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Posted to commits@nuttx.apache.org by GitBox <gi...@apache.org> on 2020/09/15 22:04:40 UTC
[GitHub] [incubator-nuttx] davids5 commented on a change in pull request #1797: LED: Support for WS2812 LED controller (aka Adafruit NeoPixel)
davids5 commented on a change in pull request #1797:
URL: https://github.com/apache/incubator-nuttx/pull/1797#discussion_r489011256
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File path: drivers/leds/ws2812.c
##########
@@ -0,0 +1,475 @@
+/****************************************************************************
+ * drivers/sensors/ws2812.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * 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/ws2812.h>
+
+#ifdef CONFIG_WS2812
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#ifndef CONFIG_WS2812_FREQUENCY
+# define CONFIG_WS2812_FREQUENCY 8000000
+#endif
+
+/* These are the tuning parameters to meeting timeing requirements */
+
+#if CONFIG_WS2812_FREQUENCY == 4000000
+# define WS2812_RST_CYCLES 30 /* 60us (>50us)*/
+# define WS2812_ZERO_BYTE 0b01000000 /* 250 ns (200ns - 500ns) */
+# define WS2812_ONE_BYTE 0b01110000 /* 750 ns (550ns - 850ns) */
+#elif CONFIG_WS2812_FREQUENCY == 8000000
+# define WS2812_RST_CYCLES 60 /* 60us (>50us)*/
+# define WS2812_ZERO_BYTE 0b01100000 /* 250 ns (200ns - 500ns) */
+# define WS2812_ONE_BYTE 0b01111100 /* 750 ns (550ns - 850ns) */
+#else
+# error "Unsupported SPI Frequency"
+#endif
+
+#define WS2812_BYTES_PER_LED 8 * 3
+#define WS2812_RW_PIXEL_SIZE 4
+
+/* Transmit buffer looks like:
+ * [<----reset bytes---->|<-RGBn->...<-RGB0->|<----reset bytes---->]
+ *
+ * It is important that this is shipped as close to one chunk as possible
+ * in order to meet timeing requirements and to keep MOSI from going high
+ * between transactions. Some chips will leave MOSI at the state of the
+ * MSB of the last byte for this reason it is recommended to shift the
+ * bytes that represents the zero and one so that the MSB is 1. The reset
+ * clocks will pad the shortend low at the end.
+ */
+
+#define TXBUFF_SIZE(n) (WS2812_RST_CYCLES * 2 + n * WS2812_BYTES_PER_LED)
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct ws2812_dev_s
+{
+ FAR struct spi_dev_s *spi; /* SPI interface */
+ uint16_t nleds; /* Number of addressable LEDs */
+ uint8_t *tx_buf; /* Buffer for write transaction and state */
+ sem_t exclsem; /* Assures exclusive access to the driver */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static inline void ws2812_configspi(FAR struct spi_dev_s *spi);
+static void ws2812_pack(FAR uint8_t *buf, uint32_t rgb);
+
+/* Character driver methods */
+
+static int ws2812_open(FAR struct file *filep);
+static int ws2812_close(FAR struct file *filep);
+static ssize_t ws2812_read(FAR struct file *filep, FAR char *buffer,
+ size_t buflen);
+static ssize_t ws2812_write(FAR struct file *filep, FAR const char *buffer,
+ size_t buflen);
+static off_t ws2812_seek(FAR struct file *filep, off_t offset, int whence);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct file_operations g_ws2812fops =
+{
+ ws2812_open, /* open */
+ ws2812_close, /* close */
+ ws2812_read, /* read */
+ ws2812_write, /* write */
+ ws2812_seek, /* seek */
+ NULL, /* ioctl */
+ NULL, /* poll */
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+ NULL /* unlink */
+#endif
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: ws2812_configspi
+ *
+ * Description:
+ * Set the SPI bus configuration
+ *
+ ****************************************************************************/
+
+static inline void ws2812_configspi(FAR struct spi_dev_s *spi)
+{
+ /* Configure SPI for the WS2812 */
+
+ SPI_SETMODE(spi, SPIDEV_MODE3);
+ SPI_SETBITS(spi, 8);
+ SPI_HWFEATURES(spi, 0);
+ SPI_SETFREQUENCY(spi, CONFIG_WS2812_FREQUENCY);
+}
+
+/****************************************************************************
+ * Name: ws2812_pack
+ *
+ * Description:
+ * This writes the expanded SPI transaction to the transaction buffer
+ * for a given 24bit RGB value.
