This errata occurs when the ARDY interrupt generation is enabled.
At the begining of every new transaction the ARDY interrupt is cleared.
On continuous i2c transactions where after clearing the ARDY bit from
I2C_STAT register (clearing the interrupt), the IRQ line is reasserted and the
I2C_STAT[ARDY] bit set again on 1. In fact, the ARDY status bit is not cleared
at the write access to I2C_STAT[ARDY] and only the IRQ line is deasserted and
then reasserted. This is not captured in the usual errata documents.
The workaround is to have a double clear of ARDY status in irq handler.
Signed-off-by: Richard woodruff <r-woodruff2@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
When runtime PM is enabled, each OMAP i2c device is suspended after
each i2c xfer. However, there are two cases when the static suspend
methods must be used to ensure the devices are suspended:
1) runtime PM is disabled, either at compile time or dynamically
via /sys/devices/.../power/control.
2) an i2c client driver uses i2c during it's suspend callback, thus
leaving the i2c driver active (NOTE: runtime suspend transitions are
disabled during system suspend, so i2c activity during system
suspend will runtime resume the device, but not runtime (re)suspend it.)
Since the actual work to suspend the device is handled by the
subsytem, call the bus methods to take care of it.
NOTE: This takes care of a known suspend problem on OMAP3 where the
TWL RTC driver does i2c xfers during its suspend path leaving the i2c
driver in an active state (since runtime suspend transistions are
disabled.)
Signed-off-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The SCx200 ACB driver supports ISA hardware as well as PCI. The PCI
hardware is CS5535/CS5536 based, and the device that it grabs is handled by
the cs5535-mfd driver. This converts the SCx200 driver to use a
platform_driver rather than the previous PCI hackery.
The driver used to manually track the iface list (via linked list); now it
only does this for ISA devices. PCI ifaces are handled through standard
driver model lists.
It's unclear what happens in case of errors in the old ISA code; rather than
pretending the code actually cares, I've dropped the (implicit) ignorance
of return values and marked it with a comment.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* 'for-linus/i2c-2638' of git://git.fluff.org/bjdooks/linux:
i2c-bfin-twi: move setup to the earlier subsys initcall
i2c-bfin-twi: handle faulty slave devices better
i2c-mv64xxx: send repeated START between messages in xfer
i2c-nomadik: fix regression on adapter name
i2c-omap: Set latency requirements only once for several messages
i2c-eg20t: add driver for Intel EG20T
i2c-ocores: add some device tree documentation
i2c-ocores: Use devres for resource allocation
i2c-ocores: Adapt for device tree
i2c-iop3xx: add iomem annotation
Some systems using this bus sometimes have very basic devices such as
regulators on the bus, so the I2C bus master needs to be loaded early.
This also matches the behavior of many other I2C bus master drivers.
Therefore initialize via subsys_initcall().
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Faulty slave devices might drive SDA low after a transfer finishes. So,
when this scenario is detected, have the master generate up to 9 extra
clocks until the SDA is properly released.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Commit 5a0e3ad6af added direct inclusion
of <linux/slab.h> to those source files that appeared to need it, but
somehow missed this. On most architectures <linux/slab.h> is still
indirectly included, but there are exceptions such as alpha.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
As stated into file include/linux/i2c.h we must send a repeated START
between messages in the same xfer groupset:
* Except when I2C "protocol mangling" is used, all I2C adapters implement
* the standard rules for I2C transactions. Each transaction begins with a
* START. That is followed by the slave address, and a bit encoding read
* versus write. Then follow all the data bytes, possibly including a byte
* with SMBus PEC. The transfer terminates with a NAK, or when all those
* bytes have been transferred and ACKed. If this is the last message in a
* group, it is followed by a STOP. Otherwise it is followed by the next
* @i2c_msg transaction segment, beginning with a (repeated) START.
Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Mauro Barella <mbarella@vds-it.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The Nomadik I2C adapter does not provide a name for the struct
passed into i2c_add_numbered_adapter() causing a regression on
2.6.37-rc3 due to commit 2236baa75f
adding sanity checks for adapters. Fix this by providing a name
proper.
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Ordinary I2C read consist of two messages. First a write operation
to tell register address and then read operation to get data.
CPU wake up latency is set and removed twice in read case.
Set latency requirement before the message processing loop
and remove the requirement after the loop to remove latency
adjustment operations between the messages.
Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This puts some documentation for the device tree configuration at the head
of the driver file. Hopefully this can get moved to a common area for this
type of documentation at a later date; unfortunately, there isn't really
such a place in the kernel tree at this time.
Furthermore, the regstep and clock-frequency parameters are really bus
parameters and should probably be passed to the driver in a better way.
Consider that a TODO.
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch converts the i2c-cores driver to use devres routines for
resource allocation.
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Ben Dooks
Richard woodruff
Balaji T K
Kevin Hilman
Wolfram Sang
Andres Salomon
Linus Torvalds
Michael Hennerich
Joe Perches
Ben Hutchings
Rodolfo Giometti
Linus Walleij
Samu Onkalo
Tomoya MORINAGA
Jonas Bonn