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1// SPDX-License-Identifier: GPL-2.0-or-later2#include <linux/module.h>3#include <linux/sched.h>4#include <linux/slab.h>5 6#include "charlcd.h"7#include "hd44780_common.h"8 9/* LCD commands */10#define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */11 12#define LCD_CMD_ENTRY_MODE 0x04 /* Set entry mode */13#define LCD_CMD_CURSOR_INC 0x02 /* Increment cursor */14 15#define LCD_CMD_DISPLAY_CTRL 0x08 /* Display control */16#define LCD_CMD_DISPLAY_ON 0x04 /* Set display on */17#define LCD_CMD_CURSOR_ON 0x02 /* Set cursor on */18#define LCD_CMD_BLINK_ON 0x01 /* Set blink on */19 20#define LCD_CMD_SHIFT 0x10 /* Shift cursor/display */21#define LCD_CMD_DISPLAY_SHIFT 0x08 /* Shift display instead of cursor */22#define LCD_CMD_SHIFT_RIGHT 0x04 /* Shift display/cursor to the right */23 24#define LCD_CMD_FUNCTION_SET 0x20 /* Set function */25#define LCD_CMD_DATA_LEN_8BITS 0x10 /* Set data length to 8 bits */26#define LCD_CMD_TWO_LINES 0x08 /* Set to two display lines */27#define LCD_CMD_FONT_5X10_DOTS 0x04 /* Set char font to 5x10 dots */28 29#define LCD_CMD_SET_CGRAM_ADDR 0x40 /* Set char generator RAM address */30 31#define LCD_CMD_SET_DDRAM_ADDR 0x80 /* Set display data RAM address */32 33/* sleeps that many milliseconds with a reschedule */34static void long_sleep(int ms)35{36 schedule_timeout_interruptible(msecs_to_jiffies(ms));37}38 39int hd44780_common_print(struct charlcd *lcd, int c)40{41 struct hd44780_common *hdc = lcd->drvdata;42 43 if (lcd->addr.x < hdc->bwidth) {44 hdc->write_data(hdc, c);45 return 0;46 }47 48 return 1;49}50EXPORT_SYMBOL_GPL(hd44780_common_print);51 52int hd44780_common_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y)53{54 struct hd44780_common *hdc = lcd->drvdata;55 unsigned int addr;56 57 /*58 * we force the cursor to stay at the end of the59 * line if it wants to go farther60 */61 addr = x < hdc->bwidth ? x & (hdc->hwidth - 1) : hdc->bwidth - 1;62 if (y & 1)63 addr += hdc->hwidth;64 if (y & 2)65 addr += hdc->bwidth;66 hdc->write_cmd(hdc, LCD_CMD_SET_DDRAM_ADDR | addr);67 return 0;68}69EXPORT_SYMBOL_GPL(hd44780_common_gotoxy);70 71int hd44780_common_home(struct charlcd *lcd)72{73 return hd44780_common_gotoxy(lcd, 0, 0);74}75EXPORT_SYMBOL_GPL(hd44780_common_home);76 77/* clears the display and resets X/Y */78int hd44780_common_clear_display(struct charlcd *lcd)79{80 struct hd44780_common *hdc = lcd->drvdata;81 82 hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CLEAR);83 /* datasheet says to wait 1,64 milliseconds */84 long_sleep(2);85 86 /*87 * The Hitachi HD44780 controller (and compatible ones) reset the DDRAM88 * address when executing the DISPLAY_CLEAR command, thus the89 * following call is not required. However, other controllers do not90 * (e.g. NewHaven NHD-0220DZW-AG5), thus move the cursor to home91 * unconditionally to support both.92 */93 return hd44780_common_home(lcd);94}95EXPORT_SYMBOL_GPL(hd44780_common_clear_display);96 97int hd44780_common_init_display(struct charlcd *lcd)98{99 struct hd44780_common *hdc = lcd->drvdata;100 101 void (*write_cmd_raw)(struct hd44780_common *hdc, int cmd);102 u8 init;103 104 if (hdc->ifwidth != 4 && hdc->ifwidth != 8)105 return -EINVAL;106 107 hdc->hd44780_common_flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) |108 LCD_FLAG_D | LCD_FLAG_C | LCD_FLAG_B;109 110 long_sleep(20); /* wait 20 ms after power-up for the paranoid */111 112 /*113 * 