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- /****************************************************************************
- * drivers/lcd/pcf8574_lcd_backpack.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 <poll.h>
- #include <string.h>
- #include <errno.h>
- #include <debug.h>
- #include <nuttx/kmalloc.h>
- #include <nuttx/signal.h>
- #include <nuttx/ascii.h>
- #include <nuttx/fs/fs.h>
- #include <nuttx/lcd/slcd_codec.h>
- #include <nuttx/lcd/pcf8574_lcd_backpack.h>
- #ifndef CONFIG_LIB_SLCDCODEC
- # error please also select Library Routines, Segment LCD CODEC
- #endif
- /****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
- /* The PCF8574 is a 100 KHz device */
- #define I2C_FREQ 100000
- /* timing characteristics of the LCD interface */
- #define DELAY_US_NYBBLE0 20
- #define DELAY_US_NYBBLE1 10
- #define DELAY_US_WRITE 40
- #define DELAY_US_HOMECLEAR 2000
- /* HD44780 commands */
- #define CMD_CLEAR 0x01
- #define CMD_HOME 0x02
- #define CMD_CURSOR_ON_SOLID 0x0e
- #define CMD_CURSOR_OFF 0x0c
- #define CMD_CURSOR_ON_BLINK 0x0f
- #define CMD_SET_CGADDR 0x40
- #define CMD_SET_DDADDR 0x80
- #define MAX_OPENCNT (255) /* Limit of uint8_t */
- /****************************************************************************
- * Private Types
- ****************************************************************************/
- struct pcf8574_lcd_dev_s
- {
- FAR struct i2c_master_s *i2c; /* I2C interface */
- struct pcf8574_lcd_backpack_config_s cfg; /* gpio configuration */
- uint8_t bl_bit; /* current backlight bit */
- uint8_t refs; /* Number of references */
- uint8_t unlinked; /* We are unlinked, so teardown
- * on last close */
- sem_t sem_excl; /* mutex */
- };
- struct lcd_instream_s
- {
- struct lib_instream_s stream;
- FAR const char *buffer;
- ssize_t nbytes;
- };
- /****************************************************************************
- * Private Function Prototypes
- ****************************************************************************/
- /* Character driver methods */
- static int pcf8574_lcd_open(FAR struct file *filep);
- static int pcf8574_lcd_close(FAR struct file *filep);
- static ssize_t pcf8574_lcd_read(FAR struct file *filep, FAR char *buffer,
- size_t buflen);
- static ssize_t pcf8574_lcd_write(FAR struct file *filep,
- FAR const char *buffer, size_t buflen);
- static off_t pcf8574_lcd_seek(FAR struct file *filep, off_t offset,
- int whence);
- static int pcf8574_lcd_ioctl(FAR struct file *filep, int cmd,
- unsigned long arg);
- static int pcf8574lcd_poll(FAR struct file *filep, FAR struct pollfd *fds,
- bool setup);
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- static int pcf8574_lcd_unlink(FAR struct inode *inode);
- #endif
- /****************************************************************************
- * Private Data
- ****************************************************************************/
- static const struct file_operations g_pcf8574_lcd_fops =
- {
- pcf8574_lcd_open, /* open */
- pcf8574_lcd_close, /* close */
- pcf8574_lcd_read, /* read */
- pcf8574_lcd_write, /* write */
- pcf8574_lcd_seek, /* seek */
- pcf8574_lcd_ioctl, /* ioctl */
- pcf8574lcd_poll, /* poll */
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- pcf8574_lcd_unlink /* unlink */
- #endif
- };
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: pca8574_write
- *
- * Description:
- * primitive I2C write operation for the PCA8574, which is the IO expander
- * device used on the board. The board essentially byte-bangs the
- * parallel interface in nybble mode much as one might with a conventional
- * GPIO based interface. The I2C interface simply sets the state of the
- * 8 IO lines to control the 4 data, 3 control, and one for backlight,
- * signals.
- *
- ****************************************************************************/
- static void pca8574_write(FAR struct pcf8574_lcd_dev_s *priv, uint8_t data)
- {
- struct i2c_config_s config;
- int ret;
- /* Set up the I2C configuration */
- config.frequency = I2C_FREQ;
- config.address = priv->cfg.addr;
- config.addrlen = 7;
- /* Write the value */
- ret = i2c_write(priv->i2c, &config, &data, 1);
- if (ret < 0)
- {
- lcdinfo("pca8574_write() failed: %d\n", ret);
- return;
- }
- return;
- }
- /****************************************************************************
- * Name: pca8574_read
- *
- * Description:
- * primitive I2C read operation for the PCA8574, which is the IO expander
- * device used on the board. The PCF8574 is 'interesting' in that it
- * doesn't really have a data direction register, but instead the outputs
- * are current-limited when high, so by setting an IO line high, you are
- * also making it an input. Consequently, before using this method, you'll
- * need to perform a pca8574_write() setting the bits you are interested in
- * reading to 1's, then call this method.
