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1// SPDX-License-Identifier: GPL-2.0+2/*3 * LCD-OLinuXino support for panel driver4 *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 0x4F4CB72725#define LCD_OLINUXINO_DATA_LEN 25626 27struct 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 41struct 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 50struct 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 61struct 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 73static inline struct lcd_olinuxino *to_lcd_olinuxino(struct drm_panel *panel)74{75 return container_of(panel, struct lcd_olinuxino, panel);76}77 78static 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 88static 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 102static 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 161static 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 167static 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 249static 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 256static const struct of_device_id lcd_olinuxino_of_ids[] = {257 { .compatible = "olimex,lcd-olinuxino" },258 { }259};260MODULE_DEVICE_TABLE(of, lcd_olinuxino_of_ids);261 262static 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 271module_i2c_driver(lcd_olinuxino_driver);272 273MODULE_AUTHOR("Stefan Mavrodiev <stefan@olimex.com>");274MODULE_DESCRIPTION("LCD-OLinuXino driver");275MODULE_LICENSE("GPL");276