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 struct regulator *supply;
68 struct gpio_desc *enable_gpio;
69
70 struct lcd_olinuxino_eeprom eeprom;
71 };
72
to_lcd_olinuxino(struct drm_panel * panel)73 static inline struct lcd_olinuxino *to_lcd_olinuxino(struct drm_panel *panel)
74 {
75 return container_of(panel, struct lcd_olinuxino, panel);
76 }
77
lcd_olinuxino_unprepare(struct drm_panel * panel)78 static int lcd_olinuxino_unprepare(struct drm_panel *panel)
79 {
80 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
81
82 gpiod_set_value_cansleep(lcd->enable_gpio, 0);
83 regulator_disable(lcd->supply);
84
85 return 0;
86 }
87
lcd_olinuxino_prepare(struct drm_panel * panel)88 static int lcd_olinuxino_prepare(struct drm_panel *panel)
89 {
90 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
91 int ret;
92
93 ret = regulator_enable(lcd->supply);
94 if (ret < 0)
95 return ret;
96
97 gpiod_set_value_cansleep(lcd->enable_gpio, 1);
98
99 return 0;
100 }
101
lcd_olinuxino_get_modes(struct drm_panel * panel,struct drm_connector * connector)102 static int lcd_olinuxino_get_modes(struct drm_panel *panel,
103 struct drm_connector *connector)
104 {
105 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
106 struct lcd_olinuxino_info *lcd_info = &lcd->eeprom.info;
107 struct lcd_olinuxino_mode *lcd_mode;
108 struct drm_display_mode *mode;
109 u32 i, num = 0;
110
111 for (i = 0; i < lcd->eeprom.num_modes; i++) {
112 lcd_mode = (struct lcd_olinuxino_mode *)
113 &lcd->eeprom.reserved[i * sizeof(*lcd_mode)];
114
115 mode = drm_mode_create(connector->dev);
116 if (!mode) {
117 dev_err(panel->dev, "failed to add mode %ux%u@%u\n",
118 lcd_mode->hactive,
119 lcd_mode->vactive,
120 lcd_mode->refresh);
121 continue;
122 }
123
124 mode->clock = lcd_mode->pixelclock;
125 mode->hdisplay = lcd_mode->hactive;
126 mode->hsync_start = lcd_mode->hactive + lcd_mode->hfp;
127 mode->hsync_end = lcd_mode->hactive + lcd_mode->hfp +
128 lcd_mode->hpw;
129 mode->htotal = lcd_mode->hactive + lcd_mode->hfp +
130 lcd_mode->hpw + lcd_mode->hbp;
131 mode->vdisplay = lcd_mode->vactive;
132 mode->vsync_start = lcd_mode->vactive + lcd_mode->vfp;
133 mode->vsync_end = lcd_mode->vactive + lcd_mode->vfp +
134 lcd_mode->vpw;
135 mode->vtotal = lcd_mode->vactive + lcd_mode->vfp +
136 lcd_mode->vpw + lcd_mode->vbp;
137
138 /* Always make the first mode preferred */
139 if (i == 0)
140 mode->type |= DRM_MODE_TYPE_PREFERRED;
141 mode->type |= DRM_MODE_TYPE_DRIVER;
142
143 drm_mode_set_name(mode);
144 drm_mode_probed_add(connector, mode);
145
146 num++;
147 }
148
149 connector->display_info.width_mm = lcd_info->width_mm;
150 connector->display_info.height_mm = lcd_info->height_mm;
151 connector->display_info.bpc = lcd_info->bpc;
152
153 if (lcd_info->bus_format)
154 drm_display_info_set_bus_formats(&connector->display_info,
155 &lcd_info->bus_format, 1);
156 connector->display_info.bus_flags = lcd_info->bus_flag;
157
158 return num;
159 }
160
161 static const struct drm_panel_funcs lcd_olinuxino_funcs = {
162 .unprepare = lcd_olinuxino_unprepare,
163 .prepare = lcd_olinuxino_prepare,