- *
- ****************************************************************************/
- static int pca8574_read(FAR struct pcf8574_lcd_dev_s *priv, uint8_t *data)
- {
- struct i2c_config_s config;
- int ret;
- /* Set up the I2C configuration */
- config.frequency = I2C_FREQ;
- config.address = priv->cfg.addr;
- config.addrlen = 7;
- /* Read the value */
- ret = i2c_read(priv->i2c, &config, data, 1);
- if (ret < 0)
- {
- lcdinfo("pca8574_read() failed: %d\n", ret);
- }
- return ret;
- }
- /****************************************************************************
- * Name: lcd_backlight
- *
- * Description:
- * turn on, or off, the LCD backlight
- *
- ****************************************************************************/
- static void lcd_backlight(FAR struct pcf8574_lcd_dev_s *priv, bool blon)
- {
- uint8_t data;
- data = ((blon && priv->cfg.bl_active_high) ||
- (!blon && !priv->cfg.bl_active_high)) ? (1 << priv->cfg.bl) : 0;
- pca8574_write(priv, data);
- priv->bl_bit = data;
- }
- /****************************************************************************
- * Name: rc2addr
- *
- * Description:
- * This converts a row/column pair to a screen memory address.
- *
- ****************************************************************************/
- static inline uint8_t rc2addr(FAR struct pcf8574_lcd_dev_s *priv,
- uint8_t row, uint8_t col)
- {
- if (row < 2)
- {
- /* 1 and 2 line displays are simple; line0 @ 0x00, line1 @ 0x40 */
- return row * 0x40 + col;
- }
- else
- {
- /* 4 line displays are interesting; third line really is a continuation
- * of first line, and fourth line is a continuation of second.
- */
- return (row - 2) * 0x40 + (col + priv->cfg.cols);
- }
- }
- /****************************************************************************
- * Name: addr2rc
- *
- * Description:
- * This converts a screen memory address to a row/column pair.
- *
- ****************************************************************************/
- static inline void addr2rc(FAR struct pcf8574_lcd_dev_s *priv, uint8_t addr,
- FAR uint8_t *row, FAR uint8_t *col)
- {
- *row = addr / 0x40;
- *col = addr % 0x40;
- if (*col >= priv->cfg.cols)
- {
- /* 4 line displays have third and fourth lines really as continuation
- * of the first and second.
- */
- *row += 2;
- *col -= priv->cfg.cols;
- }
- }
- /****************************************************************************
- * Name: prepare_nybble
- *
- * Description:
- * This is a bit tedious, but scramble the bits of the nybble into position
- * as per this board's particular wiring. Most boards are either on the
- * top four bits, or bottom four, so a shift would do typically in those
- * cases, but this gives us ultimate flexibility.
- *
- ****************************************************************************/
- uint8_t prepare_nybble(FAR struct pcf8574_lcd_dev_s *priv, uint8_t nybble)
- {
- uint8_t lcddata = 0;
- if (nybble & 0x08)
- {
- lcddata |= (1 << priv->cfg.d7);
- }
- if (nybble & 0x04)
- {
- lcddata |= (1 << priv->cfg.d6);
- }
- if (nybble & 0x02)
- {
- lcddata |= (1 << priv->cfg.d5);
- }
- if (nybble & 0x01)
- {
- lcddata |= (1 << priv->cfg.d4);
- }
- return lcddata;
- }
- /****************************************************************************
- * Name: unprepare_nybble
- *
- * Description:
- * This is the opposite of prepare_nybble(), and is used to unscramble bits
- * when reading data from the display, as per board wiring.
- *
- ****************************************************************************/
- uint8_t unprepare_nybble(FAR struct pcf8574_lcd_dev_s *priv, uint8_t lcddata)
- {
- uint8_t data = 0;
- if (lcddata & (1 << priv->cfg.d7))
- {
- data |= 0x08;
- }
- if (lcddata & (1 << priv->cfg.d6))
- {
- data |= 0x04;
- }
- if (lcddata & (1 << priv->cfg.d5))
- {
- data |= 0x02;
- }
- if (lcddata & (1 << priv->cfg.d4))
- {
- data |= 0x01;
- }
- return data;
- }
- /****************************************************************************
- * Name: latch_nybble
- *
- * Description:
- * Latch a nybble on the LCD bus. This is done for each of two halves of a
- * write operation in 4-bit mode. The 'rs' param is false for command
- * transfers, and true for data transfers.
- *
- ****************************************************************************/
- static void latch_nybble(FAR struct pcf8574_lcd_dev_s *priv, uint8_t nybble,
- bool rs)
- {
- uint8_t lcddata;
- uint8_t en_bit;
- uint8_t rs_bit;
- en_bit = 1 << priv->cfg.en;
- rs_bit = rs ? (1 << priv->cfg.rs) : 0;
- /* Put the nybble, preserving backlight, reset R/~W and maybe RS */
- lcddata = prepare_nybble(priv, nybble) | priv->bl_bit | rs_bit;
- pca8574_write(priv, lcddata);
- /* Now set EN */
- lcddata |= en_bit;
- pca8574_write(priv, lcddata);
- up_udelay(DELAY_US_NYBBLE0); /* setup */
- /* Latch on EN falling edge */
- lcddata &= ~en_bit;
- pca8574_write(priv, lcddata);
- up_udelay(DELAY_US_NYBBLE1); /* hold */
- }
- /****************************************************************************
- * Name: load_nybble
- *
- * Description:
- * Load a nybble from the LCD bus. This is done for each of two halves of a
- * read operation in 4-bit mode. The 'rs' param is false for command
- * transfers (the only one is to read status and the address register), and
- * true for data transfers.
