user/sven/linux.git/include/linux/i2c.h, branch v3.12.23

i2c: Re-instate body of i2c_parent_is_i2c_adapter()

2014-01-25T16:49:28Z

commit 2fac2b891f287691c27ee8d2eeecf39571b27fea upstream. The body of i2c_parent_is_i2c_adapter() is currently guarded by I2C_MUX. It should be CONFIG_I2C_MUX instead. Among potentially other problems, this resulted in i2c_lock_adapter() only locking I2C mux child adapters, and not the parent adapter. In turn, this could allow inter-mingling of mux child selection and I2C transactions, which could result in I2C transactions being directed to the wrong I2C bus, and possibly even switching between busses in the middle of a transaction. One concrete issue caused by this bug was corrupted HDMI EDID reads during boot on the NVIDIA Tegra Seaboard system, although this only became apparent in recent linux-next, when the boot timing was changed just enough to trigger the race condition. Fixes: 3923172b3d70 ("i2c: reduce parent checking to a NOOP in non-I2C_MUX case") Cc: Phil Carmody Signed-off-by: Stephen Warren Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman

i2c: move ACPI helpers into the core

2013-08-23T08:22:29Z

This follows what has already been done for the DeviceTree helpers. Move the ACPI helpers from drivers/acpi/acpi_i2c.c to the I2C core and update documentation accordingly. This also solves a problem reported by Jerry Snitselaar that we can't build the ACPI I2C helpers as a module. Signed-off-by: Mika Westerberg Acked-by: Rafael J. Wysocki Signed-off-by: Wolfram Sang

i2c: move OF helpers into the core

2013-08-23T08:22:20Z

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

i2c: reduce parent checking to a NOOP in non-I2C_MUX case

2013-08-07T14:58:08Z

In 0826374 - i2c: Multiplexed I2C bus core support core i2c code increased in size and complexity even when I2C_MUX wasn't selected. Turning this check into a constant NULL in the n case lets the client functions in be simplified too, not needing to include never-called calls to the mux-specific helpers. Signed-off-by: Phil Carmody Signed-off-by: Wolfram Sang

i2c: Make return type of i2c_del_adapter() void

2013-04-02T05:06:17Z

i2c_del_adapter() is usually called from a drivers remove callback. The Linux device driver model does not allow the remove callback to fail and all resources allocated in the probe callback need to be freed, as well as all resources which have been provided to the rest of the kernel(for example a I2C adapter) need to be revoked. So any function revoking such resources isn't allowed to fail either. i2c_del_adapter() adheres to this requirement and will never fail. But i2c_del_adapter()'s return type is int, which may cause driver authors to think that it can fail. This led to code constructs like: ret = i2c_del_adapter(...); BUG_ON(ret); Since i2c_del_adapter() always returns 0 the BUG_ON is never hit and essentially becomes dead code, which means it can be removed. Making the return type of i2c_del_adapter() void makes it explicit that the function will never fail and should prevent constructs like the above from re-appearing in the kernel code. All callers of i2c_del_adapter() have already been updated in a previous patch to ignore the return value, so the conversion of the return type from int to void can be done without causing any build failures. Signed-off-by: Lars-Peter Clausen Reviewed-by: Jean Delvare Signed-off-by: Wolfram Sang

i2c: Remove detach_adapter

2013-04-02T05:03:28Z

The detach_adapter callback has been deprecated for quite some time and has no user left. Keeping it alive blocks other cleanups, so remove it. Signed-off-by: Lars-Peter Clausen Reviewed-by: Jean Delvare Signed-off-by: Wolfram Sang

i2c: Add bus recovery infrastructure

2013-03-24T09:30:54Z

Add i2c bus recovery infrastructure to i2c adapters as specified in the i2c protocol Rev. 03 section 3.1.16 titled "Bus clear". http://www.nxp.com/documents/user_manual/UM10204.pdf Sometimes during operation i2c bus hangs and we need to give dummy clocks to slave device to start the transfer again. Now we may have capability in the bus controller to generate these clocks or platform may have gpio pins which can be toggled to generate dummy clocks. This patch supports both. This patch also adds in generic bus recovery routines gpio or scl line based which can be used by bus controller. In addition controller driver may provide its own version of the bus recovery routine. This doesn't support multi-master recovery for now. Signed-off-by: Viresh Kumar [wsa: changed gpio type to int and minor reformatting] Signed-off-by: Wolfram Sang

i2c / ACPI: add ACPI enumeration support

2012-11-23T11:23:40Z

ACPI 5 introduced I2cSerialBus resource that makes it possible to enumerate and configure the I2C slave devices behind the I2C controller. This patch adds helper functions to support I2C slave enumeration. An ACPI enabled I2C controller driver only needs to call acpi_i2c_register_devices() in order to get its slave devices enumerated, created and bound to the corresponding ACPI handle. Signed-off-by: Mika Westerberg Signed-off-by: Rafael J. Wysocki

UAPI: (Scripted) Disintegrate include/linux

2012-10-13T09:46:48Z

Signed-off-by: David Howells Acked-by: Arnd Bergmann Acked-by: Thomas Gleixner Acked-by: Michael Kerrisk Acked-by: Paul E. McKenney Acked-by: Dave Jones

i2c: Correct struct i2c_driver doc about detection

2012-10-05T20:23:54Z

s/address_data/address_list/ in addition to c3813d6. Signed-off-by: Vivien Didelot Signed-off-by: Jean Delvare