1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * LCD-OLinuXino support for panel driver
4 *
5 * Copyright (C) 2018 Olimex Ltd.
6 * Author: Stefan Mavrodiev <stefan@olimex.com>
7 */
8
9 #include <linux/crc32.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/i2c.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/of.h>
15 #include <linux/regulator/consumer.h>
16
17 #include <video/videomode.h>
18 #include <video/display_timing.h>
19
20 #include <drm/drm_device.h>
21 #include <drm/drm_modes.h>
22 #include <drm/drm_panel.h>
23
24 #define LCD_OLINUXINO_HEADER_MAGIC 0x4F4CB727
25 #define LCD_OLINUXINO_DATA_LEN 256
26
27 struct lcd_olinuxino_mode {
28 u32 pixelclock;
29 u32 hactive;
30 u32 hfp;
31 u32 hbp;
32 u32 hpw;
33 u32 vactive;
34 u32 vfp;
35 u32 vbp;
36 u32 vpw;
37 u32 refresh;
38 u32 flags;
39 };
40
41 struct lcd_olinuxino_info {
42 char name[32];
43 u32 width_mm;
44 u32 height_mm;
45 u32 bpc;
46 u32 bus_format;
47 u32 bus_flag;
48 } __attribute__((__packed__));
49
50 struct lcd_olinuxino_eeprom {
51 u32 header;
52 u32 id;
53 char revision[4];
54 u32 serial;
55 struct lcd_olinuxino_info info;
56 u32 num_modes;
57 u8 reserved[180];
58 u32 checksum;
59 } __attribute__((__packed__));
60
61 struct lcd_olinuxino {
62 struct drm_panel panel;
63 struct device *dev;
64 struct i2c_client *client;
65 struct mutex mutex;
66
67 bool prepared;
68 bool enabled;
69
70 struct regulator *supply;
71 struct gpio_desc *enable_gpio;
72
73 struct lcd_olinuxino_eeprom eeprom;
74 };
75
to_lcd_olinuxino(struct drm_panel * panel)76 static inline struct lcd_olinuxino *to_lcd_olinuxino(struct drm_panel *panel)
77 {
78 return container_of(panel, struct lcd_olinuxino, panel);
79 }
80
lcd_olinuxino_disable(struct drm_panel * panel)81 static int lcd_olinuxino_disable(struct drm_panel *panel)
82 {
83 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
84
85 if (!lcd->enabled)
86 return 0;
87
88 lcd->enabled = false;
89
90 return 0;
91 }
92
lcd_olinuxino_unprepare(struct drm_panel * panel)93 static int lcd_olinuxino_unprepare(struct drm_panel *panel)
94 {
95 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
96
97 if (!lcd->prepared)
98 return 0;
99
100 gpiod_set_value_cansleep(lcd->enable_gpio, 0);
101 regulator_disable(lcd->supply);
102
103 lcd->prepared = false;
104
105 return 0;
106 }
107
lcd_olinuxino_prepare(struct drm_panel * panel)108 static int lcd_olinuxino_prepare(struct drm_panel *panel)
109 {
110 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
111 int ret;
112
113 if (lcd->prepared)
114 return 0;
115
116 ret = regulator_enable(lcd->supply);
117 if (ret < 0)
118 return ret;
119
120 gpiod_set_value_cansleep(lcd->enable_gpio, 1);
121 lcd->prepared = true;
122
123 return 0;
124 }
125
lcd_olinuxino_enable(struct drm_panel * panel)126 static int lcd_olinuxino_enable(struct drm_panel *panel)
127 {
128 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
129
130 if (lcd->enabled)
131 return 0;
132
133 lcd->enabled = true;
134
135 return 0;
136 }
137
lcd_olinuxino_get_modes(struct drm_panel * panel,struct drm_connector * connector)138 static int lcd_olinuxino_get_modes(struct drm_panel *panel,
139 struct drm_connector *connector)
140 {
141 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
142 struct lcd_olinuxino_info *lcd_info = &lcd->eeprom.info;
143 struct lcd_olinuxino_mode *lcd_mode;
144 struct drm_display_mode *mode;
145 u32 i, num = 0;
146
147 for (i = 0; i < lcd->eeprom.num_modes; i++) {
148 lcd_mode = (struct lcd_olinuxino_mode *)
149 &lcd->eeprom.reserved[i * sizeof(*lcd_mode)];
150
151 mode = drm_mode_create(connector->dev);
152 if (!mode) {
153 dev_err(panel->dev, "failed to add mode %ux%u@%u\n",
154 lcd_mode->hactive,
155 lcd_mode->vactive,
156 lcd_mode->refresh);
157 continue;
158 }
159
160 mode->clock = lcd_mode->pixelclock;
161 mode->hdisplay = lcd_mode->hactive;
162 mode->hsync_start = lcd_mode->hactive + lcd_mode->hfp;
163 mode->hsync_end = lcd_mode->hactive + lcd_mode->hfp +
164 lcd_mode->hpw;
165 mode->htotal = lcd_mode->hactive + lcd_mode->hfp +
166 lcd_mode->hpw + lcd_mode->hbp;
167 mode->vdisplay = lcd_mode->vactive;
168 mode->vsync_start = lcd_mode->vactive + lcd_mode->vfp;
169 mode->vsync_end = lcd_mode->vactive + lcd_mode->vfp +
