linux/drivers/auxdisplay/charlcd.c
Mans Rullgard cc5d04d840 auxdisplay: charlcd: make backlight initial state configurable
The charlcd driver currently flashes the backlight once on init.
This may not be desirable.  Thus, add options for turning the
backlight off or on as well.

Signed-off-by: Mans Rullgard <mans@mansr.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2019-03-17 08:48:45 +01:00

900 lines
21 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Character LCD driver for Linux
*
* Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
* Copyright (C) 2016-2017 Glider bvba
*/
#include <linux/atomic.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/workqueue.h>
#include <generated/utsrelease.h>
#include <misc/charlcd.h>
#define LCD_MINOR 156
#define DEFAULT_LCD_BWIDTH 40
#define DEFAULT_LCD_HWIDTH 64
/* Keep the backlight on this many seconds for each flash */
#define LCD_BL_TEMPO_PERIOD 4
#define LCD_FLAG_B 0x0004 /* Blink on */
#define LCD_FLAG_C 0x0008 /* Cursor on */
#define LCD_FLAG_D 0x0010 /* Display on */
#define LCD_FLAG_F 0x0020 /* Large font mode */
#define LCD_FLAG_N 0x0040 /* 2-rows mode */
#define LCD_FLAG_L 0x0080 /* Backlight enabled */
/* LCD commands */
#define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */
#define LCD_CMD_ENTRY_MODE 0x04 /* Set entry mode */
#define LCD_CMD_CURSOR_INC 0x02 /* Increment cursor */
#define LCD_CMD_DISPLAY_CTRL 0x08 /* Display control */
#define LCD_CMD_DISPLAY_ON 0x04 /* Set display on */
#define LCD_CMD_CURSOR_ON 0x02 /* Set cursor on */
#define LCD_CMD_BLINK_ON 0x01 /* Set blink on */
#define LCD_CMD_SHIFT 0x10 /* Shift cursor/display */
#define LCD_CMD_DISPLAY_SHIFT 0x08 /* Shift display instead of cursor */
#define LCD_CMD_SHIFT_RIGHT 0x04 /* Shift display/cursor to the right */
#define LCD_CMD_FUNCTION_SET 0x20 /* Set function */
#define LCD_CMD_DATA_LEN_8BITS 0x10 /* Set data length to 8 bits */
#define LCD_CMD_TWO_LINES 0x08 /* Set to two display lines */
#define LCD_CMD_FONT_5X10_DOTS 0x04 /* Set char font to 5x10 dots */
#define LCD_CMD_SET_CGRAM_ADDR 0x40 /* Set char generator RAM address */
#define LCD_CMD_SET_DDRAM_ADDR 0x80 /* Set display data RAM address */
#define LCD_ESCAPE_LEN 24 /* Max chars for LCD escape command */
#define LCD_ESCAPE_CHAR 27 /* Use char 27 for escape command */
struct charlcd_priv {
struct charlcd lcd;
struct delayed_work bl_work;
struct mutex bl_tempo_lock; /* Protects access to bl_tempo */
bool bl_tempo;
bool must_clear;
/* contains the LCD config state */
unsigned long int flags;
/* Contains the LCD X and Y offset */
struct {
unsigned long int x;
unsigned long int y;
} addr;
/* Current escape sequence and it's length or -1 if outside */
struct {
char buf[LCD_ESCAPE_LEN + 1];
int len;
} esc_seq;
unsigned long long drvdata[0];
};
#define charlcd_to_priv(p) container_of(p, struct charlcd_priv, lcd)
/* Device single-open policy control */
static atomic_t charlcd_available = ATOMIC_INIT(1);
/* sleeps that many milliseconds with a reschedule */
static void long_sleep(int ms)
{
schedule_timeout_interruptible(msecs_to_jiffies(ms));
}
/* turn the backlight on or off */
static void charlcd_backlight(struct charlcd *lcd, int on)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
if (!lcd->ops->backlight)
return;
mutex_lock(&priv->bl_tempo_lock);
if (!priv->bl_tempo)
lcd->ops->backlight(lcd, on);
mutex_unlock(&priv->bl_tempo_lock);
}
static void charlcd_bl_off(struct work_struct *work)
{
struct delayed_work *dwork = to_delayed_work(work);
struct charlcd_priv *priv =
container_of(dwork, struct charlcd_priv, bl_work);
mutex_lock(&priv->bl_tempo_lock);
if (priv->bl_tempo) {
priv->bl_tempo = false;
if (!(priv->flags & LCD_FLAG_L))
priv->lcd.ops->backlight(&priv->lcd, 0);
}
mutex_unlock(&priv->bl_tempo_lock);
}
