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![Jia-Ju Bai](/assets/img/avatar_default.png)
The function long_sleep() calls mdelay() when in an interrupt handler. But only charlcd_clear_display() and charlcd_init_display calls long_sleep(), and my tool finds that the two functions are never called in an interrupt handler. Thus mdelay() and in_interrupt() are not necessary. This is found by a static analysis tool named DCNS written by myself. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Acked-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
881 lines
21 KiB
C
881 lines
21 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Character LCD driver for Linux
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*
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* Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
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* Copyright (C) 2016-2017 Glider bvba
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*/
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#include <linux/atomic.h>
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#include <linux/ctype.h>
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#include <linux/delay.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/workqueue.h>
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#include <generated/utsrelease.h>
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#include <misc/charlcd.h>
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#define LCD_MINOR 156
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#define DEFAULT_LCD_BWIDTH 40
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#define DEFAULT_LCD_HWIDTH 64
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/* Keep the backlight on this many seconds for each flash */
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#define LCD_BL_TEMPO_PERIOD 4
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#define LCD_FLAG_B 0x0004 /* Blink on */
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#define LCD_FLAG_C 0x0008 /* Cursor on */
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#define LCD_FLAG_D 0x0010 /* Display on */
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#define LCD_FLAG_F 0x0020 /* Large font mode */
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#define LCD_FLAG_N 0x0040 /* 2-rows mode */
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#define LCD_FLAG_L 0x0080 /* Backlight enabled */
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/* LCD commands */
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#define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */
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#define LCD_CMD_ENTRY_MODE 0x04 /* Set entry mode */
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#define LCD_CMD_CURSOR_INC 0x02 /* Increment cursor */
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#define LCD_CMD_DISPLAY_CTRL 0x08 /* Display control */
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#define LCD_CMD_DISPLAY_ON 0x04 /* Set display on */
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#define LCD_CMD_CURSOR_ON 0x02 /* Set cursor on */
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#define LCD_CMD_BLINK_ON 0x01 /* Set blink on */
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#define LCD_CMD_SHIFT 0x10 /* Shift cursor/display */
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#define LCD_CMD_DISPLAY_SHIFT 0x08 /* Shift display instead of cursor */
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#define LCD_CMD_SHIFT_RIGHT 0x04 /* Shift display/cursor to the right */
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#define LCD_CMD_FUNCTION_SET 0x20 /* Set function */
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#define LCD_CMD_DATA_LEN_8BITS 0x10 /* Set data length to 8 bits */
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#define LCD_CMD_TWO_LINES 0x08 /* Set to two display lines */
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#define LCD_CMD_FONT_5X10_DOTS 0x04 /* Set char font to 5x10 dots */
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#define LCD_CMD_SET_CGRAM_ADDR 0x40 /* Set char generator RAM address */
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#define LCD_CMD_SET_DDRAM_ADDR 0x80 /* Set display data RAM address */
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#define LCD_ESCAPE_LEN 24 /* Max chars for LCD escape command */
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#define LCD_ESCAPE_CHAR 27 /* Use char 27 for escape command */
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struct charlcd_priv {
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struct charlcd lcd;
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struct delayed_work bl_work;
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struct mutex bl_tempo_lock; /* Protects access to bl_tempo */
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bool bl_tempo;
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bool must_clear;
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/* contains the LCD config state */
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unsigned long int flags;
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/* Contains the LCD X and Y offset */
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struct {
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unsigned long int x;
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unsigned long int y;
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} addr;
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/* Current escape sequence and it's length or -1 if outside */
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struct {
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char buf[LCD_ESCAPE_LEN + 1];
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int len;
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} esc_seq;
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unsigned long long drvdata[0];
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};
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#define to_priv(p) container_of(p, struct charlcd_priv, lcd)
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/* Device single-open policy control */
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static atomic_t charlcd_available = ATOMIC_INIT(1);
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/* sleeps that many milliseconds with a reschedule */
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static void long_sleep(int ms)
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{
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schedule_timeout_interruptible(msecs_to_jiffies(ms));
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}
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/* turn the backlight on or off */
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static void charlcd_backlight(struct charlcd *lcd, int on)
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{
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struct charlcd_priv *priv = to_priv(lcd);
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if (!lcd->ops->backlight)
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return;
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mutex_lock(&priv->bl_tempo_lock);
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if (!priv->bl_tempo)
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lcd->ops->backlight(lcd, on);
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mutex_unlock(&priv->bl_tempo_lock);
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}
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static void charlcd_bl_off(struct work_struct *work)
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{
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struct delayed_work *dwork = to_delayed_work(work);
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struct charlcd_priv *priv =
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container_of(dwork, struct charlcd_priv, bl_work);
