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
 22static 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 */
 33struct 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 */
 45struct cros_feature_to_cells {
 46	unsigned int id;
 47	const struct mfd_cell *mfd_cells;
 48	unsigned int num_cells;
 49};
 50
 51static 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
 74static const struct mfd_cell cros_ec_cec_cells[] = {
 75	{ .name = "cros-ec-cec", },
 76};
 77
 78static const struct mfd_cell cros_ec_rtc_cells[] = {
 79	{ .name = "cros-ec-rtc", },
 80};
 81
 82static const struct mfd_cell cros_ec_sensorhub_cells[] = {
 83	{ .name = "cros-ec-sensorhub", },
 84};
 85
 86static const struct mfd_cell cros_usbpd_charger_cells[] = {
 87	{ .name = "cros-usbpd-charger", },
 88	{ .name = "cros-usbpd-logger", },
 89};
 90
 91static const struct mfd_cell cros_usbpd_notify_cells[] = {
 92	{ .name = "cros-usbpd-notify", },
 93};
 94
 95static 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
113static 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
120static const struct mfd_cell cros_ec_lightbar_cells[] = {
121	{ .name = "cros-ec-lightbar", }
122};
123
124static const struct mfd_cell cros_ec_vbc_cells[] = {
125	{ .name = "cros-ec-vbc", }
126};
127
128static void cros_ec_class_release(struct device *dev)
129{
130	kfree(to_cros_ec_dev(dev));
131}
132
133static 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
268failed:
269	put_device(&ec->class_dev);
270	return retval;
271}
272
273static 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
282static const struct platform_device_id cros_ec_id[] = {
283	{ DRV_NAME, 0 },
284	{ /* sentinel */ }
285};
286MODULE_DEVICE_TABLE(platform, cros_ec_id);
287
288static 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
297static 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
315failed_devreg:
316	class_unregister(&cros_class);
317	return ret;
318}
319
320static void __exit cros_ec_dev_exit(void)
321{
322	platform_driver_unregister(&cros_ec_dev_driver);
323	class_unregister(&cros_class);
324}
325
326module_init(cros_ec_dev_init);
327module_exit(cros_ec_dev_exit);
328
329MODULE_ALIAS("platform:" DRV_NAME);
330MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
331MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
332MODULE_VERSION("1.0");
333MODULE_LICENSE("GPL");