- *
- ****************************************************************************/
- static uint8_t load_nybble(FAR struct pcf8574_lcd_dev_s *priv, bool rs)
- {
- uint8_t lcddata;
- uint8_t en_bit;
- uint8_t rs_bit;
- uint8_t rw_bit;
- uint8_t data;
- en_bit = 1 << priv->cfg.en;
- rs_bit = rs ? (1 << priv->cfg.rs) : 0;
- rw_bit = 1 << priv->cfg.rw;
- /* Put highs on the data lines, preserve, set R/~W and maybe RS */
- lcddata = prepare_nybble(priv, 0x0f) | priv->bl_bit | rw_bit | rs_bit;
- pca8574_write(priv, lcddata);
- /* Now set EN */
- lcddata |= en_bit;
- pca8574_write(priv, lcddata);
- up_udelay(DELAY_US_NYBBLE0); /* setup */
- /* Now read the data */
- pca8574_read(priv, &data);
- data = unprepare_nybble(priv, data);
- /* Transaction completed on EN falling edge */
- lcddata &= ~en_bit;
- pca8574_write(priv, lcddata);
- up_udelay(DELAY_US_NYBBLE1); /* hold */
- return data;
- }
- /****************************************************************************
- * Name: lcd_putcmd
- *
- * Description:
- * Write a command to the LCD. Most of the time this is done in nybble
- * mode in two phases, but in special cases (like initialization) we do not
- * do two phases.
- *
- ****************************************************************************/
- static void lcd_putcmd(FAR struct pcf8574_lcd_dev_s *priv, uint8_t data)
- {
- latch_nybble(priv, data >> 4, false);
- latch_nybble(priv, data, false);
- up_udelay(DELAY_US_WRITE);
- }
- /****************************************************************************
- * Name: lcd_putdata
- *
- * Description:
- * Write a byte to the LCD. This is used both for screen data and for
- * character generator data, depending on a previous command that selected
- * which ever is the destination.
- *
- ****************************************************************************/
- static inline void lcd_putdata(FAR struct pcf8574_lcd_dev_s *priv,
- uint8_t data)
- {
- latch_nybble(priv, data >> 4, true);
- latch_nybble(priv, data, true);
- up_udelay(DELAY_US_WRITE);
- }
- /****************************************************************************
- * Name: lcd_getdata
- *
- * Description:
- * Read a data byte from the LCD.
- *
- ****************************************************************************/
- static inline uint8_t lcd_getdata(FAR struct pcf8574_lcd_dev_s *priv)
- {
- uint8_t data;
- data = (load_nybble(priv, true) << 4) | load_nybble(priv, true);
- return data;
- }
- /****************************************************************************
- * Name: lcd_getcmd
- *
- * Description:
- * Read a command byte from the LCD. There really is only one such read:
- * get 'busy' status, and current address value.
- *
- ****************************************************************************/
- static inline uint8_t lcd_getcmd(FAR struct pcf8574_lcd_dev_s *priv)
- {
- uint8_t data;
- data = (load_nybble(priv, false) << 4) | load_nybble(priv, false);
- return data;
- }
- /****************************************************************************
- * Name: lcd_read_busy_addr
- *
- * Description:
- * Read the busy flag, and, optionally, the current value of the address
- * register (data or character generator dependent on a previous command).
- *
- ****************************************************************************/
- static bool lcd_read_busy_addr(FAR struct pcf8574_lcd_dev_s *priv,
- FAR uint8_t *addr)
- {
- uint8_t data = lcd_getcmd(priv);
- if (NULL != addr)
- {
- *addr = data & 0x7f;
- }
- return (data & 0x80) ? true : false;
- }
- /****************************************************************************
- * Name: lcd_init
- *
- * Description:
- * perform the initialization sequence to get the LCD into a known state.
- *
- ****************************************************************************/
- static void lcd_init(FAR struct pcf8574_lcd_dev_s *priv)
- {
- /* Wait for more than 15 ms after Vcc for the LCD to stabilize */
- nxsig_usleep(50000);
- /* Perform the init sequence. This sequence of commands is constructed so
- * that it will get the device into nybble mode irrespective of what state
- * the device is currently in (could be 8 bit, 4 bit nyb 0, 4 bit nyb 1).
- * By sending the 'set 8-bit mode' three times, we will definitely end up
- * in 8 bit mode, and then we can reliably transition to 4 bit mode for
- * the remainder of operations.
- */
- /* Send Command 0x30, set 8-bit mode, and wait > 4.1 ms */
- latch_nybble(priv, 0x30 >> 4, false);
- nxsig_usleep(5000);
- /* Send Command 0x30, set 8-bit mode, and wait > 100 us */
- latch_nybble(priv, 0x30 >> 4, false);
- nxsig_usleep(5000);
- /* Send Command 0x30, set 8-bit mode */
- latch_nybble(priv, 0x30 >> 4, false);
- nxsig_usleep(200);
- /* now Function set: Set interface to be 4 bits long (only 1 cycle write
- * for the first time).
- */
- latch_nybble(priv, 0x20 >> 4, false);
- nxsig_usleep(5000);
- /* Function set: DL=0;Interface is 4 bits, N=1 (2 Lines), F=0 (5x8 dots
- * font)
- */
- lcd_putcmd(priv, 0x28);
- /* Display Off: D=0 (Display off), C=0 (Cursor Off), B=0 (Blinking Off) */
- lcd_putcmd(priv, 0x08);
- /* Display Clear */
- lcd_putcmd(priv, CMD_CLEAR);
- up_udelay(DELAY_US_HOMECLEAR); /* clear needs extra time */
- /* Entry Mode Set: I/D=1 (Increment), S=0 (No shift) */
- lcd_putcmd(priv, 0x06);
- /* Display On, Cursor Off */
- lcd_putcmd(priv, 0x0c);
- }
- /****************************************************************************
- * Name: lcd_create_char
- *
- * Description:
- * This creates a custom character pattern. There can be 8 5x8 patterns.
