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authorLars Poeschel <poeschel@lemonage.de>2020-11-03 12:58:17 +0300
committerMiguel Ojeda <ojeda@kernel.org>2020-11-04 13:04:04 +0300
commit01ec46dfa633a52ccfe38d4a194460d6adb2ba00 (patch)
tree14e67817c60048d0e3c361d498041b6ef64039da /drivers/auxdisplay/hd44780_common.c
parentbd26b181d14af003a1c9903831f5735f431530f6 (diff)
downloadlinux-01ec46dfa633a52ccfe38d4a194460d6adb2ba00.tar.xz
auxdisplay: Move init_display to hd44780_common
The init_display function is moved over to hd44780_common. charlcd uses it via its ops function pointer and drivers initialize the ops with the common hd44780_common_init_display function. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'drivers/auxdisplay/hd44780_common.c')
-rw-r--r--drivers/auxdisplay/hd44780_common.c88
1 files changed, 88 insertions, 0 deletions
diff --git a/drivers/auxdisplay/hd44780_common.c b/drivers/auxdisplay/hd44780_common.c
index 2f7d55668eb4..7d4aea36cc55 100644
--- a/drivers/auxdisplay/hd44780_common.c
+++ b/drivers/auxdisplay/hd44780_common.c
@@ -9,6 +9,19 @@
/* 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 */
@@ -70,6 +83,81 @@ int hd44780_common_clear_display(struct charlcd *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);
+
struct hd44780_common *hd44780_common_alloc(void)
{
struct hd44780_common *hd;