The current support for controlling i2c bus speed is an inconsistant mess.
There are 4 symbolic speed values defined, UNKNOWN, SLOW, FAST, FASTEST.
It seems to be universally assumed that SLOW means the standard 100KHz
rate from the original spec. Nothing ever calls iicbus_reset() with a
speed of FAST, although some drivers would treat it as the 400KHz standard
speed. Mostly iicbus_reset() is called with the speed set to UNKNOWN or
FASTEST, and there's really no telling what any individual driver will do
with those.
The speed of an i2c bus is limited by the speed of the slowest device on
the bus. This means that generally the bus speed needs to be configured
based on the board/system and the components within it. Historically for
i2c we've configured with device hints. Newer systems use FDT data and it
documents a clock-frequency property for i2c busses. Hobbyists and
developers are likely to want on the fly changes. These changes provide
all 3 methods, but do not require any existing drivers to change to use
the new facilities.
This adds an iicbus method, iicbus_get_frequency(dev, speed) that gets the
frequency for the requested symbolic speed. If the symbolic speed is SLOW
or if there is no speed configured for the bus, the returned value is
100KHz, always. Otherwise, if bus speed is configured by hints, fdt,
tunable, or sysctl, that speed is returned. It also adds a helper
function, iicbus_init_frequency() that any bus driver subclassed from
iicbus can initialize the frequency from some other source of info.
Initial driver implementations are provided for Freescale and TI.
Differential Revision: https://reviews.freebsd.org/D1174
PR: 195009
I originally overlooked a couple flag bits defined in the fdt binding docs.
One flag suppresses the pad configuration (pullup/pulldown/etc). The other
one requires that the SION (set input on) flag be set in the mux register.
Also, it appears from the data involved that if the input register
address in the config tuple is zero, there is no input configuration. The
old code was writing to register zero, which contains a collection of misc
control bits (having nothing to do with input configuration) that probably
shouldn't get overwritten arbitrarily. The bindings doc doesn't explictly
mention this.
unit 0.
It seems that this 'simplification' was copied to all GPIO drivers in tree.
This fix a bug where a GPIO controller could fail to attach its children
(gpioc and gpiobus) if another GPIO driver attach first.
workaround for an imx6 chip erratum. Linux works around the bug with
changes in fdt data that we can't currently handle, so to enable running
with standard vendor-supplied fdt data, this watches for an attempt to map
the gpio1_6 interrupt and remaps it back to the standard ethernet interrupt.
This can be undone when the intrng project is completed and our gpio drivers
can also be interrupt controllers.
for, or that are required to run the chip (such as busses). Turn off all
the devices we don't yet have drivers for.
Some day we will have a fully functional imx6 clock driver so that we can
manage clocks based on fdt data. This will have to do until then.
timecounter resolution is available, so ask for a 1 GHz frequency. It
won't actually get one that fast, but that'll get the fastest available
clock and use a divisor of 1 (probably 132 or 66mhz on current hardware).
bus_new_pass() handler so it doesn't happen until BUS_PASS_CPU. This allows
the anatop driver to outbid the generic simplebus driver (which the FDT
data describes as compatible).
Some day when we handle power regulators, this driver may actually
become a functional simplebus and attach the regulators as children, as
described in the FDT data.
few "general purpose registers" whose values control chip behavior in ways
that have nothing to do with IO pin mux control. Define a simple API that
other soc-specific code can use to read and write the registers, and provide
the imx51 implementation of them.
soc-wide info lives. It was under dev.imx6_anatop.0.
What does anatop mean anyway? Nobody seems to know, so it's probably
not where somebody will think to look for imx6 hardware info.
These changes prevent sysctl(8) from returning proper output,
such as:
1) no output from sysctl(8)
2) erroneously returning ENOMEM with tools like truss(1)
or uname(1)
truss: can not get etype: Cannot allocate memory
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.
Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.
MFC after: 2 weeks
Sponsored by: Mellanox Technologies
platform code, it is expected these will be merged in the future when the
ARM code is more complete.
Until more boards can be tested only use this with the Raspberry Pi and
rrename the functions on the other SoCs.
Reviewed by: ian@
define a few imx_ccm_foo() functions that are implemented by the imx51 or
imx6 ccm code. Of course, the imx6 ccm code is still more a wish than
reality, so for now its implementations just return hard-coded numbers.
This adds the concept of "operating points," combinations of frequency
and voltage at which the cpu is known to work correctly. Some day these
should come from FDT data, but for now the table is hard-coded.
This also allows tuning the min and max operating frequencies. The min
frequency is what the thermal management code will slow down to if the
core temperature gets too high. The max frequency is what gets used if
the temperature is okay.
Normally the max cannot be set higher than the value burned into the
ocotp fuses as the chip's rated max, but there is now a new sysctl+tunable
cpu_overclock_enable; when set to non-zero it allows raising the frequency
above the ocotp value: USE WITH CARE! (At least one of my imx6 boards
has a cpu whose ocotp values never got set correctly; they claim a max
of 792mhz, but the physical markings on the chip say it's good to 1ghz.)
Because all these values affect the entire SoC, there is a new sysctl
node, hw.imx6, where all these values live. The values that are currently
under dev.imx6_anatop.0 should probably move to hw.imx6 too, because
"anatop" doesn't even mean anything to me, let alone to an end user.
