iio: light: ltr501: Drop ACPI_PTR() usage

Avoiding unused variable warnings when using this macro adds
complexity that in simple cases like this one is not justified
for the small saving in data.

Include linux/mod_devicetable.h which includes the definition of
struct acpi_device_id (hence somewhat related to the main change)

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20231231183514.566609-15-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Switch i2c drivers back to use .probe()

After commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new()
call-back type"), all drivers being converted to .probe_new() and then
03c835f498b5 ("i2c: Switch .probe() to not take an id parameter") convert
back to (the new) .probe() to be able to eventually drop .probe_new() from
struct i2c_driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230515205048.19561-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: light: ltr501: Convert to i2c's .probe_new()

.probe_new() doesn't get the i2c_device_id * parameter, so determine
that explicitly in the probe function.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221118224540.619276-130-uwe@kleine-koenig.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: light: ltr501: Use devm_regulator_bulk_get_enable()

This driver only turns the power for some regulators on at probe and off
via a custom devm_add_action_or_reset() callback. The new
devm_regulator_bulk_get_enable() replaces all this boilerplate code.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20221016163409.320197-11-jic23@kernel.org

i2c: Make remove callback return void

The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

iio:light:ltr501: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr() etc

Letting the compiler remove these functions when the kernel is built
without CONFIG_PM_SLEEP support is simpler and less error prone than the
use of #ifdef based config guards.

Removing instances of this approach from IIO also stops them being
copied into new drivers.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Maslov Dmitry <maslovdmitry@seeed.cc>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220130193147.279148-24-jic23@kernel.org

iio:light:ltr501: White space cleanup of spacing around {} in id tables

The spacing in this driver was inconsistent so make sure we have a space
after { and before } for the two id tables.
Part of aim is to avoid providing examples of this inconsistency that
get copied into new drivers.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Nikita Travkin <nikita@trvn.ru>
Cc: Maslov Dmitry <maslovdmitry@seeed.cc>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Link: https://lore.kernel.org/r/20211230174911.78291-6-jic23@kernel.org

iio: ltr501: Export near level property for proximity sensor

Userspace tools like iio-sensor-proxy need to know the proximity level
that should be considered "near". This value is hardware-specific and
can be defined via the devicetree. Allow the driver to export the near
level.

Signed-off-by: Nikita Travkin <nikita@trvn.ru>
Link: https://lore.kernel.org/r/20211125125646.54831-2-nikita@trvn.ru
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: light: ltr501: Added ltr303 driver support

Previously ltr501 driver supported a number of light and,
proximity sensors including ltr501, ltr559 and ltr301.
This adds support for another light sensor ltr303
used in Seeed Studio reTerminal, a carrier board
for Raspberry Pi 4 CM.

Signed-off-by: Maslov Dmitry <maslovdmitry@seeed.cc>
Link: https://lore.kernel.org/r/20211106174137.6783-1-maslovdmitry@seeed.cc
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ltr501: Don't return error code in trigger handler

IIO trigger handlers need to return one of the irqreturn_t values.
Returning an error code is not supported.

The ltr501 interrupt handler gets this right for most error paths, but
there is one case where it returns the error code.

In addition for this particular case the trigger handler does not call
`iio_trigger_notify_done()`. Which when not done keeps the triggered
disabled forever.

Modify the code so that the function returns a valid irqreturn_t value as
well as calling `iio_trigger_notify_done()` on all exit paths.

Fixes: 2690be905123 ("iio: Add Lite-On ltr501 ambient light / proximity sensor driver")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20211024171251.22896-1-lars@metafoo.de
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: light: ltr501: Add of_device_id table

Add of_device_id table so the driver can be used on DT platforms without
relying on i2c_device_id fallback. (So DT schema validation is possible)

Signed-off-by: Nikita Travkin <nikita@trvn.ru>
Link: https://lore.kernel.org/r/20211006163058.145842-4-nikita@trvn.ru
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: light: ltr501: Add rudimentary regulator support

On some platforms the supply regulators must be enabled before the
sensor can work. Add vdd and vddio regulators for the sensor and IO bus
power respectively.

