1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (c) 2014 Google, Inc 4 */ 5 6 #include <common.h> 7 #include <dm.h> 8 #include <i2c.h> 9 #include <dm/device-internal.h> 10 #include <dm/uclass-internal.h> 11 12 /* 13 * i2c emulation works using an 'emul' node at the bus level. Each device in 14 * that node is in the UCLASS_I2C_EMUL uclass, and emulates one i2c device. A 15 * pointer to the device it emulates is in the 'dev' property of the emul device 16 * uclass platdata (struct i2c_emul_platdata), put there by i2c_emul_find(). 17 * When sandbox wants an emulator for a device, it calls i2c_emul_find() which 18 * searches for the emulator with the correct address. To find the device for an 19 * emulator, call i2c_emul_get_device(). 20 * 21 * The 'emul' node is in the UCLASS_I2C_EMUL_PARENT uclass. We use a separate 22 * uclass so avoid having strange devices on the I2C bus. 23 */ 24 25 /** 26 * struct i2c_emul_uc_platdata - information about the emulator for this device 27 * 28 * This is used by devices in UCLASS_I2C_EMUL to record information about the 29 * device being emulated. It is accessible with dev_get_uclass_platdata() 30 * 31 * @dev: Device being emulated 32 */ 33 struct i2c_emul_uc_platdata { 34 struct udevice *dev; 35 }; 36 37 struct udevice *i2c_emul_get_device(struct udevice *emul) 38 { 39 struct i2c_emul_uc_platdata *uc_plat = dev_get_uclass_platdata(emul); 40 41 return uc_plat->dev; 42 } 43 44 int i2c_emul_find(struct udevice *dev, struct udevice **emulp) 45 { 46 struct i2c_emul_uc_platdata *uc_plat; 47 struct udevice *emul; 48 int ret; 49 50 ret = uclass_find_device_by_phandle(UCLASS_I2C_EMUL, dev, 51 "sandbox,emul", &emul); 52 if (ret) { 53 log_err("No emulators for device '%s'\n", dev->name); 54 return ret; 55 } 56 uc_plat = dev_get_uclass_platdata(emul); 57 uc_plat->dev = dev; 58 *emulp = emul; 59 60 return device_probe(emul); 61 } 62 63 UCLASS_DRIVER(i2c_emul) = { 64 .id = UCLASS_I2C_EMUL, 65 .name = "i2c_emul", 66 .per_device_platdata_auto_alloc_size = 67 sizeof(struct i2c_emul_uc_platdata), 68 }; 69 70 /* 71 * This uclass is a child of the i2c bus. Its platdata is not defined here so 72 * is defined by its parent, UCLASS_I2C, which uses struct dm_i2c_chip. See 73 * per_child_platdata_auto_alloc_size in UCLASS_DRIVER(i2c). 74 */ 75 UCLASS_DRIVER(i2c_emul_parent) = { 76 .id = UCLASS_I2C_EMUL_PARENT, 77 .name = "i2c_emul_parent", 78 .post_bind = dm_scan_fdt_dev, 79 }; 80 81 static const struct udevice_id i2c_emul_parent_ids[] = { 82 { .compatible = "sandbox,i2c-emul-parent" }, 83 { } 84 }; 85 86 U_BOOT_DRIVER(i2c_emul_parent_drv) = { 87 .name = "i2c_emul_parent_drv", 88 .id = UCLASS_I2C_EMUL_PARENT, 89 .of_match = i2c_emul_parent_ids, 90 }; 91