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 { .name = "cros-ec-pchg", }, 118 }; 119 120 static const struct mfd_cell cros_ec_lightbar_cells[] = { 121 { .name = "cros-ec-lightbar", } 122 }; 123 124 static const struct mfd_cell cros_ec_vbc_cells[] = { 125 { .name = "cros-ec-vbc", } 126 }; 127 128 static void cros_ec_class_release(struct device *dev) 129 { 130 kfree(to_cros_ec_dev(dev)); 131 } 132 133 static int ec_device_probe(struct platform_device *pdev) 134 { 135 int retval = -ENOMEM; 136 struct device_node *node; 137 struct device *dev = &pdev->dev; 138 struct cros_ec_platform *ec_platform = dev_get_platdata(dev); 139 struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL); 140 int i; 141 142 if (!ec) 143 return retval; 144 145 dev_set_drvdata(dev, ec); 146 ec->ec_dev = dev_get_drvdata(dev->parent); 147 ec->dev = dev; 148 ec->cmd_offset = ec_platform->cmd_offset; 149 ec->features[0] = -1U; /* Not cached yet */ 150 ec->features[1] = -1U; /* Not cached yet */ 151 device_initialize(&ec->class_dev); 152 153 for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) { 154 /* 155 * Check whether this is actually a dedicated MCU rather 156 * than an standard EC. 157 */ 158 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) { 159 dev_info(dev, "CrOS %s MCU detected\n", 160 cros_mcu_devices[i].desc); 161 /* 162 * Help userspace differentiating ECs from other MCU, 163 * regardless of the probing order. 164 */ 165 ec_platform->ec_name = cros_mcu_devices[i].name; 166 break; 167 } 168 } 169 170 /* 171 * Add the class device 172 */ 173 ec->class_dev.class = &cros_class; 174 ec->class_dev.parent = dev; 175 ec->class_dev.release = cros_ec_class_release; 176 177 retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name); 178 if (retval) { 179 dev_err(dev, "dev_set_name failed => %d\n", retval); 180 goto failed; 181 } 182 183 retval = device_add(&ec->class_dev); 184 if (retval) 185 goto failed; 186 187 /* check whether this EC is a sensor hub. */ 188 if (cros_ec_get_sensor_count(ec) > 0) { 189 retval = mfd_add_hotplug_devices(ec->dev, 190 cros_ec_sensorhub_cells, 191 ARRAY_SIZE(cros_ec_sensorhub_cells)); 192 if (retval) 193 dev_err(ec->dev, "failed to add %s subdevice: %d\n", 194 cros_ec_sensorhub_cells->name, retval); 195 } 196 197 /* 198 * The following subdevices can be detected by sending the 199 * EC_FEATURE_GET_CMD Embedded Controller device. 200 */ 201 for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) { 202 if (cros_ec_check_features(ec, cros_subdevices[i].id)) { 203 retval = mfd_add_hotplug_devices(ec->dev, 204 cros_subdevices[i].mfd_cells, 205 cros_subdevices[i].num_cells); 206 if (retval) 207 dev_err(ec->dev, 208 "failed to add %s subdevice: %d\n", 209 cros_subdevices[i].mfd_cells->name, 210 retval); 211 } 212 } 213 214 /* 215 * Lightbar is a special case. Newer devices support autodetection, 216 * but older ones do not. 217 */ 218 if (cros_ec_check_features(ec, EC_FEATURE_LIGHTBAR) || 219 dmi_match(DMI_PRODUCT_NAME, "Link")) { 220 retval = mfd_add_hotplug_devices(ec->dev, 221 cros_ec_lightbar_cells, 222 ARRAY_SIZE(cros_ec_lightbar_cells)); 223 if (retval) 224 dev_warn(ec->dev, "failed to add lightbar: %d\n", 225 retval); 226 } 227 228 /* 229 * The PD notifier driver cell is separate since it only needs to be 230 * explicitly added on platforms that don't have the PD notifier ACPI 231 * device entry defined. 232 */ 233 if (IS_ENABLED(CONFIG_OF) && ec->ec_dev->dev->of_node) { 234 if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) { 235 retval = mfd_add_hotplug_devices(ec->dev, 236 cros_usbpd_notify_cells, 237 ARRAY_SIZE(cros_usbpd_notify_cells)); 238 if (retval) 239 dev_err(ec->dev, 240 "failed to add PD notify devices: %d\n", 241 retval); 242 } 243 } 244 245 /* 246 * The following subdevices cannot be detected by sending the 247 * EC_FEATURE_GET_CMD to the Embedded Controller device. 248 */ 249 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells, 250 ARRAY_SIZE(cros_ec_platform_cells)); 251 if (retval) 252 dev_warn(ec->dev, 253 "failed to add cros-ec platform devices: %d\n", 254 retval); 255 256 /* Check whether this EC instance has a VBC NVRAM */ 257 node = ec->ec_dev->dev->of_node; 258 if (of_property_read_bool(node, "google,has-vbc-nvram")) { 259 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells, 260 ARRAY_SIZE(cros_ec_vbc_cells)); 261 if (retval) 262 dev_warn(ec->dev, "failed to add VBC devices: %d\n", 263 retval); 264 } 265 266 return 0; 267 268 failed: 269 put_device(&ec->class_dev); 270 return retval; 271 } 272 273 static int ec_device_remove(struct platform_device *pdev) 274 { 275 struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev); 276 277 mfd_remove_devices(ec->dev); 278 device_unregister(&ec->class_dev); 279 return 0; 280 } 281 282 static const struct platform_device_id cros_ec_id[] = { 283 { DRV_NAME, 0 }, 284 { /* sentinel */ } 285 }; 286 MODULE_DEVICE_TABLE(platform, cros_ec_id); 287 288 static struct platform_driver cros_ec_dev_driver = { 289 .driver = { 290 .name = DRV_NAME, 291 }, 292 .id_table = cros_ec_id, 293 .probe = ec_device_probe, 294 .remove = ec_device_remove, 295 }; 296 297 static int __init cros_ec_dev_init(void) 298 { 299 int ret; 300 301 ret = class_register(&cros_class); 302 if (ret) { 303 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n"); 304 return ret; 305 } 306 307 /* Register the driver */ 308 ret = platform_driver_register(&cros_ec_dev_driver); 309 if (ret < 0) { 310 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret); 311 goto failed_devreg; 312 } 313 return 0; 314 315 failed_devreg: 316 class_unregister(&cros_class); 317 return ret; 318 } 319 320 static void __exit cros_ec_dev_exit(void) 321 { 322 platform_driver_unregister(&cros_ec_dev_driver); 323 class_unregister(&cros_class); 324 } 325 326 module_init(cros_ec_dev_init); 327 module_exit(cros_ec_dev_exit); 328 329 MODULE_ALIAS("platform:" DRV_NAME); 330 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>"); 331 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller"); 332 MODULE_VERSION("1.0"); 333 MODULE_LICENSE("GPL"); 334