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure114 * the LCD is in 8-bit mode afterwards115 */116 init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS;117 if (hdc->ifwidth == 4) {118 init >>= 4;119 write_cmd_raw = hdc->write_cmd_raw4;120 } else {121 write_cmd_raw = hdc->write_cmd;122 }123 write_cmd_raw(hdc, init);124 long_sleep(10);125 write_cmd_raw(hdc, init);126 long_sleep(10);127 write_cmd_raw(hdc, init);128 long_sleep(10);129 130 if (hdc->ifwidth == 4) {131 /* Switch to 4-bit mode, 1 line, small fonts */132 hdc->write_cmd_raw4(hdc, LCD_CMD_FUNCTION_SET >> 4);133 long_sleep(10);134 }135 136 /* set font height and lines number */137 hdc->write_cmd(hdc,138 LCD_CMD_FUNCTION_SET |139 ((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |140 ((hdc->hd44780_common_flags & LCD_FLAG_F) ?141 LCD_CMD_FONT_5X10_DOTS : 0) |142 ((hdc->hd44780_common_flags & LCD_FLAG_N) ?143 LCD_CMD_TWO_LINES : 0));144 long_sleep(10);145 146 /* display off, cursor off, blink off */147 hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CTRL);148 long_sleep(10);149 150 hdc->write_cmd(hdc,151 LCD_CMD_DISPLAY_CTRL | /* set display mode */152 ((hdc->hd44780_common_flags & LCD_FLAG_D) ?153 LCD_CMD_DISPLAY_ON : 0) |154 ((hdc->hd44780_common_flags & LCD_FLAG_C) ?155 LCD_CMD_CURSOR_ON : 0) |156 ((hdc->hd44780_common_flags & LCD_FLAG_B) ?157 LCD_CMD_BLINK_ON : 0));158 159 charlcd_backlight(lcd,160 (hdc->hd44780_common_flags & LCD_FLAG_L) ? 1 : 0);161 162 long_sleep(10);163 164 /* entry mode set : increment, cursor shifting */165 hdc->write_cmd(hdc, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC);166 167 hd44780_common_clear_display(lcd);168 return 0;169}170EXPORT_SYMBOL_GPL(hd44780_common_init_display);171 172int hd44780_common_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir)173{174 struct hd44780_common *hdc = lcd->drvdata;175 176 if (dir == CHARLCD_SHIFT_LEFT) {177 /* back one char if not at end of line */178 if (lcd->addr.x < hdc->bwidth)179 hdc->write_cmd(hdc, LCD_CMD_SHIFT);180 } else if (dir == CHARLCD_SHIFT_RIGHT) {181 /* allow the cursor to pass the end of the line */182 if (lcd->addr.x < (hdc->bwidth - 1))183 hdc->write_cmd(hdc,184 LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT);185 }186 187 return 0;188}189EXPORT_SYMBOL_GPL(hd44780_common_shift_cursor);190 191int hd44780_common_shift_display(struct charlcd *lcd,192 enum charlcd_shift_dir dir)193{194 struct hd44780_common *hdc = lcd->drvdata;195 196 if (dir == CHARLCD_SHIFT_LEFT)197 hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT);198 else if (dir == CHARLCD_SHIFT_RIGHT)199 hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT |200 LCD_CMD_SHIFT_RIGHT);201 202 return 0;203}204EXPORT_SYMBOL_GPL(hd44780_common_shift_display);205 206static void hd44780_common_set_mode(struct hd44780_common *hdc)207{208 hdc->write_cmd(hdc,209 LCD_CMD_DISPLAY_CTRL |210 ((hdc->hd44780_common_flags & LCD_FLAG_D) ?211 LCD_CMD_DISPLAY_ON : 0) |212 ((hdc->hd44780_common_flags & LCD_FLAG_C) ?213 LCD_CMD_CURSOR_ON : 0) |214 ((hdc->hd44780_common_flags & LCD_FLAG_B) ?215 LCD_CMD_BLINK_ON : 0));216}217 218int hd44780_common_display(struct charlcd *lcd, enum charlcd_onoff on)219{220 struct hd44780_common *hdc = lcd->drvdata;221 222 if (on == CHARLCD_ON)223 hdc->hd44780_common_flags |= LCD_FLAG_D;224 else225 hdc->hd44780_common_flags &= ~LCD_FLAG_D;226 227 hd44780_common_set_mode(hdc);228 return 0;229}230EXPORT_SYMBOL_GPL(hd44780_common_display);231 232int hd44780_common_cursor(struct