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mutex_lock(&priv->bl_tempo_lock);
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if (priv->bl_tempo) {
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priv->bl_tempo = false;
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if (!(priv->flags & LCD_FLAG_L))
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priv->lcd.ops->backlight(&priv->lcd, 0);
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}
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mutex_unlock(&priv->bl_tempo_lock);
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}
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/* turn the backlight on for a little while */
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void charlcd_poke(struct charlcd *lcd)
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{
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struct charlcd_priv *priv = to_priv(lcd);
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if (!lcd->ops->backlight)
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return;
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cancel_delayed_work_sync(&priv->bl_work);
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mutex_lock(&priv->bl_tempo_lock);
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if (!priv->bl_tempo && !(priv->flags & LCD_FLAG_L))
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lcd->ops->backlight(lcd, 1);
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priv->bl_tempo = true;
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schedule_delayed_work(&priv->bl_work, LCD_BL_TEMPO_PERIOD * HZ);
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mutex_unlock(&priv->bl_tempo_lock);
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}
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EXPORT_SYMBOL_GPL(charlcd_poke);
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static void charlcd_gotoxy(struct charlcd *lcd)
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{
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struct charlcd_priv *priv = to_priv(lcd);
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unsigned int addr;
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/*
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* we force the cursor to stay at the end of the
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* line if it wants to go farther
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*/
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addr = priv->addr.x < lcd->bwidth ? priv->addr.x & (lcd->hwidth - 1)
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: lcd->bwidth - 1;
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if (priv->addr.y & 1)
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addr += lcd->hwidth;
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if (priv->addr.y & 2)
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addr += lcd->bwidth;
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lcd->ops->write_cmd(lcd, LCD_CMD_SET_DDRAM_ADDR | addr);
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}
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static void charlcd_home(struct charlcd *lcd)
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{
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struct charlcd_priv *priv = to_priv(lcd);
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priv->addr.x = 0;
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priv->addr.y = 0;
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charlcd_gotoxy(lcd);
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}
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static void charlcd_print(struct charlcd *lcd, char c)
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{
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struct charlcd_priv *priv = to_priv(lcd);
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if (priv->addr.x < lcd->bwidth) {
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if (lcd->char_conv)
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c = lcd->char_conv[(unsigned char)c];
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lcd->ops->write_data(lcd, c);
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priv->addr.x++;
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/* prevents the cursor from wrapping onto the next line */
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if (priv->addr.x == lcd->bwidth)
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charlcd_gotoxy(lcd);
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}
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}
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static void charlcd_clear_fast(struct charlcd *lcd)
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{
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int pos;
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charlcd_home(lcd);
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if (lcd->ops->clear_fast)
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lcd->ops->clear_fast(lcd);
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else
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for (pos = 0; pos < min(2, lcd->height) * lcd->hwidth; pos++)
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lcd->ops->write_data(lcd, ' ');
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charlcd_home(lcd);
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}
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/* clears the display and resets X/Y */
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static void charlcd_clear_display(struct charlcd *lcd)
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{
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struct charlcd_priv *priv = to_priv(lcd);
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lcd->ops->write_cmd(lcd, LCD_CMD_DISPLAY_CLEAR);
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priv->addr.x = 0;
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priv->addr.y = 0;
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/* we must wait a few milliseconds (15) */
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long_sleep(15);
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}
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static int charlcd_init_display(struct charlcd *lcd)
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{
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void (*write_cmd_raw)(struct charlcd *lcd, int cmd);
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struct charlcd_priv *priv = to_priv(lcd);
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u8 init;
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if (lcd->ifwidth != 4 && lcd->ifwidth != 8)
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return -EINVAL;
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priv->flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | LCD_FLAG_D |
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LCD_FLAG_C | LCD_FLAG_B;
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long_sleep(20); /* wait 20 ms after power-up for the paranoid */
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/*
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* 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure
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* the LCD is in 8-bit mode afterwards
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*/
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init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS;
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if (lcd->ifwidth == 4) {
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init >>= 4;
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write_cmd_raw = lcd->ops->write_cmd_raw4;
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} else {
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write_cmd_raw = lcd->ops->write_cmd;
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}
