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