266 lines
7.4 KiB
C
266 lines
7.4 KiB
C
/****************************************************************************
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* drivers/leds/apa102.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/* Character driver to control LED strips with APA102.
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*
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* More info:
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* https://cpldcpu.com/2014/11/30/understanding-the-apa102-superled/
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*/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/spi/spi.h>
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#include <nuttx/leds/apa102.h>
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#if defined(CONFIG_SPI) && defined(CONFIG_LEDS_APA102)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct apa102_dev_s
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{
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FAR struct spi_dev_s *spi; /* SPI interface */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static inline void apa102_configspi(FAR struct spi_dev_s *spi);
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static inline void apa102_write32(FAR struct apa102_dev_s *priv,
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FAR uint32_t value);
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/* Character driver methods */
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static ssize_t apa102_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t apa102_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_apa102fops =
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{
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NULL, /* open */
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NULL, /* close */
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apa102_read, /* read */
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apa102_write, /* write */
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NULL, /* seek */
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NULL, /* ioctl */
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NULL /* poll */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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, NULL /* unlink */
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#endif
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: apa102_configspi
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*
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* Description:
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* Set the SPI bus configuration
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*
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****************************************************************************/
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static inline void apa102_configspi(FAR struct spi_dev_s *spi)
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{
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/* Configure SPI for the APA102 */
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SPI_SETMODE(spi, SPIDEV_MODE0);
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SPI_SETBITS(spi, 8);
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SPI_HWFEATURES(spi, 0);
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SPI_SETFREQUENCY(spi, APA102_SPI_MAXFREQUENCY);
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}
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/****************************************************************************
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* Name: apa102_write32
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*
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* Description:
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* Write 32-bit to APA102
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*
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****************************************************************************/
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static inline void apa102_write32(FAR struct apa102_dev_s *priv,
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FAR uint32_t value)
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{
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/* If SPI bus is shared then lock and configure it */
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SPI_LOCK(priv->spi, true);
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apa102_configspi(priv->spi);
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/* Note: APA102 doesn't use chip select */
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/* Send 32 bits (4 bytes) */
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SPI_SEND(priv->spi, (value & 0xff));
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SPI_SEND(priv->spi, ((value & 0xff00) >> 8));
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SPI_SEND(priv->spi, ((value & 0xff0000) >> 16));
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SPI_SEND(priv->spi, ((value & 0xff000000) >> 24));
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/* Unlock bus */
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SPI_LOCK(priv->spi, false);
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}
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/****************************************************************************
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* Name: apa102_read
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****************************************************************************/
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static ssize_t apa102_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen)
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{
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return -ENOSYS;
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}
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/****************************************************************************
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* Name: apa102_write
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****************************************************************************/
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static ssize_t apa102_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct apa102_dev_s *priv = inode->i_private;
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FAR uint32_t *leds = (FAR uint32_t *) buffer;
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uint16_t nleds;
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uint16_t i;
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if (!leds)
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{
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snerr("ERROR: Buffer is null\n");
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return -1;
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}
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/* At least one LED, so 4 bytes */
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if (buflen < 4)
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{
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snerr("ERROR: You need to control at least 1 LED!\n");
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return -1;
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}
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/* It needs to be multiple of 4 */
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if ((buflen % 4) != 0)
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{
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snerr("ERROR: Each LED uses 4 bytes, so (buflen % 4)"
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" needs to be 0!\n");
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return -1;
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}
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nleds = buflen / 4;
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/* Send a start of frame */
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apa102_write32(priv, APA102_START_FRAME);
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/* Write all LEDs */
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for (i = 0; i < nleds; i++)
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{
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/* Send the LED color, the LSB is the Bright and Header */
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apa102_write32(priv, (uint32_t) (leds[i] | APA102_HEADER_FRAME));
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}
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/* Send an end of frame */
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apa102_write32(priv, APA102_END_FRAME);
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for (i = 0; i < (1 + nleds / 32); i++)
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{
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apa102_write32(priv, 0);
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}
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/* All bytes were written */
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return buflen;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: apa102_register
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*
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* Description:
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* Register the APA102 character device as 'devpath'
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*
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* Input Parameters:
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* devpath - The full path to the driver to register. E.g., "/dev/temp0"
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* spi - An instance of the SPI interface to use to communicate with
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* APA102
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*
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* Returned Value:
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* Zero (OK) on success; a negated errno value on failure.
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*
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****************************************************************************/
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int apa102_register(FAR const char *devpath, FAR struct spi_dev_s *spi)
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{
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FAR struct apa102_dev_s *priv;
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int ret;
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/* Initialize the APA102 device structure */
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priv = (FAR struct apa102_dev_s *)kmm_malloc(sizeof(struct apa102_dev_s));
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if (!priv)
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{
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snerr("ERROR: Failed to allocate instance\n");
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return -ENOMEM;
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}
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priv->spi = spi;
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/* Configure SPI for the APA102 */
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apa102_configspi(spi);
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/* Register the character driver */
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ret = register_driver(devpath, &g_apa102fops, 0666, priv);
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if (ret < 0)
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{
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snerr("ERROR: Failed to register driver: %d\n", ret);
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kmm_free(priv);
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}
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return ret;
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}
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#endif /* CONFIG_SPI && CONFIG_APA102 */
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