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incubator-nuttx/drivers/lcd/max7219.c

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/****************************************************************************
* drivers/lcd/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.
*
****************************************************************************/
/* Driver for the Maxim MAX7219 used for driver 8x8 LED display chains. */
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/spi/spi.h>
#include <nuttx/lcd/lcd.h>
#include <nuttx/lcd/max7219.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/* MAX7219 Configuration Settings:
*
* CONFIG_MAX7219_NHORIZONTALBLKS - Specifies the number of physical
* MAX7219 devices that are connected together horizontally.
*
* CONFIG_MAX7219_NVERTICALBLKS - Specifies the number of physical
* MAX7219 devices that are connected together vertically.
*
* CONFIG_LCD_INTENSITY - Defines the default bright of LEDs.
*
* Required LCD driver settings:
* CONFIG_LCD_MAX7219 - Enable MAX7219 support
*
*/
/* Verify that all configuration requirements have been met */
/* SPI frequency */
#ifndef CONFIG_MAX7219_FREQUENCY
# define CONFIG_MAX7219_FREQUENCY 10000000
#endif
/* MAX7219_NHORIZONTALBLKS determines the number of physical 8x8 LEDs
* matrices that are used connected horizontally.
*/
#ifndef CONFIG_MAX7219_NHORIZONTALBLKS
# define CONFIG_MAX7219_NHORIZONTALBLKS 1
#endif
/* MAX7219_NVERTICALBLKS determines the number of physical 8x8 LEDs
* matrices that are used connected vertically.
*/
#ifndef CONFIG_MAX7219_NVERTICALBLKS
# define CONFIG_MAX7219_NVERTICALBLKS 1
#endif
#if CONFIG_LCD_MAXCONTRAST > 15
# undef CONFIG_LCD_MAXCONTRAST
# define CONFIG_LCD_MAXCONTRAST 15
#endif
/* Color Properties *********************************************************/
/* The MAX7219 chip can handle resolution of 8x8, 16x8, 8x16, 16x16, 24x8,
* etc.
*/
/* Display Resolution */
#define MAX7219_XRES (8 * CONFIG_MAX7219_NHORIZONTALBLKS)
#define MAX7219_YRES (8 * CONFIG_MAX7219_NVERTICALBLKS)
/* Color depth and format */
#define MAX7219_BPP 1
#define MAX7219_COLORFMT FB_FMT_Y1
/* Bytes per logical row and actual device row */
#define MAX7219_XSTRIDE (MAX7219_XRES >> 3) /* Pixels arrange "horizontally for user" */
#define MAX7219_YSTRIDE (MAX7219_YRES >> 3) /* Pixels arrange "vertically for user" */
/* The size of the shadow frame buffer */
#define MAX7219_FBSIZE (MAX7219_XRES * MAX7219_YSTRIDE) + 1
/* Bit helpers */
#define LS_BIT (1 << 0)
#define MS_BIT (1 << 7)
#define BIT(nr) (1 << (nr))
#define BITS_PER_BYTE 8
#define BIT_MASK(nr) (1 << ((nr) % BITS_PER_BYTE))
#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
/****************************************************************************
* Private Type Definition
****************************************************************************/
/* This structure describes the state of this driver */
struct max7219_dev_s
{
/* Publicly visible device structure */
struct lcd_dev_s dev;
/* Private LCD-specific information follows */
FAR struct spi_dev_s *spi;
uint8_t contrast;
uint8_t powered;
/* The MAX7219 does not support reading from the display memory in SPI
* mode. Since there is 1 BPP and access is byte-by-byte, it is necessary
* to keep a shadow copy of the framebuffer memory.
