Add driver for APA102 LED controller. These LEDs are used on LED Strips and...

Add driver for APA102 LED controller.  These LEDs are used on LED Strips and are controlled over SPI.

drivers/leds/Kconfig

@@ -41,6 +41,13 @@ config USERLED_LOWER
 
 endif # USERLED
 
+config LEDS_APA102
+	bool "APA102 LED Strip"
+	default n
+	select SPI
+	---help---
+		Enable support for the APA102 LED Strip driver.
+
 config RGBLED
         bool "RGB LED Driver Support"
         default n

drivers/leds/Make.defs

@@ -50,6 +50,12 @@ endif
   LEDVPATH = :leds
 endif
 
+ifeq ($(CONFIG_LEDS_APA102),y)
+  CSRCS += apa102.c
+  LEDDEPATH = --dep-path leds
+  LEDVPATH = :leds
+endif
+
 ifeq ($(CONFIG_RGBLED),y)
   CSRCS += rgbled.c
   LEDDEPATH = --dep-path leds

drivers/leds/apa102.c

+/****************************************************************************
+ * drivers/sensors/apa102.c
+ * Character driver to control LED strips with APA102.
+ *
+ *   Copyright (C) 2017 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2017 Alan Carvalho de Assis
+ *   Author: Alan Carvalho de Assis <acassis@gmail.com>
+ *
+ * More info:
+ * https://cpldcpu.com/2014/11/30/understanding-the-apa102-superled/
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdlib.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/spi/spi.h>
+#include <nuttx/leds/apa102.h>
+
+#if defined(CONFIG_SPI) && defined(CONFIG_LEDS_APA102)
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct apa102_dev_s
+{
+  FAR struct spi_dev_s *spi; /* SPI interface */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static inline void apa102_configspi(FAR struct spi_dev_s *spi);
+static inline void apa102_write32(FAR struct apa102_dev_s *priv,
+                                  FAR uint32_t value);
+
+/* Character driver methods */
+
+static int     apa102_open(FAR struct file *filep);
+static int     apa102_close(FAR struct file *filep);
+static ssize_t apa102_read(FAR struct file *filep, FAR char *buffer,
+                            size_t buflen);
+static ssize_t apa102_write(FAR struct file *filep, FAR const char *buffer,
+                            size_t buflen);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct file_operations g_apa102fops =
+{
+  apa102_open,   /* open */
+  apa102_close,  /* close */
+  apa102_read,   /* read */
+  apa102_write,  /* write */
+  0,             /* seek */
+  0,             /* ioctl */
+#ifndef CONFIG_DISABLE_POLL
+  0,             /* poll */
+#endif
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+  , NULL         /* unlink */
+#endif
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: apa102_configspi
+ *
+ * Description:
+ *   Set the SPI bus configuration
+ *
+ ****************************************************************************/
+
+static inline void apa102_configspi(FAR struct spi_dev_s *spi)
+{
+  /* Configure SPI for the APA102 */
+
+  SPI_SETMODE(spi, SPIDEV_MODE0);
+  SPI_SETBITS(spi, 8);
+  (void)SPI_HWFEATURES(spi, 0);
+  (void)SPI_SETFREQUENCY(spi, APA102_SPI_MAXFREQUENCY);
+}
+
+/****************************************************************************
+ * Name: apa102_write32
+ *
+ * Description:
+ *   Write 32-bit to APA102
+ *
+ ****************************************************************************/
+
+static inline void apa102_write32(FAR struct apa102_dev_s *priv,
+                                  FAR uint32_t value)
+{
+  /* If SPI bus is shared then lock and configure it */
+
+  (void)SPI_LOCK(priv->spi, true);
+
+  apa102_configspi(priv->spi);
+
+  /* Note: APA102 doesn't use chip select */
+  /* Send 32 bits (4 bytes) */
+
+  (void)SPI_SEND(priv->spi, (value & 0xff));
+  (void)SPI_SEND(priv->spi, ((value & 0xff00) >> 8));
+  (void)SPI_SEND(priv->spi, ((value & 0xff0000) >> 16));
+  (void)SPI_SEND(priv->spi, ((value & 0xff000000) >> 24));
+
+  /* Unlock bus */
+
+  (void)SPI_LOCK(priv->spi, false);
+}
+
+/****************************************************************************
+ * Name: apa102_open
+ *
+ * Description:
+ *   This function is called whenever the APA102 device is opened.
+ *
+ ****************************************************************************/
+
+static int apa102_open(FAR struct file *filep)
+{
+  return OK;
+}
+
+/****************************************************************************
+ * Name: apa102_close
+ *
+ * Description:
+ *   This routine is called when the LM-75 device is closed.
+ *
+ ****************************************************************************/
+
+static int apa102_close(FAR struct file *filep)
+{
+  return OK;
+}
+
+/****************************************************************************
+ * Name: apa102_read
+ ****************************************************************************/
+
+static ssize_t apa102_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
+{
+  return -ENOSYS;
+}
+
+/****************************************************************************
+ * Name: apa102_write
+ ****************************************************************************/
+
+static ssize_t apa102_write(FAR struct file *filep, FAR const char *buffer,
+                          size_t buflen)
+{
+  FAR struct inode *inode = filep->f_inode;
+  FAR struct apa102_dev_s *priv = inode->i_private;
+  FAR uint32_t *leds = (FAR uint32_t *) buffer;
+  uint16_t nleds;
+  uint16_t i;
+
+  if (!leds)
+    {
+      snerr("ERROR: Buffer is null\n");
+      return -1;
+    }
+
+  /* At least one LED, so 4 bytes */
+
+  if (buflen < 4)
+    {
+      snerr("ERROR: You need to control at least 1 LED!\n");
+      return -1;
+    }
+
+  /* It needs to be multiple of 4 */
+
+  if ((buflen % 4) != 0)
+    {
+      snerr("ERROR: Each LED uses 4 bytes, so (buflen % 4) needs to be 0!\n");
+      return -1;
+    }
+
+  nleds = buflen / 4;
+
+  /* Send a start of frame */
+
+  apa102_write32(priv, APA102_START_FRAME);
+
+  /* Write all LEDs */
+
+  for (i = 0; i < nleds; i++)
+    {
+      /* Send the LED color, the LSB is the Bright and Header */
+
+      apa102_write32(priv, (uint32_t) (leds[i] | APA102_HEADER_FRAME));
+    }
+
+  /* Send an end of frame */
+
+  apa102_write32(priv, APA102_END_FRAME);
+
+  for (i = 0; i < (1 + nleds/32); i++)
+    {
+      apa102_write32(priv, 0);
+    }
+
+  /* All bytes were written */
+
+  return buflen;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: apa102_register
+ *
+ * Description:
+ *   Register the APA102 character device as 'devpath'
+ *
+ * Input Parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/temp0"
+ *   i2c     - An instance of the I2C interface to use to communicate with
+ *             APA102
+ *   addr    - The I2C address of the LM-75.  The base I2C address of the
+ *             APA102 is 0x48.  Bits 0-3 can be controlled to get 8 unique
+ *             addresses from 0x48 through 0x4f.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int apa102_register(FAR const char *devpath, FAR struct spi_dev_s *spi)
+{
+  FAR struct apa102_dev_s *priv;
+  int ret;
+
+  /* Initialize the APA102 device structure */
+
+  priv = (FAR struct apa102_dev_s *)kmm_malloc(sizeof(struct apa102_dev_s));
+  if (!priv)
+    {
+      snerr("ERROR: Failed to allocate instance\n");
+      return -ENOMEM;
+    }
+
+  priv->spi = spi;
+
+  /* Configure SPI for the APA102 */
+
+  apa102_configspi(spi);
+
+  /* Register the character driver */
+
+  ret = register_driver(devpath, &g_apa102fops, 0666, priv);
+  if (ret < 0)
+    {
+      snerr("ERROR: Failed to register driver: %d\n", ret);
+      kmm_free(priv);
+    }
+
+  return ret;
+}
+#endif /* CONFIG_SPI && CONFIG_APA102 */

