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
 22static 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 */
 32struct 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 */
 44struct cros_feature_to_cells {
 45	unsigned int id;
 46	const struct mfd_cell *mfd_cells;
 47	unsigned int num_cells;
 48};
 49
 50static 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
 73static const struct mfd_cell cros_ec_cec_cells[] = {
 74	{ .name = "cros-ec-cec", },
 75};
 76
 77static const struct mfd_cell cros_ec_rtc_cells[] = {
 78	{ .name = "cros-ec-rtc", },
 79};
 80
 81static const struct mfd_cell cros_ec_sensorhub_cells[] = {
 82	{ .name = "cros-ec-sensorhub", },
 83};
 84
 85static const struct mfd_cell cros_usbpd_charger_cells[] = {
 86	{ .name = "cros-usbpd-charger", },
 87	{ .name = "cros-usbpd-logger", },
 88};
 89
 90static const struct mfd_cell cros_usbpd_notify_cells[] = {
 91	{ .name = "cros-usbpd-notify", },
 92};
 93
 94static 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
112static 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
118static const struct mfd_cell cros_ec_pchg_cells[] = {
119	{ .name = "cros-ec-pchg", },
120};
121
122static const struct mfd_cell cros_ec_lightbar_cells[] = {
123	{ .name = "cros-ec-lightbar", }
124};
125
126static const struct mfd_cell cros_ec_vbc_cells[] = {
127	{ .name = "cros-ec-vbc", }
128};
129
130static void cros_ec_class_release(struct device *dev)
131{
132	kfree(to_cros_ec_dev(dev));
133}
134
135static 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
286failed:
287	put_device(&ec->class_dev);
288	return retval;
289}
290
291static void 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}
298
299static const struct platform_device_id cros_ec_id[] = {
300	{ DRV_NAME, 0 },
301	{ /* sentinel */ }
302};
303MODULE_DEVICE_TABLE(platform, cros_ec_id);
304
305static struct platform_driver cros_ec_dev_driver = {
306	.driver = {
307		.name = DRV_NAME,
308	},
309	.id_table = cros_ec_id,
310	.probe = ec_device_probe,
311	.remove_new = ec_device_remove,
312};
313
314static int __init cros_ec_dev_init(void)
315{
316	int ret;
317
318	ret  = class_register(&cros_class);
319	if (ret) {
320		pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
321		return ret;
322	}
323
324	/* Register the driver */
325	ret = platform_driver_register(&cros_ec_dev_driver);
326	if (ret < 0) {
327		pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
328		goto failed_devreg;
329	}
330	return 0;
331
332failed_devreg:
333	class_unregister(&cros_class);
334	return ret;
335}
336
337static void __exit cros_ec_dev_exit(void)
338{
339	platform_driver_unregister(&cros_ec_dev_driver);
340	class_unregister(&cros_class);
341}
342
343module_init(cros_ec_dev_init);
344module_exit(cros_ec_dev_exit);
345
346MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
347MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
348MODULE_VERSION("1.0");
349MODULE_LICENSE("GPL");