// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "charlcd.h"
#include "hd44780_common.h"
/* 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 */
/* sleeps that many milliseconds with a reschedule */
static void long_sleep(int ms)
{
schedule_timeout_interruptible(msecs_to_jiffies(ms));
}
int hd44780_common_print(struct charlcd *lcd, int c)
{
struct hd44780_common *hdc = lcd->drvdata;
if (lcd->addr.x < hdc->bwidth) {
hdc->write_data(hdc, c);
return 0;
}
return 1;
}
EXPORT_SYMBOL_GPL(hd44780_common_print);
int hd44780_common_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y)
{
struct hd44780_common *hdc = lcd->drvdata;
unsigned int addr;
/*
* we force the cursor to stay at the end of the
* line if it wants to go farther
*/
addr = x < hdc->bwidth ? x & (hdc->hwidth - 1) : hdc->bwidth - 1;
if (y & 1)
addr += hdc->hwidth;
if (y & 2)
addr += hdc->bwidth;
hdc->write_cmd(hdc, LCD_CMD_SET_DDRAM_ADDR | addr);
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_gotoxy);
int hd44780_common_home(struct charlcd *lcd)
{
return hd44780_common_gotoxy(lcd, 0, 0);
}
EXPORT_SYMBOL_GPL(hd44780_common_home);
/* clears the display and resets X/Y */
int hd44780_common_clear_display(struct charlcd *lcd)
{
struct hd44780_common *hdc = lcd->drvdata;
hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CLEAR);
/* datasheet says to wait 1,64 milliseconds */
long_sleep(2);
/*
* The Hitachi HD44780 controller (and compatible ones) reset the DDRAM
* address when executing the DISPLAY_CLEAR command, thus the
* following call is not required. However, other controllers do not
* (e.g. NewHaven NHD-0220DZW-AG5), thus move the cursor to home
* unconditionally to support both.
*/
return hd44780_common_home(lcd);
}
EXPORT_SYMBOL_GPL(hd44780_common_clear_display);
int hd44780_common_init_display(struct charlcd *lcd)
{
struct hd44780_common *hdc = lcd->drvdata;
void (*write_cmd_raw)(struct hd44780_common *hdc, int cmd);
u8 init;
if (hdc->ifwidth != 4 && hdc->ifwidth != 8)
return -EINVAL;
hdc->hd44780_common_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 (hdc->ifwidth == 4) {
init >>= 4;
write_cmd_raw = hdc->write_cmd_raw4;
} else {
write_cmd_raw = hdc->write_cmd;
}
write_cmd_raw(hdc, init);
long_sleep(10);
write_cmd_raw(hdc, init);
long_sleep(10);
write_cmd_raw(hdc, init);
long_sleep(10);
if (hdc->ifwidth == 4) {
/* Switch to 4-bit mode, 1 line, small fonts */
hdc->write_cmd_raw4(hdc, LCD_CMD_FUNCTION_SET >> 4);
long_sleep(10);
}
/* set font height and lines number */
hdc->write_cmd(hdc,
LCD_CMD_FUNCTION_SET |
((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
((hdc->hd44780_common_flags & LCD_FLAG_F) ?
LCD_CMD_FONT_5X10_DOTS : 0) |
((hdc->hd44780_common_flags & LCD_FLAG_N) ?
LCD_CMD_TWO_LINES : 0));
long_sleep(10);
/* display off, cursor off, blink off */
hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CTRL);
long_sleep(10);
hdc->write_cmd(hdc,
LCD_CMD_DISPLAY_CTRL | /* set display mode */
((hdc->hd44780_common_flags & LCD_FLAG_D) ?
LCD_CMD_DISPLAY_ON : 0) |
((hdc->hd44780_common_flags & LCD_FLAG_C) ?
LCD_CMD_CURSOR_ON : 0) |
((hdc->hd44780_common_flags & LCD_FLAG_B) ?
LCD_CMD_BLINK_ON : 0));
charlcd_backlight(lcd,
(hdc->hd44780_common_flags & LCD_FLAG_L) ? 1 : 0);
long_sleep(10);
/* entry mode set : increment, cursor shifting */
hdc->write_cmd(hdc, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC);
hd44780_common_clear_display(lcd);
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_init_display);
int hd44780_common_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir)
{
struct hd44780_common *hdc = lcd->drvdata;
if (dir == CHARLCD_SHIFT_LEFT) {
/* back one char if not at end of line */
if (lcd->addr.x < hdc->bwidth)
hdc->write_cmd(hdc, LCD_CMD_SHIFT);
} else if (dir == CHARLCD_SHIFT_RIGHT) {
/* allow the cursor to pass the end of the line */
if (lcd->addr.x < (hdc->bwidth - 1))
hdc->write_cmd(hdc,
LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT);
}
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_shift_cursor);
int hd44780_common_shift_display(struct charlcd *lcd,
enum charlcd_shift_dir dir)
{
struct hd44780_common *hdc = lcd->drvdata;
if (dir == CHARLCD_SHIFT_LEFT)
hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT);
else if (dir == CHARLCD_SHIFT_RIGHT)
hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT |
LCD_CMD_SHIFT_RIGHT);
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_shift_display);
static void hd44780_common_set_mode(struct hd44780_common *hdc)
{
hdc->write_cmd(hdc,
LCD_CMD_DISPLAY_CTRL |
((hdc->hd44780_common_flags & LCD_FLAG_D) ?
