Merge pull request #6753 from haukepetersen/add_apa102

drivers: add driver for apa102 RGB LEDs

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

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

drivers/apa102/Makefile

+include $(RIOTBASE)/Makefile.base

drivers/apa102/apa102.c

+/*
+ * 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);
+}

drivers/apa102/include/apa102_params.h

+/*
+ * 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 */
+/** @} */

drivers/include/apa102.h

+/*
+ * 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 */
+/** @} */

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
  *

tests/driver_apa102/Makefile

+APPLICATION = driver_apa102
+include ../Makefile.tests_common
+
+USEMODULE += apa102
+USEMODULE += color
+USEMODULE += xtimer
+
+include $(RIOTBASE)/Makefile.include

tests/driver_apa102/README.md

+# 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
+```

tests/driver_apa102/main.c

+/*
+ * 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;
+}