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write_cmd_raw(lcd, init);
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long_sleep(10);
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write_cmd_raw(lcd, init);
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long_sleep(10);
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write_cmd_raw(lcd, init);
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long_sleep(10);
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if (lcd->ifwidth == 4) {
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/* Switch to 4-bit mode, 1 line, small fonts */
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lcd->ops->write_cmd_raw4(lcd, LCD_CMD_FUNCTION_SET >> 4);
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long_sleep(10);
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}
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/* set font height and lines number */
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lcd->ops->write_cmd(lcd,
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LCD_CMD_FUNCTION_SET |
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((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
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((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS : 0) |
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((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
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long_sleep(10);
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/* display off, cursor off, blink off */
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lcd->ops->write_cmd(lcd, LCD_CMD_DISPLAY_CTRL);
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long_sleep(10);
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lcd->ops->write_cmd(lcd,
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LCD_CMD_DISPLAY_CTRL | /* set display mode */
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((priv->flags & LCD_FLAG_D) ? LCD_CMD_DISPLAY_ON : 0) |
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((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
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((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
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charlcd_backlight(lcd, (priv->flags & LCD_FLAG_L) ? 1 : 0);
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long_sleep(10);
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/* entry mode set : increment, cursor shifting */
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lcd->ops->write_cmd(lcd, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC);
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charlcd_clear_display(lcd);
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return 0;
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}
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/*
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* Parses an unsigned integer from a string, until a non-digit character
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* is found. The empty string is not accepted. No overflow checks are done.
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*
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* Returns whether the parsing was successful. Only in that case
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* the output parameters are written to.
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*
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* TODO: If the kernel adds an inplace version of kstrtoul(), this function
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* could be easily replaced by that.
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*/
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static bool parse_n(const char *s, unsigned long *res, const char **next_s)
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{
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if (!isdigit(*s))
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return false;
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*res = 0;
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while (isdigit(*s)) {
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*res = *res * 10 + (*s - '0');
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++s;
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}
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*next_s = s;
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return true;
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}
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/*
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* Parses a movement command of the form "(.*);", where the group can be
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* any number of subcommands of the form "(x|y)[0-9]+".
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*
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* Returns whether the command is valid. The position arguments are
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* only written if the parsing was successful.
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*
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* For instance:
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* - ";" returns (<original x>, <original y>).
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* - "x1;" returns (1, <original y>).
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* - "y2x1;" returns (1, 2).
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* - "x12y34x56;" returns (56, 34).
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* - "" fails.
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* - "x" fails.
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* - "x;" fails.
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* - "x1" fails.
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* - "xy12;" fails.
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* - "x12yy12;" fails.
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* - "xx" fails.
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*/
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static bool parse_xy(const char *s, unsigned long *x, unsigned long *y)
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{
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unsigned long new_x = *x;
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unsigned long new_y = *y;
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for (;;) {
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if (!*s)
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return false;
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if (*s == ';')
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break;
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if (*s == 'x') {
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if (!parse_n(s + 1, &new_x, &s))
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return false;
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} else if (*s == 'y') {
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if (!parse_n(s + 1, &new_y, &s))
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return false;
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} else {
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return false;
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}
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}
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*x = new_x;
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*y = new_y;
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return true;
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}
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/*
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* These are the file operation function for user access to /dev/lcd
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* This function can also be called from inside the kernel, by
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* setting file and ppos to NULL.
