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 <[email protected]>
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 5480", 0x29),
48 DELL_LIS3LV02D_DMI_ENTRY("Latitude E6330", 0x29),
49 DELL_LIS3LV02D_DMI_ENTRY("Latitude E6430", 0x29),
50 DELL_LIS3LV02D_DMI_ENTRY("Precision 3540", 0x29),
51 DELL_LIS3LV02D_DMI_ENTRY("Precision M6800", 0x29),
52 DELL_LIS3LV02D_DMI_ENTRY("Vostro V131", 0x1d),
53 DELL_LIS3LV02D_DMI_ENTRY("Vostro 5568", 0x29),
54 DELL_LIS3LV02D_DMI_ENTRY("XPS 15 7590", 0x29),
55 DELL_LIS3LV02D_DMI_ENTRY("XPS 15 9550", 0x29),
56 { }
57 };
58
59 static u8 i2c_addr;
60 static struct i2c_client *i2c_dev;
61 static bool notifier_registered;
62
63 static bool probe_i2c_addr;
64 module_param(probe_i2c_addr, bool, 0444);
65 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.");
66
detect_lis3lv02d(struct i2c_adapter * adap,unsigned short addr)67 static int detect_lis3lv02d(struct i2c_adapter *adap, unsigned short addr)
68 {
69 union i2c_smbus_data smbus_data;
70 int err;
71
72 dev_info(&adap->dev, "Probing for lis3lv02d on address 0x%02x\n", addr);
73
74 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, LIS3_WHO_AM_I,
75 I2C_SMBUS_BYTE_DATA, &smbus_data);
76 if (err < 0)
77 return 0; /* Not found */
78
79 /* valid who-am-i values are from drivers/misc/lis3lv02d/lis3lv02d.c */
80 switch (smbus_data.byte) {
81 case 0x32:
82 case 0x33:
83 case 0x3a:
84 case 0x3b:
85 break;
86 default:
87 dev_warn(&adap->dev, "Unknown who-am-i register value 0x%02x\n",
88 smbus_data.byte);
89 return 0; /* Not found */
90 }
91
92 dev_info(&adap->dev,
93 "Detected lis3lv02d on address 0x%02x, please report this upstream to [email protected] so that a quirk can be added\n",
94 addr);
95
96 return 1; /* Found */
97 }
98
i2c_adapter_is_main_i801(struct i2c_adapter * adap)99 static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap)
100 {
101 /*
102 * Only match the main I801 adapter and reject secondary adapters
103 * which names start with "SMBus I801 IDF adapter".
104 */
105 return strstarts(adap->name, "SMBus I801 adapter");
106 }
107
find_i801(struct device * dev,void * data)108 static int find_i801(struct device *dev, void *data)
109 {
110 struct i2c_adapter *adap, **adap_ret = data;
111
112 adap = i2c_verify_adapter(dev);
113 if (!adap)
114 return 0;
115
116 if (!i2c_adapter_is_main_i801(adap))
117 return 0;
118
119 *adap_ret = i2c_get_adapter(adap->nr);
120 return 1;
121 }
122
instantiate_i2c_client(struct work_struct * work)123 static void instantiate_i2c_client(struct work_struct *work)
124 {
125 struct i2c_board_info info = { };
126 struct i2c_adapter *adap = NULL;
127
128 if (i2c_dev)
129 return;
130
131 /*
132 * bus_for_each_dev() and not i2c_for_each_dev() to avoid
133 * a deadlock when find_i801() calls i2c_get_adapter().
