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/backlight.h> 10 #include <linux/crc32.h> 11 #include <linux/gpio/consumer.h> 12 #include <linux/i2c.h> 13 #include <linux/module.h> 14 #include <linux/mutex.h> 15 #include <linux/of.h> 16 #include <linux/regulator/consumer.h> 17 18 #include <video/videomode.h> 19 #include <video/display_timing.h> 20 21 #include <drm/drm_device.h> 22 #include <drm/drm_modes.h> 23 #include <drm/drm_panel.h> 24 25 #define LCD_OLINUXINO_HEADER_MAGIC 0x4F4CB727 26 #define LCD_OLINUXINO_DATA_LEN 256 27 28 struct lcd_olinuxino_mode { 29 u32 pixelclock; 30 u32 hactive; 31 u32 hfp; 32 u32 hbp; 33 u32 hpw; 34 u32 vactive; 35 u32 vfp; 36 u32 vbp; 37 u32 vpw; 38 u32 refresh; 39 u32 flags; 40 }; 41 42 struct lcd_olinuxino_info { 43 char name[32]; 44 u32 width_mm; 45 u32 height_mm; 46 u32 bpc; 47 u32 bus_format; 48 u32 bus_flag; 49 } __attribute__((__packed__)); 50 51 struct lcd_olinuxino_eeprom { 52 u32 header; 53 u32 id; 54 char revision[4]; 55 u32 serial; 56 struct lcd_olinuxino_info info; 57 u32 num_modes; 58 u8 reserved[180]; 59 u32 checksum; 60 } __attribute__((__packed__)); 61 62 struct lcd_olinuxino { 63 struct drm_panel panel; 64 struct device *dev; 65 struct i2c_client *client; 66 struct mutex mutex; 67 68 bool prepared; 69 bool enabled; 70 71 struct backlight_device *backlight; 72 struct regulator *supply; 73 struct gpio_desc *enable_gpio; 74 75 struct lcd_olinuxino_eeprom eeprom; 76 }; 77 78 static inline struct lcd_olinuxino *to_lcd_olinuxino(struct drm_panel *panel) 79 { 80 return container_of(panel, struct lcd_olinuxino, panel); 81 } 82 83 static int lcd_olinuxino_disable(struct drm_panel *panel) 84 { 85 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel); 86 87 if (!lcd->enabled) 88 return 0; 89 90 backlight_disable(lcd->backlight); 91 92 lcd->enabled = false; 93 94 return 0; 95 } 96 97 static int lcd_olinuxino_unprepare(struct drm_panel *panel) 98 { 99 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel); 100 101 if (!lcd->prepared) 102 return 0; 103 104 gpiod_set_value_cansleep(lcd->enable_gpio, 0); 105 regulator_disable(lcd->supply); 106 107 lcd->prepared = false; 108 109 return 0; 110 } 111 112 static int lcd_olinuxino_prepare(struct drm_panel *panel) 113 { 114 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel); 115 int ret; 116 117 if (lcd->prepared) 118 return 0; 119 120 ret = regulator_enable(lcd->supply); 121 if (ret < 0) 122 return ret; 123 124 gpiod_set_value_cansleep(lcd->enable_gpio, 1); 125 lcd->prepared = true; 126 127 return 0; 128 } 129 130 static int lcd_olinuxino_enable(struct drm_panel *panel) 131 { 132 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel); 133 134 if (lcd->enabled) 135 return 0; 136 137 backlight_enable(lcd->backlight); 138 139 lcd->enabled = true; 140 141 return 0; 142 } 143 144 static int lcd_olinuxino_get_modes(struct drm_panel *panel) 145 { 146 struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel); 147 struct drm_connector *connector = lcd->panel.connector; 148 struct lcd_olinuxino_info *lcd_info = &lcd->eeprom.info; 149 struct drm_device *drm = lcd->panel.drm; 150 struct lcd_olinuxino_mode *lcd_mode; 151 struct drm_display_mode *mode; 152 u32 i, num = 0; 153 154 for (i = 0; i < lcd->eeprom.num_modes; i++) { 155 lcd_mode = (struct lcd_olinuxino_mode *) 156 &lcd->eeprom.reserved[i * sizeof(*lcd_mode)]; 157 158 mode = drm_mode_create(drm); 159 if (!mode) { 160 dev_err(drm->dev, "failed to add mode %ux%u@%u\n", 161 lcd_mode->hactive, 162 lcd_mode->vactive, 163 lcd_mode->refresh); 164 continue; 165 } 166 167 mode->clock = lcd_mode->pixelclock; 168 mode->hdisplay = lcd_mode->hactive; 169 mode->hsync_start = lcd_mode->hactive + lcd_mode->hfp; 170 mode->hsync_end = lcd_mode->hactive + lcd_mode->hfp + 171 lcd_mode->hpw; 172 mode->htotal = lcd_mode->hactive + lcd_mode->hfp + 173 lcd_mode->hpw + lcd_mode->hbp; 174 mode->vdisplay = lcd_mode->vactive; 175 mode->vsync_start = lcd_mode->vactive + lcd_mode->vfp; 176 mode->vsync_end = lcd_mode->vactive + lcd_mode->vfp + 177 lcd_mode->vpw; 178 mode->vtotal = lcd_mode->vactive + lcd_mode->vfp + 179 lcd_mode->vpw + lcd_mode->vbp; 