include/nuttx/leds/apa102.h

+/****************************************************************************
+ * include/nuttx/leds/apa102.h
+ *
+ *   Copyright (C) 2017 Alan Carvalho de Assis.
+ *   Author: Alan Carvalho de Assis <acassis@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_LEDS_APA102_H
+#define __INCLUDE_NUTTX_LEDS_APA102_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+/* Configuration
+ * CONFIG_SPI         - Enables support for SPI drivers
+ * CONFIG_LEDS_APA102 - Enables support for the APA102 driver
+ */
+
+#if defined(CONFIG_SPI) && defined(CONFIG_LEDS_APA102)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* SPI definitions */
+
+#define APA102_SPI_MAXFREQUENCY    (100000) /* Default 4MHz */
+
+/* APA102 register addresses */
+
+#define APA102_START_FRAME         0x00000000
+#define APA102_HEADER_FRAME        0xe1
+#define APA102_END_FRAME           0x00
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+struct apa102_ledstrip_s
+{
+  uint8_t bright;
+  uint8_t blue;
+  uint8_t green;
+  uint8_t red;
+};
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Name: apa102_register
+ *
+ * Description:
+ *   Register the APA102 device as 'devpath'
+ *
+ * Input Parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/leddrv0".
+ *   spi     - An instance of the SPI interface to use to communicate
+ *             with the APA102.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int apa102_register(FAR const char *devpath, FAR struct spi_dev_s *spi);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CONFIG_SPI && CONFIG_LEDS_APA102 */
+#endif /* __INCLUDE_NUTTX_LEDS_APA102_H */