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incubator-nuttx/drivers/leds/max7219.c

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/****************************************************************************
* drivers/leds/max7219.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.
*
****************************************************************************/
/* Maxim MAX7219 driver used to control 7-segment display. */
/****************************************************************************
* 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/max7219.h>
#if defined(CONFIG_SPI) && defined(CONFIG_LEDS_MAX7219)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* SPI frequency */
#ifndef CONFIG_MAX7219_FREQUENCY
# define CONFIG_MAX7219_FREQUENCY 5000000
#endif
#ifndef CONFIG_MAX7219_INTENSITY
# define CONFIG_MAX7219_INTENSITY 8
#endif
/****************************************************************************
* Private Types
****************************************************************************/
struct max7219_dev_s
{
FAR struct spi_dev_s *spi; /* SPI interface */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static inline void max7219_configspi(FAR struct spi_dev_s *spi);
static inline void max7219_write16(FAR struct max7219_dev_s *priv,
uint16_t value);
/* Character driver methods */
static ssize_t max7219_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t max7219_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_max7219fops =
{
NULL, /* open */
NULL, /* close */
max7219_read, /* read */
max7219_write, /* write */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: max7219_configspi
*
* Description:
* Set the SPI bus configuration
*
****************************************************************************/
static inline void max7219_configspi(FAR struct spi_dev_s *spi)
{
/* Configure SPI for the MAX7219 */
SPI_SETMODE(spi, SPIDEV_MODE0);
SPI_SETBITS(spi, 8);
SPI_HWFEATURES(spi, 0);
SPI_SETFREQUENCY(spi, CONFIG_MAX7219_FREQUENCY);
}
/****************************************************************************
* Name: max7219_write16
*
* Description:
* Write 16-bit to MAX7219
*
****************************************************************************/
static inline void max7219_write16(FAR struct max7219_dev_s *priv,
uint16_t value)
{
/* If SPI bus is shared then lock and configure it */
SPI_LOCK(priv->spi, true);
/* Configure the SPI */
max7219_configspi(priv->spi);
/* Select */
SPI_SELECT(priv->spi, SPIDEV_DISPLAY(0), true);
/* Send 16 bits (2 bytes) */
SPI_SNDBLOCK(priv->spi, &value, 2);
/* De-select */
SPI_SELECT(priv->spi, SPIDEV_DISPLAY(0), false);
/* Unlock bus */
SPI_LOCK(priv->spi, false);
}
/****************************************************************************
* Name: max7219_read
****************************************************************************/
static ssize_t max7219_read(FAR struct file *filep,
FAR char *buffer, size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: max7219_write
****************************************************************************/
static ssize_t max7219_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct max7219_dev_s *priv = inode->i_private;
uint16_t data;
uint8_t digits[8];
uint8_t digcnt = 0;
uint8_t i;
if (buffer == NULL)
{
lederr("ERROR: Buffer is null\n");
return -1;
}
/* We need at least one display, so 1 byte */
if (buflen < 1)
{
lederr("ERROR: You need to control at least 1 digit!\n");
return -1;
}
/* Get and count the valid digits */
for (i = 0; i < buflen; i++)
{
if (buffer[i] >= '0' && buffer[i] <= '9')
{
digits[digcnt] = buffer[i] - '0';
digcnt++;
}
else
{
switch (buffer[i])
{
case '-':
digits[digcnt] = 0x0a;
digcnt++;
break;
case 'E':
digits[digcnt] = 0x0b;
digcnt++;
break;
case 'H':
digits[digcnt] = 0x0c;
digcnt++;
break;
case 'L':
digits[digcnt] = 0x0d;
digcnt++;
break;
case 'P':
digits[digcnt] = 0x0e;
digcnt++;
break;
case ' ':
digits[digcnt] = 0x0f;
digcnt++;
break;
case '.':
if (i == 0)
{
digits[0] = 0x0f | 0x80;
digcnt++;
}
else
{
digits[digcnt - 1] |= 0x80;
}
break;
default:
lederr("Digit code unsupported\n");
break;
}
}
/* If we reach 8 digits then stop */
if (digcnt >= 8 && buffer[i + 1] != '.')
{
ledwarn("ERROR: The limit is 8 digits!\n");
break;
}
}
/* Blank the display */
for (i = 0; i < 8; i++)
{
data = (MAX7219_DIGIT0 + i) | (0x0f << 8);
max7219_write16(priv, data);
}
/* Write each digit */
for (i = 0; i < digcnt; i++)
{
data = (MAX7219_DIGIT0 + i) | (digits[digcnt - i - 1]) << 8;
max7219_write16(priv, data);
}
/* All bytes were written */
return buflen;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: max7219_leds_register
*
* Description:
* Register the MAX7219 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
* MAX7219
* addr - The I2C address of the LM-75. The base I2C address of the
* MAX7219 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 max7219_leds_register(FAR const char *devpath, FAR struct spi_dev_s *spi)
{
FAR struct max7219_dev_s *priv;
uint16_t data;
int ret;
int i;
/* Initialize the MAX7219 device structure */
priv = (FAR struct max7219_dev_s *)
kmm_malloc(sizeof(struct max7219_dev_s));
if (!priv)
{
lederr("ERROR: Failed to allocate instance\n");
return -ENOMEM;
}
priv->spi = spi;
/* Setup defined intensity */
data = (MAX7219_INTENSITY) |
(DISPLAY_INTENSITY(CONFIG_MAX7219_INTENSITY) << 8);
max7219_write16(priv, data);
/* Enable decoding for all digits */
data = (MAX7219_DECODE_MODE) | (ENABLE_DECODE << 8);
max7219_write16(priv, data);
/* Display all digits */
data = (MAX7219_SCAN_LIMIT) | (0x07 << 8);
max7219_write16(priv, data);
/* Leave the shutdown mode */
data = (MAX7219_SHUTDOWN) | (MAX7219_POWER_ON << 8);
max7219_write16(priv, data);
/* Blank the display */
for (i = 0; i < 8; i++)
{
data = (MAX7219_DIGIT0 + i) | (0x0f << 8);
max7219_write16(priv, data);
}
/* Register the character driver */
ret = register_driver(devpath, &g_max7219fops, 0666, priv);
if (ret < 0)
{
lederr("ERROR: Failed to register driver: %d\n", ret);
kmm_free(priv);
}
return ret;
}
#endif /* CONFIG_SPI && CONFIG_MAX7219 */
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