dell-lis3lv02d.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * lis3lv02d i2c-client instantiation for ACPI SMO88xx devices without I2C resources.
  4 *
  5 *  Copyright (C) 2024 Hans de Goede <hansg@kernel.org>
  6 */
  7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  8
  9#include <linux/device/bus.h>
 10#include <linux/dmi.h>
 11#include <linux/i2c.h>
 12#include <linux/module.h>
 13#include <linux/notifier.h>
 14#include <linux/platform_device.h>
 15#include <linux/workqueue.h>
 16#include "dell-smo8800-ids.h"
 17
 18#define LIS3_WHO_AM_I 0x0f
 19
 20#define DELL_LIS3LV02D_DMI_ENTRY(product_name, i2c_addr)                 \
 21	{                                                                \
 22		.matches = {                                             \
 23			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),    \
 24			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, product_name), \
 25		},                                                       \
 26		.driver_data = (void *)(uintptr_t)(i2c_addr),            \
 27	}
 28
 29/*
 30 * Accelerometer's I2C address is not specified in DMI nor ACPI,
 31 * so it is needed to define mapping table based on DMI product names.
 32 */
 33static const struct dmi_system_id lis3lv02d_devices[] __initconst = {
 34	/*
 35	 * Dell platform team told us that these Latitude devices have
 36	 * ST microelectronics accelerometer at I2C address 0x29.
 37	 */
 38	DELL_LIS3LV02D_DMI_ENTRY("Latitude E5250",     0x29),
 39	DELL_LIS3LV02D_DMI_ENTRY("Latitude E5450",     0x29),
 40	DELL_LIS3LV02D_DMI_ENTRY("Latitude E5550",     0x29),
 41	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6440",     0x29),
 42	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6440 ATG", 0x29),
 43	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6540",     0x29),
 44	/*
 45	 * Additional individual entries were added after verification.
 46	 */
 47	DELL_LIS3LV02D_DMI_ENTRY("Latitude 5400",      0x29),
 48	DELL_LIS3LV02D_DMI_ENTRY("Latitude 5480",      0x29),
 49	DELL_LIS3LV02D_DMI_ENTRY("Latitude 5500",      0x29),
 50	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6330",     0x29),
 51	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6430",     0x29),
 52	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6530",     0x29),
 53	DELL_LIS3LV02D_DMI_ENTRY("Precision 3540",     0x29),
 54	DELL_LIS3LV02D_DMI_ENTRY("Precision 3551",     0x29),
 55	DELL_LIS3LV02D_DMI_ENTRY("Precision M6800",    0x29),
 56	DELL_LIS3LV02D_DMI_ENTRY("Vostro V131",        0x1d),
 57	DELL_LIS3LV02D_DMI_ENTRY("Vostro 5568",        0x29),
 58	DELL_LIS3LV02D_DMI_ENTRY("XPS 15 7590",        0x29),
 59	DELL_LIS3LV02D_DMI_ENTRY("XPS 15 9550",        0x29),
 60	{ }
 61};
 62
 63static u8 i2c_addr;
 64static struct i2c_client *i2c_dev;
 65static bool notifier_registered;
 66
 67static bool probe_i2c_addr;
 68module_param(probe_i2c_addr, bool, 0444);
 69MODULE_PARM_DESC(probe_i2c_addr, "Probe the i801 I2C bus for the accelerometer on models where the address is unknown, this may be dangerous.");
 70
 71static int detect_lis3lv02d(struct i2c_adapter *adap, unsigned short addr)
 72{
 73	union i2c_smbus_data smbus_data;
 74	int err;
 75
 76	dev_info(&adap->dev, "Probing for lis3lv02d on address 0x%02x\n", addr);
 77
 78	err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, LIS3_WHO_AM_I,
 79			     I2C_SMBUS_BYTE_DATA, &smbus_data);
 80	if (err < 0)
 81		return 0; /* Not found */
 82
 83	/* valid who-am-i values are from drivers/misc/lis3lv02d/lis3lv02d.c */
 84	switch (smbus_data.byte) {
 85	case 0x32:
 86	case 0x33:
 87	case 0x3a:
 88	case 0x3b:
 89		break;
 90	default:
 91		dev_warn(&adap->dev, "Unknown who-am-i register value 0x%02x\n",
 92			 smbus_data.byte);
 93		return 0; /* Not found */
 94	}
 95
 96	dev_info(&adap->dev,
 97		 "Detected lis3lv02d on address 0x%02x, please report this upstream to platform-driver-x86@vger.kernel.org so that a quirk can be added\n",
 98		 addr);
 99
100	return 1; /* Found */
101}
102
103static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap)
104{
105	/*
106	 * Only match the main I801 adapter and reject secondary adapters
107	 * which names start with "SMBus I801 IDF adapter".
