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https://github.com/torvalds/linux
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88645a86e3
This adds a home function to the charlcd_ops struct and offer an implementation for hd44780_common. This implementation is used by our two hd44780 drivers. This is to make charlcd device independent. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
68 lines
1.4 KiB
C
68 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#include <linux/module.h>
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#include <linux/slab.h>
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#include "charlcd.h"
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#include "hd44780_common.h"
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/* LCD commands */
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#define LCD_CMD_SET_DDRAM_ADDR 0x80 /* Set display data RAM address */
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int hd44780_common_print(struct charlcd *lcd, int c)
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{
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struct hd44780_common *hdc = lcd->drvdata;
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if (lcd->addr.x < hdc->bwidth) {
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hdc->write_data(hdc, c);
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return 0;
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}
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return 1;
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}
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EXPORT_SYMBOL_GPL(hd44780_common_print);
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int hd44780_common_gotoxy(struct charlcd *lcd)
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{
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struct hd44780_common *hdc = lcd->drvdata;
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unsigned int addr;
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/*
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* we force the cursor to stay at the end of the
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* line if it wants to go farther
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*/
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addr = lcd->addr.x < hdc->bwidth ? lcd->addr.x & (hdc->hwidth - 1)
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: hdc->bwidth - 1;
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if (lcd->addr.y & 1)
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addr += hdc->hwidth;
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if (lcd->addr.y & 2)
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addr += hdc->bwidth;
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hdc->write_cmd(hdc, LCD_CMD_SET_DDRAM_ADDR | addr);
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return 0;
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}
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EXPORT_SYMBOL_GPL(hd44780_common_gotoxy);
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int hd44780_common_home(struct charlcd *lcd)
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{
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lcd->addr.x = 0;
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lcd->addr.y = 0;
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return hd44780_common_gotoxy(lcd);
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}
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EXPORT_SYMBOL_GPL(hd44780_common_home);
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struct hd44780_common *hd44780_common_alloc(void)
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{
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struct hd44780_common *hd;
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hd = kzalloc(sizeof(*hd), GFP_KERNEL);
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if (!hd)
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return NULL;
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hd->ifwidth = 8;
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hd->bwidth = DEFAULT_LCD_BWIDTH;
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hd->hwidth = DEFAULT_LCD_HWIDTH;
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return hd;
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}
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EXPORT_SYMBOL_GPL(hd44780_common_alloc);
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MODULE_LICENSE("GPL");
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