auxdisplay: charlcd: Extract character LCD core from misc/panel (39f8ea46) · Commits · 戴 / test

drivers/auxdisplay/Kconfig

+3 −0

Original line number	Diff line number	Diff line
		@@ -13,6 +13,9 @@ menuconfig AUXDISPLAY

		If you say N, all options in this submenu will be skipped and disabled.

		config CHARLCD
		tristate "Character LCD core support" if COMPILE_TEST

		if AUXDISPLAY

		config KS0108

drivers/auxdisplay/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -2,6 +2,7 @@
		# Makefile for the kernel auxiliary displays device drivers.
		#

		obj-$(CONFIG_CHARLCD) += charlcd.o
		obj-$(CONFIG_KS0108) += ks0108.o
		obj-$(CONFIG_CFAG12864B) += cfag12864b.o cfag12864bfb.o
		obj-$(CONFIG_IMG_ASCII_LCD) += img-ascii-lcd.o

drivers/auxdisplay/charlcd.c

0 → 100644

+790 −0

Original line number	Diff line number	Diff line
		/*
		* Character LCD driver for Linux
		*
		* Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
		* Copyright (C) 2016-2017 Glider bvba
		*
		* This program is free software; you can redistribute it and/or
		* modify it under the terms of the GNU General Public License
		* as published by the Free Software Foundation; either version
		* 2 of the License, or (at your option) any later version.
		*/

		#include <linux/atomic.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 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)
		{
		if (in_interrupt())
		mdelay(ms);
		else
		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 = 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 = 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 = to_priv(lcd);

		lcd->ops->write_cmd(lcd,
		LCD_CMD_SET_DDRAM_ADDR \| (priv->addr.y ? lcd->hwidth : 0) \|
		/*
		* we force the cursor to stay at the end of the
		* line if it wants to go farther
		*/
		((priv->addr.x < lcd->bwidth) ? priv->addr.x & (lcd->hwidth - 1)
		: lcd->bwidth - 1));
		}

		static void charlcd_home(struct charlcd *lcd)
		{
		struct charlcd_priv *priv = 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 = 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 < 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 = 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)
		{
		struct charlcd_priv *priv = to_priv(lcd);

		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 */

		/* 8bits, 1 line, small fonts; let's do it 3 times */
		lcd->ops->write_cmd(lcd, LCD_CMD_FUNCTION_SET \| LCD_CMD_DATA_LEN_8BITS);
		long_sleep(10);
		lcd->ops->write_cmd(lcd, LCD_CMD_FUNCTION_SET \| LCD_CMD_DATA_LEN_8BITS);
		long_sleep(10);
		lcd->ops->write_cmd(lcd, LCD_CMD_FUNCTION_SET \| LCD_CMD_DATA_LEN_8BITS);
		long_sleep(10);

		/* set font height and lines number */
		lcd->ops->write_cmd(lcd,
		LCD_CMD_FUNCTION_SET \| LCD_CMD_DATA_LEN_8BITS \|
		((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;
		}

		/*
		* 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 = 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;
		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 <= 'Z') {
		value \|= (*esc - 'A' + 10) << shift;
		} else if (esc >= 'a' && esc <= 'z') {
		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 (!strchr(esc, ';'))
		break;

		while (*esc) {
		if (*esc == 'x') {
		esc++;
		if (kstrtoul(esc, 10, &priv->addr.x) < 0)
		break;
		} else if (*esc == 'y') {
		esc++;
		if (kstrtoul(esc, 10, &priv->addr.y) < 0)
		break;
		} else {
		break;
		}
		}

		charlcd_gotoxy(lcd);
		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_CMD_DATA_LEN_8BITS \|
		((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 = 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 '\014':
		/* 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 = to_priv(the_charlcd);

		if (!atomic_dec_and_test(&charlcd_available))
		return -EBUSY; /* open only once at a time */

		if (file->f_mode & FMODE_READ) /* device is write-only */
		return -EPERM;

		if (priv->must_clear) {
		charlcd_clear_display(&priv->lcd);
		priv->must_clear = false;
		}
		return nonseekable_open(inode, file);
		}

		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);
		}
		}

		/* initialize the LCD driver */
		static int charlcd_init(struct charlcd *lcd)
		{
		struct charlcd_priv *priv = 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 */
		#ifdef CONFIG_PANEL_CHANGE_MESSAGE
		#ifdef CONFIG_PANEL_BOOT_MESSAGE
		charlcd_puts(lcd, "\x1b[Lc\x1b[Lb\x1b[L*" CONFIG_PANEL_BOOT_MESSAGE);
		#endif
		#else
		charlcd_puts(lcd, "\x1b[Lc\x1b[Lb\x1b[L*Linux-" UTS_RELEASE "\n");
		#endif
		/* 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->bwidth = DEFAULT_LCD_BWIDTH;
		lcd->hwidth = DEFAULT_LCD_HWIDTH;
		lcd->drvdata = priv->drvdata;

		return lcd;
		}
		EXPORT_SYMBOL_GPL(charlcd_alloc);

		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 = 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");

drivers/misc/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -495,6 +495,7 @@ config VEXPRESS_SYSCFG
		config PANEL
		tristate "Parallel port LCD/Keypad Panel support"
		depends on PARPORT
		select CHARLCD
		---help---
		Say Y here if you have an HD44780 or KS-0074 LCD connected to your
		parallel port. This driver also features 4 and 6-key keypads. The LCD

drivers/misc/panel.c

+92 −735

File changed.

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