| Commit message (Collapse) | Author | Age | Files | Lines |
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With a i2c topology like the following
GPIO ---| ------ BAT1
| v /
I2C -----+----------+---- MUX
| \
EEPROM ------ BAT2
there is a locking problem with the GPIO controller since it is a client
on the same i2c bus that it muxes. Transfers to the mux clients (e.g. BAT1)
will lock the whole i2c bus prior to attempting to switch the mux to the
correct i2c segment. In the above case, the GPIO device is an I/O expander
with an i2c interface, and since the GPIO subsystem knows nothing (and
rightfully so) about the lockless needs of the i2c mux code, this results
in a deadlock when the GPIO driver issues i2c transfers to modify the
mux.
So, observing that while it is needed to have the i2c bus locked during the
actual MUX update in order to avoid random garbage on the slave side, it
is not strictly a must to have it locked over the whole sequence of a full
select-transfer-deselect mux client operation. The mux itself needs to be
locked, so transfers to clients behind the mux are serialized, and the mux
needs to be stable during all i2c traffic (otherwise individual mux slave
segments might see garbage, or worse).
Introduce this new locking concept as "mux-locked" muxes, and call the
pre-existing mux locking scheme "parent-locked".
Modify the i2c mux locking so that muxes that are "mux-locked" locks only
the muxes on the parent adapter instead of the whole i2c bus when there is
a transfer to the slave side of the mux. This lock serializes transfers to
the slave side of the muxes on the parent adapter.
Add code to i2c-mux-gpio and i2c-mux-pinctrl that checks if all involved
gpio/pinctrl devices have a parent that is an i2c adapter in the same
adapter tree that is muxed, and request a "mux-locked mux" if that is the
case.
Modify the select-transfer-deselect code for "mux-locked" muxes so
that each of the select-transfer-deselect ops locks the mux parent
adapter individually.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Every call of of_parse_phandle() increments user count of found device
node, if OF_DYNAMIC is enabled.
The change fixes all similar addressed cases in drivers/i2c.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Probe deferral is not an error case. It happens only when
the necessary dependencies are not there yet.
The driver core is already printing a message when a driver
requests probe deferral, so this can be traced in the logs
without these error prints.
This patch removes the error messages for these deferral cases.
Signed-off-by: Ionut Nicu <ioan.nicu.ext@nokia.com>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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A platform_driver does not need to set an owner, it will be populated by the
driver core.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>. Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c changes from Wolfram Sang:
- new drivers for exynos5, bcm kona, and st micro
- bigger overhauls for drivers mxs and rcar
- typical driver bugfixes, cleanups, improvements
- got rid of the superfluous 'driver' member in i2c_client struct This
touches a few drivers in other subsystems. All acked.
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (38 commits)
i2c: bcm-kona: fix error return code in bcm_kona_i2c_probe()
i2c: i2c-eg20t: do not print error message in syslog if no ACK received
i2c: bcm-kona: Introduce Broadcom I2C Driver
i2c: cbus-gpio: Fix device tree binding
i2c: wmt: add missing clk_disable_unprepare() on error
i2c: designware: add new ACPI IDs
i2c: i801: Add Device IDs for Intel Wildcat Point-LP PCH
i2c: exynos5: Remove incorrect clk_disable_unprepare
i2c: i2c-st: Add ST I2C controller
i2c: exynos5: add High Speed I2C controller driver
i2c: rcar: fixup rcar type naming
i2c: scmi: remove some bogus NULL checks
i2c: sh_mobile & rcar: Enable the driver on all ARM platforms
i2c: sh_mobile: Convert to clk_prepare/unprepare
i2c: mux: gpio: use reg value for i2c_add_mux_adapter
i2c: mux: gpio: use gpio_set_value_cansleep()
i2c: Include linux/of.h header
i2c: mxs: Fix PIO mode on i.MX23
i2c: mxs: Rework the PIO mode operation
i2c: mxs: distinguish i.MX23 and i.MX28 based I2C controller
...
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The i2c-mux driver requires that the chan_id parameter
passed to the i2c_add_mux_adapter() function is equal
to the reg value for that adapter:
for_each_child_of_node(mux_dev->of_node, child) {
ret = of_property_read_u32(child, "reg", ®);
if (ret)
continue;
if (chan_id == reg) {
priv->adap.dev.of_node = child;
break;
}
}
The i2c-mux-gpio driver uses an internal logical index
for chan_id when calling i2c_add_mux_adapter() instead
of using the reg value.
Because of this, there will problems in selecting the
right adapter when the i2c-mux-gpio's index into
mux->data.values doesn't match the reg value.
