Messages in this thread Patch in this message | | | From | Robert Abel <> | Subject | [PATCH 4/4] auxdisplay: charlcd: make home command unshift display | Date | Mon, 26 Feb 2018 00:54:32 +0100 |
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A user has no way of unshifting the display programmatically once shifted. Users cannot rely on ^[[H (home) to result in their message being seen either. Use the actual HOME command 0x02 instead of only returning to x0/y0. Users can still do ^[[Lx0y0; (go to x/y) if they wish to use the 'old' home function. Implement fast clearing of LCD by going to x0/y0 first, clearing display and then calling home to possibly unshift display possibly avoiding artifacts by not unshifting before clearing display.
Signed-off-by: Robert Abel <rabel@robertabel.eu> --- drivers/auxdisplay/charlcd.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c index 24cabe88c7f0..41f9aa4a73d4 100644 --- a/drivers/auxdisplay/charlcd.c +++ b/drivers/auxdisplay/charlcd.c @@ -43,6 +43,8 @@ /* LCD commands */ #define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */ +#define LCD_CMD_HOME 0x02 /* Set DDRAM address to 0 and unshift display */ + #define LCD_CMD_ENTRY_MODE 0x04 /* Set entry mode */ #define LCD_CMD_CURSOR_INC 0x02 /* Increment cursor */ @@ -182,7 +184,8 @@ static void charlcd_home(struct charlcd *lcd) priv->addr.x = 0; priv->addr.y = 0; - charlcd_gotoxy(lcd); + lcd->ops->write_cmd(lcd, LCD_CMD_HOME); + long_sleep(2); } static void charlcd_print(struct charlcd *lcd, char c) @@ -202,9 +205,12 @@ static void charlcd_print(struct charlcd *lcd, char c) static void charlcd_clear_fast(struct charlcd *lcd) { + struct charlcd_priv *priv = to_priv(lcd); int pos; - charlcd_home(lcd); + priv->addr.x = 0; + priv->addr.y = 0; + charlcd_gotoxy(lcd); if (lcd->ops->clear_fast) lcd->ops->clear_fast(lcd); -- 2.11.0
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