS_PERIPH_TIMER_PERIODIC
+    select HAS_PERIPH_TIMER_POLL
     select HAS_PERIPH_TIMER_QUERY_FREQS
     select HAS_PERIPH_UART_MODECFG
     select HAS_PERIPH_WDT

cpu/nrf5x_common/Kconfig

@@ -20,6 +20,7 @@ depends on !CPU_FAM_NRF53
     select HAS_PERIPH_HWRNG
     select HAS_PERIPH_TEMPERATURE
     select HAS_PERIPH_TIMER_PERIODIC
+    select HAS_PERIPH_TIMER_POLL
     select HAS_PERIPH_TIMER_QUERY_FREQS
     select HAS_PERIPH_RTT_OVERFLOW
     select HAS_PERIPH_UART_MODECFG

cpu/nrf5x_common/Makefile.features

@@ -5,6 +5,7 @@ FEATURES_PROVIDED += periph_flashpage_in_address_space
 FEATURES_PROVIDED += periph_flashpage_pagewise
 FEATURES_PROVIDED += periph_gpio periph_gpio_irq
 FEATURES_PROVIDED += periph_timer_periodic
+FEATURES_PROVIDED += periph_timer_poll
 FEATURES_PROVIDED += periph_timer_query_freqs
 FEATURES_PROVIDED += periph_uart_modecfg
 FEATURES_PROVIDED += periph_wdt periph_wdt_cb

cpu/nrf5x_common/include/timer_arch.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2015 Jan Wagner <mail@jwagner.eu>
+ *               2015-2016 Freie Universität Berlin
+ *               2019 Inria
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_nrf5x_common
+ * @ingroup     drivers_periph_timer
+ * @{
+ *
+ * @file
+ * @brief       CPU specific part of the timer API
+ *
+ * @author      Christian Amsüss <chrysn@fsfe.org>
+ */
+
+#ifndef TIMER_ARCH_H
+#define TIMER_ARCH_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef DOXYGEN /* hide implementation specific details from Doxygen */
+
+static inline bool timer_poll_channel(tim_t tim, int channel)
+{
+    return timer_config[tim].dev->EVENTS_COMPARE[channel];
+}
+
+#endif /* DOXYGEN */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* TIMER_ARCH_H */
+/** @} */

cpu/nrf5x_common/periph/timer.c

@@ -111,7 +111,9 @@ int timer_init(tim_t tim, uint32_t freq, timer_cb_t cb, void *arg)
     }
 
     /* enable interrupts */
-    NVIC_EnableIRQ(timer_config[tim].irqn);
+    if (cb != NULL) {
+        NVIC_EnableIRQ(timer_config[tim].irqn);
+    }
     /* start the timer */
     dev(tim)->TASKS_START = 1;
 

cpu/nrf9160/Kconfig

@@ -17,6 +17,7 @@ config CPU_FAM_NRF9160
     select HAS_PERIPH_GPIO_LL_IRQ
     select HAS_PERIPH_GPIO_LL_IRQ_UNMASK
     select HAS_PERIPH_TIMER_PERIODIC
+    select HAS_PERIPH_TIMER_POLL
     select HAS_PERIPH_TIMER_QUERY_FREQS
     select HAS_PERIPH_UART_MODECFG
     select HAS_PERIPH_SPI_GPIO_MODE

drivers/include/periph/timer.h

@@ -35,6 +35,7 @@
 
 #include <limits.h>
 #include <stdint.h>
+#include <stdbool.h>
 
 #include "architecture.h"
 #include "periph_cpu.h"
@@ -295,6 +296,39 @@ uword_t timer_query_channel_numof(tim_t dev);
  */
 uint32_t timer_query_freqs(tim_t dev, uword_t index);
 
