1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * ee1004 - driver for DDR4 SPD EEPROMs
5  * Copyright (C) 2017-2019 Jean Delvare
8  * Copyright (C) 2005-2007 David Brownell
19 #include <linux/nvmem-provider.h>
23  * specification. These are 512-byte EEPROMs using a single I2C address
24  * in the 0x50-0x57 range for data. One of two 256-byte page is selected
25  * by writing a command to I2C address 0x36 or 0x37 on the same I2C bus.
62 /*-------------------------------------------------------------------------*/
82 static int ee1004_get_current_page(struct ee1004_bus_data *bd)  in ee1004_get_current_page()  argument
86 	err = i2c_smbus_read_byte(bd->set_page[0]);  in ee1004_get_current_page()
87 	if (err == -ENXIO) {  in ee1004_get_current_page()
102 	struct ee1004_bus_data *bd = i2c_get_clientdata(client);  in ee1004_set_current_page()  local
105 	if (page == bd->current_page)  in ee1004_set_current_page()
109 	ret = i2c_smbus_write_byte(bd->set_page[page], 0x00);  in ee1004_set_current_page()
114 	if (ret == -ENXIO && ee1004_get_current_page(bd) == page)  in ee1004_set_current_page()
117 		dev_err(&client->dev, "Failed to select page %d (%d)\n", page, ret);  in ee1004_set_current_page()
121 	dev_dbg(&client->dev, "Selected page %d\n", page);  in ee1004_set_current_page()
122 	bd->current_page = page;  in ee1004_set_current_page()
133 	offset &= (1 << EE1004_PAGE_SHIFT) - 1;  in ee1004_eeprom_read()
141 		count = EE1004_PAGE_SIZE - offset;  in ee1004_eeprom_read()
159 		return -EINVAL;  in ee1004_read()
176 		count -= ret;  in ee1004_read()
187 	unsigned short addr = 0x18 | (client->addr & 7);  in ee1004_probe_temp_sensor()
203 		 * with SPD revision 1.0, check the thermal sensor address  in ee1004_probe_temp_sensor()
205 		 * that address.  in ee1004_probe_temp_sensor()
207 		 * temperature sensor address since i2c_new_scanned_device()  in ee1004_probe_temp_sensor()
214 	i2c_new_scanned_device(client->adapter, &info, addr_list, NULL);  in ee1004_probe_temp_sensor()
217 static void ee1004_cleanup(int idx, struct ee1004_bus_data *bd)  in ee1004_cleanup()  argument
219 	if (--bd->dev_count == 0) {  in ee1004_cleanup()
220 		while (--idx >= 0)  in ee1004_cleanup()
221 			i2c_unregister_device(bd->set_page[idx]);  in ee1004_cleanup()
222 		memset(bd, 0, sizeof(struct ee1004_bus_data));  in ee1004_cleanup()
228 	struct ee1004_bus_data *bd = data;  in ee1004_cleanup_bus_data()  local
232 	ee1004_cleanup(EE1004_NUM_PAGES, bd);  in ee1004_cleanup_bus_data()
238 	struct ee1004_bus_data *bd;  in ee1004_init_bus_data()  local
241 	bd = ee1004_get_bus_data(client->adapter);  in ee1004_init_bus_data()
242 	if (!bd)  in ee1004_init_bus_data()
243 		return dev_err_probe(&client->dev, -ENOSPC, "Only %d busses supported",  in ee1004_init_bus_data()
246 	i2c_set_clientdata(client, bd);  in ee1004_init_bus_data()
248 	if (++bd->dev_count == 1) {  in ee1004_init_bus_data()
253 			cl = i2c_new_dummy_device(client->adapter, EE1004_ADDR_SET_PAGE + cnr);  in ee1004_init_bus_data()
259 			bd->set_page[cnr] = cl;  in ee1004_init_bus_data()
263 		err = ee1004_get_current_page(bd);  in ee1004_init_bus_data()
267 		dev_dbg(&client->dev, "Currently selected page: %d\n", err);  in ee1004_init_bus_data()
268 		bd->current_page = err;  in ee1004_init_bus_data()
274 	ee1004_cleanup(cnr, bd);  in ee1004_init_bus_data()
282 		.dev = &client->dev,  in ee1004_probe()
283 		.name = dev_name(&client->dev),  in ee1004_probe()
295 		.base_dev = &client->dev,  in ee1004_probe()
301 	if (!i2c_check_functionality(client->adapter,  in ee1004_probe()
303 	    !i2c_check_functionality(client->adapter,  in ee1004_probe()
305 		return -EPFNOSUPPORT;  in ee1004_probe()
319 	err = devm_add_action_or_reset(&client->dev, ee1004_cleanup_bus_data,  in ee1004_probe()
324 	ndev = devm_nvmem_register(&client->dev, &config);  in ee1004_probe()
328 	dev_info(&client->dev,  in ee1004_probe()
329 		 "%u byte EE1004-compliant SPD EEPROM, read-only\n",  in ee1004_probe()
335 /*-------------------------------------------------------------------------*/
346 MODULE_DESCRIPTION("Driver for EE1004-compliant DDR4 SPD EEPROMs");