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 <[email protected]>
   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
  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
  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
  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
 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
 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_kzalloc(dev, sizeof(*lcd), GFP_KERNEL);
 179         if (!lcd)
 180                 return -ENOMEM;
 181
 182         i2c_set_clientdata(client, lcd);
 183         lcd->dev = dev;
 184         lcd->client = client;
 185
 186         mutex_init(&lcd->mutex);
 187
 188         /* Copy data into buffer */
 189         for (i = 0; i < LCD_OLINUXINO_DATA_LEN; i += I2C_SMBUS_BLOCK_MAX) {
 190                 mutex_lock(&lcd->mutex);
 191                 ret = i2c_smbus_read_i2c_block_data(client,
 192                                                     i,
 193                                                     I2C_SMBUS_BLOCK_MAX,
 194                                                     (u8 *)&lcd->eeprom + i);
 195                 mutex_unlock(&lcd->mutex);
 196                 if (ret < 0) {
 197                         dev_err(dev, "error reading from device at %02x\n", i);
 198                         return ret;
 199                 }
 200         }
 201
 202         /* Check configuration checksum */
 203         checksum = ~crc32(~0, (u8 *)&lcd->eeprom, 252);
 204         if (checksum != lcd->eeprom.checksum) {
 205                 dev_err(dev, "configuration checksum does not match!\n");
 206                 return -EINVAL;
 207         }
 208
 209         /* Check magic header */
 210         if (lcd->eeprom.header != LCD_OLINUXINO_HEADER_MAGIC) {
 211                 dev_err(dev, "magic header does not match\n");
 212                 return -EINVAL;
 213         }
 214
 215         dev_info(dev, "Detected %s, Rev. %s, Serial: %08x\n",
 216                  lcd->eeprom.info.name,
 217                  lcd->eeprom.revision,
 218                  lcd->eeprom.serial);
 219
 220         /*
 221          * The eeprom can hold up to 4 modes.
 222          * If the stored value is bigger, overwrite it.
 223          */
 224         if (lcd->eeprom.num_modes > 4) {
 225                 dev_warn(dev, "invalid number of modes, falling back to 4\n");
 226                 lcd->eeprom.num_modes = 4;
 227         }
 228
 229         lcd->supply = devm_regulator_get(dev, "power");
 230         if (IS_ERR(lcd->supply))
 231                 return PTR_ERR(lcd->supply);
 232
 233         lcd->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
 234         if (IS_ERR(lcd->enable_gpio))
 235                 return PTR_ERR(lcd->enable_gpio);
 236
 237         drm_panel_init(&lcd->panel, dev, &lcd_olinuxino_funcs,
 238                        DRM_MODE_CONNECTOR_DPI);
 239
 240         ret = drm_panel_of_backlight(&lcd->panel);
 241         if (ret)
 242                 return ret;
 243
 244         drm_panel_add(&lcd->panel);
 245
 246         return 0;
 247 }
 248
 249 static void lcd_olinuxino_remove(struct i2c_client *client)
 250 {
 251         struct lcd_olinuxino *panel = i2c_get_clientdata(client);
 252
 253         drm_panel_remove(&panel->panel);
 254 }
 255
 256 static const struct of_device_id lcd_olinuxino_of_ids[] = {
 257         { .compatible = "olimex,lcd-olinuxino" },
 258         { }
 259 };
 260 MODULE_DEVICE_TABLE(of, lcd_olinuxino_of_ids);
 261
 262 static struct i2c_driver lcd_olinuxino_driver = {
 263         .driver = {
 264                 .name = "lcd_olinuxino",
 265                 .of_match_table = lcd_olinuxino_of_ids,
 266         },
 267         .probe = lcd_olinuxino_probe,
 268         .remove = lcd_olinuxino_remove,
 269 };
 270
 271 module_i2c_driver(lcd_olinuxino_driver);
 272
 273 MODULE_AUTHOR("Stefan Mavrodiev <[email protected]>");
 274 MODULE_DESCRIPTION("LCD-OLinuXino driver");
 275 MODULE_LICENSE("GPL");