+#if defined(DOXYGEN)
+/**
+ * @brief Check whether a compare channel has matched
+ *
+ * @return true once after the channel has matched.
+ *
+ * It is currently not defined whether this keeps returning true after a
+ * channel has been polled until that channel is set, or whether later calls
+ * return false.
+ *
+ * This is typically used in spin loops that wait for a timer's completion:
+ *
+ * ~~~
+ * while (!timer_poll_channel(tim, chan)) {};
+ * ~~~
+ *
+ * This function is only available on platforms that implement the
+ * `periph_timer_poll` peripheral in addition to `periph_timer`.
+ *
+ */
+/* As this function is polled, it needs to be inlined, so it is typically
+ * provided through timer_arch.h. If a platform ever does not need to go
+ * through static inline here, this declaration's condition can be extended to
+ * be `(defined(MODULE_PERIPH_TIMER_POLL) &&
+ * !defined(PERIPH_TIMER_PROVIDES_INLINE_POLL_CHANNEL) || defined(DOXYGEN)` or
+ * similar. */
+bool timer_poll_channel(tim_t dev, int channel);
+#endif
+
+#if defined(MODULE_PERIPH_TIMER_POLL)
+#include "timer_arch.h"
+#endif
+
 #ifdef __cplusplus
 }
 #endif

drivers/periph_common/Kconfig

@@ -78,6 +78,8 @@ rsource "Kconfig.flashpage"
 
 rsource "Kconfig.gpio"
 
+rsource "Kconfig.gpio_ll"
+
 config MODULE_PERIPH_HWRNG
     bool "HWRNG peripheral driver"
     depends on HAS_PERIPH_HWRNG
@@ -157,6 +159,12 @@ config MODULE_PERIPH_INIT_RTT
     default y if MODULE_PERIPH_INIT
     depends on MODULE_PERIPH_RTT
 
+config MODULE_PERIPH_TIMER_POLL
+    bool "Timer poll"
+    depends on HAS_PERIPH_TIMER_POLL
+    help
+        Enables the timer_poll_channel function.
+
 rsource "Kconfig.sdmmc"
 rsource "Kconfig.spi"
 

drivers/periph_common/Kconfig.gpio_ll

@@ -0,0 +1,22 @@
+# Copyright (c) 2023 HAW Hamburg
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+#
+
+menuconfig MODULE_PERIPH_GPIO_LL
+    bool "Low-level GPIO peripheral driver"
+    depends on HAS_PERIPH_GPIO_LL
+
+if MODULE_PERIPH_GPIO_LL
+
+config MODULE_PERIPH_GPIO_LL_IRQ_UNMASK
+    bool "Unmask GPIO peripheral interrupts"
+    default y
+    depends on HAS_PERIPH_GPIO_LL_IRQ_UNMASK
+    help
+        Enables GPIO peripheral unmasking interrupts without
+        clearing pending IRQs that came in while masked.
+
+endif # MODULE_PERIPH_GPIO_LL

drivers/ws281x/Kconfig

@@ -7,12 +7,13 @@
 
 config MODULE_WS281X
     bool "WS2812/SK6812 RGB LED (NeoPixel)"
-    depends on HAS_CPU_CORE_ATMEGA || HAS_ARCH_ESP32 || HAS_ARCH_NATIVE
+    depends on HAS_CPU_CORE_ATMEGA || HAS_ARCH_ESP32 || HAS_ARCH_NATIVE || HAS_PERIPH_TIMER_POLL
     depends on TEST_KCONFIG
     select MODULE_XTIMER
     select MODULE_WS281X_ATMEGA if HAS_CPU_CORE_ATMEGA
     select MODULE_WS281X_VT100 if HAS_ARCH_NATIVE
     select MODULE_WS281X_ESP32 if HAS_ARCH_ESP32
+    select MODULE_WS281X_TIMER_GPIO_LL if HAS_PERIPH_TIMER_POLL
 
 config MODULE_WS281X_ATMEGA
     bool
@@ -45,6 +46,16 @@ config MODULE_WS281X_ESP32_SW
         Use the bit-banging software implementation to generate the RGB LED
         signal.
 
+config MODULE_WS281X_TIMER_GPIO_LL
+    bool
+    depends on HAS_PERIPH_TIMER_POLL
+    select MODULE_PERIPH_TIMER_POLL
+    depends on HAS_PERIPH_GPIO_LL
+    select MODULE_PERIPH_GPIO_LL
+    help
+        Use a platform independent bit-banging software implementation to
+        generate the RGB LED signal.
+
 config HAVE_WS281X
     bool
     help

drivers/ws281x/Makefile.dep

@@ -1,4 +1,5 @@
-FEATURES_REQUIRED_ANY += cpu_core_atmega|arch_esp32|arch_native
+# Actually |(periph_timer_poll and periph_gpio_ll), but that's too complex for FEATURES_REQUIRED_ANY to express
+FEATURES_REQUIRED_ANY += cpu_core_atmega|arch_esp32|arch_native|periph_timer_poll
 