*/
uint8_t fb[MAX7219_FBSIZE];
};
/****************************************************************************
* Private Function Protototypes
****************************************************************************/
/* SPI helpers */
static void max7219_select(FAR struct spi_dev_s *spi);
static void max7219_deselect(FAR struct spi_dev_s *spi);
/* LCD Data Transfer Methods */
static int max7219_putrun(fb_coord_t row, fb_coord_t col,
FAR const uint8_t *buffer, size_t npixels);
static int max7219_getrun(fb_coord_t row, fb_coord_t col,
FAR uint8_t *buffer, size_t npixels);
/* LCD Configuration */
static int max7219_getvideoinfo(FAR struct lcd_dev_s *dev,
FAR struct fb_videoinfo_s *vinfo);
static int max7219_getplaneinfo(FAR struct lcd_dev_s *dev,
unsigned int planeno, FAR struct lcd_planeinfo_s *pinfo);
/* LCD RGB Mapping */
#ifdef CONFIG_FB_CMAP
# error "RGB color mapping not supported by this driver"
#endif
/* Cursor Controls */
#ifdef CONFIG_FB_HWCURSOR
# error "Cursor control not supported by this driver"
#endif
/* LCD Specific Controls */
static int max7219_getpower(FAR struct lcd_dev_s *dev);
static int max7219_setpower(FAR struct lcd_dev_s *dev, int power);
static int max7219_getcontrast(FAR struct lcd_dev_s *dev);
static int max7219_setcontrast(FAR struct lcd_dev_s *dev,
unsigned int contrast);
/* Initialization */
static inline void up_clear(FAR struct max7219_dev_s *priv);
/****************************************************************************
* Private Data
****************************************************************************/
/* This is working memory allocated by the LCD driver for each LCD device
* and for each color plane. This memory will hold one raster line of data.
* The size of the allocated run buffer must therefore be at least
* (bpp * xres / 8). Actual alignment of the buffer must conform to the
* bitwidth of the underlying pixel type.
*
* If there are multiple planes, they may share the same working buffer
* because different planes will not be operate on concurrently. However,
* if there are multiple LCD devices, they must each have unique run buffers.
*/
static uint8_t g_runbuffer[MAX7219_XSTRIDE + 1];
/* This structure describes the overall LCD video controller */
static const struct fb_videoinfo_s g_videoinfo =
{
MAX7219_COLORFMT, /* Color format: RGB16-565: RRRR RGGG GGGB BBBB */
MAX7219_XRES, /* Horizontal resolution in pixel columns */
MAX7219_YRES, /* Vertical resolution in pixel rows */
1, /* Number of color planes supported */
};
/* This is the standard, NuttX Plane information object */
static const struct lcd_planeinfo_s g_planeinfo =
{
.putrun = max7219_putrun, /* Put a run into LCD memory */
.getrun = max7219_getrun, /* Get a run from LCD memory */
.buffer = (FAR uint8_t *)g_runbuffer, /* Run scratch buffer */
.bpp = MAX7219_BPP, /* Bits-per-pixel */
};
/* This is the standard, NuttX LCD driver object */
static struct max7219_dev_s g_max7219dev =
{
/* struct lcd_dev_s */
{
/* LCD Configuration */
max7219_getvideoinfo,
max7219_getplaneinfo,
#ifdef CONFIG_FB_CMAP
/* LCD RGB Mapping -- Not supported */
NULL,
NULL,
#endif
#ifdef CONFIG_FB_HWCURSOR
/* Cursor Controls -- Not supported */
NULL,
NULL,
#endif
/* LCD Specific Controls */
max7219_getpower,
max7219_setpower,
max7219_getcontrast,
max7219_setcontrast,
},
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* __set_bit - Set a bit in memory
*
* nr - The bit to set
* addr - The address to start counting from
*
* Unlike set_bit(), this function is non-atomic and may be reordered.
* If it's called on the same region of memory simultaneously, the effect
* may be that only one operation succeeds.
*
****************************************************************************/
static inline void __set_bit(int nr, uint8_t * addr)
{
uint8_t mask = BIT_MASK(nr);
uint8_t *p = ((uint8_t *) addr) + BIT_BYTE(nr);
*p |= mask;
}
static inline void __clear_bit(int nr, uint8_t * addr)
{
uint8_t mask = BIT_MASK(nr);
uint8_t *p = ((uint8_t *) addr) + BIT_BYTE(nr);
*p &= ~mask;
}
static inline int __test_bit(int nr, const volatile uint8_t * addr)
{
return 1 & (addr[BIT_BYTE(nr)] >> (nr & (BITS_PER_BYTE - 1)));
}
/****************************************************************************
* Name: max7219_powerstring
*
* Description:
* Convert the power setting to a string.
