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drivers/lcd/pcf8574_lcd_backpack.c: Fix seek method. Had the same problems as noted for st7032.c driver.

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This commit is contained in:
Gregory Nutt 2019-01-14 16:38:57 -06:00
parent 508f90605c
commit dc5d18a092
1 changed files with 49 additions and 17 deletions
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66
drivers/lcd/pcf8574_lcd_backpack.c
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@ -1371,36 +1371,68 @@ static off_t pcf8574_lcd_seek(FAR struct file *filep, off_t offset, int whence)
{ {
FAR struct inode *inode = filep->f_inode; 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 pcf8574_lcd_dev_s *priv = (FAR struct pcf8574_lcd_dev_s *)inode->i_private;
off_t pos;
int maxpos; int maxpos;
nxsem_wait(&priv->sem_excl); nxsem_wait(&priv->sem_excl);
maxpos = priv->cfg.rows * priv->cfg.cols + (priv->cfg.rows - 1); maxpos = priv->cfg.rows * priv->cfg.cols + (priv->cfg.rows - 1);
pos = filep->f_pos;
switch (whence) switch (whence)
{ {
case SEEK_CUR: case SEEK_CUR:
filep->f_pos += offset; pos += offset;
if (filep->f_pos > maxpos) if (pos > maxpos)
filep->f_pos = maxpos; {
break; pos = maxpos;
}
else if (pos < 0)
{
pos = 0;
}
case SEEK_SET: filep->f_pos = pos;
filep->f_pos = offset; break;
if (filep->f_pos > maxpos)
filep->f_pos = maxpos;
break;
case SEEK_END: case SEEK_SET:
filep->f_pos = maxpos; pos = offset;
break; if (pos > maxpos)
{
pos = maxpos;
}
else if (pos < 0)
{
pos = 0;
}
default: filep->f_pos = pos;
/* Return EINVAL if the whence argument is invalid */ break;
filep->f_pos = -EINVAL;
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); nxsem_post(&priv->sem_excl);
return filep->f_pos; return pos;
} }
/**************************************************************************** /****************************************************************************