fleshed out rest of fileops interface; read now takes into consideration current file position (so the display can be read in multiple operations, and indiate EOF correctly), seek (really just to facilitate rewind), and unlink (to facilitate dropping from system at runtime).
This commit is contained in:
ziggurat29
parent
4643fcdfd8
commit
bb7a579681
@ -86,6 +86,8 @@
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# define lcdvdbg(x...)
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#endif
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#define MAX_OPENCNT (255) /* Limit of uint8_t */
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/****************************************************************************
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* Private Types
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****************************************************************************/
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@ -95,6 +97,8 @@ struct pcf8574_lcd_dev_s
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FAR struct i2c_master_s *i2c; /* I2C interface */
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struct pcf8574_lcd_backpack_config_s cfg; /* gpio configuration */
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uint8_t bl_bit; /* current backlight bit */
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uint8_t refs; /* Number of references */
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uint8_t unlinked; /* We are unlinked, so teardown on last close */
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sem_t sem_excl; /* mutex */
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};
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@ -117,12 +121,16 @@ static ssize_t pcf8574_lcd_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t pcf8574_lcd_write(FAR struct file *filep,
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FAR const char *buffer, size_t buflen);
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static off_t pcf8574_lcd_seek(FAR struct file *filep, off_t offset, int whence);
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static int pcf8574_lcd_ioctl(FAR struct file *filep, int cmd,
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unsigned long arg);
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#ifndef CONFIG_DISABLE_POLL
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static int pcf8574lcd_poll(FAR struct file *filep, FAR struct pollfd *fds,
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bool setup);
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#endif
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int pcf8574_lcd_unlink(FAR struct inode *inode);
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#endif
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/****************************************************************************
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* Private Data
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@ -134,12 +142,14 @@ static const struct file_operations g_pcf8574_lcd_fops =
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pcf8574_lcd_close, /* close */
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pcf8574_lcd_read, /* read */
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pcf8574_lcd_write, /* write */
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0, /* seek */
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pcf8574_lcd_seek, /* seek */
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pcf8574_lcd_ioctl, /* ioctl */
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#ifndef CONFIG_DISABLE_POLL
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pcf8574lcd_poll, /* poll */
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#endif
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0 /* unlink */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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pcf8574_lcd_unlink /* unlink */
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#endif
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};
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/****************************************************************************
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@ -1000,6 +1010,53 @@ static int lcd_getstream(FAR struct lib_instream_s *instream)
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return EOF;
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}
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/****************************************************************************
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* Name: lcd_fpos_to_curpos
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*
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* Description:
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* Convert a file logical offset to a screen cursor pos (row,col). This
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* discounts 'synthesized' line feeds at the end of screen lines.
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*
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****************************************************************************/
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static void lcd_fpos_to_curpos(FAR struct pcf8574_lcd_dev_s *priv,
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off_t fpos, uint8_t *row, uint8_t *col, bool* onlf)
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{
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int virtcols;
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virtcols = (priv->cfg.cols + 1);
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/* Determine if this is a 'virtual' position (on the synthetic LF) */
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*onlf = (priv->cfg.cols == fpos % virtcols);
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/* Adjust off any preceding synthetic LF's to get linear position */
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fpos -= fpos / virtcols;
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/* Compute row/col from linear position */
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*row = fpos / priv->cfg.cols;
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*col = fpos % priv->cfg.cols;
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}
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/****************************************************************************
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* Name: lcd_curpos_to_fpos
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*
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* Description:
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* Convert a screen cursor pos (row,col) to a file logical offset. This
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* includes 'synthesized' line feeds at the end of screen lines.
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*
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****************************************************************************/
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static void lcd_curpos_to_fpos(FAR struct pcf8574_lcd_dev_s *priv,
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uint8_t row, uint8_t col, off_t* fpos)
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{
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/* the logical file position is the linear position plus any synthetic LF */
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*fpos = (row * priv->cfg.cols) + col + row;
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}
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/****************************************************************************
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* Name: pcf8574_lcd_open
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*
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@ -1010,6 +1067,22 @@ static int lcd_getstream(FAR struct lib_instream_s *instream)
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static int pcf8574_lcd_open(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct pcf8574_lcd_dev_s *priv = (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
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/* Increment the reference count */
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sem_wait(&priv->sem_excl);
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if (priv->refs == MAX_OPENCNT)
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{
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return -EMFILE;
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}
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else
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{
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priv->refs++;
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}
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sem_post(&priv->sem_excl);
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return OK;
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}
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@ -1023,7 +1096,35 @@ static int pcf8574_lcd_open(FAR struct file *filep)
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static int pcf8574_lcd_close(FAR struct file *filep)
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{
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return OK;
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FAR struct inode *inode = filep->f_inode;
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FAR struct pcf8574_lcd_dev_s *priv = (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
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int ret;
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/* Decrement the reference count */
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sem_wait(&priv->sem_excl);
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if (priv->refs == 0)
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{
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ret = -EIO;
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}
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else
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{
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priv->refs--;
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/* If we had previously unlinked, but there were open references at the
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* time, we need to do the final teardown now.