*
****************************************************************************/
static inline FAR const char *max7219_powerstring(uint8_t power)
{
if (power == MAX7219_POWER_OFF)
{
return "OFF";
}
else if (power == MAX7219_POWER_ON)
{
return "ON";
}
else
{
return "ERROR";
}
}
/****************************************************************************
* Name: max7219_select
*
* Description:
* Select the SPI, locking and re-configuring if necessary
*
* Input Parameters:
* spi - Reference to the SPI driver structure
*
* Returned Value:
* None
*
****************************************************************************/
static void max7219_select(FAR struct spi_dev_s *spi)
{
/* Select MAX7219 chip (locking the SPI bus in case there are multiple
* devices competing for the SPI bus
*/
SPI_LOCK(spi, true);
SPI_SELECT(spi, SPIDEV_DISPLAY(0), true);
/* Now make sure that the SPI bus is configured for the MAX7219 (it
* might have gotten configured for a different device while unlocked)
*/
SPI_SETMODE(spi, SPIDEV_MODE0);
SPI_SETBITS(spi, 8);
SPI_HWFEATURES(spi, 0);
SPI_SETFREQUENCY(spi, CONFIG_MAX7219_FREQUENCY);
}
/****************************************************************************
* Name: max7219_deselect
*
* Description:
* De-select the SPI
*
* Input Parameters:
* spi - Reference to the SPI driver structure
*
* Returned Value:
* None
*
****************************************************************************/
static void max7219_deselect(FAR struct spi_dev_s *spi)
{
/* De-select MAX7219 chip and relinquish the SPI bus. */
SPI_SELECT(spi, SPIDEV_DISPLAY(0), false);
SPI_LOCK(spi, false);
}
/****************************************************************************
* Name: max7219_putrun
*
* Description:
* This method can be used to write a partial raster line to the LCD:
*
* row - Starting row to write to (range: 0 <= row < yres)
* col - Starting column to write to (range: 0 <= col <= xres-npixels)
* buffer - The buffer containing the run to be written to the LCD
* npixels - The number of pixels to write to the LCD
* (range: 0 < npixels <= xres-col)
*
****************************************************************************/
static int max7219_putrun(fb_coord_t row, fb_coord_t col,
FAR const uint8_t *buffer, size_t npixels)
{
/* Because of this line of code, we will only be able to support a single
* MAX7219 device .
*/
FAR struct max7219_dev_s *priv = &g_max7219dev;
FAR uint8_t *fbptr;
FAR uint8_t *ptr;
uint16_t data;
uint8_t usrmask;
int i;
int pixlen;
int newrow;
ginfo("row: %d col: %d npixels: %d\n", row, col, npixels);
DEBUGASSERT(buffer);
/* Clip the run to the display */
pixlen = npixels;
if ((unsigned int)col + (unsigned int)pixlen > (unsigned int)MAX7219_XRES)
{
pixlen = (int)MAX7219_XRES - (int)col;
}
/* Verify that some portion of the run remains on the display */
if (pixlen <= 0 || row > MAX7219_YRES)
{
return OK;
}
/* Get real row position in the strip */
newrow = (int) (row % 8);
/* Divide row by 8 */
row = (row >> 3);
col = col + (row * MAX7219_XRES);
row = newrow;
#ifdef CONFIG_LCD_PACKEDMSFIRST
usrmask = MS_BIT;
#else
usrmask = LS_BIT;
#endif
#ifdef CONFIG_LCD_PACKEDMSFIRST
usrmask = MS_BIT;
#else
usrmask = LS_BIT;
#endif
fbptr = &priv->fb[row * MAX7219_XSTRIDE * MAX7219_YSTRIDE];
ptr = fbptr + (col >> 3);
for (i = 0; i < pixlen; i++)
{
if ((*buffer & usrmask) != 0)
{
__set_bit(col % 8 + i, ptr);
}
else
{
__clear_bit(col % 8 + i, ptr);
}
#ifdef CONFIG_LCD_PACKEDMSFIRST
if (usrmask == LS_BIT)
{
buffer++;
usrmask = MS_BIT;
}
else
{
usrmask >>= 1;
}
#else
if (usrmask == MS_BIT)
{
buffer++;
usrmask = LS_BIT;
}
else
{
usrmask <<= 1;
}
#endif
}
/* Lock and select the device */
max7219_select(priv->spi);
/* We need to send last row/column first to avoid mirror image */
for (i = (MAX7219_XSTRIDE * MAX7219_YSTRIDE) - 1; i >= 0; i--)
{
/* Setup the row data */
data = (8 - row) | (*(fbptr + i) << 8);
/* Then transfer all 8 columns of data */
SPI_SNDBLOCK(priv->spi, &data, 2);
}
/* Unlock */
max7219_deselect(priv->spi);
return OK;
}
/****************************************************************************
* Name: max7219_getrun
*
* Description:
* This method can be used to read a partial raster line from the LCD:
*
* row - Starting row to read from (range: 0 <= row < yres)
* col - Starting column to read read (range: 0 <= col <= xres-npixels)
* buffer - The buffer in which to return the run read from the LCD
* npixels - The number of pixels to read from the LCD
* (range: 0 < npixels <= xres-col)
*
****************************************************************************/
static int max7219_getrun(fb_coord_t row, fb_coord_t col,
FAR uint8_t *buffer, size_t npixels)
{
/* Because of this line of code, we will only be able to support a single
* MAX7219 device.
