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/kconfig.h> 9 #include <linux/mfd/core.h> 10 #include <linux/module.h> 11 #include <linux/mod_devicetable.h> 12 #include <linux/of_platform.h> 13 #include <linux/platform_device.h> 14 #include <linux/platform_data/cros_ec_chardev.h> 15 #include <linux/platform_data/cros_ec_commands.h> 16 #include <linux/platform_data/cros_ec_proto.h> 17 #include <linux/slab.h> 18 19 #define DRV_NAME "cros-ec-dev" 20 21 static struct class cros_class = { 22 .owner = THIS_MODULE, 23 .name = "chromeos", 24 }; 25 26 /** 27 * 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 * 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_rtc_cells[] = { 78 { .name = "cros-ec-rtc", }, 79 }; 80 81 static const struct mfd_cell cros_ec_sensorhub_cells[] = { 82 { .name = "cros-ec-sensorhub", }, 83 }; 84 85 static const struct mfd_cell cros_usbpd_charger_cells[] = { 86 { .name = "cros-usbpd-charger", }, 87 { .name = "cros-usbpd-logger", }, 88 }; 89 90 static const struct mfd_cell cros_usbpd_notify_cells[] = { 91 { .name = "cros-usbpd-notify", }, 92 }; 93 94 static const struct cros_feature_to_cells cros_subdevices[] = { 95 { 96 .id = EC_FEATURE_CEC, 97 .mfd_cells = cros_ec_cec_cells, 98 .num_cells = ARRAY_SIZE(cros_ec_cec_cells), 99 }, 100 { 101 .id = EC_FEATURE_RTC, 102 .mfd_cells = cros_ec_rtc_cells, 103 .num_cells = ARRAY_SIZE(cros_ec_rtc_cells), 104 }, 105 { 106 .id = EC_FEATURE_USB_PD, 107 .mfd_cells = cros_usbpd_charger_cells, 108 .num_cells = ARRAY_SIZE(cros_usbpd_charger_cells), 109 }, 110 }; 111 112 static const struct mfd_cell cros_ec_platform_cells[] = { 113 { .name = "cros-ec-chardev", }, 114 { .name = "cros-ec-debugfs", }, 115 { .name = "cros-ec-lightbar", }, 116 { .name = "cros-ec-sysfs", }, 117 }; 118 119 static const struct mfd_cell cros_ec_vbc_cells[] = { 120 { .name = "cros-ec-vbc", } 121 }; 122 123 static void cros_ec_class_release(struct device *dev) 124 { 125 kfree(to_cros_ec_dev(dev)); 126 } 127 128 static int ec_device_probe(struct platform_device *pdev) 129 { 130 int retval = -ENOMEM; 131 struct device_node *node; 132 struct device *dev = &pdev->dev; 133 struct cros_ec_platform *ec_platform = dev_get_platdata(dev); 134 struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL); 135 int i; 136 137 if (!ec) 138 return retval; 139 140 dev_set_drvdata(dev, ec); 141 ec->ec_dev = dev_get_drvdata(dev->parent); 142 ec->dev = dev; 143 ec->cmd_offset = ec_platform->cmd_offset; 144 ec->features[0] = -1U; /* Not cached yet */ 145 ec->features[1] = -1U; /* Not cached yet */ 146 device_initialize(&ec->class_dev); 147 148 for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) { 149 /* 150 * Check whether this is actually a dedicated MCU rather 151 * than an standard EC. 152 */ 153 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) { 154 dev_info(dev, "CrOS %s MCU detected\n", 155 cros_mcu_devices[i].desc); 156 /* 157 * Help userspace differentiating ECs from other MCU, 158 * regardless of the probing order. 159 */ 160 ec_platform->ec_name = cros_mcu_devices[i].name; 161 break; 162 } 163 } 164 165 /* 166 * Add the class device 167 */ 168 ec->class_dev.class = &cros_class; 169 ec->class_dev.parent = dev; 170 ec->class_dev.release = cros_ec_class_release; 171 172 retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name); 173 if (retval) { 174 dev_err(dev, "dev_set_name failed => %d\n", retval); 175 goto failed; 176 } 177 178 retval = device_add(&ec->class_dev); 179 if (retval) 180 goto failed; 181 182 /* check whether this EC is a sensor hub. */ 183 if (cros_ec_get_sensor_count(ec) > 0) { 184 retval = mfd_add_hotplug_devices(ec->dev, 185 cros_ec_sensorhub_cells, 186 ARRAY_SIZE(cros_ec_sensorhub_cells)); 187 if (retval) 188 dev_err(ec->dev, "failed to add %s subdevice: %d\n", 189 cros_ec_sensorhub_cells->name, retval); 190 } 191 192 /* 193 * The following subdevices can be detected by sending the 194 * EC_FEATURE_GET_CMD Embedded Controller device. 