1 // SPDX-License-Identifier: GPL-2.0-only
3  * I2C slave mode EEPROM simulator
5  * Copyright (C) 2014 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
9  * this driver does not support simulating EEPROM types which take more than
15  * The ST-M24C64 sends only 0xff then. Needs verification with other
43 #define I2C_SLAVE_DEVICE_MAGIC(_len, _flags) ((_flags) | ((_len) - 1))
48 	struct eeprom_data *eeprom = i2c_get_clientdata(client);  in i2c_slave_eeprom_slave_cb()  local
52 		if (eeprom->idx_write_cnt < eeprom->num_address_bytes) {  in i2c_slave_eeprom_slave_cb()
53 			if (eeprom->idx_write_cnt == 0)  in i2c_slave_eeprom_slave_cb()
54 				eeprom->buffer_idx = 0;  in i2c_slave_eeprom_slave_cb()
55 			eeprom->buffer_idx = *val | (eeprom->buffer_idx << 8);  in i2c_slave_eeprom_slave_cb()
56 			eeprom->idx_write_cnt++;  in i2c_slave_eeprom_slave_cb()
58 			if (!eeprom->read_only) {  in i2c_slave_eeprom_slave_cb()
59 				spin_lock(&eeprom->buffer_lock);  in i2c_slave_eeprom_slave_cb()
60 				eeprom->buffer[eeprom->buffer_idx++ & eeprom->address_mask] = *val;  in i2c_slave_eeprom_slave_cb()
61 				spin_unlock(&eeprom->buffer_lock);  in i2c_slave_eeprom_slave_cb()
68 		eeprom->buffer_idx++;  in i2c_slave_eeprom_slave_cb()
71 		spin_lock(&eeprom->buffer_lock);  in i2c_slave_eeprom_slave_cb()
72 		*val = eeprom->buffer[eeprom->buffer_idx & eeprom->address_mask];  in i2c_slave_eeprom_slave_cb()
73 		spin_unlock(&eeprom->buffer_lock);  in i2c_slave_eeprom_slave_cb()
83 		eeprom->idx_write_cnt = 0;  in i2c_slave_eeprom_slave_cb()
96 	struct eeprom_data *eeprom;  in i2c_slave_eeprom_bin_read()  local
99 	eeprom = dev_get_drvdata(kobj_to_dev(kobj));  in i2c_slave_eeprom_bin_read()
101 	spin_lock_irqsave(&eeprom->buffer_lock, flags);  in i2c_slave_eeprom_bin_read()
102 	memcpy(buf, &eeprom->buffer[off], count);  in i2c_slave_eeprom_bin_read()
103 	spin_unlock_irqrestore(&eeprom->buffer_lock, flags);  in i2c_slave_eeprom_bin_read()
111 	struct eeprom_data *eeprom;  in i2c_slave_eeprom_bin_write()  local
114 	eeprom = dev_get_drvdata(kobj_to_dev(kobj));  in i2c_slave_eeprom_bin_write()
116 	spin_lock_irqsave(&eeprom->buffer_lock, flags);  in i2c_slave_eeprom_bin_write()
117 	memcpy(&eeprom->buffer[off], buf, count);  in i2c_slave_eeprom_bin_write()
118 	spin_unlock_irqrestore(&eeprom->buffer_lock, flags);  in i2c_slave_eeprom_bin_write()
123 static int i2c_slave_init_eeprom_data(struct eeprom_data *eeprom, struct i2c_client *client,  in i2c_slave_init_eeprom_data()  argument
128 	int ret = device_property_read_string(&client->dev, "firmware-name", &eeprom_data);  in i2c_slave_init_eeprom_data()
131 		ret = request_firmware_into_buf(&fw, eeprom_data, &client->dev,  in i2c_slave_init_eeprom_data()
132 						eeprom->buffer, size);  in i2c_slave_init_eeprom_data()