*/
FAR struct max7219_dev_s *priv = &g_max7219dev;
FAR uint8_t *fbptr;
FAR uint8_t *ptr;
uint8_t usrmask;
int i;
int pixlen;
ginfo("row: %d col: %d npixels: %d\n", row, col, npixels);
DEBUGASSERT(buffer);
/* Clip the run to the display */
pixlen = npixels;
if ((unsigned int)col + (unsigned int)pixlen > (unsigned int)MAX7219_XRES)
{
pixlen = (int)MAX7219_XRES - (int)col;
}
/* Verify that some portion of the run is actually the display */
if (pixlen <= 0 || row > MAX7219_YRES)
{
return -EINVAL;
}
#ifdef CONFIG_LCD_PACKEDMSFIRST
usrmask = MS_BIT;
#else
usrmask = LS_BIT;
#endif
fbptr = &priv->fb[row * MAX7219_XSTRIDE];
ptr = fbptr + (col >> 3);
for (i = 0; i < pixlen; i++)
{
if (__test_bit(col % 8 + i, ptr))
{
*buffer |= usrmask;
}
else
{
*buffer &= ~usrmask;
}
#ifdef CONFIG_LCD_PACKEDMSFIRST
if (usrmask == LS_BIT)
{
buffer++;
usrmask = MS_BIT;
}
else
{
usrmask >>= 1;
}
#else
if (usrmask == MS_BIT)
{
buffer++;
usrmask = LS_BIT;
}
else
{
usrmask <<= 1;
}
#endif
}
return OK;
}
/****************************************************************************
* Name: max7219_getvideoinfo
*
* Description:
* Get information about the LCD video controller configuration.
*
****************************************************************************/
static int max7219_getvideoinfo(FAR struct lcd_dev_s *dev,
FAR struct fb_videoinfo_s *vinfo)
{
DEBUGASSERT(dev && vinfo);
ginfo("fmt: %d xres: %d yres: %d nplanes: %d\n",
g_videoinfo.fmt, g_videoinfo.xres, g_videoinfo.yres,
g_videoinfo.nplanes);
memcpy(vinfo, &g_videoinfo, sizeof(struct fb_videoinfo_s));
return OK;
}
/****************************************************************************
* Name: max7219_getplaneinfo
*
* Description:
* Get information about the configuration of each LCD color plane.
*
****************************************************************************/
static int max7219_getplaneinfo(FAR struct lcd_dev_s *dev,
unsigned int planeno,
FAR struct lcd_planeinfo_s *pinfo)
{
DEBUGASSERT(dev && pinfo && planeno == 0);
ginfo("planeno: %d bpp: %d\n", planeno, g_planeinfo.bpp);
memcpy(pinfo, &g_planeinfo, sizeof(struct lcd_planeinfo_s));
return OK;
}
/****************************************************************************
* Name: max7219_getpower
*
* Description:
* Get the LCD panel power status (0: full off - CONFIG_LCD_MAXPOWER: full
* on). On backlit LCDs, this setting may correspond to the backlight
* setting.
*
****************************************************************************/
static int max7219_getpower(struct lcd_dev_s *dev)
{
struct max7219_dev_s *priv = (struct max7219_dev_s *)dev;
DEBUGASSERT(priv);
ginfo("powered: %s\n", max7219_powerstring(priv->powered));
return priv->powered;
}
/****************************************************************************
* Name: max7219_setpower
*
* Description:
* Enable/disable LCD panel power (0: full off - CONFIG_LCD_MAXPOWER: full
* on). On backlit LCDs, this setting may correspond to the backlight
* setting.
*
****************************************************************************/
static int max7219_setpower(struct lcd_dev_s *dev, int power)
{
struct max7219_dev_s *priv = (struct max7219_dev_s *)dev;
uint16_t data;
DEBUGASSERT(priv && (unsigned)power <= CONFIG_LCD_MAXPOWER);
ginfo("power: %s powered: %s\n",
max7219_powerstring(power), max7219_powerstring(priv->powered));
/* Select and lock the device */
max7219_select(priv->spi);
if (power <= MAX7219_POWER_OFF)
{
data = (MAX7219_SHUTDOWN) | (MAX7219_POWER_OFF << 8);
/* Turn the display off (power-down) */
SPI_SNDBLOCK(priv->spi, &data, 2);
priv->powered = MAX7219_POWER_OFF;
}
else
{
data = (MAX7219_SHUTDOWN) | (MAX7219_POWER_ON << 8);
/* Leave the power-down */
SPI_SNDBLOCK(priv->spi, &data, 2);
priv->powered = MAX7219_POWER_ON;
}
/* Let go of the SPI lock and de-select the device */
max7219_deselect(priv->spi);
return OK;
}
/****************************************************************************
* Name: max7219_getcontrast
*
* Description:
* Get the current contrast setting (0-CONFIG_LCD_MAXCONTRAST).