108	 */
109	return strstarts(adap->name, "SMBus I801 adapter");
110}
111
112static int find_i801(struct device *dev, void *data)
113{
114	struct i2c_adapter *adap, **adap_ret = data;
115
116	adap = i2c_verify_adapter(dev);
117	if (!adap)
118		return 0;
119
120	if (!i2c_adapter_is_main_i801(adap))
121		return 0;
122
123	*adap_ret = i2c_get_adapter(adap->nr);
124	return 1;
125}
126
127static void instantiate_i2c_client(struct work_struct *work)
128{
129	struct i2c_board_info info = { };
130	struct i2c_adapter *adap = NULL;
131
132	if (i2c_dev)
133		return;
134
135	/*
136	 * bus_for_each_dev() and not i2c_for_each_dev() to avoid
137	 * a deadlock when find_i801() calls i2c_get_adapter().
138	 */
139	bus_for_each_dev(&i2c_bus_type, NULL, &adap, find_i801);
140	if (!adap)
141		return;
142
143	strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE);
144
145	if (i2c_addr) {
146		info.addr = i2c_addr;
147		i2c_dev = i2c_new_client_device(adap, &info);
148	} else {
149		/* First try address 0x29 (most used) and then try 0x1d */
150		static const unsigned short addr_list[] = { 0x29, 0x1d, I2C_CLIENT_END };
151
152		i2c_dev = i2c_new_scanned_device(adap, &info, addr_list, detect_lis3lv02d);
153	}
154
155	if (IS_ERR(i2c_dev)) {
156		dev_err(&adap->dev, "error %ld registering i2c_client\n", PTR_ERR(i2c_dev));
157		i2c_dev = NULL;
158	} else {
159		dev_dbg(&adap->dev, "registered lis3lv02d on address 0x%02x\n", info.addr);
160	}
161
162	i2c_put_adapter(adap);
163}
164static DECLARE_WORK(i2c_work, instantiate_i2c_client);
165
166static int i2c_bus_notify(struct notifier_block *nb, unsigned long action, void *data)
167{
168	struct device *dev = data;
169	struct i2c_client *client;
170	struct i2c_adapter *adap;
171
172	switch (action) {
173	case BUS_NOTIFY_ADD_DEVICE:
174		adap = i2c_verify_adapter(dev);
175		if (!adap)
176			break;
177
178		if (i2c_adapter_is_main_i801(adap))
179			queue_work(system_long_wq, &i2c_work);
180		break;
181	case BUS_NOTIFY_REMOVED_DEVICE:
182		client = i2c_verify_client(dev);
183		if (!client)
184			break;
185
186		if (i2c_dev == client) {
187			dev_dbg(&client->adapter->dev, "lis3lv02d i2c_client removed\n");
188			i2c_dev = NULL;
189		}
190		break;
191	default:
192		break;
193	}
194
195	return 0;
196}
197static struct notifier_block i2c_nb = { .notifier_call = i2c_bus_notify };
198
199static int __init match_acpi_device_ids(struct device *dev, const void *data)
200{
201	return acpi_match_device(data, dev) ? 1 : 0;
202}
203
204static int __init dell_lis3lv02d_init(void)
205{
206	const struct dmi_system_id *lis3lv02d_dmi_id;
207	struct device *dev;
208	int err;
209
210	/*
211	 * First check for a matching platform_device. This protects against
212	 * SMO88xx ACPI fwnodes which actually do have an I2C resource, which
213	 * will already have an i2c_client instantiated (not a platform_device).
214	 */
215	dev = bus_find_device(&platform_bus_type, NULL, smo8800_ids, match_acpi_device_ids);
216	if (!dev) {
217		pr_debug("No SMO88xx platform-device found\n");
218		return 0;
219	}
220	put_device(dev);
221
222	lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices);
223	if (!lis3lv02d_dmi_id && !probe_i2c_addr) {
224		pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n");
225		pr_info("Pass dell_lis3lv02d.probe_i2c_addr=1 on the kernel command line to probe, this may be dangerous!\n");
226		return 0;
227	}
228
229	if (lis3lv02d_dmi_id)
230		i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
231
232	/*
233	 * Register i2c-bus notifier + queue initial scan for lis3lv02d
234	 * i2c_client instantiation.
235	 */
236	err = bus_register_notifier(&i2c_bus_type, &i2c_nb);
237	if (err)
238		return err;
239
240	notifier_registered = true;
241
242	queue_work(system_long_wq, &i2c_work);
243	return 0;
244}
245module_init(dell_lis3lv02d_init);
246
247static void __exit dell_lis3lv02d_module_exit(void)
248{
249	if (!notifier_registered)
250		return;
251
252	bus_unregister_notifier(&i2c_bus_type, &i2c_nb);
253	cancel_work_sync(&i2c_work);
254	i2c_unregister_device(i2c_dev);
255}
256module_exit(dell_lis3lv02d_module_exit);
257
258MODULE_DESCRIPTION("lis3lv02d i2c-client instantiation for ACPI SMO88xx devices");
259MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
260MODULE_LICENSE("GPL");