Add ACPI part for ig4 driver to make it work on Intel BayTrail SoC where
ig4 device is available only through ACPI
Reviewed by: avg
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D8742
Summary:
The hardware does not expose a classic SMBus interface.
Instead it has a lower level interface that can express a far richer
I2C protocol than what smbus offers. However, the interface does not
provide a way to explicitly generate the I2C stop and start conditions.
It's only possible to request that the stop condition is generated
after transferring the next byte in either direction. So, at least
one data byte must always be transferred.
Thus, some I2C sequences are impossible to generate, e.g., an equivalent
of smbus quick command (<start>-<slave addr>-<r/w bit>-<stop>).
At the same time isl(4) and cyapa(4) are moved to iicbus and now they use
iicbus_transfer for communication. Previously they used smbus_trans()
interface that is not defined by the SMBus protocol and was implemented
only by ig4(4). In fact, that interface was impossible to implement
for the typical SMBus controllers like intpm(4) or ichsmb(4) where
a type of the SMBus command must be programmed.
The plan is to remove smbus_trans() and all its uses.
As an aside, the smbus_trans() method deviates from the standard,
but perhaps backwards, FreeBSD convention of using 8-bit slave
addresses (shifted by 1 bit to the left). The method expects
7-bit addresses.
There is a user facing consequence of this change.
A user must now provide device hints for isl and cyapa that specify an iicbus to use
and a slave address on it.
On Chromebook hardware where isl and cyapa devices are commonly found
it is also possible to use a new chromebook_platform(4) driver that
automatically configures isl and cyapa devices. There is no need to
provide the device hints in that case,
Right now smbus(4) driver tries to discover all slaves on the bus.
That is very dangerous. Fortunately, the probing code uses smbus_trans()
to do its job, so it is really enabled for ig4 only.
The plan is to remove that auto-probing code and smbus_trans().
Tested by: grembo, Matthias Apitz <guru@unixarea.de> (w/o
chromebook_platform)
Discussed with: grembo, imp
Reviewed by: wblock (docs)
MFC after: 1 month
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D8172
The driver currently supports chips that are fully compliant with the
JEDEC SPD / EEPROM / TS standard (JEDEC Standard 21-C,
TSE2002 Specification, frequenlty referred to as JEDEC JC 42.4).
Additionally some chips from STMicroelectronics are supported as well.
They are compliant except for their Device ID pattern.
Given the continued lack of any common sensor infrastructure, the driver
uses an ad-hoc sysctl to report the temperature.
Reviewed by: wblock (documentation)
MFC after: 2 weeks
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D8174
ismt(4) supports the SMBus Message Transport controller found on Intel
C2000 series (Avoton) and S1200 series (Briarwood) Atom SoCs.
Sponsored by: Intel
Use MACHINE_CPUARCH in preference to MACHINE_ARCH. The former is the
source code location of the machine, the latter the binary output. In
general, we want to use MACHINE_CPUARCH instead of MACHINE_ARCH unless
we're tesitng for a specific target. The isn't even moot for
i386/amd64 where there's momemntum towards a MACHINE_CPUARCH == x86,
although a specific cleanup for that likely would be needed...
around to force the IO port to a fixed address. They were only turned
on in the module build and were present since the original import. This
breaks soft power-off on the Asus A7V since it reprograms the SMBus base
address to a different one than the BIOS expects. A similar issue was
found in the alpm(4) module build.
PR: kern/113986, i386/97468
MFC after: 3 days
Approved by: re
drivers I started quite some time before.
Retire the old i386-only pcf driver, and activate the new general
driver that has been sitting in the tree already for quite some
time.
Build the i2c modules for sparc64 architectures as well (where I've
been developing all this on).