/* turn the backlight on for a little while */
void charlcd_poke(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
if (!lcd->ops->backlight)
return;
cancel_delayed_work_sync(&priv->bl_work);
mutex_lock(&priv->bl_tempo_lock);
if (!priv->bl_tempo && !(priv->flags & LCD_FLAG_L))
lcd->ops->backlight(lcd, 1);
priv->bl_tempo = true;
schedule_delayed_work(&priv->bl_work, LCD_BL_TEMPO_PERIOD * HZ);
mutex_unlock(&priv->bl_tempo_lock);
}
EXPORT_SYMBOL_GPL(charlcd_poke);
static void charlcd_gotoxy(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
unsigned int addr;
/*
* we force the cursor to stay at the end of the
* line if it wants to go farther
*/
addr = priv->addr.x < lcd->bwidth ? priv->addr.x & (lcd->hwidth - 1)
: lcd->bwidth - 1;
if (priv->addr.y & 1)
addr += lcd->hwidth;
if (priv->addr.y & 2)
addr += lcd->bwidth;
lcd->ops->write_cmd(lcd, LCD_CMD_SET_DDRAM_ADDR | addr);
}
static void charlcd_home(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
priv->addr.x = 0;
priv->addr.y = 0;
charlcd_gotoxy(lcd);
}
static void charlcd_print(struct charlcd *lcd, char c)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
if (priv->addr.x < lcd->bwidth) {
if (lcd->char_conv)
c = lcd->char_conv[(unsigned char)c];
lcd->ops->write_data(lcd, c);
priv->addr.x++;
/* prevents the cursor from wrapping onto the next line */
if (priv->addr.x == lcd->bwidth)
charlcd_gotoxy(lcd);
}
}
static void charlcd_clear_fast(struct charlcd *lcd)
{
int pos;
charlcd_home(lcd);
if (lcd->ops->clear_fast)
lcd->ops->clear_fast(lcd);
else
for (pos = 0; pos < min(2, lcd->height) * lcd->hwidth; pos++)
lcd->ops->write_data(lcd, ' ');
charlcd_home(lcd);
}
/* clears the display and resets X/Y */
static void charlcd_clear_display(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
lcd->ops->write_cmd(lcd, LCD_CMD_DISPLAY_CLEAR);
priv->addr.x = 0;
priv->addr.y = 0;
/* we must wait a few milliseconds (15) */
long_sleep(15);
}
static int charlcd_init_display(struct charlcd *lcd)
{
void (*write_cmd_raw)(struct charlcd *lcd, int cmd);
struct charlcd_priv *priv = charlcd_to_priv(lcd);
u8 init;
if (lcd->ifwidth != 4 && lcd->ifwidth != 8)
return -EINVAL;
priv->flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | LCD_FLAG_D |
LCD_FLAG_C | LCD_FLAG_B;
long_sleep(20); /* wait 20 ms after power-up for the paranoid */
/*
* 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure
* the LCD is in 8-bit mode afterwards
*/
init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS;
if (lcd->ifwidth == 4) {
init >>= 4;
write_cmd_raw = lcd->ops->write_cmd_raw4;
} else {
write_cmd_raw = lcd->ops->write_cmd;
}
write_cmd_raw(lcd, init);
long_sleep(10);
write_cmd_raw(lcd, init);
long_sleep(10);
write_cmd_raw(lcd, init);
long_sleep(10);
if (lcd->ifwidth == 4) {
/* Switch to 4-bit mode, 1 line, small fonts */
lcd->ops->write_cmd_raw4(lcd, LCD_CMD_FUNCTION_SET >> 4);
long_sleep(10);
}
/* set font height and lines number */
lcd->ops->write_cmd(lcd,
LCD_CMD_FUNCTION_SET |
((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS : 0) |
((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
long_sleep(10);
/* display off, cursor off, blink off */
lcd->ops->write_cmd(lcd, LCD_CMD_DISPLAY_CTRL);
long_sleep(10);
lcd->ops->write_cmd(lcd,
LCD_CMD_DISPLAY_CTRL | /* set display mode */
((priv->flags & LCD_FLAG_D) ? LCD_CMD_DISPLAY_ON : 0) |
((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
charlcd_backlight(lcd, (priv->flags & LCD_FLAG_L) ? 1 : 0);
long_sleep(10);
/* entry mode set : increment, cursor shifting */
lcd->ops->write_cmd(lcd, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC);
charlcd_clear_display(lcd);
return 0;
}
/*
* Parses an unsigned integer from a string, until a non-digit character
* is found. The empty string is not accepted. No overflow checks are done.
