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.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 .name = "chromeos",
24 };
25
26 /**
27 * struct 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 * struct 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-sysfs", },
116 };
117
118 static const struct mfd_cell cros_ec_pchg_cells[] = {
119 { .name = "cros-ec-pchg", },
120 };
121
122 static const struct mfd_cell cros_ec_lightbar_cells[] = {
123 { .name = "cros-ec-lightbar", }
124 };
125
126 static const struct mfd_cell cros_ec_vbc_cells[] = {
127 { .name = "cros-ec-vbc", }
128 };
129
cros_ec_class_release(struct device * dev)130 static void cros_ec_class_release(struct device *dev)
131 {
132 kfree(to_cros_ec_dev(dev));
133 }
134
ec_device_probe(struct platform_device * pdev)135 static int ec_device_probe(struct platform_device *pdev)
136 {
137 int retval = -ENOMEM;
138 struct device_node *node;
139 struct device *dev = &pdev->dev;
140 struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
141 struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
142 struct ec_response_pchg_count pchg_count;
143 int i;
144
145 if (!ec)
146 return retval;
147
148 dev_set_drvdata(dev, ec);
149 ec->ec_dev = dev_get_drvdata(dev->parent);
150 ec->dev = dev;
151 ec->cmd_offset = ec_platform->cmd_offset;
152 ec->features.flags[0] = -1U; /* Not cached yet */
153 ec->features.flags[1] = -1U; /* Not cached yet */
154 device_initialize(&ec->class_dev);
155
156 for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
157 /*
158 * Check whether this is actually a dedicated MCU rather
159 * than an standard EC.
160 */
161 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
162 dev_info(dev, "CrOS %s MCU detected\n",
163 cros_mcu_devices[i].desc);
164 /*
165 * Help userspace differentiating ECs from other MCU,
166 * regardless of the probing order.
167 */
168 ec_platform->ec_name = cros_mcu_devices[i].name;
169 break;
170 }
171 }
172
173 /*
174 * Add the class device
175 */
176 ec->class_dev.class = &cros_class;
177 ec->class_dev.parent = dev;
178 ec->class_dev.release = cros_ec_class_release;
179
180 retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
181 if (retval) {
182 dev_err(dev, "dev_set_name failed => %d\n", retval);
183 goto failed;
184 }
185
186 retval = device_add(&ec->class_dev);
187 if (retval)
188 goto failed;
189
190 /* check whether this EC is a sensor hub. */
191 if (cros_ec_get_sensor_count(ec) > 0) {
192 retval = mfd_add_hotplug_devices(ec->dev,
193 cros_ec_sensorhub_cells,
194 ARRAY_SIZE(cros_ec_sensorhub_cells));
195 if (retval)
196 dev_err(ec->dev, "failed to add %s subdevice: %d\n",
197 cros_ec_sensorhub_cells->name, retval);
198 }
199
200 /*
201 * The following subdevices can be detected by sending the
202 * EC_FEATURE_GET_CMD Embedded Controller device.
203 */
204 for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
205 if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
206 retval = mfd_add_hotplug_devices(ec->dev,
207 cros_subdevices[i].mfd_cells,
208 cros_subdevices[i].num_cells);
209 if (retval)
210 dev_err(ec->dev,
211 "failed to add %s subdevice: %d\n",
212 cros_subdevices[i].mfd_cells->name,
213 retval);
214 }
215 }
216
217 /*
218 * Lightbar is a special case. Newer devices support autodetection,
219 * but older ones do not.
220 */
221 if (cros_ec_check_features(ec, EC_FEATURE_LIGHTBAR) ||
222 dmi_match(DMI_PRODUCT_NAME, "Link")) {
223 retval = mfd_add_hotplug_devices(ec->dev,
224 cros_ec_lightbar_cells,
225 ARRAY_SIZE(cros_ec_lightbar_cells));
226 if (retval)
227 dev_warn(ec->dev, "failed to add lightbar: %d\n",
228 retval);
229 }
230
231 /*
232 * The PD notifier driver cell is separate since it only needs to be
233 * explicitly added on platforms that don't have the PD notifier ACPI
234 * device entry defined.