134 */
135 bus_for_each_dev(&i2c_bus_type, NULL, &adap, find_i801);
136 if (!adap)
137 return;
138
139 strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE);
140
141 if (i2c_addr) {
142 info.addr = i2c_addr;
143 i2c_dev = i2c_new_client_device(adap, &info);
144 } else {
145 /* First try address 0x29 (most used) and then try 0x1d */
146 static const unsigned short addr_list[] = { 0x29, 0x1d, I2C_CLIENT_END };
147
148 i2c_dev = i2c_new_scanned_device(adap, &info, addr_list, detect_lis3lv02d);
149 }
150
151 if (IS_ERR(i2c_dev)) {
152 dev_err(&adap->dev, "error %ld registering i2c_client\n", PTR_ERR(i2c_dev));
153 i2c_dev = NULL;
154 } else {
155 dev_dbg(&adap->dev, "registered lis3lv02d on address 0x%02x\n", info.addr);
156 }
157
158 i2c_put_adapter(adap);
159 }
160 static DECLARE_WORK(i2c_work, instantiate_i2c_client);
161
i2c_bus_notify(struct notifier_block * nb,unsigned long action,void * data)162 static int i2c_bus_notify(struct notifier_block *nb, unsigned long action, void *data)
163 {
164 struct device *dev = data;
165 struct i2c_client *client;
166 struct i2c_adapter *adap;
167
168 switch (action) {
169 case BUS_NOTIFY_ADD_DEVICE:
170 adap = i2c_verify_adapter(dev);
171 if (!adap)
172 break;
173
174 if (i2c_adapter_is_main_i801(adap))
175 queue_work(system_long_wq, &i2c_work);
176 break;
177 case BUS_NOTIFY_REMOVED_DEVICE:
178 client = i2c_verify_client(dev);
179 if (!client)
180 break;
181
182 if (i2c_dev == client) {
183 dev_dbg(&client->adapter->dev, "lis3lv02d i2c_client removed\n");
184 i2c_dev = NULL;
185 }
186 break;
187 default:
188 break;
189 }
190
191 return 0;
192 }
193 static struct notifier_block i2c_nb = { .notifier_call = i2c_bus_notify };
194
match_acpi_device_ids(struct device * dev,const void * data)195 static int __init match_acpi_device_ids(struct device *dev, const void *data)
196 {
197 return acpi_match_device(data, dev) ? 1 : 0;
198 }
199
dell_lis3lv02d_init(void)200 static int __init dell_lis3lv02d_init(void)
201 {
202 const struct dmi_system_id *lis3lv02d_dmi_id;
203 struct device *dev;
204 int err;
205
206 /*
207 * First check for a matching platform_device. This protects against
208 * SMO88xx ACPI fwnodes which actually do have an I2C resource, which
209 * will already have an i2c_client instantiated (not a platform_device).
210 */
211 dev = bus_find_device(&platform_bus_type, NULL, smo8800_ids, match_acpi_device_ids);
212 if (!dev) {
213 pr_debug("No SMO88xx platform-device found\n");
214 return 0;
215 }
216 put_device(dev);
217
218 lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices);
219 if (!lis3lv02d_dmi_id && !probe_i2c_addr) {
220 pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n");
221 pr_info("Pass dell_lis3lv02d.probe_i2c_addr=1 on the kernel command line to probe, this may be dangerous!\n");
222 return 0;
223 }
224
225 if (lis3lv02d_dmi_id)
226 i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
227
228 /*
229 * Register i2c-bus notifier + queue initial scan for lis3lv02d
230 * i2c_client instantiation.
231 */
232 err = bus_register_notifier(&i2c_bus_type, &i2c_nb);
233 if (err)
234 return err;
235
236 notifier_registered = true;
237
238 queue_work(system_long_wq, &i2c_work);
239 return 0;
240 }
241 module_init(dell_lis3lv02d_init);
242
dell_lis3lv02d_module_exit(void)243 static void __exit dell_lis3lv02d_module_exit(void)
244 {
245 if (!notifier_registered)
246 return;
247
248 bus_unregister_notifier(&i2c_bus_type, &i2c_nb);
249 cancel_work_sync(&i2c_work);
250 i2c_unregister_device(i2c_dev);
251 }
252 module_exit(dell_lis3lv02d_module_exit);
253
254 MODULE_DESCRIPTION("lis3lv02d i2c-client instantiation for ACPI SMO88xx devices");
255 MODULE_AUTHOR("Hans de Goede <[email protected]>");
256 MODULE_LICENSE("GPL");
257