[linux-block.git] / drivers / auxdisplay / hd44780.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * HD44780 Character LCD driver for Linux
 *
 * Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
 * Copyright (C) 2016-2017 Glider bvba
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/slab.h>

#include "charlcd.h"
#include "hd44780_common.h"

enum hd44780_pin {
	/* Order does matter due to writing to GPIO array subsets! */
	PIN_DATA0,	/* Optional */
	PIN_DATA1,	/* Optional */
	PIN_DATA2,	/* Optional */
	PIN_DATA3,	/* Optional */
	PIN_DATA4,
	PIN_DATA5,
	PIN_DATA6,
	PIN_DATA7,
	PIN_CTRL_RS,
	PIN_CTRL_RW,	/* Optional */
	PIN_CTRL_E,
	PIN_CTRL_BL,   /* Optional */
	PIN_NUM
};

struct hd44780 {
	struct gpio_desc *pins[PIN_NUM];
};

static void hd44780_backlight(struct charlcd *lcd, enum charlcd_onoff on)
{
	struct hd44780_common *hdc = lcd->drvdata;
	struct hd44780 *hd = hdc->hd44780;

	if (hd->pins[PIN_CTRL_BL])
		gpiod_set_value_cansleep(hd->pins[PIN_CTRL_BL], on);
}

static void hd44780_strobe_gpio(struct hd44780 *hd)
{
	/* Maintain the data during 20 us before the strobe */
	udelay(20);

	gpiod_set_value_cansleep(hd->pins[PIN_CTRL_E], 1);

	/* Maintain the strobe during 40 us */
	udelay(40);

	gpiod_set_value_cansleep(hd->pins[PIN_CTRL_E], 0);
}

/* write to an LCD panel register in 8 bit GPIO mode */
static void hd44780_write_gpio8(struct hd44780 *hd, u8 val, unsigned int rs)
{
	DECLARE_BITMAP(values, 10); /* for DATA[0-7], RS, RW */
	unsigned int n;

	values[0] = val;
	__assign_bit(8, values, rs);
	n = hd->pins[PIN_CTRL_RW] ? 10 : 9;

	/* Present the data to the port */
	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA0], NULL, values);

	hd44780_strobe_gpio(hd);
}

/* write to an LCD panel register in 4 bit GPIO mode */
static void hd44780_write_gpio4(struct hd44780 *hd, u8 val, unsigned int rs)
{
	DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */
	unsigned int n;

	/* High nibble + RS, RW */
	values[0] = val >> 4;
	__assign_bit(4, values, rs);
	n = hd->pins[PIN_CTRL_RW] ? 6 : 5;

	/* Present the data to the port */
	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);

	hd44780_strobe_gpio(hd);

	/* Low nibble */
	values[0] &= ~0x0fUL;
	values[0] |= val & 0x0f;

	/* Present the data to the port */
	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);

	hd44780_strobe_gpio(hd);
}

/* Send a command to the LCD panel in 8 bit GPIO mode */
static void hd44780_write_cmd_gpio8(struct hd44780_common *hdc, int cmd)
{
	struct hd44780 *hd = hdc->hd44780;

	hd44780_write_gpio8(hd, cmd, 0);

	/* The shortest command takes at least 120 us */
	udelay(120);
}

/* Send data to the LCD panel in 8 bit GPIO mode */
static void hd44780_write_data_gpio8(struct hd44780_common *hdc, int data)
{
	struct hd44780 *hd = hdc->hd44780;

	hd44780_write_gpio8(hd, data, 1);

	/* The shortest data takes at least 45 us */
	udelay(45);
}

static const struct charlcd_ops hd44780_ops_gpio8 = {
	.backlight	= hd44780_backlight,
};

/* Send a command to the LCD panel in 4 bit GPIO mode */
static void hd44780_write_cmd_gpio4(struct hd44780_common *hdc, int cmd)
{
	struct hd44780 *hd = hdc->hd44780;

	hd44780_write_gpio4(hd, cmd, 0);