- * The bitmap proceeds top to bottom, msb-lsb, and is right justified (i.e.
- * only bits 4-0 are used). By convention, you are meant to always leave
- * the last line (byte) zero so that the cursor can use this line, but this
- * is not strictly required.
- *
- * Input Parameters:
- * priv - device instance
- * idxchar - which character is being imaged; 0 - 7
- * chardata - the character image bitmap; must be 8 bytes always
- *
- ****************************************************************************/
- static void lcd_create_char(FAR struct pcf8574_lcd_dev_s *priv,
- uint8_t idxchar, FAR const uint8_t *chardata)
- {
- int nidx;
- uint8_t addr;
- lcd_read_busy_addr(priv, &addr);
- lcd_putcmd(priv, CMD_SET_CGADDR | (idxchar << 3)); /* set CGRAM address */
- for (nidx = 0; nidx < 8; ++nidx)
- {
- lcd_putdata(priv, chardata[nidx]);
- }
- lcd_putcmd(priv, CMD_SET_DDADDR | addr); /* restore DDRAM address */
- }
- /****************************************************************************
- * Name: lcd_set_curpos
- *
- * Description:
- * This sets the cursor position based on row, column addressing.
- *
- * Input Parameters:
- * priv - device instance
- * row - row position
- * col - column position
- *
- ****************************************************************************/
- static void lcd_set_curpos(FAR struct pcf8574_lcd_dev_s *priv,
- uint8_t row, uint8_t col)
- {
- uint8_t addr;
- addr = rc2addr(priv, row, col);
- lcd_putcmd(priv, CMD_SET_DDADDR | addr); /* set DDRAM address */
- }
- /****************************************************************************
- * Name: lcd_get_curpos
- *
- * Description:
- * This gets the cursor position based on row, column addressing.
- *
- * Input Parameters:
- * priv - device instance
- * row - row position
- * col - column position
- *
- ****************************************************************************/
- static void lcd_get_curpos(FAR struct pcf8574_lcd_dev_s *priv,
- FAR uint8_t *row, FAR uint8_t *col)
- {
- uint8_t addr;
- lcd_read_busy_addr(priv, &addr);
- addr2rc(priv, addr, row, col);
- }
- /****************************************************************************
- * Name: lcd_scroll_up
- *
- * Description:
- * Scroll the display up, and clear the new (last) line.
- *
- ****************************************************************************/
- static void lcd_scroll_up(FAR struct pcf8574_lcd_dev_s *priv)
- {
- FAR uint8_t *data;
- int nrow;
- int ncol;
- data = (FAR uint8_t *)kmm_malloc(priv->cfg.cols);
- if (NULL == data)
- {
- lcdinfo("Failed to allocate buffer in lcd_scroll_up()\n");
- return;
- }
- for (nrow = 1; nrow < priv->cfg.rows; ++nrow)
- {
- lcd_set_curpos(priv, nrow, 0);
- for (ncol = 0; ncol < priv->cfg.cols; ++ncol)
- {
- data[ncol] = lcd_getdata(priv);
- }
- lcd_set_curpos(priv, nrow - 1, 0);
- for (ncol = 0; ncol < priv->cfg.cols; ++ncol)
- {
- lcd_putdata(priv, data[ncol]);
- }
- }
- lcd_set_curpos(priv, priv->cfg.rows - 1, 0);
- for (ncol = 0; ncol < priv->cfg.cols; ++ncol)
- {
- lcd_putdata(priv, ' ');
- }
- lcd_set_curpos(priv, priv->cfg.rows - 1, 0);
- kmm_free(data);
- return;
- }
- /****************************************************************************
- * Name: lcd_codec_action
- *
- * Description:
- * Perform an 'action' as per the Segment LCD codec.
