drivers: added driver for LPD8808 LED strips

drivers/Makefile.dep

@@ -94,6 +94,11 @@ ifneq (,$(filter lm75a,$(USEMODULE)))
     USEMODULE += xtimer
 endif
 
+ifneq (,$(filter lpd8808,$(USEMODULE)))
+    USEMODULE += color
+    FEATURES_REQUIRED += periph_gpio
+endif
+
 ifneq (,$(filter ltc4150,$(USEMODULE)))
     USEMODULE += xtimer
 endif

drivers/Makefile.include

@@ -67,3 +67,6 @@ endif
 ifneq (,$(filter cc2420,$(USEMODULE)))
     USEMODULE_INCLUDES += $(RIOTBASE)/drivers/cc2420/include
 endif
+ifneq (,$(filter lpd8808,$(USEMODULE)))
+    USEMODULE_INCLUDES += $(RIOTBASE)/drivers/lpd8808/include
+endif

drivers/include/lpd8808.h

+/*
+ * Copyright (C) 2016 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_lpd8808 LPD8808 based LED Strip
+ * @ingroup     drivers
+ * @brief       Driver for LPD8808 based LED strips
+ *
+ * LPD8808 based LED strips consist of a number of LEDs driven by LPD8808 chips.
+ * In these strips, each LED can be controlled individually. For this, every two
+ * LEDs are driven by a LPD8808 chip, which are chained and form a long shift
+ * register. To control a certain LED, the target color value needs to be
+ * shifted to the LEDs position on the strip.
+ *
+ * This driver implementation does not buffer the current values for each LED.
+ * It expects the application to take care of this.
+ *
+ * @{
+ * @file
+ * @brief       Interface definition for the LPD8808 LED strip driver
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef LPD8808_H
+#define LPD8808_H
+
+#include "color.h"
+#include "periph/gpio.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Parameters needed for configuration
+ */
+typedef struct {
+    int led_cnt;        /**< number of LEDs on the strip */
+    gpio_t pin_clk;     /**< pin connected to the strip's clock signal */
+    gpio_t pin_dat;     /**< pin connected to the strip's data signal */
+} lpd8808_params_t;
+
+/**
+ * @brief   Device descriptor, same as the configuration parameters
+ */
+typedef lpd8808_params_t lpd8808_t;
+
+/**
+ * @brief   Initialize the given LPD8808 based LED strip
+ *
+ * @param[out] dev      device to initialize
+ * @param[in]  params   parameters used for initialization
+ *
+ * @return  0 on success
+ * @return  <0 on error
+ */
+int lpd8808_init(lpd8808_t *dev, const lpd8808_params_t *params);
+
+/**
+ * @brief   Set the color value of each LED on the strip
+ *
+ * This function sets the color value of each LED on the strip by shifting out
+ * the corresponding color values one after the other. The function expects an
+ * array of @p color_rgb_t values of the same length as LEDs on the strip.
+ *
+ * @param[in] dev       device to load color values to
+ * @param[in] vals      array of color values, MUST be of same length as LEDs on
+ *                      the strip
+ */
+void lpd8808_load_rgb(lpd8808_t *dev, color_rgb_t vals[]);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LPD8808_H */
+/** @} */

drivers/lpd8808/Makefile

+include $(RIOTBASE)/Makefile.base

drivers/lpd8808/include/lpd8808_params.h

+/*
+ * Copyright (C) 2016 Hauke Petersen <devel@haukepetersen.de>
+ *
+ * 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_lpd8808
+ *
+ * @{
+ * @file
+ * @brief       Default configuration for LPD8808 based LED strips
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef LPD8808_PARAMS_H
+#define LPD8808_PARAMS_H
+
+#include "board.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Set default configuration parameters for the LPD8808 driver
+ * @{
+ */
+#ifndef LPD8808_PARAM_LED_CNT
+#define LPD8808_PARAM_LED_CNT       (64)    /* most have 64 per meter... */
+#endif
+#ifndef LPD8808_PARAM_PIN_CLK
+#define LPD8808_PARAM_PIN_CLK       (GPIO_PIN(0, 0))
+#endif
+#ifndef LPD8808_PARAM_PIN_DAT
+#define LPD8808_PARAM_PIN_DAT       (GPIO_PIN(0, 1))
+#endif
+
+#define LPD8808_PARAMS_DEFAULT      {.led_cnt = LPD8808_PARAM_LED_CNT, \
+                                     .pin_clk = LPD8808_PARAM_PIN_CLK, \
+                                     .pin_dat = LPD8808_PARAM_PIN_DAT }
+/**@}*/
+
+/**
+ * @brief   LPD8808 parameter allocation
+ */
+static const lpd8808_params_t lpd8808_params[] =
+{
+#ifdef LPD8808_PARAMS_BOARD
+    LPD8808_PARAMS_BOARD,
+#else
+    LPD8808_PARAMS_DEFAULT,
+#endif
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LPD8808_PARAMS_H */
+/** @} */

drivers/lpd8808/lpd8808.c

+/*
+ * Copyright (C) 2016 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     lpd8808
+ * @{
+ *
+ * @file
+ * @brief       LPD8808 based LED strip driver implementation
+ *
+ * @author      Hauke Petersen <mail@haukepetersen.de>
+ *
+ * @}
+ */
+
+#include <string.h>
+
+#include "lpd8808.h"
+
+/**
+ * @brief   Shift a single byte to the strip
+ *
+ * @param[in] dev   device to use
+ * @param[in] d     byte to shift out
+ */
+static void put_byte(lpd8808_t *dev, uint8_t d)
+{
+    for (int i = 0; i < 8; i++) {
+        gpio_write(dev->pin_dat, d & 0x80);
+        gpio_set(dev->pin_clk);
+        gpio_clear(dev->pin_clk);
+        d <<= 1;
+    }
+}
+
+/**
+ * @brief   Flush the previous input
+ *
+ * LPD8808 based strips need to be flushed after loading values for each LED.
+ * This is done by feeding the strip with one zero byte for every 32 LEDs on
+ * the strip.
+ *
+ * @param[in] dev   device to flush
+ */
+static void flush(lpd8808_t *dev)
+{
+    for (int i = 0; i < ((dev->led_cnt + 31) / 32); i++) {
+        put_byte(dev, 0);
+    }
+}
+
+int lpd8808_init(lpd8808_t *dev, const lpd8808_params_t *params)
+{
+    memcpy(dev, params, sizeof(lpd8808_params_t));
+
+    /* initialize pins */
+    gpio_init(dev->pin_dat, GPIO_OUT);
+    gpio_init(dev->pin_clk, GPIO_OUT);
+    flush(dev);
+
+    return 0;
+}
+
+void lpd8808_load_rgb(lpd8808_t *dev, color_rgb_t vals[])
+{
+    for (int i = 0; i < dev->led_cnt; i++) {
+        put_byte(dev, ((vals[i].g >> 1) | 0x80));
+        put_byte(dev, ((vals[i].r >> 1) | 0x80));
+        put_byte(dev, ((vals[i].b >> 1) | 0x80));
+    }
+    flush(dev);
+}