Signed-off-by: Nikita Travkin <nikita@trvn.ru>
Link: https://lore.kernel.org/r/20211006163058.145842-3-nikita@trvn.ru
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ltr501: mark ltr501_chip_info as const

This patch marks the struct ltr501_chip_info as constant.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Tested-by: Nikita Travkin <nikita@trvn.ru> # ltr559
Link: https://lore.kernel.org/r/20210610134619.2101372-5-mkl@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ltr501: ltr501_read_ps(): add missing endianness conversion

The PS ADC Channel data is spread over 2 registers in little-endian
form. This patch adds the missing endianness conversion.

Fixes: 2690be905123 ("iio: Add Lite-On ltr501 ambient light / proximity sensor driver")
Signed-off-by: Oliver Lang <Oliver.Lang@gossenmetrawatt.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Tested-by: Nikita Travkin <nikita@trvn.ru> # ltr559
Link: https://lore.kernel.org/r/20210610134619.2101372-4-mkl@pengutronix.de
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ltr501: ltr559: fix initialization of LTR501_ALS_CONTR

The ltr559 chip uses only the lowest bit of the ALS_CONTR register to
configure between active and stand-by mode. In the original driver
BIT(1) is used, which does a software reset instead.

This patch fixes the problem by using BIT(0) as als_mode_active for
the ltr559 chip.

Fixes: 8592a7eefa54 ("iio: ltr501: Add support for ltr559 chip")
Signed-off-by: Oliver Lang <Oliver.Lang@gossenmetrawatt.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Tested-by: Nikita Travkin <nikita@trvn.ru> # ltr559
Link: https://lore.kernel.org/r/20210610134619.2101372-3-mkl@pengutronix.de
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ltr501: mark register holding upper 8 bits of ALS_DATA{0,1} and PS_DATA as volatile, too

The regmap is configured for 8 bit registers, uses a RB-Tree cache and
marks several registers as volatile (i.e. do not cache).

The ALS and PS data registers in the chip are 16 bit wide and spans
two regmap registers. In the current driver only the base register is
marked as volatile, resulting in the upper register only read once.

Further the data sheet notes:

| When the I2C read operation starts, all four ALS data registers are
| locked until the I2C read operation of register 0x8B is completed.

Which results in the registers never update after the 2nd read.

This patch fixes the problem by marking the upper 8 bits of the ALS
and PS registers as volatile, too.

Fixes: 2f2c96338afc ("iio: ltr501: Add regmap support.")
Reported-by: Oliver Lang <Oliver.Lang@gossenmetrawatt.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Tested-by: Nikita Travkin <nikita@trvn.ru> # ltr559
Link: https://lore.kernel.org/r/20210610134619.2101372-2-mkl@pengutronix.de
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:light:ltr501 Fix timestamp alignment issue.

One of a class of bugs pointed out by Lars in a recent review.
iio_push_to_buffers_with_timestamp assumes the buffer used is aligned
to the size of the timestamp (8 bytes). This is not guaranteed in
this driver which uses an array of smaller elements on the stack.
Here we use a structure on the stack. The driver already did an
explicit memset so no data leak was possible.

Forced alignment of ts is not strictly necessary but probably makes
the code slightly less fragile.

Note there has been some rework in this driver of the years, so no
way this will apply cleanly all the way back.

Fixes: 2690be905123 ("iio: Add Lite-On ltr501 ambient light / proximity sensor driver")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: <Stable@vger.kernel.org>

iio: remove left-over parent assignments

These were found by doing some shell magic:
------------
for file in $(git grep -w devm_iio_device_alloc | cut -d: -f1 | sort | uniq) ; do
if grep 'parent =' $file | grep -v trig | grep -vq devm_; then
echo "$file -> $(grep "parent =" $file)"
fi
done
-----------

The output is bearable [after the semantic patch is applied].
There is a mix of trigger assignments with some iio device parent
assignments that are removed via this patch.

