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_SCP_C1,
69 .name = CROS_EC_DEV_SCP_C1_NAME,
70 .desc = "System Control Processor 2nd Core",
71 },
72 {
73 .id = EC_FEATURE_TOUCHPAD,
74 .name = CROS_EC_DEV_TP_NAME,
75 .desc = "Touchpad",
76 },
77 };
78
79 static const struct mfd_cell cros_ec_cec_cells[] = {
80 { .name = "cros-ec-cec", },
81 };
82
83 static const struct mfd_cell cros_ec_rtc_cells[] = {
84 { .name = "cros-ec-rtc", },
85 };
86
87 static const struct mfd_cell cros_ec_sensorhub_cells[] = {
88 { .name = "cros-ec-sensorhub", },
89 };
90
91 static const struct mfd_cell cros_usbpd_charger_cells[] = {
92 { .name = "cros-usbpd-charger", },
93 { .name = "cros-usbpd-logger", },
94 };
95
96 static const struct mfd_cell cros_usbpd_notify_cells[] = {
97 { .name = "cros-usbpd-notify", },
98 };
99
100 static const struct cros_feature_to_cells cros_subdevices[] = {
101 {
102 .id = EC_FEATURE_CEC,
103 .mfd_cells = cros_ec_cec_cells,
104 .num_cells = ARRAY_SIZE(cros_ec_cec_cells),
105 },
106 {
107 .id = EC_FEATURE_RTC,
108 .mfd_cells = cros_ec_rtc_cells,
109 .num_cells = ARRAY_SIZE(cros_ec_rtc_cells),
110 },
111 {
112 .id = EC_FEATURE_USB_PD,
113 .mfd_cells = cros_usbpd_charger_cells,
114 .num_cells = ARRAY_SIZE(cros_usbpd_charger_cells),
115 },
116 };
117
118 static const struct mfd_cell cros_ec_platform_cells[] = {
119 { .name = "cros-ec-chardev", },
120 { .name = "cros-ec-debugfs", },
121 { .name = "cros-ec-sysfs", },
122 };
123
124 static const struct mfd_cell cros_ec_pchg_cells[] = {
125 { .name = "cros-ec-pchg", },
126 };
127
128 static const struct mfd_cell cros_ec_lightbar_cells[] = {
129 { .name = "cros-ec-lightbar", }
130 };
131
132 static const struct mfd_cell cros_ec_vbc_cells[] = {
133 { .name = "cros-ec-vbc", }
134 };
135
cros_ec_class_release(struct device * dev)136 static void cros_ec_class_release(struct device *dev)
137 {
138 kfree(to_cros_ec_dev(dev));
139 }
140
ec_device_probe(struct platform_device * pdev)141 static int ec_device_probe(struct platform_device *pdev)
142 {
143 int retval = -ENOMEM;
144 struct device_node *node;
145 struct device *dev = &pdev->dev;
146 struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
147 struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
148 struct ec_response_pchg_count pchg_count;
149 int i;
150
151 if (!ec)
152 return retval;
153
154 dev_set_drvdata(dev, ec);
155 ec->ec_dev = dev_get_drvdata(dev->parent);
156 ec->dev = dev;
157 ec->cmd_offset = ec_platform->cmd_offset;
158 ec->features.flags[0] = -1U; /* Not cached yet */
159 ec->features.flags[1] = -1U; /* Not cached yet */
160 device_initialize(&ec->class_dev);
161
162 for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
163 /*
164 * Check whether this is actually a dedicated MCU rather
165 * than an standard EC.
166 */
167 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
168 dev_info(dev, "CrOS %s MCU detected\n",
169 cros_mcu_devices[i].desc);
170 /*
171 * Help userspace differentiating ECs from other MCU,
172 * regardless of the probing order.
173 */
174 ec_platform->ec_name = cros_mcu_devices[i].name;
175 break;
176 }
177 }
178
179 /*
180 * Add the class device
181 */
182 ec->class_dev.class = &cros_class;
183 ec->class_dev.parent = dev;
184 ec->class_dev.release = cros_ec_class_release;
185
186 retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
187 if (retval) {
188 dev_err(dev, "dev_set_name failed => %d\n", retval);
189 goto failed;
190 }
191
192 retval = device_add(&ec->class_dev);
193 if (retval)
194 goto failed;
195
196 /* check whether this EC is a sensor hub. */
197 if (cros_ec_get_sensor_count(ec) > 0) {
198 retval = mfd_add_hotplug_devices(ec->dev,
199 cros_ec_sensorhub_cells,
200 ARRAY_SIZE(cros_ec_sensorhub_cells));
201 if (retval)
202 dev_err(ec->dev, "failed to add %s subdevice: %d\n",
203 cros_ec_sensorhub_cells->name, retval);
204 }
205
206 /*
207 * The following subdevices can be detected by sending the
208 * EC_FEATURE_GET_CMD Embedded Controller device.