LCD_CMD_DISPLAY_ON : 0) |
((hdc->hd44780_common_flags & LCD_FLAG_C) ?
LCD_CMD_CURSOR_ON : 0) |
((hdc->hd44780_common_flags & LCD_FLAG_B) ?
LCD_CMD_BLINK_ON : 0));
}
int hd44780_common_display(struct charlcd *lcd, enum charlcd_onoff on)
{
struct hd44780_common *hdc = lcd->drvdata;
if (on == CHARLCD_ON)
hdc->hd44780_common_flags |= LCD_FLAG_D;
else
hdc->hd44780_common_flags &= ~LCD_FLAG_D;
hd44780_common_set_mode(hdc);
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_display);
int hd44780_common_cursor(struct charlcd *lcd, enum charlcd_onoff on)
{
struct hd44780_common *hdc = lcd->drvdata;
if (on == CHARLCD_ON)
hdc->hd44780_common_flags |= LCD_FLAG_C;
else
hdc->hd44780_common_flags &= ~LCD_FLAG_C;
hd44780_common_set_mode(hdc);
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_cursor);
int hd44780_common_blink(struct charlcd *lcd, enum charlcd_onoff on)
{
struct hd44780_common *hdc = lcd->drvdata;
if (on == CHARLCD_ON)
hdc->hd44780_common_flags |= LCD_FLAG_B;
else
hdc->hd44780_common_flags &= ~LCD_FLAG_B;
hd44780_common_set_mode(hdc);
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_blink);
static void hd44780_common_set_function(struct hd44780_common *hdc)
{
hdc->write_cmd(hdc,
LCD_CMD_FUNCTION_SET |
((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
((hdc->hd44780_common_flags & LCD_FLAG_F) ?
LCD_CMD_FONT_5X10_DOTS : 0) |
((hdc->hd44780_common_flags & LCD_FLAG_N) ?
LCD_CMD_TWO_LINES : 0));
}
int hd44780_common_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)
{
struct hd44780_common *hdc = lcd->drvdata;
if (size == CHARLCD_FONTSIZE_LARGE)
hdc->hd44780_common_flags |= LCD_FLAG_F;
else
hdc->hd44780_common_flags &= ~LCD_FLAG_F;
hd44780_common_set_function(hdc);
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_fontsize);
int hd44780_common_lines(struct charlcd *lcd, enum charlcd_lines lines)
{
struct hd44780_common *hdc = lcd->drvdata;
if (lines == CHARLCD_LINES_2)
hdc->hd44780_common_flags |= LCD_FLAG_N;
else
hdc->hd44780_common_flags &= ~LCD_FLAG_N;
hd44780_common_set_function(hdc);
return 0;
}
EXPORT_SYMBOL_GPL(hd44780_common_lines);
int hd44780_common_redefine_char(struct charlcd *lcd, char *esc)
{
/* 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.
*/
struct hd44780_common *hdc = lcd->drvdata;
unsigned char cgbytes[8];
unsigned char cgaddr;
int cgoffset;
int shift;
char value;
int addr;
if (!strchr(esc, ';'))
return 0;
esc++;
cgaddr = *(esc++) - '0';
if (cgaddr > 7)
return 1;
cgoffset = 0;
shift = 0;
value = 0;
while (*esc && cgoffset < 8) {
int half;
shift ^= 4;
half = hex_to_bin(*esc++);
if (half < 0)
continue;
value |= half << shift;
if (shift == 0) {
cgbytes[cgoffset++] = value;
value = 0;
}
}
hdc->write_cmd(hdc, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8));
for (addr = 0; addr < cgoffset; addr++)
hdc->write_data(hdc, cgbytes[addr]);
/* ensures that we stop writing to CGRAM */
lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y);
return 1;
}
EXPORT_SYMBOL_GPL(hd44780_common_redefine_char);
struct hd44780_common *hd44780_common_alloc(void)
{
struct hd44780_common *hd;
hd = kzalloc(sizeof(*hd), GFP_KERNEL);
if (!hd)
return NULL;
hd->ifwidth = 8;
hd->bwidth = DEFAULT_LCD_BWIDTH;
hd->hwidth = DEFAULT_LCD_HWIDTH;
return hd;
}
EXPORT_SYMBOL_GPL(hd44780_common_alloc);
MODULE_DESCRIPTION("Common functions for HD44780 (and compatibles) LCD displays");
MODULE_LICENSE("GPL");
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