1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * cros_ec_dev - expose the Chrome OS Embedded Controller to user-space 4 * 5 * Copyright (C) 2014 Google, Inc. 6 */ 7 8 #include <linux/dmi.h> 9 #include <linux/kconfig.h> 10 #include <linux/mfd/core.h> 11 #include <linux/module.h> 12 #include <linux/mod_devicetable.h> 13 #include <linux/of.h> 14 #include <linux/platform_device.h> 15 #include <linux/platform_data/cros_ec_chardev.h> 16 #include <linux/platform_data/cros_ec_commands.h> 17 #include <linux/platform_data/cros_ec_proto.h> 18 #include <linux/slab.h> 19 20 #define DRV_NAME "cros-ec-dev" 21 22 static struct class cros_class = { 23 .name = "chromeos", 24 }; 25 26 /** 27 * struct cros_feature_to_name - CrOS feature id to name/short description. 28 * @id: The feature identifier. 29 * @name: Device name associated with the feature id. 30 * @desc: Short name that will be displayed. 31 */ 32 struct cros_feature_to_name { 33 unsigned int id; 34 const char *name; 35 const char *desc; 36 }; 37 38 /** 39 * struct cros_feature_to_cells - CrOS feature id to mfd cells association. 40 * @id: The feature identifier. 41 * @mfd_cells: Pointer to the array of mfd cells that needs to be added. 42 * @num_cells: Number of mfd cells into the array. 43 */ 44 struct cros_feature_to_cells { 45 unsigned int id; 46 const struct mfd_cell *mfd_cells; 47 unsigned int num_cells; 48 }; 49 50 static const struct cros_feature_to_name cros_mcu_devices[] = { 51 { 52 .id = EC_FEATURE_FINGERPRINT, 53 .name = CROS_EC_DEV_FP_NAME, 54 .desc = "Fingerprint", 55 }, 56 { 57 .id = EC_FEATURE_ISH, 58 .name = CROS_EC_DEV_ISH_NAME, 59 .desc = "Integrated Sensor Hub", 60 }, 61 { 62 .id = EC_FEATURE_SCP, 63 .name = CROS_EC_DEV_SCP_NAME, 64 .desc = "System Control Processor", 65 }, 66 { 67 .id = EC_FEATURE_TOUCHPAD, 68 .name = CROS_EC_DEV_TP_NAME, 69 .desc = "Touchpad", 70 }, 71 }; 72 73 static const struct mfd_cell cros_ec_cec_cells[] = { 74 { .name = "cros-ec-cec", }, 75 }; 76 77 static const struct mfd_cell cros_ec_gpio_cells[] = { 78 { .name = "cros-ec-gpio", }, 79 }; 80 81 static const struct mfd_cell cros_ec_rtc_cells[] = { 82 { .name = "cros-ec-rtc", }, 83 }; 84 85 static const struct mfd_cell cros_ec_sensorhub_cells[] = { 86 { .name = "cros-ec-sensorhub", }, 87 }; 88 89 static const struct mfd_cell cros_usbpd_charger_cells[] = { 90 { .name = "cros-usbpd-charger", }, 91 { .name = "cros-usbpd-logger", }, 92 }; 93 94 static const struct mfd_cell cros_usbpd_notify_cells[] = { 95 { .name = "cros-usbpd-notify", }, 96 }; 97 98 static const struct mfd_cell cros_ec_wdt_cells[] = { 99 { .name = "cros-ec-wdt", } 100 }; 101 102 static const struct cros_feature_to_cells cros_subdevices[] = { 103 { 104 .id = EC_FEATURE_CEC, 105 .mfd_cells = cros_ec_cec_cells, 106 .num_cells = ARRAY_SIZE(cros_ec_cec_cells), 107 }, 108 { 109 .id = EC_FEATURE_GPIO, 110 .mfd_cells = cros_ec_gpio_cells, 111 .num_cells = ARRAY_SIZE(cros_ec_gpio_cells), 112 }, 113 { 114 .id = EC_FEATURE_RTC, 115 .mfd_cells = cros_ec_rtc_cells, 116 .num_cells = ARRAY_SIZE(cros_ec_rtc_cells), 117 }, 118 { 119 .id = EC_FEATURE_USB_PD, 120 .mfd_cells = cros_usbpd_charger_cells, 121 .num_cells = ARRAY_SIZE(cros_usbpd_charger_cells), 122 }, 123 { 124 .id = EC_FEATURE_HANG_DETECT, 125 .mfd_cells = cros_ec_wdt_cells, 126 .num_cells = ARRAY_SIZE(cros_ec_wdt_cells), 127 }, 128 }; 129 130 static const struct mfd_cell