	/* The shortest command takes at least 120 us */
	udelay(120);
}

/* Send 4-bits of a command to the LCD panel in raw 4 bit GPIO mode */
static void hd44780_write_cmd_raw_gpio4(struct hd44780_common *hdc, int cmd)
{
	DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */
	struct hd44780 *hd = hdc->hd44780;
	unsigned int n;

	/* Command nibble + RS, RW */
	values[0] = cmd & 0x0f;
	n = hd->pins[PIN_CTRL_RW] ? 6 : 5;

	/* Present the data to the port */
	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);

	hd44780_strobe_gpio(hd);
}

/* Send data to the LCD panel in 4 bit GPIO mode */
static void hd44780_write_data_gpio4(struct hd44780_common *hdc, int data)
{
	struct hd44780 *hd = hdc->hd44780;

	hd44780_write_gpio4(hd, data, 1);

	/* The shortest data takes at least 45 us */
	udelay(45);
}

static const struct charlcd_ops hd44780_ops_gpio4 = {
	.backlight	= hd44780_backlight,
};

static int hd44780_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	unsigned int i, base;
	struct charlcd *lcd;
	struct hd44780_common *hdc;
	struct hd44780 *hd;
	int ifwidth, ret = -ENOMEM;

	/* Required pins */
	ifwidth = gpiod_count(dev, "data");
	if (ifwidth < 0)
		return ifwidth;

	switch (ifwidth) {
	case 4:
		base = PIN_DATA4;
		break;
	case 8:
		base = PIN_DATA0;
		break;
	default:
		return -EINVAL;
	}

	hdc = hd44780_common_alloc();
	if (!hdc)
		return -ENOMEM;

	lcd = charlcd_alloc();
	if (!lcd)
		goto fail1;

	hd = kzalloc(sizeof(struct hd44780), GFP_KERNEL);
	if (!hd)
		goto fail2;

	hdc->hd44780 = hd;
	lcd->drvdata = hdc;
	for (i = 0; i < ifwidth; i++) {
		hd->pins[base + i] = devm_gpiod_get_index(dev, "data", i,
							  GPIOD_OUT_LOW);
		if (IS_ERR(hd->pins[base + i])) {
			ret = PTR_ERR(hd->pins[base + i]);
			goto fail3;
		}
	}

	hd->pins[PIN_CTRL_E] = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
	if (IS_ERR(hd->pins[PIN_CTRL_E])) {
		ret = PTR_ERR(hd->pins[PIN_CTRL_E]);
		goto fail3;
	}

	hd->pins[PIN_CTRL_RS] = devm_gpiod_get(dev, "rs", GPIOD_OUT_HIGH);
	if (IS_ERR(hd->pins[PIN_CTRL_RS])) {
		ret = PTR_ERR(hd->pins[PIN_CTRL_RS]);
		goto fail3;
	}

	/* Optional pins */
	hd->pins[PIN_CTRL_RW] = devm_gpiod_get_optional(dev, "rw",
							GPIOD_OUT_LOW);
	if (IS_ERR(hd->pins[PIN_CTRL_RW])) {
		ret = PTR_ERR(hd->pins[PIN_CTRL_RW]);
		goto fail3;
	}

	hd->pins[PIN_CTRL_BL] = devm_gpiod_get_optional(dev, "backlight",
							GPIOD_OUT_LOW);
	if (IS_ERR(hd->pins[PIN_CTRL_BL])) {
		ret = PTR_ERR(hd->pins[PIN_CTRL_BL]);
		goto fail3;
	}

	/* Required properties */
	ret = device_property_read_u32(dev, "display-height-chars",
				       &lcd->height);
	if (ret)
		goto fail3;
	ret = device_property_read_u32(dev, "display-width-chars", &lcd->width);
	if (ret)
		goto fail3;

	/*
	 * On displays with more than two rows, the internal buffer width is
	 * usually equal to the display width
	 */
	if (lcd->height > 2)
		hdc->bwidth = lcd->width;

