drivers/gpu/drm/panel/panel-olimex-lcd-olinuxino.c

   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
  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
  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
  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
 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
 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
 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                 mode->vrefresh = lcd_mode->refresh;
 174
 175                 /* Always make the first mode preferred */
 176                 if (i == 0)
 177                         mode->type |= DRM_MODE_TYPE_PREFERRED;
 178                 mode->type |= DRM_MODE_TYPE_DRIVER;
 179
 180                 drm_mode_set_name(mode);
 181                 drm_mode_probed_add(connector, mode);
 182
 183                 num++;
 184         }
 185
 186         connector->display_info.width_mm = lcd_info->width_mm;
 187         connector->display_info.height_mm = lcd_info->height_mm;
 188         connector->display_info.bpc = lcd_info->bpc;
 189
 190         if (lcd_info->bus_format)
 191                 drm_display_info_set_bus_formats(&connector->display_info,
 192                                                  &lcd_info->bus_format, 1);
 193         connector->display_info.bus_flags = lcd_info->bus_flag;
 194
 195         return num;
 196 }
 197
 198 static const struct drm_panel_funcs lcd_olinuxino_funcs = {
 199         .disable = lcd_olinuxino_disable,
 200         .unprepare = lcd_olinuxino_unprepare,
 201         .prepare = lcd_olinuxino_prepare,
 202         .enable = lcd_olinuxino_enable,
 203         .get_modes = lcd_olinuxino_get_modes,
 204 };
 205
 206 static int lcd_olinuxino_probe(struct i2c_client *client,
 207                                const struct i2c_device_id *id)
 208 {
 209         struct device *dev = &client->dev;
 210         struct lcd_olinuxino *lcd;
 211         u32 checksum, i;
 212         int ret = 0;
 213
 214         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 215                                      I2C_FUNC_SMBUS_READ_I2C_BLOCK))
 216                 return -ENODEV;
 217
 218         lcd = devm_kzalloc(dev, sizeof(*lcd), GFP_KERNEL);
 219         if (!lcd)
 220                 return -ENOMEM;
 221
 222         i2c_set_clientdata(client, lcd);
 223         lcd->dev = dev;
 224         lcd->client = client;
 225
 226         mutex_init(&lcd->mutex);
 227
 228         /* Copy data into buffer */
 229         for (i = 0; i < LCD_OLINUXINO_DATA_LEN; i += I2C_SMBUS_BLOCK_MAX) {
 230                 mutex_lock(&lcd->mutex);
 231                 ret = i2c_smbus_read_i2c_block_data(client,
 232                                                     i,
 233                                                     I2C_SMBUS_BLOCK_MAX,
 234                                                     (u8 *)&lcd->eeprom + i);
 235                 mutex_unlock(&lcd->mutex);
 236                 if (ret < 0) {
 237                         dev_err(dev, "error reading from device at %02x\n", i);
 238                         return ret;
 239                 }
 240         }
 241
 242         /* Check configuration checksum */
 243         checksum = ~crc32(~0, (u8 *)&lcd->eeprom, 252);
 244         if (checksum != lcd->eeprom.checksum) {
 245                 dev_err(dev, "configuration checksum does not match!\n");
 246                 return -EINVAL;
 247         }
 248
 249         /* Check magic header */
 250         if (lcd->eeprom.header != LCD_OLINUXINO_HEADER_MAGIC) {
 251                 dev_err(dev, "magic header does not match\n");
 252                 return -EINVAL;
 253         }
 254
 255         dev_info(dev, "Detected %s, Rev. %s, Serial: %08x\n",
 256                  lcd->eeprom.info.name,
 257                  lcd->eeprom.revision,
 258                  lcd->eeprom.serial);
 259
 260         /*
 261          * The eeprom can hold up to 4 modes.
 262          * If the stored value is bigger, overwrite it.
 263          */
 264         if (lcd->eeprom.num_modes > 4) {
 265                 dev_warn(dev, "invalid number of modes, falling back to 4\n");
 266                 lcd->eeprom.num_modes = 4;
 267         }
 268
 269         lcd->enabled = false;
 270         lcd->prepared = false;
 271
 272         lcd->supply = devm_regulator_get(dev, "power");
 273         if (IS_ERR(lcd->supply))
 274                 return PTR_ERR(lcd->supply);
 275
 276         lcd->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
 277         if (IS_ERR(lcd->enable_gpio))
 278                 return PTR_ERR(lcd->enable_gpio);
 279
 280         drm_panel_init(&lcd->panel, dev, &lcd_olinuxino_funcs,
 281                        DRM_MODE_CONNECTOR_DPI);
 282
 283         ret = drm_panel_of_backlight(&lcd->panel);
 284         if (ret)
 285                 return ret;
 286
 287         return drm_panel_add(&lcd->panel);
 288 }
 289
 290 static int 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         return 0;
 300 }
 301
 302 static const struct of_device_id lcd_olinuxino_of_ids[] = {
 303         { .compatible = "olimex,lcd-olinuxino" },
 304         { }
 305 };
 306 MODULE_DEVICE_TABLE(of, lcd_olinuxino_of_ids);
 307
 308 static struct i2c_driver lcd_olinuxino_driver = {
 309         .driver = {
 310                 .name = "lcd_olinuxino",
 311                 .of_match_table = lcd_olinuxino_of_ids,
 312         },
 313         .probe = lcd_olinuxino_probe,
 314         .remove = lcd_olinuxino_remove,
 315 };
 316
 317 module_i2c_driver(lcd_olinuxino_driver);
 318
 319 MODULE_AUTHOR("Stefan Mavrodiev <stefan@olimex.com>");
 320 MODULE_DESCRIPTION("LCD-OLinuXino driver");
 321 MODULE_LICENSE("GPL");