1 // SPDX-License-Identifier: GPL-2.0+
3  * HD44780 Character LCD driver for Linux
5  * Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
6  * Copyright (C) 2016-2017 Glider bvba
40 static void hd44780_backlight(struct charlcd *lcd, int on)  in hd44780_backlight()  argument
42 	struct hd44780 *hd = lcd->drvdata;  in hd44780_backlight()
44 	if (hd->pins[PIN_CTRL_BL])  in hd44780_backlight()
45 		gpiod_set_value_cansleep(hd->pins[PIN_CTRL_BL], on);  in hd44780_backlight()
53 	gpiod_set_value_cansleep(hd->pins[PIN_CTRL_E], 1);  in hd44780_strobe_gpio()
58 	gpiod_set_value_cansleep(hd->pins[PIN_CTRL_E], 0);  in hd44780_strobe_gpio()
61 /* write to an LCD panel register in 8 bit GPIO mode */
64 	DECLARE_BITMAP(values, 10); /* for DATA[0-7], RS, RW */  in hd44780_write_gpio8()
69 	n = hd->pins[PIN_CTRL_RW] ? 10 : 9;  in hd44780_write_gpio8()
72 	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA0], NULL, values);  in hd44780_write_gpio8()
77 /* write to an LCD panel register in 4 bit GPIO mode */
80 	DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */  in hd44780_write_gpio4()
86 	n = hd->pins[PIN_CTRL_RW] ? 6 : 5;  in hd44780_write_gpio4()
89 	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);  in hd44780_write_gpio4()
98 	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);  in hd44780_write_gpio4()
103 /* Send a command to the LCD panel in 8 bit GPIO mode */
104 static void hd44780_write_cmd_gpio8(struct charlcd *lcd, int cmd)  in hd44780_write_cmd_gpio8()  argument
106 	struct hd44780 *hd = lcd->drvdata;  in hd44780_write_cmd_gpio8()
114 /* Send data to the LCD panel in 8 bit GPIO mode */
115 static void hd44780_write_data_gpio8(struct charlcd *lcd, int data)  in hd44780_write_data_gpio8()  argument
117 	struct hd44780 *hd = lcd->drvdata;  in hd44780_write_data_gpio8()
128 	.backlight	= hd44780_backlight,
131 /* Send a command to the LCD panel in 4 bit GPIO mode */
132 static void hd44780_write_cmd_gpio4(struct charlcd *lcd, int cmd)  in hd44780_write_cmd_gpio4()  argument
134 	struct hd44780 *hd = lcd->drvdata;  in hd44780_write_cmd_gpio4()
142 /* Send 4-bits of a command to the LCD panel in raw 4 bit GPIO mode */
143 static void hd44780_write_cmd_raw_gpio4(struct charlcd *lcd, int cmd)  in hd44780_write_cmd_raw_gpio4()  argument
145 	DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */  in hd44780_write_cmd_raw_gpio4()
146 	struct hd44780 *hd = lcd->drvdata;  in hd44780_write_cmd_raw_gpio4()
151 	n = hd->pins[PIN_CTRL_RW] ? 6 : 5;  in hd44780_write_cmd_raw_gpio4()
154 	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);  in hd44780_write_cmd_raw_gpio4()
159 /* Send data to the LCD panel in 4 bit GPIO mode */
160 static void hd44780_write_data_gpio4(struct charlcd *lcd, int data)  in hd44780_write_data_gpio4()  argument
162 	struct hd44780 *hd = lcd->drvdata;  in hd44780_write_data_gpio4()
174 	.backlight	= hd44780_backlight,
179 	struct device *dev = &pdev->dev;  in hd44780_probe()
181 	struct charlcd *lcd;  in hd44780_probe()  local
198 		return -EINVAL;  in hd44780_probe()
201 	lcd = charlcd_alloc(sizeof(struct hd44780));  in hd44780_probe()
202 	if (!lcd)  in hd44780_probe()
203 		return -ENOMEM;  in hd44780_probe()
205 	hd = lcd->drvdata;  in hd44780_probe()
208 		hd->pins[base + i] = devm_gpiod_get_index(dev, "data", i,  in hd44780_probe()
210 		if (IS_ERR(hd->pins[base + i])) {  in hd44780_probe()
211 			ret = PTR_ERR(hd->pins[base + i]);  in hd44780_probe()
216 	hd->pins[PIN_CTRL_E] = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);  in hd44780_probe()
217 	if (IS_ERR(hd->pins[PIN_CTRL_E])) {  in hd44780_probe()
218 		ret = PTR_ERR(hd->pins[PIN_CTRL_E]);  in hd44780_probe()
222 	hd->pins[PIN_CTRL_RS] = devm_gpiod_get(dev, "rs", GPIOD_OUT_HIGH);  in hd44780_probe()
223 	if (IS_ERR(hd->pins[PIN_CTRL_RS])) {  in hd44780_probe()
224 		ret = PTR_ERR(hd->pins[PIN_CTRL_RS]);  in hd44780_probe()
229 	hd->pins[PIN_CTRL_RW] = devm_gpiod_get_optional(dev, "rw",  in hd44780_probe()
231 	if (IS_ERR(hd->pins[PIN_CTRL_RW])) {  in hd44780_probe()
232 		ret = PTR_ERR(hd->pins[PIN_CTRL_RW]);  in hd44780_probe()
236 	hd->pins[PIN_CTRL_BL] = devm_gpiod_get_optional(dev, "backlight",  in hd44780_probe()
238 	if (IS_ERR(hd->pins[PIN_CTRL_BL])) {  in hd44780_probe()
239 		ret = PTR_ERR(hd->pins[PIN_CTRL_BL]);  in hd44780_probe()
244 	ret = device_property_read_u32(dev, "display-height-chars",  in hd44780_probe()
245 				       &lcd->height);  in hd44780_probe()
248 	ret = device_property_read_u32(dev, "display-width-chars", &lcd->width);  in hd44780_probe()
256 	if (lcd->height > 2)  in hd44780_probe()
257 		lcd->bwidth = lcd->width;  in hd44780_probe()
260 	device_property_read_u32(dev, "internal-buffer-width", &lcd->bwidth);  in hd44780_probe()
262 	lcd->ifwidth = ifwidth;  in hd44780_probe()
263 	lcd->ops = ifwidth == 8 ? &hd44780_ops_gpio8 : &hd44780_ops_gpio4;  in hd44780_probe()
265 	ret = charlcd_register(lcd);  in hd44780_probe()
269 	platform_set_drvdata(pdev, lcd);  in hd44780_probe()
273 	charlcd_free(lcd);  in hd44780_probe()
279 	struct charlcd *lcd = platform_get_drvdata(pdev);  in hd44780_remove()  local
281 	charlcd_unregister(lcd);  in hd44780_remove()
283 	charlcd_free(lcd);  in hd44780_remove()
303 MODULE_DESCRIPTION("HD44780 Character LCD driver");
304 MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");