[PATCH v2 15/32] auxdisplay: implement hd44780_common_shift_cursor

From: poeschel
Date: Mon Sep 21 2020 - 10:49:58 EST

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From: Lars Poeschel <poeschel@xxxxxxxxxxx>

Implement a hd44780_common_shift_cursor function for drivers to use and
make charlcd use this function through ops function pointer.

Signed-off-by: Lars Poeschel <poeschel@xxxxxxxxxxx>
---
drivers/auxdisplay/charlcd.c | 33 ++++++++++++-----------------
drivers/auxdisplay/charlcd.h | 7 ++++++
drivers/auxdisplay/hd44780.c | 2 ++
drivers/auxdisplay/hd44780_common.c | 22 +++++++++++++++++++
drivers/auxdisplay/hd44780_common.h | 2 ++
drivers/auxdisplay/panel.c | 3 +++
6 files changed, 50 insertions(+), 19 deletions(-)

diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
index 94f6b0afab13..85747e13bf48 100644
--- a/drivers/auxdisplay/charlcd.c
+++ b/drivers/auxdisplay/charlcd.c
@@ -288,21 +288,18 @@ static inline int handle_lcd_special_code(struct charlcd *lcd)
break;
case 'l': /* Shift Cursor Left */
if (lcd->addr.x > 0) {
- /* back one char if not at end of line */
- if (lcd->addr.x < hdc->bwidth)
- hdc->write_cmd(hdc, LCD_CMD_SHIFT);
- lcd->addr.x--;
+ if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_LEFT))
+ lcd->addr.x--;
}
+
processed = 1;
break;
case 'r': /* shift cursor right */
if (lcd->addr.x < lcd->width) {
- /* 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);
- lcd->addr.x++;
+ if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_RIGHT))
+ lcd->addr.x++;
}
+
processed = 1;
break;
case 'L': /* shift display left */
@@ -456,19 +453,17 @@ static void charlcd_write_char(struct charlcd *lcd, char c)
case '\b':
/* go back one char and clear it */
if (lcd->addr.x > 0) {
- /*
- * check if we're not at the
- * end of the line
- */
- if (lcd->addr.x < hdc->bwidth)
- /* back one char */
- hdc->write_cmd(hdc, LCD_CMD_SHIFT);
- lcd->addr.x--;
+ /* back one char */
+ if (!lcd->ops->shift_cursor(lcd,
+ CHARLCD_SHIFT_LEFT))
+ lcd->addr.x--;
}
/* replace with a space */
- hdc->write_data(hdc, ' ');
+ charlcd_print(lcd, ' ');
/* back one char again */
- hdc->write_cmd(hdc, LCD_CMD_SHIFT);
+ if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_LEFT))
+ lcd->addr.x--;
+
break;
case '\f':
/* quickly clear the display */
diff --git a/drivers/auxdisplay/charlcd.h b/drivers/auxdisplay/charlcd.h
index 6281cf299a6d..0a340beacd3e 100644
--- a/drivers/auxdisplay/charlcd.h
+++ b/drivers/auxdisplay/charlcd.h
@@ -21,6 +21,11 @@ enum charlcd_onoff {
CHARLCD_ON,
};

+enum charlcd_shift_dir {
+ CHARLCD_SHIFT_LEFT,
+ CHARLCD_SHIFT_RIGHT,
+};
+
struct charlcd {
const struct charlcd_ops *ops;
const unsigned char *char_conv; /* Optional */
@@ -53,6 +58,7 @@ struct charlcd {
* values in addr.x and addr.y are set to 0, 0 by charlcd prior to calling this
* function.
* @init_display: Initialize the display.
+ * @shift_cursor: Shift cursor left or right one position.
*/
struct charlcd_ops {
void (*clear_fast)(struct charlcd *lcd);
@@ -62,6 +68,7 @@ struct charlcd_ops {
int (*home)(struct charlcd *lcd);
int (*clear_display)(struct charlcd *lcd);
int (*init_display)(struct charlcd *lcd);
+ int (*shift_cursor)(struct charlcd *lcd, enum charlcd_shift_dir dir);
};