	/* Optional properties */
	device_property_read_u32(dev, "internal-buffer-width", &hdc->bwidth);

	hdc->ifwidth = ifwidth;
	if (ifwidth == 8) {
		lcd->ops = &hd44780_ops_gpio8;
		hdc->write_data = hd44780_write_data_gpio8;
		hdc->write_cmd = hd44780_write_cmd_gpio8;
	} else {
		lcd->ops = &hd44780_ops_gpio4;
		hdc->write_data = hd44780_write_data_gpio4;
		hdc->write_cmd = hd44780_write_cmd_gpio4;
		hdc->write_cmd_raw4 = hd44780_write_cmd_raw_gpio4;
	}

	ret = charlcd_register(lcd);
	if (ret)
		goto fail3;

	platform_set_drvdata(pdev, lcd);
	return 0;

fail3:
	kfree(hd);
fail2:
	kfree(lcd);
fail1:
	kfree(hdc);
	return ret;
}

static int hd44780_remove(struct platform_device *pdev)
{
	struct charlcd *lcd = platform_get_drvdata(pdev);

	kfree(lcd->drvdata);
	charlcd_unregister(lcd);

	kfree(lcd);
	return 0;
}

static const struct of_device_id hd44780_of_match[] = {
	{ .compatible = "hit,hd44780" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, hd44780_of_match);

static struct platform_driver hd44780_driver = {
	.probe = hd44780_probe,
	.remove = hd44780_remove,
	.driver		= {
		.name	= "hd44780",
		.of_match_table = hd44780_of_match,
	},
};