 ifeq (,$(filter ws281x_%,$(USEMODULE)))
   ifneq (,$(filter cpu_core_atmega,$(FEATURES_USED)))
@@ -10,6 +11,10 @@ ifeq (,$(filter ws281x_%,$(USEMODULE)))
   ifneq (,$(filter arch_esp32,$(FEATURES_USED)))
     USEMODULE += ws281x_esp32
   endif
+  # Not only looking for the used feature but also for the absence of any more specific driver
+  ifeq (-periph_timer_poll,$(filter ws281x_%,$(USEMODULE))-$(filter periph_timer_poll,$(FEATURES_USED)))
+    USEMODULE += ws281x_timer_gpio_ll
+  endif
 endif
 
 ifneq (,$(filter ws281x_atmega,$(USEMODULE)))
@@ -28,3 +33,7 @@ ifneq (,$(filter ws281x_esp32%,$(USEMODULE)))
     USEMODULE += ws281x_esp32_hw
   endif
 endif
+
+ifneq (,$(filter ws281x_timer_gpio_ll,$(USEMODULE)))
+  FEATURES_REQUIRED += periph_gpio_ll periph_timer periph_timer_poll
+endif

drivers/ws281x/include/ws281x_backend.h

@@ -51,6 +51,15 @@ extern "C" {
 #endif
 /** @} */
 
+/**
+ * @name    Properties of the timer_gpio_ll backend.
+ * @{
+ */
+#ifdef MODULE_WS281X_TIMER_GPIO_LL
+#define WS281X_HAVE_INIT                    (1)
+#endif
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif

drivers/ws281x/include/ws281x_params.h

@@ -64,6 +64,47 @@ static const ws281x_params_t ws281x_params[] =
     WS281X_PARAMS
 };
 
+/** @brief Timer used for WS281x (by the timer_gpio_ll implementation)
+ *
+ * A single timer is configured for any number of WS281x strands, so this does
+ * not need to be part of params.
+ *
+ * It is required that the timer has at least 2 channels. (Future versions may
+ * require a 3rd channel).
+ *
+ * It is required that the timer's MAX_VALUE is 2^n-1, which is a trivial but
+ * not explicitly stated case.
+ *
+ * This timer is configured at WS281x initialization time, and kept stopped
+ * outside of transmissions.
+ *
+ * The default value of 2 is chosen because the only platform on which the
+ * module is usable is nRF5x, where TIMER_DEV(1) is in use by the radio module.
+ * It is strongly advised to explicitly set this timer to a known free timer,
+ * as the default may change without notice.
+ * */
+#if !defined(WS281X_TIMER_DEV) || defined(DOXYGEN)
+#define WS281X_TIMER_DEV TIMER_DEV(2)
+#endif
+
+/** @brief Maximum value of the timer used for WS281x (by the timer_gpio_ll implementation)
+ *
+ * This macro needs to be defined to the `TIMER_x_MAX_VALUE` corresponding to
+ * the `TIMER_DEV(x)` in @ref WS281X_TIMER_DEV.
+ * */
+#ifndef WS281X_TIMER_MAX_VALUE
+#define WS281X_TIMER_MAX_VALUE TIMER_2_MAX_VALUE
+#endif
+
+/** @brief Frequency for the timer used for WS281x (by the timer_gpio_ll implementation)
+ *
+ * This should be set to a frequency that is a close multiple of 3MHz,
+ * depending on the precise low and high times. A value of 16MHz works well.
+ * */
+#ifndef WS281X_TIMER_FREQ
+#define WS281X_TIMER_FREQ 16000000
+#endif
+
 #ifdef __cplusplus
 }
 #endif