235 */
236 if (IS_ENABLED(CONFIG_OF) && ec->ec_dev->dev->of_node) {
237 if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
238 retval = mfd_add_hotplug_devices(ec->dev,
239 cros_usbpd_notify_cells,
240 ARRAY_SIZE(cros_usbpd_notify_cells));
241 if (retval)
242 dev_err(ec->dev,
243 "failed to add PD notify devices: %d\n",
244 retval);
245 }
246 }
247
248 /*
249 * The PCHG device cannot be detected by sending EC_FEATURE_GET_CMD, but
250 * it can be detected by querying the number of peripheral chargers.
251 */
252 retval = cros_ec_cmd(ec->ec_dev, 0, EC_CMD_PCHG_COUNT, NULL, 0,
253 &pchg_count, sizeof(pchg_count));
254 if (retval >= 0 && pchg_count.port_count) {
255 retval = mfd_add_hotplug_devices(ec->dev,
256 cros_ec_pchg_cells,
257 ARRAY_SIZE(cros_ec_pchg_cells));
258 if (retval)
259 dev_warn(ec->dev, "failed to add pchg: %d\n",
260 retval);
261 }
262
263 /*
264 * The following subdevices cannot be detected by sending the
265 * EC_FEATURE_GET_CMD to the Embedded Controller device.
266 */
267 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells,
268 ARRAY_SIZE(cros_ec_platform_cells));
269 if (retval)
270 dev_warn(ec->dev,
271 "failed to add cros-ec platform devices: %d\n",
272 retval);
273
274 /* Check whether this EC instance has a VBC NVRAM */
275 node = ec->ec_dev->dev->of_node;
276 if (of_property_read_bool(node, "google,has-vbc-nvram")) {
277 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells,
278 ARRAY_SIZE(cros_ec_vbc_cells));
279 if (retval)
280 dev_warn(ec->dev, "failed to add VBC devices: %d\n",
281 retval);
282 }
283
284 return 0;
285
286 failed:
287 put_device(&ec->class_dev);
288 return retval;
289 }
290
ec_device_remove(struct platform_device * pdev)291 static int ec_device_remove(struct platform_device *pdev)
292 {
293 struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
294
295 mfd_remove_devices(ec->dev);
296 device_unregister(&ec->class_dev);
297 return 0;
298 }
299
300 static const struct platform_device_id cros_ec_id[] = {
301 { DRV_NAME, 0 },
302 { /* sentinel */ }
303 };
304 MODULE_DEVICE_TABLE(platform, cros_ec_id);
305
306 static struct platform_driver cros_ec_dev_driver = {
307 .driver = {
308 .name = DRV_NAME,
309 },
310 .id_table = cros_ec_id,
311 .probe = ec_device_probe,
312 .remove = ec_device_remove,
313 };
314
cros_ec_dev_init(void)315 static int __init cros_ec_dev_init(void)
316 {
317 int ret;
318
319 ret = class_register(&cros_class);
320 if (ret) {
321 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
322 return ret;
323 }
324
325 /* Register the driver */
326 ret = platform_driver_register(&cros_ec_dev_driver);
327 if (ret < 0) {
328 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
329 goto failed_devreg;
330 }
331 return 0;
332
333 failed_devreg:
334 class_unregister(&cros_class);
335 return ret;
336 }
337
cros_ec_dev_exit(void)338 static void __exit cros_ec_dev_exit(void)
339 {
340 platform_driver_unregister(&cros_ec_dev_driver);
341 class_unregister(&cros_class);
342 }
343
344 module_init(cros_ec_dev_init);
345 module_exit(cros_ec_dev_exit);
346
347 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
348 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
349 MODULE_VERSION("1.0");
350 MODULE_LICENSE("GPL");
351