module_platform_driver(hd44780_driver);
MODULE_DESCRIPTION("HD44780 Character LCD driver");
MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");
MODULE_LICENSE("GPL");
Commit	Line	Data
351f683b	1	// SPDX-License-Identifier: GPL-2.0+
d47d8836 GU	2	/*
	3	* HD44780 Character LCD driver for Linux
	4	*
	5	* Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
	6	* Copyright (C) 2016-2017 Glider bvba
d47d8836 GU	7	*/
	8
	9	#include <linux/delay.h>
	10	#include <linux/gpio/consumer.h>
	11	#include <linux/module.h>
ac316725	12	#include <linux/mod_devicetable.h>
d47d8836 GU	13	#include <linux/platform_device.h>
	14	#include <linux/property.h>
	15	#include <linux/slab.h>
	16
75354284	17	#include "charlcd.h"
718e05ed	18	#include "hd44780_common.h"
d47d8836 GU	19
	20	enum hd44780_pin {
	21	/* Order does matter due to writing to GPIO array subsets! */
	22	PIN_DATA0, /* Optional */
	23	PIN_DATA1, /* Optional */
	24	PIN_DATA2, /* Optional */
	25	PIN_DATA3, /* Optional */
	26	PIN_DATA4,
	27	PIN_DATA5,
	28	PIN_DATA6,
	29	PIN_DATA7,
	30	PIN_CTRL_RS,
	31	PIN_CTRL_RW, /* Optional */
	32	PIN_CTRL_E,
	33	PIN_CTRL_BL, /* Optional */
	34	PIN_NUM
	35	};
	36
	37	struct hd44780 {
	38	struct gpio_desc *pins[PIN_NUM];
	39	};
	40
66ce7d5c	41	static void hd44780_backlight(struct charlcd *lcd, enum charlcd_onoff on)
d47d8836	42	{
2545c1c9 LP	43	struct hd44780_common *hdc = lcd->drvdata;
2545c1c9 LP	44	struct hd44780 *hd = hdc->hd44780;
d47d8836 GU	45
	46	if (hd->pins[PIN_CTRL_BL])
	47	gpiod_set_value_cansleep(hd->pins[PIN_CTRL_BL], on);
	48	}
	49
	50	static void hd44780_strobe_gpio(struct hd44780 *hd)
	51	{
	52	/* Maintain the data during 20 us before the strobe */
	53	udelay(20);
	54
	55	gpiod_set_value_cansleep(hd->pins[PIN_CTRL_E], 1);
	56
	57	/* Maintain the strobe during 40 us */
	58	udelay(40);
	59
	60	gpiod_set_value_cansleep(hd->pins[PIN_CTRL_E], 0);
	61	}
	62
	63	/* write to an LCD panel register in 8 bit GPIO mode */
	64	static void hd44780_write_gpio8(struct hd44780 *hd, u8 val, unsigned int rs)
	65	{
b9762beb JK	66	DECLARE_BITMAP(values, 10); /* for DATA[0-7], RS, RW */
	67	unsigned int n;
	68
	69	values[0] = val;
	70	__assign_bit(8, values, rs);
	71	n = hd->pins[PIN_CTRL_RW] ? 10 : 9;
d47d8836 GU	72
d47d8836 GU	73	/* Present the data to the port */
77588c14	74	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA0], NULL, values);
d47d8836 GU	75
	76	hd44780_strobe_gpio(hd);
	77	}
	78
	79	/* write to an LCD panel register in 4 bit GPIO mode */
	80	static void hd44780_write_gpio4(struct hd44780 *hd, u8 val, unsigned int rs)
	81	{
b9762beb JK	82	DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */
b9762beb JK	83	unsigned int n;
d47d8836 GU	84
d47d8836 GU	85	/* High nibble + RS, RW */
b9762beb JK	86	values[0] = val >> 4;
	87	__assign_bit(4, values, rs);
	88	n = hd->pins[PIN_CTRL_RW] ? 6 : 5;
d47d8836 GU	89
d47d8836 GU	90	/* Present the data to the port */
77588c14	91	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);
d47d8836 GU	92
	93	hd44780_strobe_gpio(hd);
	94
	95	/* Low nibble */
b9762beb JK	96	values[0] &= ~0x0fUL;
b9762beb JK	97	values[0] \|= val & 0x0f;
d47d8836 GU	98
d47d8836 GU	99	/* Present the data to the port */
77588c14	100	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);
d47d8836 GU	101
	102	hd44780_strobe_gpio(hd);
	103	}
	104
	105	/* Send a command to the LCD panel in 8 bit GPIO mode */
