diff --git a/drivers/Makefile.dep b/drivers/Makefile.dep
index 34e91a56fb9027abbfc1cd80c46ee3b3567dd30a..c9c0212f56962b8b7d76aa904fee6fd8f1d1347f 100644
--- a/drivers/Makefile.dep
+++ b/drivers/Makefile.dep
@@ -4,6 +4,10 @@ ifneq (,$(filter adxl345,$(USEMODULE)))
FEATURES_REQUIRED += periph_i2c
endif
+ifneq (,$(filter apa102,$(USEMODULE)))
+ FEATURES_REQUIRED += periph_gpio
+endif
+
ifneq (,$(filter at30tse75x,$(USEMODULE)))
USEMODULE += xtimer
FEATURES_REQUIRED += periph_i2c
diff --git a/drivers/Makefile.include b/drivers/Makefile.include
index dcbd298cfa6ad9a2de07f360599d6a3c949eb84c..5a1a902236f57be2c056f0e62038588e2c624521 100644
--- a/drivers/Makefile.include
+++ b/drivers/Makefile.include
@@ -142,3 +142,6 @@ endif
ifneq (,$(filter sx127%,$(USEMODULE)))
USEMODULE_INCLUDES += $(RIOTBASE)/drivers/sx127x/include
endif
+ifneq (,$(filter apa102,$(USEMODULE)))
+ USEMODULE_INCLUDES += $(RIOTBASE)/drivers/apa102/include
+endif
diff --git a/drivers/apa102/Makefile b/drivers/apa102/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..48422e909a47d7cd428d10fa73825060ccc8d8c2
--- /dev/null
+++ b/drivers/apa102/Makefile
@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base
diff --git a/drivers/apa102/apa102.c b/drivers/apa102/apa102.c
new file mode 100644
index 0000000000000000000000000000000000000000..f9cbacaf6f939b37aceb94aa847f0690cfa82b59
--- /dev/null
+++ b/drivers/apa102/apa102.c
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * 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_apa102
+ * @{
+ *
+ * @file
+ * @brief APA 102 RGB LED driver implementation
+ *
+ * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <string.h>
+
+#include "assert.h"
+#include "apa102.h"
+
+#define START (0x00000000)
+#define END (0xffffffff)
+
+#define HEAD (0xe0000000)
+#define BRIGHT (0x1f000000)
+#define BLUE (0x00ff0000)
+#define GREEN (0x0000ff00)
+#define RED (0x000000ff)
+#define BRIGHT_SHIFT (21U)
+#define BLUE_SHIFT (16U)
+#define GREEN_SHIFT (8U)
+
+
+static inline void shift(const apa102_t *dev, uint32_t data)
+{
+ for (int i = 31; i >= 0; i--) {
+ gpio_write(dev->data_pin, ((data >> i) & 0x01));
+ gpio_set(dev->clk_pin);
+ gpio_clear(dev->clk_pin);
+ }
+}
+
+void apa102_init(apa102_t *dev, const apa102_params_t *params)
+{
+ assert(dev && params);
+
+ memcpy(dev, params, sizeof(apa102_params_t));
+
+ gpio_init(dev->data_pin, GPIO_OUT);
+ gpio_init(dev->clk_pin, GPIO_OUT);
+ gpio_clear(dev->data_pin);
+ gpio_clear(dev->clk_pin);
+}
+
+void apa102_load_rgba(const apa102_t *dev, const color_rgba_t vals[])
+{
+ assert(dev && vals);
+
+ shift(dev, START);
+ for (int i = 0; i < dev->led_numof; i++) {
+ uint32_t data = HEAD;
+ /* we scale the 8-bit alpha value to a 5-bit value by cutting off the
+ * 3 leas significant bits */
+ data |= (((uint32_t)vals[i].alpha << BRIGHT_SHIFT) & BRIGHT);
+ data |= ((uint32_t)vals[i].color.b << BLUE_SHIFT);
+ data |= ((uint32_t)vals[i].color.g << GREEN_SHIFT);
+ data |= vals[i].color.r;
+ shift(dev, data);
+ }
+ shift(dev, END);
+}
diff --git a/drivers/apa102/include/apa102_params.h b/drivers/apa102/include/apa102_params.h
new file mode 100644
index 0000000000000000000000000000000000000000..d160eda84f44209cfc7311b48843a8f91f137444
--- /dev/null
+++ b/drivers/apa102/include/apa102_params.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * 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_apa102
+ * @{
+ *
+ * @file
+ * @brief APA102 board specific configuration
+ *
+ * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef APA102_PARAMS_H
+#define APA102_PARAMS_H
+
+#include "board.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Set default configuration parameters for the APA102 driver
+ * @{
+ */
+#ifndef APA102_PARAM_LED_NUMOF
