These realtek switch PHYs speak a variant of i2c with some slightly
modified handling.
From the submitter, slightly modified now that some further digging
has been done:
The I2C framework makes a assumption that the read/not-write bit of the first
byte (the address) indicates whether reads or writes are to follow.
The RTL8366 family uses the bus: after sending the address+read/not-write byte,
two register address bytes are sent, then the 16-bit register value is sent
or received. While the register write access can be performed as a 4-byte
write, the read access requires the read bit to be set, but the first two bytes
for the register address then need to be transmitted.
This patch maintains the i2c protocol behaviour but allows it to be relaxed
(for these kinds of switch PHYs, and whatever else Realtek may do with this
almost-but-not-quite i2c bus) - by setting the "strict" hint to 0.
The "strict" hint defaults to 1.
Submitted by: Stefan Bethke <stb@lassitu.de>
one. Interestingly, these are actually the default for quite some time
(bus_generic_driver_added(9) since r52045 and bus_generic_print_child(9)
since r52045) but even recently added device drivers do this unnecessarily.
Discussed with: jhb, marcel
- While at it, use DEVMETHOD_END.
Discussed with: jhb
- Also while at it, use __FBSDID.
This reflects actual type used to store and compare child device orders.
Change is mostly done via a Coccinelle (soon to be devel/coccinelle)
semantic patch.
Verified by LINT+modules kernel builds.
Followup to: r212213
MFC after: 10 days
indicated I2C devices, and provides an ofw_bus interface for driver probing.
This should be MI, but is currently provided only on PowerPC due to lack of
sparc64 hardware with an I2C controller.
Discussed on: freebsd-arch
subclasses as are available with PCI. Changes I2C device drivers without
real probe logic to return BUS_PROBE_NOWILDWARD to avoid interference with
firmware bus enumeration, and reduces the probe priority of the iicbus
base driver to allow subclass attachment at higher priority.
Discussed on: freebsd-arch
- Add an sx lock to the iic(4) driver to serialize open(), close(), read(),
and write and to protect sc_addr and sc_count in the softc.
- Use cdev->si_drv1 instead of using the minor number of the cdev to
lookup the softc via newbus in iic(4).
- Store the device_t in the softc to avoid a similar detour via minor
numbers in iic(4).
- Only add at most one instance of iic(4) and iicsmb(4) to each iicbus(4)
instance, and do it in the child driver.
- Add a mutex to the iicbus(4) softc to synchronize the request/release bus
stuff.
- Use __BUS_ACCESSOR() for IICBUS_ACCESSOR() instead of rolling our own.
- Add a mutex to the iicsmb(4) softc to protect softc state updated in the
interrupt handler.
- Remove Giant from all the smbus methods in iicsmb(4) now that all the
iicbus(4) backend is locked.
some devices (and not others). To get instances onto the iicbus, one
now needs hints or an identify routine. We also do not probe the bus
for devices because many iic devices cannot be safely probed (and when
they can, the probe order turns out to be somewhat difficult to get
right).
# I'm not 100% sure that the iicsmb removal is right. Please contact me if
# this causes difficulty.
forcing all transfers to do the start read/write stop by hand. Some
smart bridges prefer this sort of operation, and this allows us to
support their features more easily. When bridges don't support it, we
fall back to using the old-style opertaions. Expand the ioctl
interface to expose this function. Unlike the old-style interface,
this interface is thread safe, even on old bridges.
as pcf_ebus and pcf_isa, they should probably be fixed back to pcf),
and bti2c doesn't exist, bktr has smbus or iicbb as children..
Brought to you by: http://people.FreeBSD.org/~jmg/driver.pdf
NULL name in device_add_child(), explicitly name all of our known
child drivers in order to give them a chance to attach to us.
Otherwise, only the first one present would be probed and attached.
Reviewed by: nsouch
MFC after: 1 month
device_add_child_ordered(). 'ivars' may now be set using the
device_set_ivars() function.
This makes it easier for us to change how arbitrary data structures are
associated with a device_t. Eventually we won't be modifying device_t
to add additional pointers for ivars, softc data etc.
Despite my best efforts I've probably forgotten something so let me know
if this breaks anything. I've been running with this change for months
and its been quite involved actually isolating all the changes from
the rest of the local changes in my tree.
Reviewed by: peter, dfr
- device_print_child() either lets the BUS_PRINT_CHILD
method produce the entire device announcement message or
it prints "foo0: not found\n"
Alter sys/kern/subr_bus.c:bus_generic_print_child() to take on
the previous behavior of device_print_child() (printing the
"foo0: <FooDevice 1.1>" bit of the announce message.)
Provide bus_print_child_header() and bus_print_child_footer()
to actually print the output for bus_generic_print_child().
These functions should be used whenever possible (unless you can
just use bus_generic_print_child())
The BUS_PRINT_CHILD method now returns int instead of void.
Modify everything else that defines or uses a BUS_PRINT_CHILD
method to comply with the above changes.
- Devices are 'on' a bus, not 'at' it.
- If a custom BUS_PRINT_CHILD method does the same thing
as bus_generic_print_child(), use bus_generic_print_child()
- Use device_get_nameunit() instead of both
device_get_name() and device_get_unit()
- All BUS_PRINT_CHILD methods return the number of
characters output.
Reviewed by: dfr, peter
devices dynamically. That means,
+ only one /dev/iic or /dev/smb device for each smb/iic bus to access
+ I2C/SMB device address must be given to any ioctl
+ new devices may be plugged and accessed after boot, which was
impossible previously (device addresses were hardcoded into
the kernel)