195 */ 196 for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) { 197 if (cros_ec_check_features(ec, cros_subdevices[i].id)) { 198 retval = mfd_add_hotplug_devices(ec->dev, 199 cros_subdevices[i].mfd_cells, 200 cros_subdevices[i].num_cells); 201 if (retval) 202 dev_err(ec->dev, 203 "failed to add %s subdevice: %d\n", 204 cros_subdevices[i].mfd_cells->name, 205 retval); 206 } 207 } 208 209 /* 210 * The PD notifier driver cell is separate since it only needs to be 211 * explicitly added on platforms that don't have the PD notifier ACPI 212 * device entry defined. 213 */ 214 if (IS_ENABLED(CONFIG_OF)) { 215 if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) { 216 retval = mfd_add_hotplug_devices(ec->dev, 217 cros_usbpd_notify_cells, 218 ARRAY_SIZE(cros_usbpd_notify_cells)); 219 if (retval) 220 dev_err(ec->dev, 221 "failed to add PD notify devices: %d\n", 222 retval); 223 } 224 } 225 226 /* 227 * The following subdevices cannot be detected by sending the 228 * EC_FEATURE_GET_CMD to the Embedded Controller device. 229 */ 230 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells, 231 ARRAY_SIZE(cros_ec_platform_cells)); 232 if (retval) 233 dev_warn(ec->dev, 234 "failed to add cros-ec platform devices: %d\n", 235 retval); 236 237 /* Check whether this EC instance has a VBC NVRAM */ 238 node = ec->ec_dev->dev->of_node; 239 if (of_property_read_bool(node, "google,has-vbc-nvram")) { 240 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells, 241 ARRAY_SIZE(cros_ec_vbc_cells)); 242 if (retval) 243 dev_warn(ec->dev, "failed to add VBC devices: %d\n", 244 retval); 245 } 246 247 return 0; 248 249 failed: 250 put_device(&ec->class_dev); 251 return retval; 252 } 253 254 static int ec_device_remove(struct platform_device *pdev) 255 { 256 struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev); 257 258 mfd_remove_devices(ec->dev); 259 device_unregister(&ec->class_dev); 260 return 0; 261 } 262 263 static const struct platform_device_id cros_ec_id[] = { 264 { DRV_NAME, 0 }, 265 { /* sentinel */ } 266 }; 267 MODULE_DEVICE_TABLE(platform, cros_ec_id); 268 269 static struct platform_driver cros_ec_dev_driver = { 270 .driver = { 271 .name = DRV_NAME, 272 }, 273 .id_table = cros_ec_id, 274 .probe = ec_device_probe, 275 .remove = ec_device_remove, 276 }; 277 278 static int __init cros_ec_dev_init(void) 279 { 280 int ret; 281 282 ret = class_register(&cros_class); 283 if (ret) { 284 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n"); 285 return ret; 286 } 287 288 /* Register the driver */ 289 ret = platform_driver_register(&cros_ec_dev_driver); 290 if (ret < 0) { 291 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret); 292 goto failed_devreg; 293 } 294 return 0; 295 296 failed_devreg: 297 class_unregister(&cros_class); 298 return ret; 299 } 300 301 static void __exit cros_ec_dev_exit(void) 302 { 303 platform_driver_unregister(&cros_ec_dev_driver); 304 class_unregister(&cros_class); 305 } 306 307 module_init(cros_ec_dev_init); 308 module_exit(cros_ec_dev_exit); 309 310 MODULE_ALIAS("platform:" DRV_NAME); 311 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>"); 312 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller"); 313 MODULE_VERSION("1.0"); 314 MODULE_LICENSE("GPL"); 315