These modules need to depend on iic, not just on i2cexec. (They will
still recursively get i2cexec since the iic depends on it.)

Partial fix for kern/56772

Check the return value correctly. Pointed out by pgoyette@.

Carefully access to the I2C bus in the match function.

Access byte2...

branches: 1.22.6;
iic_acquire_bus can fail

branches: 1.21.4;
Use DEVICE_COMPAT_EOL.

Since we're using designated initialisers for compat data, we should
use a completely empty initializer for the sentinel.

Use designated initializers and a consistent termination style in
compat_data[].

branches: 1.18.8;
No need to use I2C_F_POLL here.

branches: 1.17.4;
match "i2c-at34c02", found in various sparc64 boxes

match spdmem_i2c on "atmel,spd" compatible string

branches: 1.15.2;
More cleanup to i2c autoconfiguration:

- Get all of the drivers onto the new match quality constants.
- Introduce a new helper function, iic_use_direct_match(), that has
all of the logic for direct-config matching. If it returns true,
the driver returns the match result (which may be 0). If it returns
false, the driver does indirect-config matching.
- iic_compat_match() now returns a weighted match quality; matches to
lower-indexed "compatible" device property are more-specific matches,
and return a better match quality accordingly.

branches: 1.14.2;
Use 1-byte data-buffers when writing to the "control" device for the
SPD ROMs (we do this for page-selection). The imcsmb doesn't support
zero-byte transfers.

With this, I'm able to get the data for all 8 of my DIMMs (on two
different imcsmb busses) using the spdmem(4) driver. And the data
decodes correctly using the decode-dimms utility (from the linux
i2ctools).

branches: 1.13.8;
Add code to select page "0" for DDR4 and newer SPD ROM. If the value read
is not suitable as SPD ROM, try to select page 0 and try again. The passed
arguments of iic_exec(SPDCTL_SPA) might not be correct and/or our API of
iic_exec() should be improved. See the comment for the detail.

Use this change until we find a better (or correct?) way.

Check whether iic_exec is failed or not.
- This change fixes a bug that a device that the checksum is really 0 fails
attaching.
- Reduce the number of access to one if a device doesn't exist. Without this
change and iic(4) does polling, it'll wait long time.

Handle reading of 4kbit EEPROMs in SPD devices. This is needed for DDR4 DIMMs.

i2c devices don't actually have a dependency on "iic" (the bus driver)
but on "i2cexec". Create an i2cexec module (i2c_exec.c) to mirror the
dependencies in files.i2c and switch device drivers to depend on "i2cexec"
module instead.

A kernel with a USB stack and no I2C controller / bus attachment would spit
out a bunch of "WARNING: module error: can't find builtin dependency `iic'"
messages at boot. This change solves that problem.

branches: 1.9.2; 1.9.4;
Remove extraneous sysctl setup calls now done as part of regular attach.

branches: 1.8.2;
Allow i2c addr wildcard matching. Use with care!

Call iic_exec() with I2C_F_POLL. Don't sleep in probe/attach time.

branches: 1.6.2; 1.6.4;
Initialize the sysctl(9) stuff before configuring the spd(4) devices.

Otherwise, the devices do not create their own sysctl nodes!

Update handling of sysctl stuff when built as modules

Add "dimm" found on Sun US-IIe based machines (eg. Netra X1, Blade 100).

branches: 1.3.2; 1.3.6;
now that iic is a module, add "iic" dependency to iic drivers

Modularize the spdmem(4) driver

branches: 1.1.2; 1.1.4; 1.1.6;
Split spdmem driver into a bus attachment and a common back-end
probe and ROM decode, to follow similar changes made in OpenBSD:

http://article.gmane.org/gmane.os.openbsd.cvs/94948
http://article.gmane.org/gmane.os.openbsd.cvs/94956

There exists at least one alternative attachment (for SGI IP35
systems; see http://article.gmane.org/gmane.os.openbsd.cvs/94947),
and there could be more in the future.

Thanks to Christoph Egger for pointing out the OpenBSD activity.