+#define APA102_PARAM_LED_NUMOF (64) /* many have 64 per meter... */
+#endif
+#ifndef APA102_PARAM_DATA_PIN
+#define APA102_PARAM_DATA_PIN (GPIO_PIN(0, 0))
+#endif
+#ifndef APA102_PARAM_CLK_PIN
+#define APA102_PARAM_CLK_PIN (GPIO_PIN(0, 1))
+#endif
+
+#define APA102_PARAMS_DEFAULT { .led_numof = APA102_PARAM_LED_NUMOF, \
+ .data_pin = APA102_PARAM_DATA_PIN, \
+ .clk_pin = APA102_PARAM_CLK_PIN }
+/**@}*/
+
+/**
+ * @brief APA102 configuration
+ */
+static const apa102_params_t apa102_params[] =
+{
+#ifdef APA102_PARAMS_BOARD
+ APA102_PARAMS_BOARD,
+#else
+ APA102_PARAMS_DEFAULT,
+#endif
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* APA102_PARAMS_H */
+/** @} */
diff --git a/drivers/include/apa102.h b/drivers/include/apa102.h
new file mode 100644
index 0000000000000000000000000000000000000000..df0c56ff9e11e167cdf096075c89ce1584bed533
--- /dev/null
+++ b/drivers/include/apa102.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * 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.
+ */
+
+/**
+ * @defgroup drivers_apa102 APA102 RGB LED
+ * @ingroup drivers_actuators
+ * @brief Driver for chained APA102 RGB LEDs
+ * @{
+ *
+ * @file
+ * @brief Interface for controlling APA102 LEDs
+ *
+ * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef APA102_H
+#define APA102_H
+
+#include "color.h"
+#include "periph/gpio.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Configuration parameters for (chained) APA102 LEDs
+ */
+typedef struct {
+ int led_numof; /**< number of chained LEDs */
+ gpio_t data_pin; /**< data pin */
+ gpio_t clk_pin; /**< clock pin */
+} apa102_params_t;
+
+/**
+ * @brief Device descriptor definition for APA102 LEDs
+ */
+typedef apa102_params_t apa102_t;
+
+/**
+ * @brief Initialize (chained) APA102 LEDs
+ *
+ * @param[out] dev device descriptor
+ * @param[in] params device configuration
+ *
+ * @pre @p dev != NULL
+ * @pre @p params != NULL
+ */
+void apa102_init(apa102_t *dev, const apa102_params_t *params);
+
+/**
+ * @brief Apply the given color values to the connected LED(s)
+ *
+ * @param[in] dev device descriptor
+ * @param[in] vals color values, MUST be of size `dev->led_numof`
+ *
+ * @pre @p dev != NULL
+ * @pre @p vals != NULL
+ */
+void apa102_load_rgba(const apa102_t *dev, const color_rgba_t vals[]);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* APA102_H */
+/** @} */
diff --git a/sys/include/color.h b/sys/include/color.h
index d4e6cd230b5616986553616f712f262f4698e7c4..8612e898b9a5472838fabdd139694901467b4106 100644
--- a/sys/include/color.h
+++ b/sys/include/color.h
@@ -38,6 +38,14 @@ typedef struct {
uint8_t b; /**< blue value [0 - 255] */
} color_rgb_t;
+/**
+ * @brief RGBA color value
+ */
+typedef struct {
+ color_rgb_t color; /**< RGB value */
+ uint8_t alpha; /**< alpha value [0 - 255] */
+} color_rgba_t;
+
/**
* @brief Data-structure for holding HSV colors
*/
@@ -47,7 +55,6 @@ typedef struct {
float v; /**< value [0.0 - 1.0] */
} color_hsv_t;
-
/**
* @brief Convert RGB color to HSV color
*
diff --git a/tests/driver_apa102/Makefile b/tests/driver_apa102/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..f579a21d0470948d3dc1bb3a6faf54baf00083d9
--- /dev/null
+++ b/tests/driver_apa102/Makefile
@@ -0,0 +1,8 @@
+APPLICATION = driver_apa102
+include ../Makefile.tests_common
+
+USEMODULE += apa102
+USEMODULE += color
+USEMODULE += xtimer
+
+include $(RIOTBASE)/Makefile.include
diff --git a/tests/driver_apa102/README.md b/tests/driver_apa102/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..a064b8528acf25f24880578f05fe98ed9cd16e25
--- /dev/null
+++ b/tests/driver_apa102/README.md
@@ -0,0 +1,21 @@
+# About
+This test application is made for verification of the APA102 LED strip driver.