164 .get_modes = lcd_olinuxino_get_modes,
165 };
166
lcd_olinuxino_probe(struct i2c_client * client)167 static int lcd_olinuxino_probe(struct i2c_client *client)
168 {
169 struct device *dev = &client->dev;
170 struct lcd_olinuxino *lcd;
171 u32 checksum, i;
172 int ret = 0;
173
174 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
175 I2C_FUNC_SMBUS_READ_I2C_BLOCK))
176 return -ENODEV;
177
178 lcd = devm_drm_panel_alloc(dev, struct lcd_olinuxino, panel,
179 &lcd_olinuxino_funcs,
180 DRM_MODE_CONNECTOR_DPI);
181 if (IS_ERR(lcd))
182 return PTR_ERR(lcd);
183
184 i2c_set_clientdata(client, lcd);
185 lcd->dev = dev;
186 lcd->client = client;
187
188 mutex_init(&lcd->mutex);
189
190 /* Copy data into buffer */
191 for (i = 0; i < LCD_OLINUXINO_DATA_LEN; i += I2C_SMBUS_BLOCK_MAX) {
192 mutex_lock(&lcd->mutex);
193 ret = i2c_smbus_read_i2c_block_data(client,
194 i,
195 I2C_SMBUS_BLOCK_MAX,
196 (u8 *)&lcd->eeprom + i);
197 mutex_unlock(&lcd->mutex);
198 if (ret < 0) {
199 dev_err(dev, "error reading from device at %02x\n", i);
200 return ret;
201 }
202 }
203
204 /* Check configuration checksum */
205 checksum = ~crc32(~0, (u8 *)&lcd->eeprom, 252);
206 if (checksum != lcd->eeprom.checksum) {
207 dev_err(dev, "configuration checksum does not match!\n");
208 return -EINVAL;
209 }
210
211 /* Check magic header */
212 if (lcd->eeprom.header != LCD_OLINUXINO_HEADER_MAGIC) {
213 dev_err(dev, "magic header does not match\n");
214 return -EINVAL;
215 }
216
217 dev_info(dev, "Detected %s, Rev. %s, Serial: %08x\n",
218 lcd->eeprom.info.name,
219 lcd->eeprom.revision,
220 lcd->eeprom.serial);
221
222 /*
223 * The eeprom can hold up to 4 modes.
224 * If the stored value is bigger, overwrite it.
225 */
226 if (lcd->eeprom.num_modes > 4) {
227 dev_warn(dev, "invalid number of modes, falling back to 4\n");
228 lcd->eeprom.num_modes = 4;
229 }
230
231 lcd->supply = devm_regulator_get(dev, "power");
232 if (IS_ERR(lcd->supply))
233 return PTR_ERR(lcd->supply);
234
235 lcd->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
236 if (IS_ERR(lcd->enable_gpio))
237 return PTR_ERR(lcd->enable_gpio);
238
239 ret = drm_panel_of_backlight(&lcd->panel);
240 if (ret)
241 return ret;
242
243 drm_panel_add(&lcd->panel);
244
245 return 0;
246 }
247
lcd_olinuxino_remove(struct i2c_client * client)248 static void lcd_olinuxino_remove(struct i2c_client *client)
249 {
250 struct lcd_olinuxino *panel = i2c_get_clientdata(client);
251
252 drm_panel_remove(&panel->panel);
253 }
254
255 static const struct of_device_id lcd_olinuxino_of_ids[] = {
256 { .compatible = "olimex,lcd-olinuxino" },
257 { }
258 };
259 MODULE_DEVICE_TABLE(of, lcd_olinuxino_of_ids);
260
261 static struct i2c_driver lcd_olinuxino_driver = {
262 .driver = {
263 .name = "lcd_olinuxino",
264 .of_match_table = lcd_olinuxino_of_ids,
265 },
266 .probe = lcd_olinuxino_probe,
267 .remove = lcd_olinuxino_remove,
268 };
269
270 module_i2c_driver(lcd_olinuxino_driver);
271
272 MODULE_AUTHOR("Stefan Mavrodiev <stefan@olimex.com>");
273 MODULE_DESCRIPTION("LCD-OLinuXino driver");
274 MODULE_LICENSE("GPL");
275