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// 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_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_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)
{
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 = lcd->addr.x < hdc->bwidth ? lcd->addr.x & (hdc->hwidth - 1)
: hdc->bwidth - 1;
if (lcd->addr.y & 1)
addr += hdc->hwidth;
if (lcd->addr.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)
{
lcd->addr.x = 0;
lcd->addr.y = 0;
return hd44780_common_gotoxy(lcd);
}
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);
/* we must wait a few milliseconds (15) */
long_sleep(15);
return 0;
}
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);
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_LICENSE("GPL");
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