*
* Returns whether the parsing was successful. Only in that case
* the output parameters are written to.
*
* TODO: If the kernel adds an inplace version of kstrtoul(), this function
* could be easily replaced by that.
*/
static bool parse_n(const char *s, unsigned long *res, const char **next_s)
{
if (!isdigit(*s))
return false;
*res = 0;
while (isdigit(*s)) {
*res = *res * 10 + (*s - '0');
++s;
}
*next_s = s;
return true;
}
/*
* Parses a movement command of the form "(.*);", where the group can be
* any number of subcommands of the form "(x|y)[0-9]+".
*
* Returns whether the command is valid. The position arguments are
* only written if the parsing was successful.
*
* For instance:
* - ";" returns (<original x>, <original y>).
* - "x1;" returns (1, <original y>).
* - "y2x1;" returns (1, 2).
* - "x12y34x56;" returns (56, 34).
* - "" fails.
* - "x" fails.
* - "x;" fails.
* - "x1" fails.
* - "xy12;" fails.
* - "x12yy12;" fails.
* - "xx" fails.
*/
static bool parse_xy(const char *s, unsigned long *x, unsigned long *y)
{
unsigned long new_x = *x;
unsigned long new_y = *y;
for (;;) {
if (!*s)
return false;
if (*s == ';')
break;
if (*s == 'x') {
if (!parse_n(s + 1, &new_x, &s))
return false;
} else if (*s == 'y') {
if (!parse_n(s + 1, &new_y, &s))
return false;
} else {
return false;
}
}
*x = new_x;
*y = new_y;
return true;
}
/*
* These are the file operation function for user access to /dev/lcd
* This function can also be called from inside the kernel, by
* setting file and ppos to NULL.
*
*/
static inline int handle_lcd_special_code(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
/* LCD special codes */
int processed = 0;
char *esc = priv->esc_seq.buf + 2;
int oldflags = priv->flags;
/* check for display mode flags */
switch (*esc) {
case 'D': /* Display ON */
priv->flags |= LCD_FLAG_D;
processed = 1;
break;
case 'd': /* Display OFF */
priv->flags &= ~LCD_FLAG_D;
processed = 1;
break;
case 'C': /* Cursor ON */
priv->flags |= LCD_FLAG_C;
processed = 1;
break;
case 'c': /* Cursor OFF */
priv->flags &= ~LCD_FLAG_C;
processed = 1;
break;
case 'B': /* Blink ON */
priv->flags |= LCD_FLAG_B;
processed = 1;
break;
case 'b': /* Blink OFF */
priv->flags &= ~LCD_FLAG_B;
processed = 1;
break;
case '+': /* Back light ON */
priv->flags |= LCD_FLAG_L;
processed = 1;
break;
case '-': /* Back light OFF */
priv->flags &= ~LCD_FLAG_L;
processed = 1;
break;
case '*': /* Flash back light */
charlcd_poke(lcd);
processed = 1;
break;
case 'f': /* Small Font */
priv->flags &= ~LCD_FLAG_F;
processed = 1;
break;
case 'F': /* Large Font */
priv->flags |= LCD_FLAG_F;
processed = 1;
break;
case 'n': /* One Line */
priv->flags &= ~LCD_FLAG_N;
processed = 1;
break;
case 'N': /* Two Lines */
priv->flags |= LCD_FLAG_N;
processed = 1;
break;
case 'l': /* Shift Cursor Left */
if (priv->addr.x > 0) {
/* back one char if not at end of line */
if (priv->addr.x < lcd->bwidth)
lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
priv->addr.x--;
}
processed = 1;
break;
case 'r': /* shift cursor right */
if (priv->addr.x < lcd->width) {
/* allow the cursor to pass the end of the line */
if (priv->addr.x < (lcd->bwidth - 1))
lcd->ops->write_cmd(lcd,
LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT);
priv->addr.x++;
}
processed = 1;
break;
case 'L': /* shift display left */
lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT);
processed = 1;
break;
case 'R': /* shift display right */
lcd->ops->write_cmd(lcd,
LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT |
LCD_CMD_SHIFT_RIGHT);
processed = 1;
break;
case 'k': { /* kill end of line */
int x;
for (x = priv->addr.x; x < lcd->bwidth; x++)
lcd->ops->write_data(lcd, ' ');
/* restore cursor position */
charlcd_gotoxy(lcd);
processed = 1;
break;
}
case 'I': /* reinitialize display */
charlcd_init_display(lcd);
processed = 1;
break;
case 'G': {
/* Generator : LGcxxxxx...xx; must have <c> between '0'
* and '7', representing the numerical ASCII code of the
* redefined character, and <xx...xx> a sequence of 16
* hex digits representing 8 bytes for each character.
* Most LCDs will only use 5 lower bits of the 7 first
* bytes.
*/
unsigned char cgbytes[8];
unsigned char cgaddr;
int cgoffset;
int shift;
char value;
int addr;
if (!strchr(esc, ';'))
break;
esc++;
cgaddr = *(esc++) - '0';
if (cgaddr > 7) {
processed = 1;
break;
}
cgoffset = 0;
shift = 0;
value = 0;
while (*esc && cgoffset < 8) {
shift ^= 4;
if (*esc >= '0' && *esc <= '9') {
value |= (*esc - '0') << shift;
} else if (*esc >= 'A' && *esc <= 'F') {
value |= (*esc - 'A' + 10) << shift;
} else if (*esc >= 'a' && *esc <= 'f') {
value |= (*esc - 'a' + 10) << shift;
} else {
esc++;
continue;
}
if (shift == 0) {
cgbytes[cgoffset++] = value;
value = 0;
}
esc++;
}
lcd->ops->write_cmd(lcd, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8));
for (addr = 0; addr < cgoffset; addr++)
lcd->ops->write_data(lcd, cgbytes[addr]);
/* ensures that we stop writing to CGRAM */
charlcd_gotoxy(lcd);
processed = 1;
break;
}
case 'x': /* gotoxy : LxXXX[yYYY]; */
case 'y': /* gotoxy : LyYYY[xXXX]; */
if (priv->esc_seq.buf[priv->esc_seq.len - 1] != ';')
break;
/* If the command is valid, move to the new address */
if (parse_xy(esc, &priv->addr.x, &priv->addr.y))
charlcd_gotoxy(lcd);
/* Regardless of its validity, mark as processed */
processed = 1;
break;
}
/* TODO: This indent party here got ugly, clean it! */
/* Check whether one flag was changed */
if (oldflags == priv->flags)
return processed;
/* check whether one of B,C,D flags were changed */
if ((oldflags ^ priv->flags) &
(LCD_FLAG_B | LCD_FLAG_C | LCD_FLAG_D))
/* set display mode */
lcd->ops->write_cmd(lcd,
LCD_CMD_DISPLAY_CTRL |
((priv->flags & LCD_FLAG_D) ? LCD_CMD_DISPLAY_ON : 0) |
((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
/* check whether one of F,N flags was changed */
else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N))
lcd->ops->write_cmd(lcd,
LCD_CMD_FUNCTION_SET |
((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS : 0) |
((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
/* check whether L flag was changed */
else if ((oldflags ^ priv->flags) & LCD_FLAG_L)
charlcd_backlight(lcd, !!(priv->flags & LCD_FLAG_L));
return processed;
}
static void charlcd_write_char(struct charlcd *lcd, char c)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
/* first, we'll test if we're in escape mode */
if ((c != '\n') && priv->esc_seq.len >= 0) {