An example of such a case:
mux->data.values = { 1, 0 }
For chan_id = 0, i2c-mux will bind the adapter to the
of_node with reg = <0>, but when it will call the
select() callback with chan_id set to 0, the i2c-mux-gpio
will use it as an index into mux->data.values and it will
actually select the bus with reg = <1>.
Signed-off-by: Ionut Nicu <ioan.nicu.ext@nsn.com>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nsn.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
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Some gpio chips may have get/set operations that
can sleep. gpio_set_value() only works for chips
which do not sleep, for the others we will get a
kernel warning. Using gpio_set_value_cansleep()
will work for both chips that do sleep and those
who don't.
Signed-off-by: Ionut Nicu <ioan.nicu.ext@nsn.com>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
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The data structure of_match_ptr() protects is always compiled in.
Hence of_match_ptr() is not needed.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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If the i2c-parent bus driver is not loaded, returning
-ENODEV will force people to unload and then reload the
module again to get it working.
Signed-off-by: Ionut Nicu <ioan.nicu.ext@nsn.com>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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of_get_named_gpio could return -E_PROBE_DEFER or another
error code. This error should be passed further instead
of being ignored.
Signed-off-by: Ionut Nicu <ioan.nicu.ext@nsn.com>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
that it is much cleaner to have this in the core. This also removes a
circular dependency between the helpers and the core, and so we can
finally register child nodes in the core instead of doing this manually
in each driver. So, fix the drivers and documentation, too.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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gpio_direction_output() may fail, check for that and deal with it
appropriately. Also log an error message if gpio_request() fails.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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There is simply no reason to be manually setting the private driver
data to NULL in the remove/fail to probe cases. This is just extra
cruft code that can be removed.
A few notes:
* Nothing relies on drvdata being set to NULL.
* The __device_release_driver() function eventually calls
dev_set_drvdata(dev, NULL) anyway, so there's no need to do it
twice.
* I verified that there were no cases where xxx_get_drvdata() was
being called in these drivers and checking for / relying on the NULL
return value.
This could be cleaned up kernel-wide but for now just take the baby
step and remove from the i2c subsystem.
Reported-by: Wolfram Sang <wsa@the-dreams.de>
Reported-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>
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CONFIG_HOTPLUG is going away as an option. As result the __dev*
markings will be going away.
Remove use of __devinit, __devexit_p, __devinitdata, __devinitconst,
and __devexit.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com> (for ocores and mux-gpio)
Acked-by: Havard Skinnemoen <hskinnemoen@gmail.com> (for i2c-gpio)
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn> (for puf3)
Acked-by: Barry Song <baohua.song@csr.com> (for sirf)
Reviewed-by: Jean Delvare <khali@linux-fr.org>
[wsa: Fixed "foo* bar" flaws while we are here]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
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Allow the i2c-mux-gpio to be used by a device tree enabled device. The
bindings are inspired by the one found in the i2c-mux-pinctrl driver.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
[wsa: fixed some whitespace]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
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The code instantiating an i2c-mux-gpio platform device doesn't
necessarily know in advance the GPIO pin numbers it wants to use. If
pins are on a GPIO device which gets its base GPIO number assigned
dynamically at run-time, the values can't be hard-coded.
In that case, let the caller tell i2c-mux-gpio the name of the GPIO
chip and the (relative) GPIO pin numbers to use. At probe time, the
i2c-mux-gpio driver will look for the chip and apply the proper offset
to turn relative GPIO pin numbers to absolute GPIO pin numbers.
The same could be (and was so far) done on the caller's end, however
doing it in i2c-mux-gpio has two benefits:
* It avoids duplicating the code on every caller's side (about 30
lines of code.)
* It allows for deferred probing for the muxed part of the I2C bus
only. If finding the GPIO chip is the caller's responsibility, then
deferred probing (if the GPIO chip isn't there yet) will not only
affect the mux and the I2C bus segments behind it, but also the I2C
bus trunk.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Peter Korsgaard <peter.korsgaard@barco.com>
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Use the devm_kzalloc managed function to stripdown the error and remove
code.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
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Let I2C bus segments behind multiplexers have a class. This allows for
device auto-detection on these segments. As long as parent segments
don't share the same class, it should be fine.
I implemented support in drivers i2c-mux-gpio and i2c-mux-pca954x. I
left i2c-mux-pca9541 and i2c-mux-pinctrl alone for the moment as I
don't know if this feature makes sense for the use cases of these
drivers.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Peter Korsgaard <peter.korsgaard@barco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Michael Lawnick <ml.lawnick@gmx.de>
Cc: Rodolfo Giometti <giometti@linux.it>
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Update the MAINTAINERS entry and all other references accordingly.
Based on an original patch by Wolfram Sang.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
[wsa: fixed merge conflict due to rework in i2c_add_mux_adapter()]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
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