*
****************************************************************************/
static int max7219_getcontrast(struct lcd_dev_s *dev)
{
struct max7219_dev_s *priv = (struct max7219_dev_s *)dev;
DEBUGASSERT(priv);
return (int)priv->contrast;
}
/****************************************************************************
* Name: max7219_setcontrast
*
* Description:
* Set LCD panel contrast (0-CONFIG_LCD_MAXCONTRAST).
*
****************************************************************************/
static int max7219_setcontrast(struct lcd_dev_s *dev, unsigned int contrast)
{
struct max7219_dev_s *priv = (struct max7219_dev_s *)dev;
uint16_t data;
ginfo("contrast: %d\n", contrast);
DEBUGASSERT(priv);
if (contrast > 15)
{
return -EINVAL;
}
/* Save the contrast */
priv->contrast = contrast;
/* Select and lock the device */
max7219_select(priv->spi);
/* Configure the contrast/intensity */
data = (MAX7219_INTENSITY) | (DISPLAY_INTENSITY(contrast) << 8);
/* Set the contrast */
SPI_SNDBLOCK(priv->spi, &data, 2);
/* Let go of the SPI lock and de-select the device */
max7219_deselect(priv->spi);
return OK;
}
/****************************************************************************
* Name: up_clear
*
* Description:
* Clear the display.
*
****************************************************************************/
static inline void up_clear(FAR struct max7219_dev_s *priv)
{
FAR struct spi_dev_s *spi = priv->spi;
uint16_t data;
int row;
int i;
/* Clear the framebuffer */
memset(priv->fb, MAX7219_BLACK, MAX7219_FBSIZE);
/* Go throw max7219 all 8 rows */
for (row = 0, i = 0; i < 8; i++)
{
/* Select and lock the device */
max7219_select(priv->spi);
/* Setup the row data */
data = (row + 1) | (priv->fb[row] << 8);
/* Then transfer all 8 columns of data */
SPI_SNDBLOCK(priv->spi, &data, 2);
/* Unlock and de-select the device */
max7219_deselect(spi);
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: max7219_initialize
*
* Description:
* Initialize the MAX7219 device as a LCD interface.
*
* Input Parameters:
* spi - An instance of the SPI interface to use to communicate
* with the MAX7219.
* devno - Device number to identify current display.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
FAR struct lcd_dev_s *max7219_initialize(FAR struct spi_dev_s *spi,
unsigned int devno)
{
/* Configure and enable LCD */
FAR struct max7219_dev_s *priv = &g_max7219dev;
uint16_t data;
ginfo("Initializing\n");
DEBUGASSERT(spi && devno == 0);
/* Save the reference to the SPI device */
priv->spi = spi;
/* Select and lock the device */
max7219_select(spi);
/* Leave the shutdown mode */
data = (MAX7219_SHUTDOWN) | (MAX7219_POWER_ON << 8);
SPI_SNDBLOCK(priv->spi, &data, 2);
max7219_deselect(spi);
max7219_select(spi);
/* Disable 7 segment decoding */
data = (MAX7219_DECODE_MODE) | (DISABLE_DECODE << 8);
SPI_SNDBLOCK(priv->spi, &data, 2);
max7219_deselect(spi);
max7219_select(spi);
/* Set scan limit for all digits */
data = (MAX7219_SCAN_LIMIT) | (DEFAULT_SCAN_LIMIT << 8);
SPI_SNDBLOCK(priv->spi, &data, 2);
max7219_deselect(spi);
max7219_select(spi);
/* Set intensity level configured by the user */
data = (MAX7219_INTENSITY) |
(DISPLAY_INTENSITY(CONFIG_LCD_MAXCONTRAST) << 8);
SPI_SNDBLOCK(priv->spi, &data, 2);
/* Let go of the SPI lock and de-select the device */
max7219_deselect(spi);
/* Clear the framebuffer */
up_clear(priv);
return &priv->dev;
}
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