- *
- * Input Parameters:
- * priv - device instance
- * code - SLCD code action code
- * count - count param for those actions that take it
- *
- ****************************************************************************/
- static void lcd_codec_action(FAR struct pcf8574_lcd_dev_s *priv,
- enum slcdcode_e code, uint8_t count)
- {
- switch (code)
- {
- /* Erasure */
- case SLCDCODE_BACKDEL: /* Backspace (backward delete) N characters */
- {
- if (count <= 0) /* silly case */
- {
- break;
- }
- else
- {
- uint8_t row;
- uint8_t col;
- lcd_get_curpos(priv, &row, &col);
- if (count > col) /* saturate to preceding columns available */
- {
- count = col;
- }
- lcd_set_curpos(priv, row, col - count);
- }
- /* ... and conscientiously fall through to next case ... */
- }
- case SLCDCODE_FWDDEL: /* Delete (forward delete) N characters, moving text */
- {
- if (count <= 0) /* silly case */
- {
- break;
- }
- else
- {
- uint8_t row;
- uint8_t col;
- uint8_t start;
- uint8_t end;
- uint8_t nidx;
- uint8_t data;
- lcd_get_curpos(priv, &row, &col);
- start = col + count;
- if (start >= priv->cfg.cols) /* silly case of nothing left */
- {
- break;
- }
- end = start + count;
- if (end > priv->cfg.cols) /* saturate */
- {
- end = priv->cfg.cols;
- }
- for (nidx = col; nidx < end; ++start, ++nidx) /* much like memmove */
- {
- lcd_set_curpos(priv, row, start);
- data = lcd_getdata(priv);
- lcd_set_curpos(priv, row, nidx);
- lcd_putdata(priv, data);
- }
- for (; nidx < priv->cfg.cols; ++nidx) /* much like memset */
- {
- lcd_putdata(priv, ' ');
- }
- lcd_set_curpos(priv, row, col);
- }
- }
- break;
- case SLCDCODE_ERASE: /* Erase N characters from the cursor position */
- if (count > 0)
- {
- uint8_t row;
- uint8_t col;
- uint8_t end;
- uint8_t nidx;
- lcd_get_curpos(priv, &row, &col);
- end = col + count;
- if (end > priv->cfg.cols)
- {
- end = priv->cfg.cols;
- }
- for (nidx = col; nidx < end; ++nidx)
- {
- lcd_putdata(priv, ' ');
- }
- lcd_set_curpos(priv, row, col);
- }
- break;
- case SLCDCODE_CLEAR: /* Home the cursor and erase the entire display */
- {
- lcd_putcmd(priv, CMD_CLEAR);
- up_udelay(DELAY_US_HOMECLEAR); /* clear needs extra time */
- }
- break;
- case SLCDCODE_ERASEEOL: /* Erase from the cursor position to the end of
- * line */
- {
- uint8_t row;
- uint8_t col;
- uint8_t nidx;
- lcd_get_curpos(priv, &row, &col);
- for (nidx = col; nidx < priv->cfg.cols; ++nidx)
- {
- lcd_putdata(priv, ' ');
- }
- lcd_set_curpos(priv, row, col);
- }
- break;
- /* Cursor movement */
- case SLCDCODE_LEFT: /* Cursor left by N characters */
- {
- uint8_t row;
- uint8_t col;
- lcd_get_curpos(priv, &row, &col);
- if (count > col)
- {
- col = 0;
- }
- else
- {
- col -= count;
- }
- lcd_set_curpos(priv, row, col);
- }
- break;
- case SLCDCODE_RIGHT: /* Cursor right by N characters */
- {
- uint8_t row;
- uint8_t col;
- lcd_get_curpos(priv, &row, &col);
- col += count;
- if (col >= priv->cfg.cols)
- {
- col = priv->cfg.cols - 1;
- }
- lcd_set_curpos(priv, row, col);
- }
- break;
- case SLCDCODE_UP: /* Cursor up by N lines */
- {
- uint8_t row;
- uint8_t col;
- lcd_get_curpos(priv, &row, &col);
- if (count > row)
- {
- row = 0;
- }
- else
- {
- row -= count;
- }
- lcd_set_curpos(priv, row, col);
- }
- break;
- case SLCDCODE_DOWN: /* Cursor down by N lines */
- {
- uint8_t row;
- uint8_t col;
- lcd_get_curpos(priv, &row, &col);
- row += count;
- if (row >= priv->cfg.rows)
- {
- row = priv->cfg.rows - 1;
- }
- lcd_set_curpos(priv, row, col);
- }
- break;
- case SLCDCODE_HOME: /* Cursor home */
- {
- uint8_t row;
- uint8_t col;
- lcd_get_curpos(priv, &row, &col);
- lcd_set_curpos(priv, row, 0);
- }
- break;
- case SLCDCODE_END: /* Cursor end */
- {
- uint8_t row;
- uint8_t col;
- lcd_get_curpos(priv, &row, &col);
- lcd_set_curpos(priv, row, priv->cfg.cols - 1);
- }
- break;
- case SLCDCODE_PAGEUP: /* Cursor up by N pages */
- case SLCDCODE_PAGEDOWN: /* Cursor down by N pages */
- break; /* Not supportable on this SLCD */
- /* Blinking */
- case SLCDCODE_BLINKSTART: /* Start blinking with current cursor position */
- lcd_putcmd(priv, CMD_CURSOR_ON_BLINK);
- break;
- case SLCDCODE_BLINKEND: /* End blinking after the current cursor
- * position */
- case SLCDCODE_BLINKOFF: /* Turn blinking off */
- lcd_putcmd(priv, CMD_CURSOR_OFF);
- break; /* Not implemented */
- /* These are actually unreportable errors */
- default:
- case SLCDCODE_NORMAL: /* Not a special keycode */
- break;
- }
- }
- /****************************************************************************
- * Name: lcd_getstream
- *
- * Description:
- * Get one character from the LCD codec stream.
- *
- ****************************************************************************/
- static int lcd_getstream(FAR struct lib_instream_s *instream)
- {
- FAR struct lcd_instream_s *lcdstream =
- (FAR struct lcd_instream_s *)instream;
- if (lcdstream->nbytes > 0)
- {
- lcdstream->nbytes--;
- lcdstream->stream.nget++;
- return (int)*lcdstream->buffer++;
- }
- return EOF;
- }
- /****************************************************************************
- * Name: lcd_fpos_to_curpos
- *
- * Description:
- * Convert a file logical offset to a screen cursor pos (row,col). This
- * discounts 'synthesized' line feeds at the end of screen lines.
