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