JC: A few more added via inspection of all parent =
statements in drivers/iio. Some of these may just have crossed with this
series, others were less obvious to scripting due to some cross
file / module boundary calls.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: light: ltr501: Constify structs

Constify some data structs that are never changed. In order to do so,
also update a couple of functions that now need to accept pointers to
const struct instead of struct. While at it, update a few more functions
to accept pointers to const struct instead of pointers.

This allows the compiler to put more data in the code segment instead of
the data segment, as seen by the output of the file command:

Before:
text data bss dec hex filename
27080 8144 192 35416 8a58 drivers/iio/light/ltr501.o

After:
text data bss dec hex filename
27688 7536 192 35416 8a58 drivers/iio/light/ltr501.o
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:light:ltr501: Drop unnecessary cast of parameter in regmap_bulk_read

This only occurs once in the driver and isn't needed in this case either,
so drop it.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 330

Based on 1 normalized pattern(s):

this file is subject to the terms and conditions of version 2 of the
gnu general public license see the file copying in the main
directory of this archive for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 55 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.108941081@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio:light: drop assign iio_info.driver_module and iio_trigger_ops.owner

The equivalent of both of these are now done via macro magic when
the relevant register calls are made. The actual structure
elements will shortly go away.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

iio: light: ltr501 Fix interchanged als/ps register field

The register mapping for the IIO driver for the Liteon Light and Proximity
sensor LTR501 interrupt mode is interchanged (ALS/PS).
There is a register called INTERRUPT register (address 0x8F)
Bit 0 represents PS measurement trigger.
Bit 1 represents ALS measurement trigger.
This two bit fields are interchanged within the driver.
see datasheet page 24:
http://optoelectronics.liteon.com/upload/download/DS86-2012-0006/S_110_LTR-501ALS-01_PrelimDS_ver1%5B1%5D.pdf

Signed-off-by: Franziska Naepelt <franziska.naepelt@idt.com>
Fixes: 7ac702b3144b6 ("iio: ltr501: Add interrupt support")
Acked-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: light: ltr501: claim direct mode during raw writes

Driver was checking for direct mode but not locking it. Use
claim/release helper functions to guarantee the device stays
in direct mode during all raw write operations.

Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Acked-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: light: ltr501: claim direct mode during select raw reads

Driver was checking for direct mode but not locking it. Use
claim/release helper functions to guarantee the device stays
in direct mode during required raw read cases.

Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Acked-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:core: timestamping clock selection support

Adds a new per-device sysfs attribute "current_timestamp_clock" to allow
userspace to select a particular POSIX clock for buffered samples and
events timestamping.

Following clocks, as listed in clock_gettime(2), are supported:
CLOCK_REALTIME, CLOCK_MONOTONIC, CLOCK_MONOTONIC_RAW,
CLOCK_REALTIME_COARSE, CLOCK_MONOTONIC_COARSE, CLOCK_BOOTTIME and
CLOCK_TAI.

Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
Acked-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio-light: Use a signed return type for ltr501_match_samp_freq()

The return type "unsigned int" was used by the ltr501_match_samp_freq()
function despite of the aspect that it will eventually return a negative
error code.
Improve this implementation detail by deletion of the type modifier then.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:light:ltr501: fix variable in ltr501_init

When filling data->als_contr, the register content read into status needs
to be used, instead of the return status value of regmap_read.

Fixes: 8592a7eefa540 ("iio: ltr501: Add support for ltr559 chip")

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Drop owner assignment from i2c_driver

i2c_driver does not need to set an owner because i2c_register_driver()
will set it.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:light:ltr501: fix variable in ltr501_init

When filling data->als_contr, the register content read into status needs
to be used, instead of the return status value of regmap_read.

Fixes: 8592a7eefa540 ("iio: ltr501: Add support for ltr559 chip")

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Add light channel support

Added support to calculate lux value from visible
and IR spectrum adc count values. Also added IIO_LIGHT
channel to enable user read the lux value directly
from device using illuminance input ABI.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Fix proximity threshold boundary check

Currently, proximity sensor boundary check is done
inside the switch block but outside the case
statement.Since this code will never get executed,
moved the check outside the switch case statement.