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*
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*/
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static inline int handle_lcd_special_code(struct charlcd *lcd)
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{
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struct charlcd_priv *priv = to_priv(lcd);
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/* LCD special codes */
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int processed = 0;
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char *esc = priv->esc_seq.buf + 2;
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int oldflags = priv->flags;
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/* check for display mode flags */
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switch (*esc) {
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case 'D': /* Display ON */
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priv->flags |= LCD_FLAG_D;
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processed = 1;
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break;
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case 'd': /* Display OFF */
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priv->flags &= ~LCD_FLAG_D;
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processed = 1;
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break;
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case 'C': /* Cursor ON */
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priv->flags |= LCD_FLAG_C;
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processed = 1;
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break;
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case 'c': /* Cursor OFF */
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priv->flags &= ~LCD_FLAG_C;
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processed = 1;
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break;
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case 'B': /* Blink ON */
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priv->flags |= LCD_FLAG_B;
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processed = 1;
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break;
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case 'b': /* Blink OFF */
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priv->flags &= ~LCD_FLAG_B;
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processed = 1;
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break;
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case '+': /* Back light ON */
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priv->flags |= LCD_FLAG_L;
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processed = 1;
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break;
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case '-': /* Back light OFF */
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priv->flags &= ~LCD_FLAG_L;
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processed = 1;
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break;
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case '*': /* Flash back light */
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charlcd_poke(lcd);
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processed = 1;
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break;
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case 'f': /* Small Font */
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priv->flags &= ~LCD_FLAG_F;
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processed = 1;
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break;
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case 'F': /* Large Font */
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priv->flags |= LCD_FLAG_F;
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processed = 1;
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break;
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case 'n': /* One Line */
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priv->flags &= ~LCD_FLAG_N;
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processed = 1;
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break;
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case 'N': /* Two Lines */
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priv->flags |= LCD_FLAG_N;
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processed = 1;
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break;
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case 'l': /* Shift Cursor Left */
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if (priv->addr.x > 0) {
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/* back one char if not at end of line */
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if (priv->addr.x < lcd->bwidth)
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lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
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priv->addr.x--;
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}
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processed = 1;
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break;
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case 'r': /* shift cursor right */
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if (priv->addr.x < lcd->width) {
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/* allow the cursor to pass the end of the line */
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if (priv->addr.x < (lcd->bwidth - 1))
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lcd->ops->write_cmd(lcd,
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LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT);
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priv->addr.x++;
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}
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processed = 1;
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break;
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case 'L': /* shift display left */
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lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT);
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processed = 1;
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break;
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case 'R': /* shift display right */
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lcd->ops->write_cmd(lcd,
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LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT |
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LCD_CMD_SHIFT_RIGHT);
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processed = 1;
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break;
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case 'k': { /* kill end of line */
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int x;
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for (x = priv->addr.x; x < lcd->bwidth; x++)
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lcd->ops->write_data(lcd, ' ');
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/* restore cursor position */
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charlcd_gotoxy(lcd);
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processed = 1;
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break;
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}
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case 'I': /* reinitialize display */
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charlcd_init_display(lcd);
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processed = 1;
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break;
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case 'G': {
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/* Generator : LGcxxxxx...xx; must have <c> between '0'
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* and '7', representing the numerical ASCII code of the
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* redefined character, and <xx...xx> a sequence of 16
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* hex digits representing 8 bytes for each character.
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* Most LCDs will only use 5 lower bits of the 7 first
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* bytes.
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*/
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unsigned char cgbytes[8];
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unsigned char cgaddr;
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int cgoffset;
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int shift;
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char value;
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int addr;
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if (!strchr(esc, ';'))
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break;
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esc++;
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cgaddr = *(esc++) - '0';
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if (cgaddr > 7) {
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processed = 1;
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break;
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}
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cgoffset = 0;
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shift = 0;
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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 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 = 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 = 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);
|
|
}
|
|
}
|
|
|
|
/* 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->ifwidth = 8;
|
|
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");
|