+
+# Usage
+Connect a APA102 based LED strip to a board of your choice, build, and flash
+this application. When run, you should see the strip changing its brightness
+while lighting in red, then green, and then blue. After this sequence, you
+should see a light moving up and down the strip, changing its color.
+
+
+You might need to adjust the default parameters (number of LEDs on the strip and
+pin configuration). You can do this simply by pre-setting the `CFLAGS`
+environment variable, e.g.:
+```
+$ CFLAGS="-DAPA102_PARAM_LED_NUMOF=78"" make all
+```
+
+To change the default pins, simply override the default parameters, e.g.:
+```
+$ CFLAGS="-DAPA102_PARAM_DATA_PIN=GPIO_PIN\(2,3\) -DAPA102_PARAM_CLK_PIN=GPIO_PIN\(1,17\)" make all
+```
diff --git a/tests/driver_apa102/main.c b/tests/driver_apa102/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..4482a4f6775c1c6ad50b9dab6a5194457e680ee4
--- /dev/null
+++ b/tests/driver_apa102/main.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * 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 tests
+ * @{
+ *
+ * @file
+ * @brief Test application for the APA102 LED strip driver
+ *
+ * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include "xtimer.h"
+#include "color.h"
+
+#include "apa102.h"
+#include "apa102_params.h"
+
+/**
+ * @brief Switch to the next LED every 10ms
+ */
+#define STEP (200 * US_PER_MS)
+
+/**
+ * @brief Interval for dimming colors
+ */
+#define DIM (100 * US_PER_MS)
+
+/**
+ * @brief Step through brightness levels (0-255) in 32 steps
+ */
+#define BSTEP (8U)
+
+/**
+ * @brief Allocate the device descriptor
+ */
+static apa102_t dev;
+
+/**
+ * @brief Allocate a color_rgb_t struct for each LED on the strip
+ */
+static color_rgba_t leds[APA102_PARAM_LED_NUMOF];
+
+static void setcolor(int color, uint8_t alpha)
+{
+ for (int i = 0; i < (int)APA102_PARAM_LED_NUMOF; i++) {
+ leds[i].alpha = alpha;
+ memset(&leds[i].color, 0, sizeof(color_rgb_t));
+ switch (color) {
+ case 0:
+ leds[i].color.r = 255;
+ break;
+ case 1:
+ leds[i].color.g = 255;
+ break;
+ case 2:
+ leds[i].color.b = 255;
+ break;
+ }
+ }
+}
+
+int main(void)
+{
+ int pos = 0;
+ int step = 1;
+ color_hsv_t col = { 0.0, 1.0, 1.0 };
+
+ puts("APA102 Test App");
+
+ /* initialize all LED color values to black (off) */
+ memset(leds, 0, sizeof(color_rgba_t) * APA102_PARAM_LED_NUMOF);
+
+ /* initialize the driver */
+ apa102_init(&dev, &apa102_params[0]);
+
+ puts("Initialization done.");
+
+ /* set to each red, green, and blue, and fade each color in and out */
+ for (int col = 0; col <= 2; col++) {
+ int i = 0;
+ for (; i <= (int)UINT8_MAX; i += BSTEP) {
+ setcolor(col, (uint8_t)i);
+ apa102_load_rgba(&dev, leds);
+ xtimer_usleep(DIM);
+ }
+ i -= BSTEP;
+ for (; i >= 0; i -= BSTEP) {
+ setcolor(col, (uint8_t)i);
+ apa102_load_rgba(&dev, leds);
+ xtimer_usleep(DIM);
+ }
+ }
+
+ puts("Color Fading done");
+
+ /* reset color values */
+ setcolor(-1, 255);
+ apa102_load_rgba(&dev, leds);
+
+ xtimer_ticks32_t now = xtimer_now();
+
+ while (1) {
+ /* change the active color by running around the hue circle */
+ col.h += 1.0;
+ if (col.h > 360.0) {
+ col.h = 0.0;
+ }
+
+ /* set the active LED to the active color value */
+ memset(&leds[pos].color, 0, sizeof(color_rgb_t));
+ pos += step;
+ color_hsv2rgb(&col, &leds[pos].color);
+
+ /* apply the values to the LED strip */
+ apa102_load_rgba(&dev, leds);
+
+ /* switch direction once reaching an end of the strip */
+ if ((pos == (APA102_PARAM_LED_NUMOF - 1)) || (pos == 0)) {
+ step *= -1;
+ }
+
+ xtimer_periodic_wakeup(&now, STEP);
+ }
+
+ return 0;
+}