hd44780.c (718e05ed92ecac0d9d3954bcc8064527c3ce7565) hd44780.c (2545c1c948a6a765f1a0e820c7598138b36f67ef)
1// SPDX-License-Identifier: GPL-2.0+
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
7 */
8

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35};
36
37struct hd44780 {
38 struct gpio_desc *pins[PIN_NUM];
39};
40
41static void hd44780_backlight(struct charlcd *lcd, enum charlcd_onoff on)
42{
1// SPDX-License-Identifier: GPL-2.0+
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
7 */
8

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35};
36
37struct hd44780 {
38 struct gpio_desc *pins[PIN_NUM];
39};
40
41static void hd44780_backlight(struct charlcd *lcd, enum charlcd_onoff on)
42{
43 struct hd44780 *hd = lcd->drvdata;
43 struct hd44780_common *hdc = lcd->drvdata;
44 struct hd44780 *hd = hdc->hd44780;
44
45 if (hd->pins[PIN_CTRL_BL])
46 gpiod_set_value_cansleep(hd->pins[PIN_CTRL_BL], on);
47}
48
49static void hd44780_strobe_gpio(struct hd44780 *hd)
50{
51 /* Maintain the data during 20 us before the strobe */

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99 gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);
100
101 hd44780_strobe_gpio(hd);
102}
103
104/* Send a command to the LCD panel in 8 bit GPIO mode */
105static void hd44780_write_cmd_gpio8(struct charlcd *lcd, int cmd)
106{
45
46 if (hd->pins[PIN_CTRL_BL])
47 gpiod_set_value_cansleep(hd->pins[PIN_CTRL_BL], on);
48}
49
50static void hd44780_strobe_gpio(struct hd44780 *hd)
51{
52 /* Maintain the data during 20 us before the strobe */

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100 gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);
101
102 hd44780_strobe_gpio(hd);
103}
104
105/* Send a command to the LCD panel in 8 bit GPIO mode */
106static void hd44780_write_cmd_gpio8(struct charlcd *lcd, int cmd)
107{
107 struct hd44780 *hd = lcd->drvdata;
108 struct hd44780_common *hdc = lcd->drvdata;
109 struct hd44780 *hd = hdc->hd44780;
108
109 hd44780_write_gpio8(hd, cmd, 0);
110
111 /* The shortest command takes at least 120 us */
112 udelay(120);
113}
114
115/* Send data to the LCD panel in 8 bit GPIO mode */
116static void hd44780_write_data_gpio8(struct charlcd *lcd, int data)
117{
110
111 hd44780_write_gpio8(hd, cmd, 0);
112
113 /* The shortest command takes at least 120 us */
114 udelay(120);
115}
116
117/* Send data to the LCD panel in 8 bit GPIO mode */
118static void hd44780_write_data_gpio8(struct charlcd *lcd, int data)
119{
118 struct hd44780 *hd = lcd->drvdata;
120 struct hd44780_common *hdc = lcd->drvdata;
121 struct hd44780 *hd = hdc->hd44780;
119
120 hd44780_write_gpio8(hd, data, 1);
121
122 /* The shortest data takes at least 45 us */
123 udelay(45);
124}
125
126static const struct charlcd_ops hd44780_ops_gpio8 = {
127 .write_cmd = hd44780_write_cmd_gpio8,
128 .write_data = hd44780_write_data_gpio8,
129 .backlight = hd44780_backlight,
130};
131
132/* Send a command to the LCD panel in 4 bit GPIO mode */
133static void hd44780_write_cmd_gpio4(struct charlcd *lcd, int cmd)
134{
122
123 hd44780_write_gpio8(hd, data, 1);
124
125 /* The shortest data takes at least 45 us */
126 udelay(45);
127}
128
129static const struct charlcd_ops hd44780_ops_gpio8 = {
130 .write_cmd = hd44780_write_cmd_gpio8,
131 .write_data = hd44780_write_data_gpio8,
132 .backlight = hd44780_backlight,
133};
134
135/* Send a command to the LCD panel in 4 bit GPIO mode */
136static void hd44780_write_cmd_gpio4(struct charlcd *lcd, int cmd)
137{
135 struct hd44780 *hd = lcd->drvdata;
138 struct hd44780_common *hdc = lcd->drvdata;
139 struct hd44780 *hd = hdc->hd44780;
136
137 hd44780_write_gpio4(hd, cmd, 0);
138
139 /* The shortest command takes at least 120 us */
140 udelay(120);
141}
142
143/* Send 4-bits of a command to the LCD panel in raw 4 bit GPIO mode */
144static void hd44780_write_cmd_raw_gpio4(struct charlcd *lcd, int cmd)
145{
146 DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */
140
141 hd44780_write_gpio4(hd, cmd, 0);
142
143 /* The shortest command takes at least 120 us */
144 udelay(120);
145}
146
147/* Send 4-bits of a command to the LCD panel in raw 4 bit GPIO mode */
148static void hd44780_write_cmd_raw_gpio4(struct charlcd *lcd, int cmd)
149{
150 DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */
147 struct hd44780 *hd = lcd->drvdata;
151 struct hd44780_common *hdc = lcd->drvdata;
152 struct hd44780 *hd = hdc->hd44780;
148 unsigned int n;
149
150 /* Command nibble + RS, RW */
151 values[0] = cmd & 0x0f;
152 n = hd->pins[PIN_CTRL_RW] ? 6 : 5;
153
154 /* Present the data to the port */
155 gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);
156
157 hd44780_strobe_gpio(hd);
158}
159
160/* Send data to the LCD panel in 4 bit GPIO mode */
161static void hd44780_write_data_gpio4(struct charlcd *lcd, int data)
162{
153 unsigned int n;
154
155 /* Command nibble + RS, RW */
156 values[0] = cmd & 0x0f;
157 n = hd->pins[PIN_CTRL_RW] ? 6 : 5;
158
159 /* Present the data to the port */
160 gpiod_set_array_value_cansleep(n, &hd->pins[PIN_DATA4], NULL, values);
161
162 hd44780_strobe_gpio(hd);
163}
164
165/* Send data to the LCD panel in 4 bit GPIO mode */
166static void hd44780_write_data_gpio4(struct charlcd *lcd, int data)
167{
163 struct hd44780 *hd = lcd->drvdata;
168 struct hd44780_common *hdc = lcd->drvdata;
169 struct hd44780 *hd = hdc->hd44780;
164
165 hd44780_write_gpio4(hd, data, 1);
166
167 /* The shortest data takes at least 45 us */
168 udelay(45);
169}
170
171static const struct charlcd_ops hd44780_ops_gpio4 = {