charlcd *lcd, enum charlcd_onoff on)233{234 struct hd44780_common *hdc = lcd->drvdata;235 236 if (on == CHARLCD_ON)237 hdc->hd44780_common_flags |= LCD_FLAG_C;238 else239 hdc->hd44780_common_flags &= ~LCD_FLAG_C;240 241 hd44780_common_set_mode(hdc);242 return 0;243}244EXPORT_SYMBOL_GPL(hd44780_common_cursor);245 246int hd44780_common_blink(struct charlcd *lcd, enum charlcd_onoff on)247{248 struct hd44780_common *hdc = lcd->drvdata;249 250 if (on == CHARLCD_ON)251 hdc->hd44780_common_flags |= LCD_FLAG_B;252 else253 hdc->hd44780_common_flags &= ~LCD_FLAG_B;254 255 hd44780_common_set_mode(hdc);256 return 0;257}258EXPORT_SYMBOL_GPL(hd44780_common_blink);259 260static void hd44780_common_set_function(struct hd44780_common *hdc)261{262 hdc->write_cmd(hdc,263 LCD_CMD_FUNCTION_SET |264 ((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |265 ((hdc->hd44780_common_flags & LCD_FLAG_F) ?266 LCD_CMD_FONT_5X10_DOTS : 0) |267 ((hdc->hd44780_common_flags & LCD_FLAG_N) ?268 LCD_CMD_TWO_LINES : 0));269}270 271int hd44780_common_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)272{273 struct hd44780_common *hdc = lcd->drvdata;274 275 if (size == CHARLCD_FONTSIZE_LARGE)276 hdc->hd44780_common_flags |= LCD_FLAG_F;277 else278 hdc->hd44780_common_flags &= ~LCD_FLAG_F;279 280 hd44780_common_set_function(hdc);281 return 0;282}283EXPORT_SYMBOL_GPL(hd44780_common_fontsize);284 285int hd44780_common_lines(struct charlcd *lcd, enum charlcd_lines lines)286{287 struct hd44780_common *hdc = lcd->drvdata;288 289 if (lines == CHARLCD_LINES_2)290 hdc->hd44780_common_flags |= LCD_FLAG_N;291 else292 hdc->hd44780_common_flags &= ~LCD_FLAG_N;293 294 hd44780_common_set_function(hdc);295 return 0;296}297EXPORT_SYMBOL_GPL(hd44780_common_lines);298 299int hd44780_common_redefine_char(struct charlcd *lcd, char *esc)300{301 /* Generator : LGcxxxxx...xx; must have <c> between '0'302 * and '7', representing the numerical ASCII code of the303 * redefined character, and <xx...xx> a sequence of 16304 * hex digits representing 8 bytes for each character.305 * Most LCDs will only use 5 lower bits of the 7 first306 * bytes.307 */308 309 struct hd44780_common *hdc = lcd->drvdata;310 unsigned char cgbytes[8];311 unsigned char cgaddr;312 int cgoffset;313 int shift;314 char value;315 int addr;316 317 if (!strchr(esc, ';'))318 return 0;319 320 esc++;321 322 cgaddr = *(esc++) - '0';323 if (cgaddr > 7)324 return 1;325 326 cgoffset = 0;327 shift = 0;328 value = 0;329 while (*esc && cgoffset < 8) {330 int half;331 332 shift ^= 4;333 half = hex_to_bin(*esc++);334 if (half < 0)335 continue;336 337 value |= half << shift;338 if (shift == 0) {339 cgbytes[cgoffset++] = value;340 value = 0;341 }342 }343 344 hdc->write_cmd(hdc, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8));345 for (addr = 0; addr < cgoffset; addr++)346 hdc->write_data(hdc, cgbytes[addr]);347 348 /* ensures that we stop writing to CGRAM */349 lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y);350 return 1;351}352EXPORT_SYMBOL_GPL(hd44780_common_redefine_char);353 354struct hd44780_common *hd44780_common_alloc(void)355{356 struct hd44780_common *hd;357 358 hd = kzalloc(sizeof(*hd), GFP_KERNEL);359 if (!hd)360 return NULL;361 362 hd->ifwidth = 8;363 hd->bwidth = DEFAULT_LCD_BWIDTH;364 hd->hwidth = DEFAULT_LCD_HWIDTH;365 return hd;366}367EXPORT_SYMBOL_GPL(hd44780_common_alloc);368 369MODULE_DESCRIPTION("Common functions for HD44780 (and compatibles) LCD displays");370MODULE_LICENSE("GPL");371