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 */
33 static 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
63 static u8 i2c_addr;
64 static struct i2c_client *i2c_dev;
65 static bool notifier_registered;
66
67 static bool probe_i2c_addr;
68 module_param(probe_i2c_addr, bool, 0444);
69 MODULE_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
detect_lis3lv02d(struct i2c_adapter * adap,unsigned short addr)71 static 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
i2c_adapter_is_main_i801(struct i2c_adapter * adap)103 static 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
find_i801(struct device * dev,void * data)112 static 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
instantiate_i2c_client(struct work_struct * work)127 static 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 }
164 static DECLARE_WORK(i2c_work, instantiate_i2c_client);
165
i2c_bus_notify(struct notifier_block * nb,unsigned long action,void * data)166 static 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 }
197 static struct notifier_block i2c_nb = { .notifier_call = i2c_bus_notify };
198
match_acpi_device_ids(struct device * dev,const void * data)199 static int __init match_acpi_device_ids(struct device *dev, const void *data)
200 {
201 return acpi_match_device(data, dev) ? 1 : 0;
202 }
203
dell_lis3lv02d_init(void)204 static 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 }
245 module_init(dell_lis3lv02d_init);
246
dell_lis3lv02d_module_exit(void)247 static 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 }
256 module_exit(dell_lis3lv02d_module_exit);
257
258 MODULE_DESCRIPTION("lis3lv02d i2c-client instantiation for ACPI SMO88xx devices");
259 MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
260 MODULE_LICENSE("GPL");
261