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199 default:
200 return -EINVAL;
201 }
202
203 hdc = hd44780_common_alloc();
204 if (!hdc)
205 return -ENOMEM;
206
170
171 hd44780_write_gpio4(hd, data, 1);
172
173 /* The shortest data takes at least 45 us */
174 udelay(45);
175}
176
177static const struct charlcd_ops hd44780_ops_gpio4 = {

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205 default:
206 return -EINVAL;
207 }
208
209 hdc = hd44780_common_alloc();
210 if (!hdc)
211 return -ENOMEM;
212
207 lcd = charlcd_alloc(sizeof(struct hd44780));
213 lcd = charlcd_alloc();
208 if (!lcd)
209 goto fail1;
210
211 hd = kzalloc(sizeof(struct hd44780), GFP_KERNEL);
212 if (!hd)
213 goto fail2;
214
215 hdc->hd44780 = hd;

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259 if (ret)
260 goto fail3;
261
262 /*
263 * On displays with more than two rows, the internal buffer width is
264 * usually equal to the display width
265 */
266 if (lcd->height > 2)
214 if (!lcd)
215 goto fail1;
216
217 hd = kzalloc(sizeof(struct hd44780), GFP_KERNEL);
218 if (!hd)
219 goto fail2;
220
221 hdc->hd44780 = hd;

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265 if (ret)
266 goto fail3;
267
268 /*
269 * On displays with more than two rows, the internal buffer width is
270 * usually equal to the display width
271 */
272 if (lcd->height > 2)
267 lcd->bwidth = lcd->width;
273 hdc->bwidth = lcd->width;
268
269 /* Optional properties */
274
275 /* Optional properties */
270 device_property_read_u32(dev, "internal-buffer-width", &lcd->bwidth);
276 device_property_read_u32(dev, "internal-buffer-width", &hdc->bwidth);
271
272 lcd->ifwidth = ifwidth;
273 lcd->ops = ifwidth == 8 ? &hd44780_ops_gpio8 : &hd44780_ops_gpio4;
274
275 ret = charlcd_register(lcd);
276 if (ret)
277 goto fail3;
278

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278 lcd->ifwidth = ifwidth;
279 lcd->ops = ifwidth == 8 ? &hd44780_ops_gpio8 : &hd44780_ops_gpio4;
280
281 ret = charlcd_register(lcd);
282 if (ret)
283 goto fail3;
284

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