iio: ssp_sensors: replace usage of found with dedicated list iterator variable

To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.

To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean [1].

This removes the need to use a found variable and simply checking if
the variable was set, can determine if the break/goto was hit.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220331230632.957634-2-jakobkoschel@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ssp_sensors: add more range checking in ssp_parse_dataframe()

The "idx" is validated at the start of the loop but it gets incremented
during the iteration so it needs to be checked again.

Fixes: 50dd64d57eee ("iio: common: ssp_sensors: Add sensorhub driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20210909091336.GA26312@kili
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ssp_sensors: fix error code in ssp_print_mcu_debug()

The ssp_print_mcu_debug() function should return negative error codes on
error. Returning "length" is meaningless. This change does not affect
runtime because the callers only care about zero/non-zero.

Reported-by: Jonathan Cameron <jic23@kernel.org>
Fixes: 50dd64d57eee ("iio: common: ssp_sensors: Add sensorhub driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20210914105333.GA11657@kili
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ssp_sensors: Convert to use GPIO descriptors

These three GPIO lines used by the Samsung sensor hub is pretty
straight-forward to convert to use GPIO descriptors.

Cc: Karol Wrona <k.wrona@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

Based on 3 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [kishon] [vijay] [abraham]
[i] [kishon]@[ti] [com] this program is distributed in the hope that
it will be useful but without any warranty without even the implied
warranty of merchantability or fitness for a particular purpose see
the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [graeme] [gregory]
[gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
[kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
[hk] [hemahk]@[ti] [com] this program is distributed in the hope
that it will be useful but without any warranty without even the
implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: common: ssp_sensors: use ktime_get_real_ns() timestamps

getnstimeofday() suffers from the overflow in y2038 on 32-bit
architectures and requires a conversion into the nanosecond format that
we want here.

This changes ssp_parse_dataframe() to use ktime_get_real_ns() directly,
which does not have that problem.

An open question is what time base should be used here. Normally
timestamps should use ktime_get_ns() or ktime_get_boot_ns() to read
monotonic time instead of "real" time, which suffers from time jumps
due to settimeofday() calls or leap seconds.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: common: ssp_sensors: Add sensorhub driver

Sensorhub is MCU dedicated to collect data and manage several sensors.
Sensorhub is a spi device which provides a layer for IIO devices. It provides
some data parsing and common mechanism for sensorhub sensors.

Adds common sensorhub library for sensorhub driver and iio drivers
which uses sensorhub MCU to communicate with sensors.

Signed-off-by: Karol Wrona <k.wrona@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>