+ *
+ * Input Parameters:
+ * buf - The location in the transmit buffer to write.
+ * rgb - A 24bit RGB color 8bit red, 8-bit green, 8-bit blue
+ *
+ ****************************************************************************/
+
+static void ws2812_pack(FAR uint8_t *buf, uint32_t rgb)
+{
+ uint8_t bit_idx;
+ uint8_t byte_idx;
+ uint8_t offset = 0;
+ uint8_t color;
+ uint32_t grb;
+
+ grb = (rgb & 0x00ff00) << 8;
+ grb |= (rgb & 0xff0000) >> 8;
+ grb |= rgb & 0x0000ff;
+
+ for (byte_idx = 0; byte_idx < 3; byte_idx++)
+ {
+ color = (uint8_t)(grb >> (8 * (2 - byte_idx)));
+ for (bit_idx = 0; bit_idx < 8; bit_idx++)
+ {
+ if (color & (1 << (7 - bit_idx)))
+ {
+ buf[offset] = WS2812_ONE_BYTE;
+ }
+ else
+ {
+ buf[offset] = WS2812_ZERO_BYTE;
+ }
+
+ offset++;
+ }
+ }
+}
+
+/****************************************************************************
+ * Name: ws2812_open
+ *
+ * Description:
+ * This function is called whenever the WS2812 device is opened.
+ *
+ ****************************************************************************/
+
+static int ws2812_open(FAR struct file *filep)
+{
+ return OK;
+}
+
+/****************************************************************************
+ * Name: ws2812_close
+ *
+ * Description:
+ * This routine is called when the WS2812 device is closed.
+ *
+ ****************************************************************************/
+
+static int ws2812_close(FAR struct file *filep)
+{
+ return OK;
+}
+
+/****************************************************************************
+ * Name: ws2812_read
+ ****************************************************************************/
+
+static ssize_t ws2812_read(FAR struct file *filep, FAR char *buffer,
+ size_t buflen)
+{
+ return -ENOSYS;
+}
+
+/****************************************************************************
+ * Name: ws2812_write
+ *
+ * Description:
+ * This routine is called when writing to the WS2812 device. Data buffer
+ * should be an array of 32bit values holding 24bits of color information
+ * in host byte ordering 0x**rrggbb.
+ *
+ ****************************************************************************/
+
+static ssize_t ws2812_write(FAR struct file *filep, FAR const char *buffer,
+ size_t buflen)
+{
+ FAR struct inode *inode = filep->f_inode;
+ FAR struct ws2812_dev_s *priv = inode->i_private;
+ FAR uint8_t *tx_pixel;
+ FAR uint32_t *pixel_buf = (FAR uint32_t *)buffer;
+ size_t cur_led;
+ size_t start_led;
+ size_t end_led;
+ size_t written = 0;
+
+ if (buffer == NULL)
+ {
+ lederr("ERROR: Buffer is null\n");
+ set_errno(EINVAL);
+ return -1;
+ }
+
+ /* We need at least one display, so 1 byte */
+
+ if (buflen < 1)
+ {
+ lederr("ERROR: You need to control at least 1 LED!\n");
+ set_errno(EINVAL);
+ return -1;
+ }
+
+ if ((buflen % WS2812_RW_PIXEL_SIZE) != 0)
+ {
+ lederr("ERROR: LED values must be 24bit packed in 32bit\n");
+ set_errno(EINVAL);
+ return -1;
+ }
+
+ nxsem_wait(&priv->exclsem);
+
+ start_led = filep->f_pos / WS2812_RW_PIXEL_SIZE;
+ tx_pixel = priv->tx_buf + WS2812_RST_CYCLES + \
+ start_led * WS2812_BYTES_PER_LED;
+
+ end_led = start_led + (buflen / WS2812_RW_PIXEL_SIZE) - 1;
+ ledinfo("Start: %d End: %d\n", start_led, end_led);
+
+ if (end_led > (priv->nleds -1))
+ {
+ end_led = priv->nleds - 1;
+ }
+
+ for (cur_led = start_led; cur_led <= end_led; cur_led++)
+ {
+ ws2812_pack(tx_pixel, *pixel_buf & 0xffffff);
+ pixel_buf++;
+ tx_pixel += WS2812_BYTES_PER_LED;
+ written += WS2812_RW_PIXEL_SIZE;
+ }
+
Review comment:
Do you need to lock the SPI bus and then call ws2812_configspi here?
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