1 files changed, 361 insertions, 0 deletions
diff --git a/drivers/auxdisplay/hd44780_common.c b/drivers/auxdisplay/hd44780_common.c
new file mode 100644
index 000000000000..3934c2eebf33
--- /dev/null
+++ b/drivers/auxdisplay/hd44780_common.c
@@ -0,0 +1,361 @@
+// 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);
+	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);
+
+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");