137 		/* An empty eeprom typically has all bits set to 1 */  in i2c_slave_init_eeprom_data()
138 		memset(eeprom->buffer, 0xff, size);  in i2c_slave_init_eeprom_data()
146 	struct eeprom_data *eeprom;  in i2c_slave_eeprom_probe()  local
148 	unsigned int size = FIELD_GET(I2C_SLAVE_BYTELEN, id->driver_data) + 1;  in i2c_slave_eeprom_probe()
149 	unsigned int flag_addr16 = FIELD_GET(I2C_SLAVE_FLAG_ADDR16, id->driver_data);  in i2c_slave_eeprom_probe()
151 	eeprom = devm_kzalloc(&client->dev, sizeof(struct eeprom_data) + size, GFP_KERNEL);  in i2c_slave_eeprom_probe()
152 	if (!eeprom)  in i2c_slave_eeprom_probe()
153 		return -ENOMEM;  in i2c_slave_eeprom_probe()
155 	eeprom->num_address_bytes = flag_addr16 ? 2 : 1;  in i2c_slave_eeprom_probe()
156 	eeprom->address_mask = size - 1;  in i2c_slave_eeprom_probe()
157 	eeprom->read_only = FIELD_GET(I2C_SLAVE_FLAG_RO, id->driver_data);  in i2c_slave_eeprom_probe()
158 	spin_lock_init(&eeprom->buffer_lock);  in i2c_slave_eeprom_probe()
159 	i2c_set_clientdata(client, eeprom);  in i2c_slave_eeprom_probe()
161 	ret = i2c_slave_init_eeprom_data(eeprom, client, size);  in i2c_slave_eeprom_probe()
165 	sysfs_bin_attr_init(&eeprom->bin);  in i2c_slave_eeprom_probe()
166 	eeprom->bin.attr.name = "slave-eeprom";  in i2c_slave_eeprom_probe()
167 	eeprom->bin.attr.mode = S_IRUSR | S_IWUSR;  in i2c_slave_eeprom_probe()
168 	eeprom->bin.read = i2c_slave_eeprom_bin_read;  in i2c_slave_eeprom_probe()
169 	eeprom->bin.write = i2c_slave_eeprom_bin_write;  in i2c_slave_eeprom_probe()
170 	eeprom->bin.size = size;  in i2c_slave_eeprom_probe()
172 	ret = sysfs_create_bin_file(&client->dev.kobj, &eeprom->bin);  in i2c_slave_eeprom_probe()
178 		sysfs_remove_bin_file(&client->dev.kobj, &eeprom->bin);  in i2c_slave_eeprom_probe()
187 	struct eeprom_data *eeprom = i2c_get_clientdata(client);  in i2c_slave_eeprom_remove()  local
190 	sysfs_remove_bin_file(&client->dev.kobj, &eeprom->bin);  in i2c_slave_eeprom_remove()
194 	{ "slave-24c02", I2C_SLAVE_DEVICE_MAGIC(2048 / 8,  0) },
195 	{ "slave-24c02ro", I2C_SLAVE_DEVICE_MAGIC(2048 / 8,  I2C_SLAVE_FLAG_RO) },
196 	{ "slave-24c32", I2C_SLAVE_DEVICE_MAGIC(32768 / 8, I2C_SLAVE_FLAG_ADDR16) },
197 	{ "slave-24c32ro", I2C_SLAVE_DEVICE_MAGIC(32768 / 8, I2C_SLAVE_FLAG_ADDR16 | I2C_SLAVE_FLAG_RO) },
198 	{ "slave-24c64", I2C_SLAVE_DEVICE_MAGIC(65536 / 8, I2C_SLAVE_FLAG_ADDR16) },
199 	{ "slave-24c64ro", I2C_SLAVE_DEVICE_MAGIC(65536 / 8, I2C_SLAVE_FLAG_ADDR16 | I2C_SLAVE_FLAG_RO) },
200 	{ "slave-24c512", I2C_SLAVE_DEVICE_MAGIC(524288 / 8, I2C_SLAVE_FLAG_ADDR16) },
201 …{ "slave-24c512ro", I2C_SLAVE_DEVICE_MAGIC(524288 / 8, I2C_SLAVE_FLAG_ADDR16 | I2C_SLAVE_FLAG_RO) …
208 		.name = "i2c-slave-eeprom",
216 MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
217 MODULE_DESCRIPTION("I2C slave mode EEPROM simulator");