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path: root/drivers/i2c/i2c-mux.c
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2015-04-23i2c: mux: use proper dev when removing "channel-X" symlinksWolfram Sang1-3/+5
Those symlinks are created for the mux_dev, so we need to remove it from there. Currently, it breaks for muxes where the mux_dev is not the device of the parent adapter like this: [ 78.234644] WARNING: CPU: 0 PID: 365 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x5c/0x78() [ 78.242438] sysfs: cannot create duplicate filename '/devices/platform/i2cbus@8/channel-0' Remove confusing comments while we are here. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Fixes: c9449affad2ae0 Cc: stable@kernel.org
2014-11-18i2c: mux: create "channel-n" symlinks for child segments in the mux deviceGerlando Falauto1-0/+8
This makes the topology clearer. For instance, by adding a pca9547 device with address 0x70 to bus i2c-0, you get: /sys/class/i2c-dev/i2c-0/device/0-0070/channel-0 -> i2c-1 ... /sys/class/i2c-dev/i2c-0/device/0-0070/channel-7 -> i2c-8 Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com> [wsa: simplified sysfs-usage and fixed format string usage] Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Acked-by: Martin Belanger <martin.belanger@cyaninc.com> Acked-by: Danielle Costantino <danielle.costantino@gmail.com>
2014-11-18i2c: mux: create symlink to actual mux deviceWolfram Sang1-0/+4
The current implementation creates muxed i2c-<n> busses as immediate children of their i2c-<n> parent bus. In case of multiple muxes on one bus, it is impossible to determine which muxed bus comes from which mux. It could be argued that the parent device should be changed from the parent adapter to the mux device. This has pros and cons. To improve the topology, simply add a "mux_device" symlink pointing to the actual muxing device, so we can distinguish muxed busses. Doing it this way, we don't break the ABI. Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Tested-by: Guenter Roeck <linux@roeck-us.net>
2013-12-12i2c: mux: Inherit retry count and timeout from parent for muxed busElie De Brauwer1-0/+2
If a muxed i2c bus gets created the default retry count and timeout of the muxed bus is zero. Hence it it possible that you end up with a situation where the parent controller sets a default retry count and timeout which gets applied and used while the muxed bus (using the same controller) has a default retry count of zero and a default timeout of 1s (set in i2c_add_adapter()). This can be solved by initializing the retry count and timeout of the muxed bus with the values used by the the parent at creation time. Signed-off-by: Elie De Brauwer <eliedebrauwer@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2013-08-23i2c: move OF helpers into the coreWolfram Sang1-3/+0
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>
2013-04-02i2c: Make the return type of i2c_del_mux_adapter() voidLars-Peter Clausen1-3/+1
i2c_del_mux_adapter always returns 0 and none of it current users check its return value anyway. It is also an essential requirement of the Linux device driver model, that functions which may be called from a device's remove callback to free resources provided by the device, are not allowed to fail. This is the case for i2c_del_mux_adapter(), so make its return type void to make the fact that it won't fail explicit. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Reviewed-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2013-04-02i2c: Ignore return value of i2c_del_adapter()Lars-Peter Clausen1-4/+1
i2c_del_adapter() always returns 0. So all checks testing whether it will be non zero will always evaluate to false and the conditional code is dead code. This patch updates all callers of i2c_del_mux_adapter() to ignore the return value and assume that it will always succeed (which it will). In a subsequent patch the return type of i2c_del_adapter() will be made void. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Ben Hutchings <bhutchings@solarflare.com> Reviewed-by: Jean Delvare <khali@linux-fr.org> Acked-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2012-10-05i2c-mux: Add support for device auto-detectionJean Delvare1-0/+22
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>
2012-05-12i2c/of: Automatically populate i2c mux busses from device tree data.David Daney1-0/+23
For 'normal' i2c bus drivers, we can call of_i2c_register_devices() and have the device tree framework automatically populate the bus with the devices specified in the device tree. This patch adds a common code to the i2c mux framework to have the mux sub-busses be populated by the of_i2c_register_devices() too. If the mux device has an of_node, we populate the sub-bus' of_node so that the subsequent call to of_i2c_register_devices() will find the corresponding devices. It seemed better to put this logic in i2c_add_mux_adapter() rather than the individual mux drivers, as they will all probably want to do the same thing. Signed-off-by: David Daney <david.daney@cavium.com> Acked-by: Stephen Warren <swarren@wwwdotorg.org> Tested-by: Lars-Peter Clausen <lars@metafoo.de> [wsa: removed superfluous ret-variable and fixed a typo in a comment] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-05-12i2c: Add a struct device * parameter to i2c_add_mux_adapter()David Daney1-9/+10
And adjust all callers. The new device parameter is used in the next patch to initialize the mux's of_node so that its children may be automatically populated. Signed-off-by: David Daney <david.daney@cavium.com> Tested-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2010-11-15i2c: Mark i2c_adapter.id as deprecatedJean Delvare1-1/+0
It's about time to make it clear that i2c_adapter.id is deprecated. Hopefully this will remind the last user to move over to a different strategy. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Jarod Wilson <jarod@redhat.com> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
2010-08-11i2c: Multiplexed I2C bus core supportMichael Lawnick1-0/+165
Add multiplexed bus core support. I2C multiplexer and switches like pca954x get instantiated as new adapters per port. Signed-off-by: Michael Lawnick <ml.lawnick@gmx.de> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Jean Delvare <khali@linux-fr.org>