180 mode->vrefresh = lcd_mode->refresh; 181 182 /* Always make the first mode preferred */ 183 if (i == 0) 184 mode->type |= DRM_MODE_TYPE_PREFERRED; 185 mode->type |= DRM_MODE_TYPE_DRIVER; 186 187 drm_mode_set_name(mode); 188 drm_mode_probed_add(connector, mode); 189 190 num++; 191 } 192 193 connector->display_info.width_mm = lcd_info->width_mm; 194 connector->display_info.height_mm = lcd_info->height_mm; 195 connector->display_info.bpc = lcd_info->bpc; 196 197 if (lcd_info->bus_format) 198 drm_display_info_set_bus_formats(&connector->display_info, 199 &lcd_info->bus_format, 1); 200 connector->display_info.bus_flags = lcd_info->bus_flag; 201 202 return num; 203 } 204 205 static const struct drm_panel_funcs lcd_olinuxino_funcs = { 206 .disable = lcd_olinuxino_disable, 207 .unprepare = lcd_olinuxino_unprepare, 208 .prepare = lcd_olinuxino_prepare, 209 .enable = lcd_olinuxino_enable, 210 .get_modes = lcd_olinuxino_get_modes, 211 }; 212 213 static int lcd_olinuxino_probe(struct i2c_client *client, 214 const struct i2c_device_id *id) 215 { 216 struct device *dev = &client->dev; 217 struct lcd_olinuxino *lcd; 218 u32 checksum, i; 219 int ret = 0; 220 221 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | 222 I2C_FUNC_SMBUS_READ_I2C_BLOCK)) 223 return -ENODEV; 224 225 lcd = devm_kzalloc(dev, sizeof(*lcd), GFP_KERNEL); 226 if (!lcd) 227 return -ENOMEM; 228 229 i2c_set_clientdata(client, lcd); 230 lcd->dev = dev; 231 lcd->client = client; 232 233 mutex_init(&lcd->mutex); 234 235 /* Copy data into buffer */ 236 for (i = 0; i < LCD_OLINUXINO_DATA_LEN; i += I2C_SMBUS_BLOCK_MAX) { 237 mutex_lock(&lcd->mutex); 238 ret = i2c_smbus_read_i2c_block_data(client, 239 i, 240 I2C_SMBUS_BLOCK_MAX, 241 (u8 *)&lcd->eeprom + i); 242 mutex_unlock(&lcd->mutex); 243 if (ret < 0) { 244 dev_err(dev, "error reading from device at %02x\n", i); 245 return ret; 246 } 247 } 248 249 /* Check configuration checksum */ 250 checksum = ~crc32(~0, (u8 *)&lcd->eeprom, 252); 251 if (checksum != lcd->eeprom.checksum) { 252 dev_err(dev, "configuration checksum does not match!\n"); 253 return -EINVAL; 254 } 255 256 /* Check magic header */ 257 if (lcd->eeprom.header != LCD_OLINUXINO_HEADER_MAGIC) { 258 dev_err(dev, "magic header does not match\n"); 259 return -EINVAL; 260 } 261 262 dev_info(dev, "Detected %s, Rev. %s, Serial: %08x\n", 263 lcd->eeprom.info.name, 264 lcd->eeprom.revision, 265 lcd->eeprom.serial); 266 267 /* 268 * The eeprom can hold up to 4 modes. 269 * If the stored value is bigger, overwrite it. 270 */ 271 if (lcd->eeprom.num_modes > 4) { 272 dev_warn(dev, "invalid number of modes, falling back to 4\n"); 273 lcd->eeprom.num_modes = 4; 274 } 275 276 lcd->enabled = false; 277 lcd->prepared = false; 278 279 lcd->supply = devm_regulator_get(dev, "power"); 280 if (IS_ERR(lcd->supply)) 281 return PTR_ERR(lcd->supply); 282 283 lcd->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW); 284 if (IS_ERR(lcd->enable_gpio)) 285 return PTR_ERR(lcd->enable_gpio); 286 287 lcd->backlight = devm_of_find_backlight(dev); 288 if (IS_ERR(lcd->backlight)) 289 return PTR_ERR(lcd->backlight); 290 291 drm_panel_init(&lcd->panel, dev, &lcd_olinuxino_funcs, 292 DRM_MODE_CONNECTOR_DPI); 293 294 return drm_panel_add(&lcd->panel); 295 } 296 297 static int lcd_olinuxino_remove(struct i2c_client *client) 298 { 299 struct lcd_olinuxino *panel = i2c_get_clientdata(client); 300 301 drm_panel_remove(&panel->panel); 302 303 lcd_olinuxino_disable(&panel->panel); 304 lcd_olinuxino_unprepare(&panel->panel); 305 306 return 0; 307 } 308 309 static const struct of_device_id lcd_olinuxino_of_ids[] = { 310 { .compatible = "olimex,lcd-olinuxino" }, 311 { } 312 }; 313 MODULE_DEVICE_TABLE(of, lcd_olinuxino_of_ids); 314 315 static struct i2c_driver lcd_olinuxino_driver = { 316 .driver = { 317 .name = "lcd_olinuxino", 318 .of_match_table = lcd_olinuxino_of_ids, 319 }, 320 .probe = lcd_olinuxino_probe, 321 .remove = lcd_olinuxino_remove, 322 }; 323 324 module_i2c_driver(lcd_olinuxino_driver); 325 326 MODULE_AUTHOR("Stefan Mavrodiev <stefan@olimex.com>"); 327 MODULE_DESCRIPTION("LCD-OLinuXino driver"); 328 MODULE_LICENSE("GPL"); 329