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 5480", 0x29), 48 DELL_LIS3LV02D_DMI_ENTRY("Latitude 5500", 0x29), 49 DELL_LIS3LV02D_DMI_ENTRY("Latitude E6330", 0x29), 50 DELL_LIS3LV02D_DMI_ENTRY("Latitude E6430", 0x29), 51 DELL_LIS3LV02D_DMI_ENTRY("Precision 3540", 0x29), 52 DELL_LIS3LV02D_DMI_ENTRY("Precision 3551", 0x29), 53 DELL_LIS3LV02D_DMI_ENTRY("Precision M6800", 0x29), 54 DELL_LIS3LV02D_DMI_ENTRY("Vostro V131", 0x1d), 55 DELL_LIS3LV02D_DMI_ENTRY("Vostro 5568", 0x29), 56 DELL_LIS3LV02D_DMI_ENTRY("XPS 15 7590", 0x29), 57 DELL_LIS3LV02D_DMI_ENTRY("XPS 15 9550", 0x29), 58 { } 59 }; 60 61 static u8 i2c_addr; 62 static struct i2c_client *i2c_dev; 63 static bool notifier_registered; 64 65 static bool probe_i2c_addr; 66 module_param(probe_i2c_addr, bool, 0444); 67 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."); 68 69 static int detect_lis3lv02d(struct i2c_adapter *adap, unsigned short addr) 70 { 71 union i2c_smbus_data smbus_data; 72 int err; 73 74 dev_info(&adap->dev, "Probing for lis3lv02d on address 0x%02x\n", addr); 75 76 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, LIS3_WHO_AM_I, 77 I2C_SMBUS_BYTE_DATA, &smbus_data); 78 if (err < 0) 79 return 0; /* Not found */ 80 81 /* valid who-am-i values are from drivers/misc/lis3lv02d/lis3lv02d.c */ 82 switch (smbus_data.byte) { 83 case 0x32: 84 case 0x33: 85 case 0x3a: 86 case 0x3b: 87 break; 88 default: 89 dev_warn(&adap->dev, "Unknown who-am-i register value 0x%02x\n", 90 smbus_data.byte); 91 return 0; /* Not found */ 92 } 93 94 dev_info(&adap->dev, 95 "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", 96 addr); 97 98 return 1; /* Found */ 99 } 100 101 static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap) 102 { 103 /* 104 * Only match the main I801 adapter and reject secondary adapters 105 * which names start with "SMBus I801 IDF adapter". 106 */ 107 return strstarts(adap->name, "SMBus I801 adapter"); 108 } 109 110 static int find_i801(struct device *dev, void *data) 111 { 112 struct i2c_adapter *adap, **adap_ret = data; 113 114 adap = i2c_verify_adapter(dev); 115 if (!adap) 116 return 0; 117 118 if (!i2c_adapter_is_main_i801(adap)) 119 return 0; 120 121 *adap_ret = i2c_get_adapter(adap->nr); 122 return 1; 123 } 124 125 static void instantiate_i2c_client(struct work_struct *work) 126 { 127 struct i2c_board_info info = { }; 128 struct i2c_adapter *adap = NULL; 129 130 if (i2c_dev) 131 return; 132 133 /* 134 * bus_for_each_dev() and not i2c_for_each_dev() to avoid 135 * a deadlock when find_i801() calls i2c_get_adapter(). 136 */ 137 bus_for_each_dev(&i2c_bus_type, NULL, &adap, find_i801); 138 if (!adap) 139 return; 140 141 strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE); 142 143 if (i2c_addr) { 144 info.addr = i2c_addr; 145 i2c_dev = i2c_new_client_device(adap, &info); 146 } else { 147 /* First try address 0x29 (most used) and then try 0x1d */ 148 static const unsigned short addr_list[] = { 0x29, 0x1d, I2C_CLIENT_END }; 149 150 i2c_dev = i2c_new_scanned_device(adap, &info, addr_list, detect_lis3lv02d); 151 } 152 153 if (IS_ERR(i2c_dev)) { 154 dev_err(&adap->dev, "error %ld registering i2c_client\n", PTR_ERR(i2c_dev)); 155 i2c_dev = NULL; 156 } else { 157 dev_dbg(&adap->dev, "registered lis3lv02d on address 0x%02x\n", info.addr); 158 } 159 160 i2c_put_adapter(adap); 161 } 162 static DECLARE_WORK(i2c_work, instantiate_i2c_client); 163 164 static int i2c_bus_notify(struct notifier_block *nb, unsigned long action, void *data) 165 { 166 struct device *dev = data; 167 struct i2c_client *client; 168 struct i2c_adapter *adap; 169 170 switch (action) { 171 case BUS_NOTIFY_ADD_DEVICE: 172 adap = i2c_verify_adapter(dev); 173 if (!adap) 174 break; 175 176 if (i2c_adapter_is_main_i801(adap)) 177 queue_work(system_long_wq, &i2c_work); 178 break; 179 case BUS_NOTIFY_REMOVED_DEVICE: 180 client = i2c_verify_client(dev); 181 if (!client) 182 break; 183 184 if (i2c_dev == client) { 185 dev_dbg(&client->adapter->dev, "lis3lv02d i2c_client removed\n"); 186 i2c_dev = NULL; 187 } 188 break; 189 default: 190 break; 191 } 192 193 return 0; 194 } 195 static struct notifier_block i2c_nb = { .notifier_call = i2c_bus_notify }; 196 197 static int __init match_acpi_device_ids(struct device *dev, const void *data) 198 { 199 return acpi_match_device(data, dev) ? 1 : 0; 200 } 201 202 static int __init dell_lis3lv02d_init(void) 203 { 204 const struct dmi_system_id *lis3lv02d_dmi_id; 205 struct device *dev; 206 int err; 207 208 /* 209 * First check for a matching platform_device. This protects against 210 * SMO88xx ACPI fwnodes which actually do have an I2C resource, which 211 * will already have an i2c_client instantiated (not a platform_device). 212 */ 213 dev = bus_find_device(&platform_bus_type, NULL, smo8800_ids, match_acpi_device_ids); 214 if (!dev) { 215 pr_debug("No SMO88xx platform-device found\n"); 216 return 0; 217 } 218 put_device(dev); 219 220 lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices); 221 if (!lis3lv02d_dmi_id && !probe_i2c_addr) { 222 pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n"); 223 pr_info("Pass dell_lis3lv02d.probe_i2c_addr=1 on the kernel command line to probe, this may be dangerous!\n"); 224 return 0; 225 } 226 227 if (lis3lv02d_dmi_id) 228 i2c_addr = (long)lis3lv02d_dmi_id->driver_data; 229 230 /* 231 * Register i2c-bus notifier + queue initial scan for lis3lv02d 232 * i2c_client instantiation. 233 */ 234 err = bus_register_notifier(&i2c_bus_type, &i2c_nb); 235 if (err) 236 return err; 237 238 notifier_registered = true; 239 240 queue_work(system_long_wq, &i2c_work); 241 return 0; 242 } 243 module_init(dell_lis3lv02d_init); 244 245 static void __exit dell_lis3lv02d_module_exit(void) 246 { 247 if (!notifier_registered) 248 return; 249 250 bus_unregister_notifier(&i2c_bus_type, &i2c_nb); 251 cancel_work_sync(&i2c_work); 252 i2c_unregister_device(i2c_dev); 253 } 254 module_exit(dell_lis3lv02d_module_exit); 255 256 MODULE_DESCRIPTION("lis3lv02d i2c-client instantiation for ACPI SMO88xx devices"); 257 MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>"); 258 MODULE_LICENSE("GPL"); 259