src/drivers/i2c/at24rf08c/at24rf08c.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <device/device.h>
   4 #include <device/smbus.h>
   5 #include <console/console.h>
   6
   7 static void at24rf08c_init(struct device *dev)
   8 {
   9         int i, j;
  10
  11         if (!dev->enabled)
  12                 return;
  13
  14         /* Ensure that EEPROM/RFID chip is not accessible through RFID.
  15            Need to do it only on 5c. */
  16         if (dev->path.type != DEVICE_PATH_I2C || dev->path.i2c.device != 0x5c)
  17                 return;
  18
  19         printk(BIOS_DEBUG, "Locking EEPROM RFID\n");
  20
  21         for (i = 0; i < 8; i++) {
  22                 /* After a register write AT24RF08C sometimes stops responding.
  23                    Retry several times in case of failure. */
  24                 for (j = 0; j < 100; j++)
  25                         if (smbus_write_byte(dev, i, 0x0f) >= 0)
  26                                 break;
  27         }
  28
  29         printk(BIOS_DEBUG, "init EEPROM done\n");
  30 }
  31
  32 static struct device_operations at24rf08c_operations = {
  33         .read_resources = noop_read_resources,
  34         .set_resources = noop_set_resources,
  35         .init = at24rf08c_init,
  36 };
  37
  38 static void enable_dev(struct device *dev)
  39 {
  40         dev->ops = &at24rf08c_operations;
  41 }
  42
  43 struct chip_operations drivers_i2c_at24rf08c_ops = {
  44         .name = "AT24RF08C",
  45         .enable_dev = enable_dev,
  46 };