- *
- ****************************************************************************/
- static void lcd_fpos_to_curpos(FAR struct pcf8574_lcd_dev_s *priv,
- off_t fpos, FAR uint8_t *row,
- FAR uint8_t *col, FAR bool *onlf)
- {
- int virtcols;
- virtcols = (priv->cfg.cols + 1);
- /* Determine if this is a 'virtual' position (on the synthetic LF) */
- *onlf = (priv->cfg.cols == fpos % virtcols);
- /* Adjust off any preceding synthetic LF's to get linear position */
- fpos -= fpos / virtcols;
- /* Compute row/col from linear position */
- *row = fpos / priv->cfg.cols;
- *col = fpos % priv->cfg.cols;
- }
- /****************************************************************************
- * Name: lcd_curpos_to_fpos
- *
- * Description:
- * Convert a screen cursor pos (row,col) to a file logical offset. This
- * includes 'synthesized' line feeds at the end of screen lines.
- *
- ****************************************************************************/
- static void lcd_curpos_to_fpos(FAR struct pcf8574_lcd_dev_s *priv,
- uint8_t row, uint8_t col, FAR off_t *fpos)
- {
- /* the logical file position is the linear position plus any synthetic LF */
- *fpos = (row * priv->cfg.cols) + col + row;
- }
- /****************************************************************************
- * Name: pcf8574_lcd_open
- *
- * Description:
- * requisite device 'open' method; we don't do anything special
- *
- ****************************************************************************/
- static int pcf8574_lcd_open(FAR struct file *filep)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- /* Increment the reference count */
- nxsem_wait(&priv->sem_excl);
- if (priv->refs == MAX_OPENCNT)
- {
- return -EMFILE;
- }
- else
- {
- priv->refs++;
- }
- nxsem_post(&priv->sem_excl);
- return OK;
- }
- /****************************************************************************
- * Name: pcf8574_lcd_close
- *
- * Description:
- * requisite device 'close' method; we don't do anything special
- *
- ****************************************************************************/
- static int pcf8574_lcd_close(FAR struct file *filep)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- int ret;
- /* Decrement the reference count */
- nxsem_wait(&priv->sem_excl);
- if (priv->refs == 0)
- {
- ret = -EIO;
- }
- else
- {
- priv->refs--;
- /* If we had previously unlinked, but there were open references at
- * the time, we need to do the final teardown now.
- */
- if (priv->refs == 0 && priv->unlinked)
- {
- /* We have no real teardown at present */
- }
- ret = OK;
- }
- nxsem_post(&priv->sem_excl);
- return ret;
- }
- /****************************************************************************
- * Name: pcf8574_lcd_read
- *
- * Description:
- * This simply reads as much of the display memory as possible. This is
- * generally not very interesting, but we do it in a way that allows us to
- * 'cat' the LCD contents via the shell.
- *
- ****************************************************************************/
- static ssize_t pcf8574_lcd_read(FAR struct file *filep, FAR char *buffer,
- size_t buflen)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- int nidx;
- uint8_t addr;
- uint8_t row;
- uint8_t col;
- bool onlf;
- nxsem_wait(&priv->sem_excl);
- /* Get current cursor position so we can restore it */
- lcd_read_busy_addr(priv, &addr);
- /* Convert file position to row/col address and position DDADDR there */
- lcd_fpos_to_curpos(priv, filep->f_pos, &row, &col, &onlf);
- lcd_set_curpos(priv, row, col);
- /* Read as much of the display as possible */
- nidx = 0;
- while (nidx < buflen && row < priv->cfg.rows)
- {
- /* Synthesize end-of-line LF and advance to start of next row */
- if (onlf)
- {
- /* Synthesize LF for all but last row */
- if (row < priv->cfg.rows - 1)
- {
- buffer[nidx] = '\x0a';
- onlf = false;
- ++filep->f_pos;
- ++nidx;
- }
- ++row;
- col = 0;
- continue;
- }
- /* If we are at start of line we will need to update DDRAM address */
- if (0 == col)
- {
- lcd_set_curpos(priv, row, 0);
- }
- buffer[nidx] = lcd_getdata(priv);
- ++filep->f_pos;
- ++nidx;
- ++col;
- /* If we are now at the end of a line, we setup for the synthetic LF */
- if (priv->cfg.cols == col)
- {
- onlf = true;
- }
- }
- lcd_putcmd(priv, CMD_SET_DDADDR | addr); /* Restore DDRAM address */
- nxsem_post(&priv->sem_excl);
- return nidx;
- }
- /****************************************************************************
- * Name: pcf8574_lcd_write
- *
- * Description:
- * Output a sequence of characters to the device.