cros_ec_platform_cells[] = { 131 { .name = "cros-ec-chardev", }, 132 { .name = "cros-ec-debugfs", }, 133 { .name = "cros-ec-sysfs", }, 134 }; 135 136 static const struct mfd_cell cros_ec_pchg_cells[] = { 137 { .name = "cros-ec-pchg", }, 138 }; 139 140 static const struct mfd_cell cros_ec_lightbar_cells[] = { 141 { .name = "cros-ec-lightbar", } 142 }; 143 144 static const struct mfd_cell cros_ec_vbc_cells[] = { 145 { .name = "cros-ec-vbc", } 146 }; 147 148 static void cros_ec_class_release(struct device *dev) 149 { 150 kfree(to_cros_ec_dev(dev)); 151 } 152 153 static int ec_device_probe(struct platform_device *pdev) 154 { 155 int retval = -ENOMEM; 156 struct device_node *node; 157 struct device *dev = &pdev->dev; 158 struct cros_ec_platform *ec_platform = dev_get_platdata(dev); 159 struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL); 160 struct ec_response_pchg_count pchg_count; 161 int i; 162 163 if (!ec) 164 return retval; 165 166 dev_set_drvdata(dev, ec); 167 ec->ec_dev = dev_get_drvdata(dev->parent); 168 ec->dev = dev; 169 ec->cmd_offset = ec_platform->cmd_offset; 170 ec->features.flags[0] = -1U; /* Not cached yet */ 171 ec->features.flags[1] = -1U; /* Not cached yet */ 172 device_initialize(&ec->class_dev); 173 174 for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) { 175 /* 176 * Check whether this is actually a dedicated MCU rather 177 * than an standard EC. 178 */ 179 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) { 180 dev_info(dev, "CrOS %s MCU detected\n", 181 cros_mcu_devices[i].desc); 182 /* 183 * Help userspace differentiating ECs from other MCU, 184 * regardless of the probing order. 185 */ 186 ec_platform->ec_name = cros_mcu_devices[i].name; 187 break; 188 } 189 } 190 191 /* 192 * Add the class device 193 */ 194 ec->class_dev.class = &cros_class; 195 ec->class_dev.parent = dev; 196 ec->class_dev.release = cros_ec_class_release; 197 198 retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name); 199 if (retval) { 200 dev_err(dev, "dev_set_name failed => %d\n", retval); 201 goto failed; 202 } 203 204 retval = device_add(&ec->class_dev); 205 if (retval) 206 goto failed; 207 208 /* check whether this EC is a sensor hub. */ 209 if (cros_ec_get_sensor_count(ec) > 0) { 210 retval = mfd_add_hotplug_devices(ec->dev, 211 cros_ec_sensorhub_cells, 212 ARRAY_SIZE(cros_ec_sensorhub_cells)); 213 if (retval) 214 dev_err(ec->dev, "failed to add %s subdevice: %d\n", 215 cros_ec_sensorhub_cells->name, retval); 216 } 217 218 /* 219 * The following subdevices can be detected by sending the 220 * EC_FEATURE_GET_CMD Embedded Controller device. 221 */ 222 for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) { 223 if (cros_ec_check_features(ec, cros_subdevices[i].id)) { 224 retval = mfd_add_hotplug_devices(ec->dev, 225 cros_subdevices[i].mfd_cells, 226 cros_subdevices[i].num_cells); 227 if (retval) 228 dev_err(ec->dev, 229 "failed to add %s subdevice: %d\n", 230 cros_subdevices[i].mfd_cells->name, 231 retval); 232 } 233 } 234 235 /* 236 * Lightbar is a special case. Newer devices support autodetection, 237 * but older ones do not. 238 */ 239 if (cros_ec_check_features(ec, EC_FEATURE_LIGHTBAR) || 240 dmi_match(DMI_PRODUCT_NAME, "Link")) { 241 retval = mfd_add_hotplug_devices(ec->dev, 242 cros_ec_lightbar_cells, 243 ARRAY_SIZE(cros_ec_lightbar_cells)); 244 if (retval) 245 dev_warn(ec->dev, "failed to add lightbar: %d\n", 246 retval); 247 } 248 249 /* 250 * The PD notifier driver cell is separate since it only needs to be 251 * explicitly added on platforms that don't have the PD notifier ACPI 252 * device entry defined. 