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Diffstat (limited to '')
| -rw-r--r-- | drivers/auxdisplay/hd44780_common.c | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/drivers/auxdisplay/hd44780_common.c b/drivers/auxdisplay/hd44780_common.c new file mode 100644 index 000000000..7cbf375b0 --- /dev/null +++ b/drivers/auxdisplay/hd44780_common.c @@ -0,0 +1,369 @@ +// 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_LICENSE("GPL"); |