[U-Boot] [u-boot v2] and i2c

Heiko Schocher hs at denx.de
Tue Apr 28 09:36:46 CEST 2009


Hello Sascha,

I actually looked in the u-boot-v2.git in the i2c branch,
because I wanted to look how things in v2 work, specially
I2C Subsystem ... and I have a first question:

- In ppc area, we start running from flash and have to relocate
  code. Before setting up RAM, we maybe have to read SPD EEprom
  over I2C for this. How could this work in v2? I see in
  drivers/i2c/i2c-core.c in i2c_register_adapter () an
  INIT_LIST_HEAD(&adap->clients);

  This could not work, when running from Flash, because we have no
  usable RAM ...
  So I looked how this device approach globally works, and found in
  lib/driver.c in register_device() also:

  107
  108         list_add_tail(&new_device->list, &device_list);
  109         INIT_LIST_HEAD(&new_device->children);
  110

  so would this device_driver approach in v2 actually only work,
  if running from RAM? What if we need the devices earlier?

  Maybe I overlooked something obvious?

bye
Heiko
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