253 */ 254 if (IS_ENABLED(CONFIG_OF) && ec->ec_dev->dev->of_node) { 255 if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) { 256 retval = mfd_add_hotplug_devices(ec->dev, 257 cros_usbpd_notify_cells, 258 ARRAY_SIZE(cros_usbpd_notify_cells)); 259 if (retval) 260 dev_err(ec->dev, 261 "failed to add PD notify devices: %d\n", 262 retval); 263 } 264 } 265 266 /* 267 * The PCHG device cannot be detected by sending EC_FEATURE_GET_CMD, but 268 * it can be detected by querying the number of peripheral chargers. 269 */ 270 retval = cros_ec_cmd(ec->ec_dev, 0, EC_CMD_PCHG_COUNT, NULL, 0, 271 &pchg_count, sizeof(pchg_count)); 272 if (retval >= 0 && pchg_count.port_count) { 273 retval = mfd_add_hotplug_devices(ec->dev, 274 cros_ec_pchg_cells, 275 ARRAY_SIZE(cros_ec_pchg_cells)); 276 if (retval) 277 dev_warn(ec->dev, "failed to add pchg: %d\n", 278 retval); 279 } 280 281 /* 282 * The following subdevices cannot be detected by sending the 283 * EC_FEATURE_GET_CMD to the Embedded Controller device. 284 */ 285 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells, 286 ARRAY_SIZE(cros_ec_platform_cells)); 287 if (retval) 288 dev_warn(ec->dev, 289 "failed to add cros-ec platform devices: %d\n", 290 retval); 291 292 /* Check whether this EC instance has a VBC NVRAM */ 293 node = ec->ec_dev->dev->of_node; 294 if (of_property_read_bool(node, "google,has-vbc-nvram")) { 295 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells, 296 ARRAY_SIZE(cros_ec_vbc_cells)); 297 if (retval) 298 dev_warn(ec->dev, "failed to add VBC devices: %d\n", 299 retval); 300 } 301 302 return 0; 303 304 failed: 305 put_device(&ec->class_dev); 306 return retval; 307 } 308 309 static void ec_device_remove(struct platform_device *pdev) 310 { 311 struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev); 312 313 mfd_remove_devices(ec->dev); 314 device_unregister(&ec->class_dev); 315 } 316 317 static const struct platform_device_id cros_ec_id[] = { 318 { DRV_NAME, 0 }, 319 { /* sentinel */ } 320 }; 321 MODULE_DEVICE_TABLE(platform, cros_ec_id); 322 323 static struct platform_driver cros_ec_dev_driver = { 324 .driver = { 325 .name = DRV_NAME, 326 }, 327 .id_table = cros_ec_id, 328 .probe = ec_device_probe, 329 .remove_new = ec_device_remove, 330 }; 331 332 static int __init cros_ec_dev_init(void) 333 { 334 int ret; 335 336 ret = class_register(&cros_class); 337 if (ret) { 338 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n"); 339 return ret; 340 } 341 342 /* Register the driver */ 343 ret = platform_driver_register(&cros_ec_dev_driver); 344 if (ret < 0) { 345 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret); 346 goto failed_devreg; 347 } 348 return 0; 349 350 failed_devreg: 351 class_unregister(&cros_class); 352 return ret; 353 } 354 355 static void __exit cros_ec_dev_exit(void) 356 { 357 platform_driver_unregister(&cros_ec_dev_driver); 358 class_unregister(&cros_class); 359 } 360 361 module_init(cros_ec_dev_init); 362 module_exit(cros_ec_dev_exit); 363 364 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>"); 365 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller"); 366 MODULE_VERSION("1.0"); 367 MODULE_LICENSE("GPL"); 368