209 */
210 for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
211 if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
212 retval = mfd_add_hotplug_devices(ec->dev,
213 cros_subdevices[i].mfd_cells,
214 cros_subdevices[i].num_cells);
215 if (retval)
216 dev_err(ec->dev,
217 "failed to add %s subdevice: %d\n",
218 cros_subdevices[i].mfd_cells->name,
219 retval);
220 }
221 }
222
223 /*
224 * Lightbar is a special case. Newer devices support autodetection,
225 * but older ones do not.
226 */
227 if (cros_ec_check_features(ec, EC_FEATURE_LIGHTBAR) ||
228 dmi_match(DMI_PRODUCT_NAME, "Link")) {
229 retval = mfd_add_hotplug_devices(ec->dev,
230 cros_ec_lightbar_cells,
231 ARRAY_SIZE(cros_ec_lightbar_cells));
232 if (retval)
233 dev_warn(ec->dev, "failed to add lightbar: %d\n",
234 retval);
235 }
236
237 /*
238 * The PD notifier driver cell is separate since it only needs to be
239 * explicitly added on platforms that don't have the PD notifier ACPI
240 * device entry defined.
241 */
242 if (IS_ENABLED(CONFIG_OF) && ec->ec_dev->dev->of_node) {
243 if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
244 retval = mfd_add_hotplug_devices(ec->dev,
245 cros_usbpd_notify_cells,
246 ARRAY_SIZE(cros_usbpd_notify_cells));
247 if (retval)
248 dev_err(ec->dev,
249 "failed to add PD notify devices: %d\n",
250 retval);
251 }
252 }
253
254 /*
255 * The PCHG device cannot be detected by sending EC_FEATURE_GET_CMD, but
256 * it can be detected by querying the number of peripheral chargers.
257 */
258 retval = cros_ec_cmd(ec->ec_dev, 0, EC_CMD_PCHG_COUNT, NULL, 0,
259 &pchg_count, sizeof(pchg_count));
260 if (retval >= 0 && pchg_count.port_count) {
261 retval = mfd_add_hotplug_devices(ec->dev,
262 cros_ec_pchg_cells,
263 ARRAY_SIZE(cros_ec_pchg_cells));
264 if (retval)
265 dev_warn(ec->dev, "failed to add pchg: %d\n",
266 retval);
267 }
268
269 /*
270 * The following subdevices cannot be detected by sending the
271 * EC_FEATURE_GET_CMD to the Embedded Controller device.
272 */
273 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells,
274 ARRAY_SIZE(cros_ec_platform_cells));
275 if (retval)
276 dev_warn(ec->dev,
277 "failed to add cros-ec platform devices: %d\n",
278 retval);
279
280 /* Check whether this EC instance has a VBC NVRAM */
281 node = ec->ec_dev->dev->of_node;
282 if (of_property_read_bool(node, "google,has-vbc-nvram")) {
283 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells,
284 ARRAY_SIZE(cros_ec_vbc_cells));
285 if (retval)
286 dev_warn(ec->dev, "failed to add VBC devices: %d\n",
287 retval);
288 }
289
290 return 0;
291
292 failed:
293 put_device(&ec->class_dev);
294 return retval;
295 }
296
ec_device_remove(struct platform_device * pdev)297 static int ec_device_remove(struct platform_device *pdev)
298 {
299 struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
300
301 mfd_remove_devices(ec->dev);
302 device_unregister(&ec->class_dev);
303 return 0;
304 }
305
306 static const struct platform_device_id cros_ec_id[] = {
307 { DRV_NAME, 0 },
308 { /* sentinel */ }
309 };
310 MODULE_DEVICE_TABLE(platform, cros_ec_id);
311
312 static struct platform_driver cros_ec_dev_driver = {
313 .driver = {
314 .name = DRV_NAME,
315 },
316 .id_table = cros_ec_id,
317 .probe = ec_device_probe,
318 .remove = ec_device_remove,
319 };
320
cros_ec_dev_init(void)321 static int __init cros_ec_dev_init(void)
322 {
323 int ret;
324
325 ret = class_register(&cros_class);
326 if (ret) {
327 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
328 return ret;
329 }
330
331 /* Register the driver */
332 ret = platform_driver_register(&cros_ec_dev_driver);
333 if (ret < 0) {
334 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
335 goto failed_devreg;
336 }
337 return 0;
338
339 failed_devreg:
340 class_unregister(&cros_class);
341 return ret;
342 }
343
cros_ec_dev_exit(void)344 static void __exit cros_ec_dev_exit(void)
345 {
346 platform_driver_unregister(&cros_ec_dev_driver);
347 class_unregister(&cros_class);
348 }
349
350 module_init(cros_ec_dev_init);
351 module_exit(cros_ec_dev_exit);
352
353 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
354 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
355 MODULE_VERSION("1.0");
356 MODULE_LICENSE("GPL");
357