/* yes, let's add this char to the buffer */
priv->esc_seq.buf[priv->esc_seq.len++] = c;
priv->esc_seq.buf[priv->esc_seq.len] = '\0';
} else {
/* aborts any previous escape sequence */
priv->esc_seq.len = -1;
switch (c) {
case LCD_ESCAPE_CHAR:
/* start of an escape sequence */
priv->esc_seq.len = 0;
priv->esc_seq.buf[priv->esc_seq.len] = '\0';
break;
case '\b':
/* go back one char and clear it */
if (priv->addr.x > 0) {
/*
* check if we're not at the
* end of the line
*/
if (priv->addr.x < lcd->bwidth)
/* back one char */
lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
priv->addr.x--;
}
/* replace with a space */
lcd->ops->write_data(lcd, ' ');
/* back one char again */
lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
break;
case '\f':
/* quickly clear the display */
charlcd_clear_fast(lcd);
break;
case '\n':
/*
* flush the remainder of the current line and
* go to the beginning of the next line
*/
for (; priv->addr.x < lcd->bwidth; priv->addr.x++)
lcd->ops->write_data(lcd, ' ');
priv->addr.x = 0;
priv->addr.y = (priv->addr.y + 1) % lcd->height;
charlcd_gotoxy(lcd);
break;
case '\r':
/* go to the beginning of the same line */
priv->addr.x = 0;
charlcd_gotoxy(lcd);
break;
case '\t':
/* print a space instead of the tab */
charlcd_print(lcd, ' ');
break;
default:
/* simply print this char */
charlcd_print(lcd, c);
break;
}
}
/*
* now we'll see if we're in an escape mode and if the current
* escape sequence can be understood.
*/
if (priv->esc_seq.len >= 2) {
int processed = 0;
if (!strcmp(priv->esc_seq.buf, "[2J")) {
/* clear the display */
charlcd_clear_fast(lcd);
processed = 1;
} else if (!strcmp(priv->esc_seq.buf, "[H")) {
/* cursor to home */
charlcd_home(lcd);
processed = 1;
}
/* codes starting with ^[[L */
else if ((priv->esc_seq.len >= 3) &&
(priv->esc_seq.buf[0] == '[') &&
(priv->esc_seq.buf[1] == 'L')) {
processed = handle_lcd_special_code(lcd);
}
/* LCD special escape codes */
/*
* flush the escape sequence if it's been processed
* or if it is getting too long.
*/
if (processed || (priv->esc_seq.len >= LCD_ESCAPE_LEN))
priv->esc_seq.len = -1;
} /* escape codes */
}
static struct charlcd *the_charlcd;
static ssize_t charlcd_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
const char __user *tmp = buf;
char c;
for (; count-- > 0; (*ppos)++, tmp++) {
if (!in_interrupt() && (((count + 1) & 0x1f) == 0))
/*
* let's be a little nice with other processes
* that need some CPU
*/
schedule();
if (get_user(c, tmp))
return -EFAULT;
charlcd_write_char(the_charlcd, c);
}
return tmp - buf;
}
static int charlcd_open(struct inode *inode, struct file *file)
{
struct charlcd_priv *priv = charlcd_to_priv(the_charlcd);
int ret;
ret = -EBUSY;
if (!atomic_dec_and_test(&charlcd_available))
goto fail; /* open only once at a time */
ret = -EPERM;
if (file->f_mode & FMODE_READ) /* device is write-only */
goto fail;
if (priv->must_clear) {
charlcd_clear_display(&priv->lcd);
priv->must_clear = false;
}
return nonseekable_open(inode, file);
fail:
atomic_inc(&charlcd_available);
return ret;
}
static int charlcd_release(struct inode *inode, struct file *file)
{
atomic_inc(&charlcd_available);
return 0;
}
static const struct file_operations charlcd_fops = {
