iio: adc: ltc2497: Simplify probe()

Simpilfy probe() by replacing device_get_match_data() and id lookup for
retrieving match data by using i2c_get_match_data().

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20230902170529.62297-1-biju.das.jz@bp.renesas.com
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>

drivers: iio: adc: ltc2497: fix LSB shift

Correct the "sub_lsb" shift for the ltc2497 and drop the sub_lsb element
which is now constant.

An earlier version of the code shifted by 14 but this was a consequence
of reading three bytes into a __be32 buffer and using be32_to_cpu(), so
eight extra bits needed to be skipped. Now we use get_unaligned_be24()
and thus the additional skip is wrong.

Fixes: 2187cfeb3626 ("drivers: iio: adc: ltc2497: LTC2499 support")
Signed-off-by: Ian Ray <ian.ray@ge.com>
Link: https://lore.kernel.org/r/20230127125714.44608-1-ian.ray@ge.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ltc2497: 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/20221118224540.619276-66-uwe@kleine-koenig.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers: iio: adc: ltc2497: Rename the LTC2499 iio device

Set the iio device's name based on the chip used for the
LTC2499 only. The most common way for IIO clients to interact
with a device is to address it based on it's name. By using
the dev_name() function, the name will be set based on a
i2c_client's kobj name, which has the format i2c_instance-i2c_address
(1-0076 for example). This is not ideal, since it makes a
requirement for userspace to have knowledge about the hardware
connections of the device.

The name field is set to NULL for the LTC2497 and LTC2496, so
that the old name can kept as it is, since changing it will
result in an ABI breakage.

Signed-off-by: Ciprian Regus <ciprian.regus@analog.com>
Link: https://lore.kernel.org/r/20220916140922.2506248-6-ciprian.regus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers: iio: adc: ltc2497: LTC2499 support

The LTC2499 is a 16-channel (eight differential), 24-bit,
ADC with Easy Drive technology and a 2-wire, I2C interface.

Implement support for the LTC2499 ADC by extending the LTC2497
driver. A new chip_info struct is added to differentiate between
chip types and resolutions when reading data from the device.

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2499fe.pdf
Signed-off-by: Ciprian Regus <ciprian.regus@analog.com>
Link: https://lore.kernel.org/r/20220916140922.2506248-5-ciprian.regus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ltc2497: Fix reading conversion results

After the result of the previous conversion is read the chip
automatically starts a new conversion and doesn't accept new i2c
transfers until this conversion is completed which makes the function
return failure.

So add an early return iff the programming of the new address isn't
needed. Note this will not fix the problem in general, but all cases
that are currently used. Once this changes we get the failure back, but
this can be addressed when the need arises.

Fixes: 69548b7c2c4f ("iio: adc: ltc2497: split protocol independent part in a separate module ")
Reported-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Denys Zagorui <dzagorui@cisco.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220815091647.1523532-1-dzagorui@cisco.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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: adc: ltc2497: Fix alignment for DMA safety

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1. Switch to the updated
IIO_DMA_MINALIGN definition.

Update the comment to include 'may'.

Fixes: bc82222fcca1 ("iio:adc: Driver for Linear Technology LTC2497 ADC")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-23-jic23@kernel.org

iio:adc:ltc2497 drop of_match_ptr protection

This prevents the driver being used with ACPI PRP0001 based
bindings. Also switch include to mod_devicetable.h which devices
the used id structure.

Note this is most about removing something I don't want want cut
and paste into new driver rather than any thought that this particular
driver will be used in an ACPI system (though it might!)

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

iio: adc: ltc2497: split protocol independent part in a separate module

This allows to share most of this driver for the ltc2496 driver added in
the next commit that is an SPI variant of the ltc2497. Initially I named
the generic part ltc249x, but wild card names are frowned upon, so the
generic part is called ltc2497-core even though it's not obvious that
this is then to be reused for the ltc2496 driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 177

Based on 1 normalized pattern(s):

licensed under the gpl 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 135 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: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.071193225@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio:adc: 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:adc:ltc2497: Add support for board file based iio consumer mapping.

Add missing hooks in the LTC2497 IIO driver to allow hwmon mapping.

Signed-off-by: Gaurav Gupta <gauragup@cisco.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:adc: Driver for Linear Technology LTC2497 ADC

This patch adds support for the Analog Devices / Linear Technology
LTC2497 ADCs. The LTC2497 is a 16-channel (eight differential),
16-bit, high precision, delta-sigma ADC with an automatic, differential,
input current cancellation front end and a 2-wire, I2C interface.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>