- *
- ****************************************************************************/
- static ssize_t pcf8574_lcd_write(FAR struct file *filep,
- FAR const char *buffer, size_t buflen)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- struct lcd_instream_s instream;
- uint8_t row;
- uint8_t col;
- struct slcdstate_s state;
- enum slcdret_e result;
- uint8_t ch;
- uint8_t count;
- nxsem_wait(&priv->sem_excl);
- /* Initialize the stream for use with the SLCD CODEC */
- instream.stream.get = lcd_getstream;
- instream.stream.nget = 0;
- instream.buffer = buffer;
- instream.nbytes = buflen;
- /* Get the current cursor position now; we'll keep track of it as we go */
- lcd_get_curpos(priv, &row, &col);
- /* Now decode and process every byte in the input buffer */
- memset(&state, 0, sizeof(struct slcdstate_s));
- while ((result =
- slcd_decode(&instream.stream, &state, &ch, &count)) != SLCDRET_EOF)
- {
- if (result == SLCDRET_CHAR) /* A normal character was returned */
- {
- /* Check for ASCII control characters */
- if (ch == ASCII_TAB)
- {
- lcd_putcmd(priv, CMD_CURSOR_ON_BLINK);
- }
- else if (ch == ASCII_VT)
- {
- /* Turn the backlight on */
- lcd_backlight(priv, true);
- }
- else if (ch == ASCII_FF)
- {
- /* Turn the backlight off */
- lcd_backlight(priv, false);
- }
- else if (ch == ASCII_CR)
- {
- /* Perform a Home */
- lcd_putcmd(priv, CMD_HOME);
- up_udelay(DELAY_US_HOMECLEAR); /* home needs extra time */
- row = 0;
- col = 0;
- }
- else if (ch == ASCII_SO)
- {
- lcd_putcmd(priv, CMD_CURSOR_OFF);
- }
- else if (ch == ASCII_SI)
- {
- /* Perform the re-initialize */
- lcd_init(priv);
- row = 0;
- col = 0;
- }
- else if (ch == ASCII_LF)
- {
- /* unixian line term; go to start of next line */
- row += 1;
- if (row >= priv->cfg.rows)
- {
- lcd_scroll_up(priv);
- row = priv->cfg.rows - 1;
- }
- col = 0;
- lcd_set_curpos(priv, row, col);
- }
- else if (ch == ASCII_BS)
- {
- /* Perform the backward deletion */
- lcd_codec_action(priv, SLCDCODE_BACKDEL, 1);
- lcd_get_curpos(priv, &row, &col);
- }
- else if (ch == ASCII_DEL)
- {
- /* Perform the forward deletion */
- lcd_codec_action(priv, SLCDCODE_FWDDEL, 1);
- lcd_get_curpos(priv, &row, &col);
- }
- else
- {
- /* All others are fair game. See if we need to wrap line. */
- if (col >= priv->cfg.cols)
- {
- row += 1;
- if (row >= priv->cfg.rows)
- {
- lcd_scroll_up(priv);
- row = priv->cfg.rows - 1;
- }
- col = 0;
- lcd_set_curpos(priv, row, col);
- }
- lcd_putdata(priv, ch);
- ++col;
- }
- }
- /* A special SLCD action was returned */
- else /* (result == SLCDRET_SPEC) */
- {
- lcd_codec_action(priv, (enum slcdcode_e)ch, count);
- /* we can't know what happened, so it's easier just to re-inquire
- * as to where we are.
- */
- lcd_get_curpos(priv, &row, &col);
- }
- }
- /* Wherever we wound up, update our logical file pos to reflect it */
- lcd_curpos_to_fpos(priv, row, col, &filep->f_pos);
- nxsem_post(&priv->sem_excl);
- return buflen;
- }
- /****************************************************************************
- * Name: pcf8574_lcd_seek
- *
- * Description:
- * Seek the logical file pointer to the specified position. This is
- * probably not very interesting except possibly for (SEEK_SET, 0) to
- * rewind the pointer for a subsequent read().
- * The file pointer is logical, and includes synthesized LF chars at the
- * end of the display lines.
- *
- ****************************************************************************/
- static off_t pcf8574_lcd_seek(FAR struct file *filep, off_t offset,
- int whence)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- off_t pos;
- int maxpos;
- nxsem_wait(&priv->sem_excl);
- maxpos = priv->cfg.rows * priv->cfg.cols + (priv->cfg.rows - 1);
- pos = filep->f_pos;
- switch (whence)
- {
- case SEEK_CUR:
- pos += offset;
- if (pos > maxpos)
- {
- pos = maxpos;
- }
- else if (pos < 0)
- {
- pos = 0;
- }
- filep->f_pos = pos;
- break;
- case SEEK_SET:
- pos = offset;
- if (pos > maxpos)
- {
- pos = maxpos;
- }
- else if (pos < 0)
- {
- pos = 0;
- }
- filep->f_pos = pos;
- break;
- case SEEK_END:
- pos = maxpos + offset;
- if (pos > maxpos)
- {
- pos = maxpos;
- }
- else if (pos < 0)
- {
- pos = 0;
- }
- filep->f_pos = pos;
- break;
- default:
- /* Return EINVAL if the whence argument is invalid */
- pos = (off_t) - EINVAL;
- break;
- }
- nxsem_post(&priv->sem_excl);
- return pos;
- }
- /****************************************************************************
- * Name: pcf8574_lcd_ioctl
- *
- * Description:
- * Perform device operations that are outside the standard I/O model.