867 case IIO_PROXIMITY:
868 switch (dir) {
// Following line has been moved outside the switch block.
869 if (val > LTR501_PS_THRESH_MASK)
870 return -EINVAL;
871 case IIO_EV_DIR_RISING:

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:light:ltr501 bug in parameter sanity check.

Clearly the intent was to error if the value was not 0 or 1.
As implemented we have (A != 0 || A != 1) which is always true
as A is never both 0 and 1 at the same time.

As the autobuilder suggested, && makes more sense for this error
check.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Acked-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Add support for ltr301 chip

Added support for Liteon 301 Ambient light sensor. Since
LTR-301 and LTR-501 are register compatible(and even have same
part id), LTR-501 driver has been extended to support both
devices. LTR-501 is similar to LTR-301 in ALS sensing, But the
only difference is, LTR-501 also supports proximity sensing.

LTR-501 - ALS + Proximity combo
LTR-301 - ALS sensor.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Add support for ltr559 chip

This device is register compatible with LTR501, with a minor difference for
ALS control register as showed below:

ALS Control register for LTR501:

7 6 5 4 3 2 1 0
+------+------+------+------+------+------+------+------+
| | | | |
| Reserved | Gain | SW | ALS Mode |
| | | Reset| |
+------+------+------+------+------+------+------+------+

ALS Control register for LTR559:

7 6 5 4 3 2 1 0
+------+------+------+------+------+------+------+------+
| | | | |
| Reserved | Gain | SW | ALS |
| | | Reset| Mode |
+------+------+------+------+------+------+------+------+

We handle this difference by introducing ltr501_chip_info.

Datasheet for LTR559 is at:
http://optoelectronics.liteon.com/upload/download/DS86-2013-0003/S_110_LTR-559ALS-01_DS_V1.pdf

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Add ACPI enumeration support

Added ACPI enumeration support for LTR501 chip.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Add interrupt rate control support

Added rate control support for ALS and proximity
threshold interrupts.Also, Added support to modify
and read ALS & proximity sensor sampling frequency.

LTR-501 supports interrupt rate control using persistence
register settings. Writing <n> to persistence register
would generate interrupt only if there are <n> consecutive
data values outside the threshold range.

Since we don't have any existing ABI's to directly
control the persistence register count, we have implemented
the rate control using IIO_EV_INFO_PERIOD. _period event
attribute represents the amount of time in seconds an
event should be true for the device to generate the
interrupt. So using _period value and device frequency,
persistence count is calculated in driver using following
logic.

count = period / measurement_rate

If the given period is not a multiple of measurement rate then
we round up the value to next multiple.

This patch also handles change to persistence count whenever
there is change in frequency.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Add interrupt support

This patch adds interrupt support for Liteon 501 chip.

Interrupt will be generated whenever ALS or proximity
data exceeds values given in upper and lower threshold
register settings.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Add integration time support

Added support to modify and read ALS integration time.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ltr501: Add regmap support.

Added regmap support. It will be useful to handle
bitwise updates to als & ps control registers.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: light: ltr501: Fix alignment to match open parenthesis

This makes ltr501 code consistent with the coding style adopted
for the new drivers added to IIO.
We prepare the path for adding support for LTR559 chip.

Reported by checkpatch.pl

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: light: ltr501: Powerdown device on error

Power down device when an error occurs in order to avoid wasting
power. Move powerdown function up to be seen by the new call and
align parameters for the ltr501_write_contr() call.

Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: Add Lite-On ltr501 ambient light / proximity sensor driver

combined ambient light (two channels) and proximity sensor with I2C
interface; the ALS channels are visible+IR and IR

datasheet is here
http://optoelectronics.liteon.com/upload/download/DS86-2012-0006/P_100_LTR-501ALS-01_PrelimDS_ver1.1.pdf

v3:
* fix use of sizeof in _read_als()
v2: (thanks to Lars-Peter Clausen)
* cannot use devm_iio_device_register() due to cleanup order in _remove()
* mutex around data wait/read
* turn info message in _probe() into check for part number
* change copyright year to 2014

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>