void charlcd_backlight(struct charlcd *lcd, enum charlcd_onoff on);
diff --git a/drivers/auxdisplay/hd44780.c b/drivers/auxdisplay/hd44780.c
index 5916da09f738..6ffeeb3fb0d0 100644
--- a/drivers/auxdisplay/hd44780.c
+++ b/drivers/auxdisplay/hd44780.c
@@ -131,6 +131,7 @@ static const struct charlcd_ops hd44780_ops_gpio8 = {
.home = hd44780_common_home,
.clear_display = hd44780_common_clear_display,
.init_display = hd44780_common_init_display,
+ .shift_cursor = hd44780_common_shift_cursor,
};

/* Send a command to the LCD panel in 4 bit GPIO mode */
@@ -179,6 +180,7 @@ static const struct charlcd_ops hd44780_ops_gpio4 = {
.home = hd44780_common_home,
.clear_display = hd44780_common_clear_display,
.init_display = hd44780_common_init_display,
+ .shift_cursor = hd44780_common_shift_cursor,
};

static int hd44780_probe(struct platform_device *pdev)
diff --git a/drivers/auxdisplay/hd44780_common.c b/drivers/auxdisplay/hd44780_common.c
index 4f478ab66ed9..b2ed00635766 100644
--- a/drivers/auxdisplay/hd44780_common.c
+++ b/drivers/auxdisplay/hd44780_common.c
@@ -17,6 +17,9 @@
#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_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 */
@@ -157,6 +160,25 @@ int hd44780_common_init_display(struct charlcd *lcd)
}
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);
+
struct hd44780_common *hd44780_common_alloc(void)
{
struct hd44780_common *hd;
diff --git a/drivers/auxdisplay/hd44780_common.h b/drivers/auxdisplay/hd44780_common.h
index cefd78d67675..432fc37213cf 100644
--- a/drivers/auxdisplay/hd44780_common.h
+++ b/drivers/auxdisplay/hd44780_common.h
@@ -20,5 +20,7 @@ int hd44780_common_gotoxy(struct charlcd *lcd);
int hd44780_common_home(struct charlcd *lcd);
int hd44780_common_clear_display(struct charlcd *lcd);
int hd44780_common_init_display(struct charlcd *lcd);
+int hd44780_common_shift_cursor(struct charlcd *lcd,
+ enum charlcd_shift_dir dir);
struct hd44780_common *hd44780_common_alloc(void);

diff --git a/drivers/auxdisplay/panel.c b/drivers/auxdisplay/panel.c
index 583bd22d3abd..4275223080e8 100644
--- a/drivers/auxdisplay/panel.c
+++ b/drivers/auxdisplay/panel.c
@@ -879,6 +879,7 @@ static const struct charlcd_ops charlcd_serial_ops = {
.home = hd44780_common_home,
.clear_display = hd44780_common_clear_display,
.init_display = hd44780_common_init_display,
+ .shift_cursor = hd44780_common_shift_cursor,
};

static const struct charlcd_ops charlcd_parallel_ops = {
@@ -888,6 +889,7 @@ static const struct charlcd_ops charlcd_parallel_ops = {
.home = hd44780_common_home,
.clear_display = hd44780_common_clear_display,
.init_display = hd44780_common_init_display,
+ .shift_cursor = hd44780_common_shift_cursor,
};

static const struct charlcd_ops charlcd_tilcd_ops = {
@@ -897,6 +899,7 @@ static const struct charlcd_ops charlcd_tilcd_ops = {
.home = hd44780_common_home,
.clear_display = hd44780_common_clear_display,
.init_display = hd44780_common_init_display,
+ .shift_cursor = hd44780_common_shift_cursor,
};

/* initialize the LCD driver */
--
2.28.0

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