drivers/ws281x/timer_gpio_ll.c

@@ -0,0 +1,169 @@
+/*
+ * Copyright 2023 Christian Amsüss
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     drivers_ws281x
+ *
+ * @{
+ *
+ * @file
+ * @brief       Implementation of the WS281x abstraction based on GPIO_LL and timers
+ *
+ * When this is used, the whole @ref ws281x_write_buffer operation is conducted
+ * in a single interrupts-disabled run. As it takes about 1us per bit (eg.
+ * 0.3ms on a 100-LED strip), the use of this module needs to be carefully
+ * evaluated against other real-time requirements.
+ *
+ * (Letting the trailing pause run with interrupts enabled, or even enabling
+ * interrupts between bits, is an option that is being considered for future
+ * expansion).
+ *
+ * @author      Christian Amsüss <chrysn@fsfe.org>
+ *
+ * @}
+ */
+#include <assert.h>
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "irq.h"
+#include "time_units.h"
+#include "periph/timer.h"
+#include "periph/gpio_ll.h"
+
+#include "ws281x.h"
+#include "ws281x_params.h"
+#include "ws281x_constants.h"
+
+#define ENABLE_DEBUG 0
+#include "debug.h"
+
+/* (+ NS_PER_SEC - 1): Rounding up, as T1H is the time that needs to distinctly
+ * longer than T0H.
+ *
+ * Then adding +1 extra, because the spin loop adds another layer of jitter. A
+ * more correct version would be to add the spin loop time before rounding (and
+ * then rounding up), but as that time is not available, spending one more
+ * cycle is the next best thing to do. */
+const int ticks_one = ((uint64_t)WS281X_T_DATA_ONE_NS * WS281X_TIMER_FREQ + NS_PER_SEC - 1)
+                    / NS_PER_SEC + 1;
+/* Rounding down, zeros are better shorter */
+const int ticks_zero = (uint64_t)WS281X_T_DATA_ZERO_NS * (uint64_t)WS281X_TIMER_FREQ / NS_PER_SEC;
+/* No particular known requirements, but we're taking longer than that anyway
+ * because we don't clock the times between bits. */
+const int ticks_data = (uint64_t)WS281X_T_DATA_NS * (uint64_t)WS281X_TIMER_FREQ / NS_PER_SEC;
+
+void ws281x_write_buffer(ws281x_t *dev, const void *buf, size_t size)
+{
+    assert(dev);
+
+    const uint8_t *pos = buf;
+    const uint8_t *end = pos + size;
+
+    /* The logical sequence for a cycle would be to set high, sleep, set low,
+     * sleep. But the critical time is the high time, so we do something
+     * different: We go low, set up the timer, and then go high and back low
+     * both as controlled by the timer. That means that our logical cycles are
+     * the previous bit's low time followed by the current bit's high time -- so we store the previous bit here.
+     *
+     * It is initialized to 1 because the 1 has the longer high time, so the
+     * lower low time -- we just spend 325 instead of 600ns before actually
+     * sending the message. (This wait-before-we-start time is also part of how
+     * this implementation can get away without compensation for the time it
+     * takes to set up timers: it sets them up and then waits for some time
+     * that is known to be long enough, because that time also works
+     * mid-transmission). */
+    bool last_bit = 1;
+
+    gpio_port_t port = gpio_get_port(dev->params.pin);
+    uword_t mask = 1 << gpio_get_pin_num(dev->params.pin);
+
+    /* If a too-slow channel is used, then the critical section could be done
+     * away with: If an interrupt fires (or a higher priority thread runs;
+     * really: runs long enough to matter, but that'd need very fast switching
+     * and hundreds of MHz to be the case), the function will return with an
+     * error (or ignore the error), and the worst thing that'd happen is that
+     * if it hits the last bit of a LED, that might be flipped to a value 1.
+     * */
+    unsigned int irq_state = irq_disable();
+
+    while (pos < end) {
+        uint8_t data = *pos;
+        for (uint8_t cnt = 8; cnt > 0; cnt--) {
+            bool bit = data >> 7;
+            data <<= 1;
+            int time_to_set = last_bit ? (ticks_data - ticks_one) : (ticks_data - ticks_zero);
+            int time_to_clear = time_to_set + (bit ? ticks_one : ticks_zero);
+
+            /* I'd prefer to just zero the timer, but we don't have API for that */
+            int now = timer_read(WS281X_TIMER_DEV);
+            time_to_set = (time_to_set + now) & WS281X_TIMER_MAX_VALUE;
+            time_to_clear = (time_to_clear + now) & WS281X_TIMER_MAX_VALUE;
+
+            timer_set_absolute(WS281X_TIMER_DEV, 0, time_to_set);
+            timer_set_absolute(WS281X_TIMER_DEV, 1, time_to_clear);
+            timer_start(WS281X_TIMER_DEV);
+            /* A
+             * ~~~
+             * while ((int)timer_read(WS281X_TIMER_DEV) < time_to_set) {};
+             * ~~~
+             * would be way too slow, plus it'd impose additional requirements
+             * on the timer to avoid wrapping */
+            while (!timer_poll_channel(WS281X_TIMER_DEV, 0)) {}
+            gpio_ll_set(port, mask);
+            while (!timer_poll_channel(WS281X_TIMER_DEV, 1)) {}
+            gpio_ll_clear(port, mask);
+            timer_stop(WS281X_TIMER_DEV);
+
+            last_bit = bit;
+        }
+        pos++;
+    }
+
+    irq_restore(irq_state);
+}
+
+int ws281x_init(ws281x_t *dev, const ws281x_params_t *params)
+{
+    int err;
+
+    if (!dev || !params || !params->buf) {
+        return -EINVAL;
+    }
+
+    memset(dev, 0, sizeof(ws281x_t));
+    dev->params = *params;
+
+    gpio_port_t port = gpio_get_port(dev->params.pin);
+    uint8_t pin = gpio_get_pin_num(dev->params.pin);
+
+    err = gpio_ll_init(port, pin, &gpio_ll_out);
+    DEBUG("Initializing port %x pin %d (originally %x): %d\n",
+            port, pin, params->pin, err);
+    if (err != 0) {
+        return -EIO;
+    }
+
+    err = timer_init(WS281X_TIMER_DEV, WS281X_TIMER_FREQ, NULL, NULL);
+    DEBUG("Initialized timer to %d Hz: %d\n", WS281X_TIMER_FREQ, err);
+    if (err != 0) {
+        return -EIO;
+    }
+    timer_stop(WS281X_TIMER_DEV);
+
+    /* We're not trying to make an assessment on whether that means we can
+     * manage or not, for that also depends on the number of instructions in
+     * the loop, which adds to the granularity. (Really the relevant time is
+     * the duration converted back from ticks to time, rounded up or down
+     * randomly to the duration of the loop). */
+    DEBUG("At this speed, ones are %d ticks long and zeros %d ticks of a %d "
+            "tick transmission.\n", ticks_one, ticks_zero, ticks_data);
+
+    return 0;
+}