2c6a82f2	106	static void hd44780_write_cmd_gpio8(struct hd44780_common *hdc, int cmd)
d47d8836	107	{
2545c1c9	108	struct hd44780 *hd = hdc->hd44780;
d47d8836 GU	109
	110	hd44780_write_gpio8(hd, cmd, 0);
	111
	112	/* The shortest command takes at least 120 us */
	113	udelay(120);
	114	}
	115
	116	/* Send data to the LCD panel in 8 bit GPIO mode */
71ff701b	117	static void hd44780_write_data_gpio8(struct hd44780_common *hdc, int data)
d47d8836	118	{
2545c1c9	119	struct hd44780 *hd = hdc->hd44780;
d47d8836 GU	120
	121	hd44780_write_gpio8(hd, data, 1);
	122
	123	/* The shortest data takes at least 45 us */
	124	udelay(45);
	125	}
	126
	127	static const struct charlcd_ops hd44780_ops_gpio8 = {
d47d8836 GU	128	.backlight = hd44780_backlight,
	129	};
	130
	131	/* Send a command to the LCD panel in 4 bit GPIO mode */
2c6a82f2	132	static void hd44780_write_cmd_gpio4(struct hd44780_common *hdc, int cmd)
d47d8836	133	{
2545c1c9	134	struct hd44780 *hd = hdc->hd44780;
d47d8836 GU	135
	136	hd44780_write_gpio4(hd, cmd, 0);
	137
	138	/* The shortest command takes at least 120 us */
	139	udelay(120);
	140	}
	141
	142	/* Send 4-bits of a command to the LCD panel in raw 4 bit GPIO mode */
2c6a82f2	143	static void hd44780_write_cmd_raw_gpio4(struct hd44780_common *hdc, int cmd)
d47d8836	144	{
b9762beb	145	DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */
2545c1c9	146	struct hd44780 *hd = hdc->hd44780;
b9762beb	147	unsigned int n;
d47d8836 GU	148
d47d8836 GU	149	/* Command nibble + RS, RW */
b9762beb JK	150	values[0] = cmd & 0x0f;
b9762beb JK	151	n = hd->pins[PIN_CTRL_RW] ? 6 : 5;
d47d8836 GU	152
d47d8836 GU	153	/* Present the data to the port */
77588c14	154	gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);
d47d8836 GU	155
	156	hd44780_strobe_gpio(hd);
	157	}
	158
	159	/* Send data to the LCD panel in 4 bit GPIO mode */
71ff701b	160	static void hd44780_write_data_gpio4(struct hd44780_common *hdc, int data)
d47d8836	161	{
2545c1c9	162	struct hd44780 *hd = hdc->hd44780;
d47d8836 GU	163
	164	hd44780_write_gpio4(hd, data, 1);
	165
	166	/* The shortest data takes at least 45 us */
	167	udelay(45);
	168	}
	169
	170	static const struct charlcd_ops hd44780_ops_gpio4 = {
d47d8836 GU	171	.backlight = hd44780_backlight,
	172	};
	173
	174	static int hd44780_probe(struct platform_device *pdev)
	175	{
	176	struct device *dev = &pdev->dev;
	177	unsigned int i, base;
	178	struct charlcd *lcd;
718e05ed	179	struct hd44780_common *hdc;
d47d8836	180	struct hd44780 *hd;
718e05ed	181	int ifwidth, ret = -ENOMEM;
d47d8836 GU	182
	183	/* Required pins */
	184	ifwidth = gpiod_count(dev, "data");
	185	if (ifwidth < 0)
	186	return ifwidth;
	187
	188	switch (ifwidth) {
	189	case 4:
	190	base = PIN_DATA4;
	191	break;
	192	case 8:
	193	base = PIN_DATA0;
	194	break;
	195	default:
	196	return -EINVAL;
	197	}
	198
718e05ed LP	199	hdc = hd44780_common_alloc();
	200	if (!hdc)
	201	return -ENOMEM;
	202
2545c1c9	203	lcd = charlcd_alloc();
d47d8836	204	if (!lcd)
718e05ed	205	goto fail1;
d47d8836	206
718e05ed LP	207	hd = kzalloc(sizeof(struct hd44780), GFP_KERNEL);
	208	if (!hd)
	209	goto fail2;
d47d8836	210
718e05ed LP	211	hdc->hd44780 = hd;
718e05ed LP	212	lcd->drvdata = hdc;
d47d8836 GU	213	for (i = 0; i < ifwidth; i++) {
	214	hd->pins[base + i] = devm_gpiod_get_index(dev, "data", i,
	215	GPIOD_OUT_LOW);