.write = charlcd_write,
.open = charlcd_open,
.release = charlcd_release,
.llseek = no_llseek,
};
static struct miscdevice charlcd_dev = {
.minor = LCD_MINOR,
.name = "lcd",
.fops = &charlcd_fops,
};
static void charlcd_puts(struct charlcd *lcd, const char *s)
{
const char *tmp = s;
int count = strlen(s);
for (; count-- > 0; tmp++) {
if (!in_interrupt() && (((count + 1) & 0x1f) == 0))
/*
* let's be a little nice with other processes
* that need some CPU
*/
schedule();
charlcd_write_char(lcd, *tmp);
}
}
#ifdef CONFIG_PANEL_BOOT_MESSAGE
#define LCD_INIT_TEXT CONFIG_PANEL_BOOT_MESSAGE
#else
#define LCD_INIT_TEXT "Linux-" UTS_RELEASE "\n"
#endif
#ifdef CONFIG_CHARLCD_BL_ON
#define LCD_INIT_BL "\x1b[L+"
#elif defined(CONFIG_CHARLCD_BL_FLASH)
#define LCD_INIT_BL "\x1b[L*"
#else
#define LCD_INIT_BL "\x1b[L-"
#endif
/* initialize the LCD driver */
static int charlcd_init(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
int ret;
if (lcd->ops->backlight) {
mutex_init(&priv->bl_tempo_lock);
INIT_DELAYED_WORK(&priv->bl_work, charlcd_bl_off);
}
/*
* before this line, we must NOT send anything to the display.
* Since charlcd_init_display() needs to write data, we have to
* enable mark the LCD initialized just before.
*/
ret = charlcd_init_display(lcd);
if (ret)
return ret;
/* display a short message */
charlcd_puts(lcd, "\x1b[Lc\x1b[Lb" LCD_INIT_BL LCD_INIT_TEXT);
/* clear the display on the next device opening */
priv->must_clear = true;
charlcd_home(lcd);
return 0;
}
struct charlcd *charlcd_alloc(unsigned int drvdata_size)
{
struct charlcd_priv *priv;
struct charlcd *lcd;
priv = kzalloc(sizeof(*priv) + drvdata_size, GFP_KERNEL);
if (!priv)
return NULL;
priv->esc_seq.len = -1;
lcd = &priv->lcd;
lcd->ifwidth = 8;
lcd->bwidth = DEFAULT_LCD_BWIDTH;
lcd->hwidth = DEFAULT_LCD_HWIDTH;
lcd->drvdata = priv->drvdata;
return lcd;
}
EXPORT_SYMBOL_GPL(charlcd_alloc);
void charlcd_free(struct charlcd *lcd)
{
kfree(charlcd_to_priv(lcd));
}
EXPORT_SYMBOL_GPL(charlcd_free);
static int panel_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
struct charlcd *lcd = the_charlcd;
switch (code) {
case SYS_DOWN:
charlcd_puts(lcd,
"\x0cReloading\nSystem...\x1b[Lc\x1b[Lb\x1b[L+");
break;
case SYS_HALT:
charlcd_puts(lcd, "\x0cSystem Halted.\x1b[Lc\x1b[Lb\x1b[L+");
break;
case SYS_POWER_OFF:
charlcd_puts(lcd, "\x0cPower off.\x1b[Lc\x1b[Lb\x1b[L+");
break;
default:
break;
}
return NOTIFY_DONE;
}
static struct notifier_block panel_notifier = {
panel_notify_sys,
NULL,
0
};
int charlcd_register(struct charlcd *lcd)
{
int ret;
ret = charlcd_init(lcd);
if (ret)
return ret;
ret = misc_register(&charlcd_dev);
if (ret)
return ret;
the_charlcd = lcd;
register_reboot_notifier(&panel_notifier);
return 0;
}
EXPORT_SYMBOL_GPL(charlcd_register);
int charlcd_unregister(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
unregister_reboot_notifier(&panel_notifier);
charlcd_puts(lcd, "\x0cLCD driver unloaded.\x1b[Lc\x1b[Lb\x1b[L-");
misc_deregister(&charlcd_dev);
the_charlcd = NULL;
if (lcd->ops->backlight) {
cancel_delayed_work_sync(&priv->bl_work);
priv->lcd.ops->backlight(&priv->lcd, 0);
}
return 0;
}
EXPORT_SYMBOL_GPL(charlcd_unregister);
MODULE_LICENSE("GPL");