kconfigs/Kconfig.features

@@ -572,6 +572,12 @@ config HAS_PERIPH_TIMER_PERIODIC
         Indicates that the Timer peripheral provides the periodic timeout
         functionality.
 
+config HAS_PERIPH_TIMER_POLL
+    bool
+    help
+        Indicates that the Timer peripheral supports the timer_poll_channel
+        function.
+
 config HAS_PERIPH_TIMER_QUERY_FREQS
     bool
     help

makefiles/features_modules.inc.mk

@@ -47,6 +47,7 @@ PERIPH_IGNORE_MODULES := \
   periph_rtt_hw_rtc \
   periph_rtt_hw_sys \
   periph_spi_on_qspi \
+  periph_timer_poll \
   periph_timer_query_freqs \
   periph_uart_collision \
   periph_uart_rxstart_irq \

tests/drivers/ws281x/Makefile

@@ -4,6 +4,10 @@ include ../Makefile.drivers_common
 # Update this to your needs
 # PIN ?= GPIO_PIN(0, 0)
 # N ?= 8
+# When using the ws281x_timer_gpio_ll module, you'll also need to define those:
+# (Example values are suitable for nRF52 devices)
+# TIMER ?= 2
+# FREQ ?= 16000000
 
 USEMODULE += ws281x
 USEMODULE += xtimer
@@ -22,3 +26,9 @@ endif
 ifneq (, $(N))
   CFLAGS += '-DWS281X_PARAM_NUMOF=$(N)'
 endif
+ifneq (, $(TIMER))
+  CFLAGS += '-DWS281X_TIMER_DEV=TIMER_DEV($(TIMER))' '-DWS281X_TIMER_MAX_VALUE=TIMER_$(TIMER)_MAX_VALUE'
+endif
+ifneq (, $(FREQ))
+  CFLAGS += '-DWS281X_TIMER_FREQ=$(FREQ)'
+endif