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 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 <stefan@olimex.com>"); 274 MODULE_DESCRIPTION("LCD-OLinuXino driver"); 275 MODULE_LICENSE("GPL"); 276