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This commit adds mux hold/unhold message types to support extended
mux control for IPMB and MCTP devices. A hold or an unhold message
can be added at the end of I2C message stream wrapped by
repeated-start, also can be used as a single message independantly.
This mux hold/unhold message will be delivered throughout all mux
levels in the path. Means that if it goes to multi-level mux path,
all muxes will be held/unheld by this message.
1. Hold message
struct i2c_msg msg;
uint16_t timeout = 5000; // timeout in ms. 5 secs in this example.
msg.addr = 0x0; // any value can be used. addr will be ignored in this packet.
msg.flags = I2C_M_HOLD; // set this flag to indicate it's a hold message.
msg.len = sizeof(uint16_t); // timeout value will be delivered using two bytes buffer.
msg.buf = (uint8_t *)&timeout; // set timeout value.
2. Unhold message
struct i2c_msg msg;
uint16_t timeout = 0; // set 0 for an unhold message.
msg.addr = 0x0; // any value can be used. addr will be ignored in this packet.
msg.flags = I2C_M_HOLD; // set this flag to indicate it's an unhold message.
msg.len = sizeof(uint16_t); // timeout value will be delivered using two bytes buffer.
msg.buf = (uint8_t *)&timeout; // set timeout value.
This unhold message can be delivered to a mux adapter even when
a bus is locked so that any holding state can be unheld
immediately by invoking this unhold message.
This patch would not be welcomed from upstream so it should be kept
in downstream only.
Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@intel.com>
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Some I2C bus master drivers which support I2C_M_RECV_LEN do not set
the functionality bits of the now supported SMBus transfers. Add a
convenience macro to make this very simple.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
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Remove boilerplate because we now have the SPDX header.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
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The information about 'i2c_msg' was spread between kdoc and comments.
Move all the explanations to kdoc and duplicate only the requirements
for the flags in the comments. Also, add some redundancy and fix some
typos while here.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
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I2C has no requirement that the buffer of a message needs to be DMA
safe. In case it is, it can now be flagged, so drivers wishing to
do DMA can use the buffer directly.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be. This makes it hard for
compliance tools to determine the correct license.
Update these files with an SPDX license identifier. The identifier was
chosen based on the license information in the file.
GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:
NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".
This exception makes it possible to include GPL headers into non GPL
code, without confusing license compliance tools.
Headers which have either explicit dual licensing or are just licensed
under a non GPL license are updated with the corresponding SPDX
identifier and the GPLv2 with syscall exception identifier. The format
is:
((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)
SPDX license identifiers are a legally binding shorthand, which can be
used instead of the full boiler plate text. The update does not remove
existing license information as this has to be done on a case by case
basis and the copyright holders might have to be consulted. This will
happen in a separate step.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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SMBus Host Notify allows a slave device to act as a master on a bus to
notify the host of an interrupt. On Intel chipsets, the functionality
is directly implemented in the firmware. We just need to export a
function to call .alert() on the proper device driver.
i2c_handle_smbus_host_notify() behaves like i2c_handle_smbus_alert().
When called, it schedules a task that will be able to sleep to go through
the list of devices attached to the adapter.
The current implementation allows one Host Notification to be scheduled
while an other is running.
Tested-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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There is code out there in user space and kernel space which relies on
I2C_M_RD being bit 0 to simplify their bit operations. Add a comment to
make sure this will never break. Do proper sorting of the defines while
we are here.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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So users can check in advance if there is slave support.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
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