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*/
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if (priv->refs == 0 && priv->unlinked)
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{
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/* We have no real teardown at present */
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}
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ret = OK;
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}
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sem_post(&priv->sem_excl);
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return ret;
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}
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/****************************************************************************
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@ -1031,7 +1132,8 @@ static int pcf8574_lcd_close(FAR struct file *filep)
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*
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* Description:
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* This simply reads as much of the display memory as possible. This is
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* probably not very interesting.
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* generally not very interesting, but we do it in a way that allows us to
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* 'cat' the LCD contents via the shell.
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*
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****************************************************************************/
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@ -1044,22 +1146,44 @@ static ssize_t pcf8574_lcd_read(FAR struct file *filep, FAR char *buffer,
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uint8_t addr;
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uint8_t row;
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uint8_t col;
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bool onlf;
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sem_wait(&priv->sem_excl);
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/* Get current cursor position so we can restore it */
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(void)lcd_read_busy_addr(priv, &addr);
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addr2rc(priv, addr, &row, &col);
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/* Just read the entire display into the given buffer, as much as possible */
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/* Convert file position to row/col address and position DDADDR there */
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lcd_fpos_to_curpos(priv, filep->f_pos, &row, &col, &onlf);
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lcd_set_curpos(priv, row, col);
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/* Read as much of the display as possible */
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nIdx = 0;
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row = 0;
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col = 0;
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while (nIdx < buflen && row < priv->cfg.rows)
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{
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/* Synthesize end-of-line LF and advance to start of next row */
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if (onlf)
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{
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/* Synthesize LF for all but last row */
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if ( row < priv->cfg.rows-1)
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{
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buffer[nIdx] = '\x0a';
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onlf = false;
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++filep->f_pos;
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++nIdx;
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}
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++row;
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col = 0;
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continue;
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}
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/* If we are at start of line we will need to update DDRAM address */
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if (0 == col)
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{
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lcd_set_curpos(priv, row, 0);
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@ -1067,12 +1191,15 @@ static ssize_t pcf8574_lcd_read(FAR struct file *filep, FAR char *buffer,
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buffer[nIdx] = lcd_getdata(priv);
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++filep->f_pos;
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++nIdx;
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++col;
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/* If we are now at the end of a line, we setup for the synthetic LF */
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if (priv->cfg.cols == col)
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{
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++row;
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col = 0;
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onlf = true;
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}
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}
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@ -1226,10 +1353,62 @@ static ssize_t pcf8574_lcd_write(FAR struct file *filep,
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}
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}
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/* Wherever we wound up, update our logical file pos to reflect it */
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lcd_curpos_to_fpos(priv, row, col, &filep->f_pos);
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sem_post(&priv->sem_excl);
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return buflen;
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}
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/****************************************************************************
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* Name: pcf8574_lcd_seek
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*
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* Description:
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* Seek the logical file pointer to the specified position. This is
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* probably not very interesting except possibly for (SEEK_SET, 0) to
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* rewind the pointer for a subsequent read().
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* The file pointer is logical, and includes synthesized LF chars at the
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* end of the display lines.
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*
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****************************************************************************/
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static off_t pcf8574_lcd_seek(FAR struct file *filep, off_t offset, int whence)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct pcf8574_lcd_dev_s *priv = (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
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int maxpos;
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sem_wait(&priv->sem_excl);
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maxpos = priv->cfg.rows * priv->cfg.cols + (priv->cfg.rows - 1);
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switch (whence)
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{
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case SEEK_CUR:
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filep->f_pos += offset;
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if (filep->f_pos > maxpos)
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filep->f_pos = maxpos;
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break;
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case SEEK_SET:
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filep->f_pos = offset;
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if (filep->f_pos > maxpos)
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filep->f_pos = maxpos;
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break;
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case SEEK_END:
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filep->f_pos = maxpos;
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break;
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default:
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/* Return EINVAL if the whence argument is invalid */
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filep->f_pos = -EINVAL;
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}
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sem_post(&priv->sem_excl);
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return filep->f_pos;
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}
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/****************************************************************************
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* Name: pcf8574_lcd_ioctl
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*
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@ -1349,6 +1528,32 @@ static int pcf8574lcd_poll(FAR struct file *filep, FAR struct pollfd *fds,
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}
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#endif
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/****************************************************************************
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* Name: pcf8574_lcd_unlink
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****************************************************************************/
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int pcf8574_lcd_unlink(FAR struct inode *inode)
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{
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FAR struct pcf8574_lcd_dev_s *priv = (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
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int ret = OK;
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sem_wait(&priv->sem_excl);
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priv->unlinked = true;
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/* If there are no open references to the driver then tear it down now */
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if (priv->refs == 0)
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{
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/* We have no real teardown at present */
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ret = OK;
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}
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sem_post(&priv->sem_excl);
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return ret;
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}
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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@ -1395,6 +1600,8 @@ int pcf8574_lcd_backpack_register(FAR const char *devpath,
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priv->i2c = i2c;
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priv->cfg = *cfg;
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priv->bl_bit = priv->cfg.bl_active_high ? 0 : (1 << priv->cfg.bl);
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priv->refs = 0;
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priv->unlinked = false;
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sem_init(&priv->sem_excl, 0, 1);
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/* Initialize */
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