170 lcd_mode->vpw;
171 mode->vtotal = lcd_mode->vactive + lcd_mode->vfp +
172 lcd_mode->vpw + lcd_mode->vbp;
173
174 /* Always make the first mode preferred */
175 if (i == 0)
176 mode->type |= DRM_MODE_TYPE_PREFERRED;
177 mode->type |= DRM_MODE_TYPE_DRIVER;
178
179 drm_mode_set_name(mode);
180 drm_mode_probed_add(connector, mode);
181
182 num++;
183 }
184
185 connector->display_info.width_mm = lcd_info->width_mm;
186 connector->display_info.height_mm = lcd_info->height_mm;
187 connector->display_info.bpc = lcd_info->bpc;
188
189 if (lcd_info->bus_format)
190 drm_display_info_set_bus_formats(&connector->display_info,
191 &lcd_info->bus_format, 1);
192 connector->display_info.bus_flags = lcd_info->bus_flag;
193
194 return num;
195 }
196
197 static const struct drm_panel_funcs lcd_olinuxino_funcs = {
198 .disable = lcd_olinuxino_disable,
199 .unprepare = lcd_olinuxino_unprepare,
200 .prepare = lcd_olinuxino_prepare,
201 .enable = lcd_olinuxino_enable,
202 .get_modes = lcd_olinuxino_get_modes,
203 };
204
lcd_olinuxino_probe(struct i2c_client * client)205 static int lcd_olinuxino_probe(struct i2c_client *client)
206 {
207 struct device *dev = &client->dev;
208 struct lcd_olinuxino *lcd;
209 u32 checksum, i;
210 int ret = 0;
211
212 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
213 I2C_FUNC_SMBUS_READ_I2C_BLOCK))
214 return -ENODEV;
215
216 lcd = devm_kzalloc(dev, sizeof(*lcd), GFP_KERNEL);
217 if (!lcd)
218 return -ENOMEM;
219
220 i2c_set_clientdata(client, lcd);
221 lcd->dev = dev;
222 lcd->client = client;
223
224 mutex_init(&lcd->mutex);
225
226 /* Copy data into buffer */
227 for (i = 0; i < LCD_OLINUXINO_DATA_LEN; i += I2C_SMBUS_BLOCK_MAX) {
228 mutex_lock(&lcd->mutex);
229 ret = i2c_smbus_read_i2c_block_data(client,
230 i,
231 I2C_SMBUS_BLOCK_MAX,
232 (u8 *)&lcd->eeprom + i);
233 mutex_unlock(&lcd->mutex);
234 if (ret < 0) {
235 dev_err(dev, "error reading from device at %02x\n", i);
236 return ret;
237 }
238 }
239
240 /* Check configuration checksum */
241 checksum = ~crc32(~0, (u8 *)&lcd->eeprom, 252);
242 if (checksum != lcd->eeprom.checksum) {
243 dev_err(dev, "configuration checksum does not match!\n");
244 return -EINVAL;
245 }
246
247 /* Check magic header */
248 if (lcd->eeprom.header != LCD_OLINUXINO_HEADER_MAGIC) {
249 dev_err(dev, "magic header does not match\n");
250 return -EINVAL;
251 }
252
253 dev_info(dev, "Detected %s, Rev. %s, Serial: %08x\n",
254 lcd->eeprom.info.name,
255 lcd->eeprom.revision,
256 lcd->eeprom.serial);
257
258 /*
259 * The eeprom can hold up to 4 modes.
260 * If the stored value is bigger, overwrite it.
261 */
262 if (lcd->eeprom.num_modes > 4) {
263 dev_warn(dev, "invalid number of modes, falling back to 4\n");
264 lcd->eeprom.num_modes = 4;
265 }
266
267 lcd->enabled = false;
268 lcd->prepared = false;
269
270 lcd->supply = devm_regulator_get(dev, "power");
271 if (IS_ERR(lcd->supply))
272 return PTR_ERR(lcd->supply);
273
274 lcd->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
275 if (IS_ERR(lcd->enable_gpio))
276 return PTR_ERR(lcd->enable_gpio);
277
278 drm_panel_init(&lcd->panel, dev, &lcd_olinuxino_funcs,
279 DRM_MODE_CONNECTOR_DPI);
280
281 ret = drm_panel_of_backlight(&lcd->panel);
282 if (ret)
283 return ret;
284
285 drm_panel_add(&lcd->panel);
286
287 return 0;
288 }
289
lcd_olinuxino_remove(struct i2c_client * client)290 static void lcd_olinuxino_remove(struct i2c_client *client)
291 {
292 struct lcd_olinuxino *panel = i2c_get_clientdata(client);
293
294 drm_panel_remove(&panel->panel);
295
296 drm_panel_disable(&panel->panel);
297 drm_panel_unprepare(&panel->panel);
298 }
299
300 static const struct of_device_id lcd_olinuxino_of_ids[] = {
301 { .compatible = "olimex,lcd-olinuxino" },
302 { }
303 };
304 MODULE_DEVICE_TABLE(of, lcd_olinuxino_of_ids);
305
306 static struct i2c_driver lcd_olinuxino_driver = {
307 .driver = {
308 .name = "lcd_olinuxino",
309 .of_match_table = lcd_olinuxino_of_ids,
310 },
311 .probe = lcd_olinuxino_probe,
312 .remove = lcd_olinuxino_remove,
313 };
314
315 module_i2c_driver(lcd_olinuxino_driver);
316
317 MODULE_AUTHOR("Stefan Mavrodiev <stefan@olimex.com>");
318 MODULE_DESCRIPTION("LCD-OLinuXino driver");
319 MODULE_LICENSE("GPL");
320
