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