	216	if (IS_ERR(hd->pins[base + i])) {
	217	ret = PTR_ERR(hd->pins[base + i]);
718e05ed	218	goto fail3;
d47d8836 GU	219	}
	220	}
	221
	222	hd->pins[PIN_CTRL_E] = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
	223	if (IS_ERR(hd->pins[PIN_CTRL_E])) {
	224	ret = PTR_ERR(hd->pins[PIN_CTRL_E]);
718e05ed	225	goto fail3;
d47d8836 GU	226	}
	227
	228	hd->pins[PIN_CTRL_RS] = devm_gpiod_get(dev, "rs", GPIOD_OUT_HIGH);
	229	if (IS_ERR(hd->pins[PIN_CTRL_RS])) {
	230	ret = PTR_ERR(hd->pins[PIN_CTRL_RS]);
718e05ed	231	goto fail3;
d47d8836 GU	232	}
	233
	234	/* Optional pins */
	235	hd->pins[PIN_CTRL_RW] = devm_gpiod_get_optional(dev, "rw",
	236	GPIOD_OUT_LOW);
	237	if (IS_ERR(hd->pins[PIN_CTRL_RW])) {
	238	ret = PTR_ERR(hd->pins[PIN_CTRL_RW]);
718e05ed	239	goto fail3;
d47d8836 GU	240	}
	241
	242	hd->pins[PIN_CTRL_BL] = devm_gpiod_get_optional(dev, "backlight",
	243	GPIOD_OUT_LOW);
	244	if (IS_ERR(hd->pins[PIN_CTRL_BL])) {
	245	ret = PTR_ERR(hd->pins[PIN_CTRL_BL]);
718e05ed	246	goto fail3;
d47d8836 GU	247	}
	248
	249	/* Required properties */
c7c3f096 GU	250	ret = device_property_read_u32(dev, "display-height-chars",
c7c3f096 GU	251	&lcd->height);
d47d8836	252	if (ret)
718e05ed	253	goto fail3;
c7c3f096	254	ret = device_property_read_u32(dev, "display-width-chars", &lcd->width);
d47d8836	255	if (ret)
718e05ed	256	goto fail3;
d47d8836 GU	257
	258	/*
	259	* On displays with more than two rows, the internal buffer width is
	260	* usually equal to the display width
	261	*/
	262	if (lcd->height > 2)
2545c1c9	263	hdc->bwidth = lcd->width;
d47d8836 GU	264
d47d8836 GU	265	/* Optional properties */
2545c1c9	266	device_property_read_u32(dev, "internal-buffer-width", &hdc->bwidth);
d47d8836	267
3fc04dd7	268	hdc->ifwidth = ifwidth;
71ff701b LP	269	if (ifwidth == 8) {
	270	lcd->ops = &hd44780_ops_gpio8;
	271	hdc->write_data = hd44780_write_data_gpio8;
2c6a82f2	272	hdc->write_cmd = hd44780_write_cmd_gpio8;
71ff701b LP	273	} else {
	274	lcd->ops = &hd44780_ops_gpio4;
	275	hdc->write_data = hd44780_write_data_gpio4;
2c6a82f2 LP	276	hdc->write_cmd = hd44780_write_cmd_gpio4;
2c6a82f2 LP	277	hdc->write_cmd_raw4 = hd44780_write_cmd_raw_gpio4;
71ff701b	278	}
d47d8836 GU	279
	280	ret = charlcd_register(lcd);
	281	if (ret)
718e05ed	282	goto fail3;
d47d8836 GU	283
	284	platform_set_drvdata(pdev, lcd);
	285	return 0;
	286
718e05ed LP	287	fail3:
	288	kfree(hd);
	289	fail2:
	290	kfree(lcd);
	291	fail1:
	292	kfree(hdc);
d47d8836 GU	293	return ret;
	294	}
	295
	296	static int hd44780_remove(struct platform_device *pdev)
	297	{
	298	struct charlcd *lcd = platform_get_drvdata(pdev);
	299
718e05ed	300	kfree(lcd->drvdata);
d47d8836	301	charlcd_unregister(lcd);
41c8d0ad	302
718e05ed	303	kfree(lcd);
d47d8836 GU	304	return 0;
	305	}
	306
	307	static const struct of_device_id hd44780_of_match[] = {
	308	{ .compatible = "hit,hd44780" },
	309	{ /* sentinel */ }
	310	};
	311	MODULE_DEVICE_TABLE(of, hd44780_of_match);
	312
	313	static struct platform_driver hd44780_driver = {
	314	.probe = hd44780_probe,
	315	.remove = hd44780_remove,
	316	.driver = {
	317	.name = "hd44780",
	318	.of_match_table = hd44780_of_match,
	319	},
	320	};
	321
	322	module_platform_driver(hd44780_driver);
	323	MODULE_DESCRIPTION("HD44780 Character LCD driver");
	324	MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");
	325	MODULE_LICENSE("GPL");