- *
- ****************************************************************************/
- static int pcf8574_lcd_ioctl(FAR struct file *filep, int cmd,
- unsigned long arg)
- {
- switch (cmd)
- {
- case SLCDIOC_GETATTRIBUTES: /* SLCDIOC_GETATTRIBUTES: Get the
- * attributes of the SLCD */
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- FAR struct slcd_attributes_s *attr =
- (FAR struct slcd_attributes_s *)((uintptr_t) arg);
- lcdinfo("SLCDIOC_GETATTRIBUTES:\n");
- if (!attr)
- {
- return -EINVAL;
- }
- attr->nrows = priv->cfg.rows;
- attr->ncolumns = priv->cfg.cols;
- attr->nbars = 0;
- attr->maxcontrast = 0;
- attr->maxbrightness = 1; /* 'brightness' for us is the backlight */
- }
- break;
- case SLCDIOC_CURPOS: /* SLCDIOC_CURPOS: Get the SLCD cursor position */
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- FAR struct slcd_curpos_s *attr =
- (FAR struct slcd_curpos_s *)((uintptr_t) arg);
- uint8_t row;
- uint8_t col;
- nxsem_wait(&priv->sem_excl);
- lcd_get_curpos(priv, &row, &col);
- attr->row = row;
- attr->column = col;
- nxsem_post(&priv->sem_excl);
- }
- break;
- case SLCDIOC_GETBRIGHTNESS: /* Get the current brightness setting */
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- bool bon;
- bon = (priv->bl_bit && priv->cfg.bl_active_high) ||
- (!priv->bl_bit && !priv->cfg.bl_active_high);
- *(FAR int *)((uintptr_t) arg) = bon ? 1 : 0;
- }
- break;
- case SLCDIOC_SETBRIGHTNESS: /* Set the brightness to a new value */
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- nxsem_wait(&priv->sem_excl);
- lcd_backlight(priv, arg ? true : false);
- nxsem_post(&priv->sem_excl);
- }
- break;
- case SLCDIOC_CREATECHAR: /* Create a custom character pattern */
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- FAR struct slcd_createchar_s *attr =
- (FAR struct slcd_createchar_s *)((uintptr_t) arg);
- nxsem_wait(&priv->sem_excl);
- lcd_create_char(priv, attr->idx, attr->bmp);
- nxsem_post(&priv->sem_excl);
- }
- break;
- case SLCDIOC_SETBAR: /* SLCDIOC_SETBAR: Set bars on a bar display */
- case SLCDIOC_GETCONTRAST: /* SLCDIOC_GETCONTRAST: Get the current
- * contrast setting */
- case SLCDIOC_SETCONTRAST: /* SLCDIOC_SETCONTRAST: Set the contrast to a
- * new value */
- default:
- return -ENOTTY;
- }
- return OK;
- }
- /****************************************************************************
- * Name: pcf8574lcd_poll
- ****************************************************************************/
- static int pcf8574lcd_poll(FAR struct file *filep, FAR struct pollfd *fds,
- bool setup)
- {
- if (setup)
- {
- /* Data is always available to be read */
- fds->revents |= (fds->events & (POLLIN | POLLOUT));
- if (fds->revents != 0)
- {
- nxsem_post(fds->sem);
- }
- }
- return OK;
- }
- /****************************************************************************
- * Name: pcf8574_lcd_unlink
- ****************************************************************************/
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- static int pcf8574_lcd_unlink(FAR struct inode *inode)
- {
- FAR struct pcf8574_lcd_dev_s *priv =
- (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
- int ret = OK;
- nxsem_wait(&priv->sem_excl);
- priv->unlinked = true;
- /* If there are no open references to the driver then tear it down now */
- if (priv->refs == 0)
- {
- /* We have no real teardown at present */
- ret = OK;
- }
- nxsem_post(&priv->sem_excl);
- return ret;
- }
- #endif
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: pcf8574_lcd_backpack_register
- *
- * Description:
- * Register a character driver that is an I2C LCD 'backpack' for the
- * ever-popular HD44780 based 16x2 LCD via pcf8574 I2C IO expander.
- *
- ****************************************************************************/
- int pcf8574_lcd_backpack_register(FAR const char *devpath,
- FAR struct i2c_master_s *i2c,
- FAR struct pcf8574_lcd_backpack_config_s
- *cfg)
- {
- FAR struct pcf8574_lcd_dev_s *priv;
- int ret;
- /* Sanity check on geometry */
- if (cfg->rows < 1 || cfg->rows > 4)
- {
- lcdinfo("Display rows must be 1-4\n");
- return -EINVAL;
- }
- if ((cfg->cols < 1 || cfg->cols > 64) ||
- (cfg->rows == 4 && cfg->cols > 32))
- {
- lcdinfo("Display cols must be 1-64, and may not be part of a 4x40 "
- "configuration\n");
- return -EINVAL;
- }
- /* Initialize the device structure */
- priv = (FAR struct pcf8574_lcd_dev_s *)
- kmm_malloc(sizeof(struct pcf8574_lcd_dev_s));
- if (!priv)
- {
- lcdinfo("Failed to allocate instance\n");
- return -ENOMEM;
- }
- priv->i2c = i2c;
- priv->cfg = *cfg;
- priv->bl_bit = priv->cfg.bl_active_high ? 0 : (1 << priv->cfg.bl);
- priv->refs = 0;
- priv->unlinked = false;
- nxsem_init(&priv->sem_excl, 0, 1);
- /* Initialize */
- lcd_init(priv);
- /* If SLCD is console enable the backlight from start */
- #ifdef CONFIG_SLCD_CONSOLE
- lcd_backlight(priv, true);
- #endif
- /* Register the character driver */
- ret = register_driver(devpath, &g_pcf8574_lcd_fops, 0666, priv);
- if (ret < 0)
- {
- lcdinfo("Failed to register driver: %d\n", ret);
- kmm_free(priv);
- }
- lcdinfo("pcf8574_lcd_backpack driver loaded successfully!\n");
- return ret;
- }
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