Commit Graph

19 Commits

Author SHA1 Message Date
Lars-Peter Clausen 363c7dc72f iio: adc: ti-ads7950: Set `can_sleep` flag for GPIO chip
The ads7950 uses a mutex as well as SPI transfers in its GPIO callbacks.
This means these callbacks can sleep and the `can_sleep` flag should be
set.

Having the flag set will make sure that warnings are generated when calling
any of the callbacks from a potentially non-sleeping context.

Fixes: c97dce792d ("iio: adc: ti-ads7950: add GPIO support")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: David Lechner <david@lechnology.com>
Link: https://lore.kernel.org/r/20230312210933.2275376-1-lars@metafoo.de
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2023-03-18 16:39:35 +00:00
Jonathan Cameron dd54ba8b24 iio: adc: ti-ads7950: 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: 902c4b2446 ("iio: adc: New driver for TI ADS7950 chips")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: David Lechner <david@lechnology.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-37-jic23@kernel.org
2022-06-14 11:53:14 +01:00
Uwe Kleine-König a0386bba70
spi: make remove callback a void function
The value returned by an spi 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.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2022-02-09 13:00:45 +00:00
Cai Huoqing 42351035dc iio: adc: ti-ads7950: Make use of the helper function dev_err_probe()
When possible use dev_err_probe help to properly deal with the
PROBE_DEFER error, the benefit is that DEFER issue will be logged
in the devices_deferred debugfs file.
Using dev_err_probe() can reduce code size, and the error value
gets printed.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Link: https://lore.kernel.org/r/20211008092858.495-9-caihuoqing@baidu.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-10-20 14:43:53 +01:00
Uwe Kleine-König 9898cb24e4 iio: adc: ti-ads7950: Ensure CS is deasserted after reading channels
The ADS7950 requires that CS is deasserted after each SPI word. Before
commit e2540da86e ("iio: adc: ti-ads7950: use SPI_CS_WORD to reduce
CPU usage") the driver used a message with one spi transfer per channel
where each but the last one had .cs_change set to enforce a CS toggle.
This was wrongly translated into a message with a single transfer and
.cs_change set which results in a CS toggle after each word but the
last which corrupts the first adc conversion of all readouts after the
first readout.

Fixes: e2540da86e ("iio: adc: ti-ads7950: use SPI_CS_WORD to reduce CPU usage")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210709101110.1814294-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-07-17 18:36:53 +01:00
Alexander A. Klimov 3593cd5396 Replace HTTP links with HTTPS ones: drivers/iio
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
          If both the HTTP and HTTPS versions
          return 200 OK and serve the same content:
            Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2020-07-13 15:05:59 +01:00
Alexandru Ardelean d3be83244c iio: remove explicit IIO device parent assignment
This patch applies the semantic patch:
@@
expression I, P, SP;
@@
   I = devm_iio_device_alloc(P, SP);
   ...
-  I->dev.parent = P;

It updates 302 files and does 307 deletions.
This semantic patch also removes some comments like
'/* Establish that the iio_dev is a child of the i2c device */'

But this is is only done in case where the block is left empty.

The patch does not seem to cover all cases. It looks like in some cases a
different variable is used in some cases to assign the parent, but it
points to the same reference.
In other cases, the block covered by ... may be just too big to be covered
by the semantic patch.

However, this looks pretty good as well, as it does cover a big bulk of the
drivers that should remove the parent assignment.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2020-06-14 11:49:59 +01:00
Christophe JAILLET 32bd432460 iio: adc: ti-ads7950: Fix a typo in an error message
Fix a typo:
   s/get get/to get/

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-12-15 11:42:17 +00:00
Justin Chen c97dce792d iio: adc: ti-ads7950: add GPIO support
The ADS79XX has GPIO pins that can be used. Add support for the GPIO
pins using the GPIO chip framework.

Signed-off-by: Justin Chen <justinpopo6@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-04-04 20:19:53 +01:00
Justin Chen abbde27929 iio: adc: ti-ads7950: Fix improper use of mlock
Indio->mlock is used for protecting the different iio device modes.
It is currently not being used in this way. Replace the lock with
an internal lock specifically used for protecting the SPI transfer
buffer.

Signed-off-by: Justin Chen <justinpopo6@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-04-04 20:19:41 +01:00
David Lechner e2540da86e iio: adc: ti-ads7950: use SPI_CS_WORD to reduce CPU usage
This changes how the SPI message for the triggered buffer is setup in
the TI ADS7950 A/DC driver. By using the SPI_CS_WORD flag, we can read
multiple samples in a single SPI transfer. If the SPI controller
supports DMA transfers, we can see a significant reduction in CPU usage.

For example, on an ARM9 system running at 456MHz reading just 4 channels
at 100Hz: before this change, top shows the CPU usage of the IRQ thread
of this driver to be ~7.7%. After this change, the CPU usage drops to
~3.8%.

The use of big-endian for the raw data was cargo culted from another
driver when this driver was originally written. It used an SPI word size
of 8 bits and big-endian byte ordering to effectively emulate 16 bit
words.

Now, in order to inject a CS toggle between each word, we need to use
the correct word size, otherwise we would get a CS toggle half way
through each word 16-bit. The SPI subsystem uses CPU byte ordering for
multi-byte words. So, the data we get back from the SPI is going to be
CPU endian now no matter what. Converting that to big endian will just
add overhead on little endian systems so we opt to change the raw data
format from big endian to CPU endian.

There is a small risk that this could break some lazy userspace programs
that use the raw data without checking the data format. We can address
this if/when it actually comes up.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2018-09-22 10:09:47 +01:00
David Lechner 8134b613b0 iio: adc: ti-ads7950: allow simultaneous use of buffer and direct mode
This modifies the TI ADS7950 A/DC driver to allow the simultaneous use
of both the triggered buffer and reading channels directly (via in-
kernel API or sysfs).

The use case for this is on LEGO MINDSTORMS EV3. Two of the voltage
channels are used in-kernel by a power supply driver, which reads the
values using iio_read_channel_processed(). These channels are only read
at a slow rate (<= 1Hz).  However, we want to be able to read 12 other
channels at the same time using the triggered buffer at a high rate (>=
100Hz).

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2018-07-23 19:18:12 +01:00
David Lechner 7d7209f0c4 iio: adc: ti-ads7950: use SPDX-License-Identifier
This updates the ti-ads7950.c file to use SPDX-License-Identifier
instead of more verbose license text.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2018-07-23 19:18:12 +01:00
Jonathan Cameron 52b31bcc93 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>
2017-08-22 21:22:25 +01:00
Andy Shevchenko 8cfa26a77c iio: adc: ti-ads7950: Allow to use on ACPI platforms
ACPI enabled platforms do not have a mean of regulators. Instead we use
hard coded voltage value for reference pin. When value is 0 (default) we
fall back to request a regulator.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-08-20 15:41:11 +01:00
Andy Shevchenko fb4b6f92d1 iio: adc: ti-ads7950: Add OF device ID table
The driver doesn't have a struct of_device_id table but supported devices
are registered via Device Trees. This is working on the assumption that a
SPI device registered via OF will always match a legacy SPI device ID and
that the MODALIAS reported will always be of the form spi:<device>.

There is an ACPI method to enumerate such devices via specific ACPI ID
and use of compatible strings. It will not work for the drivers which
have no OF match ID table present.

Besides this could change in the future so the correct approach is to
have an OF device ID table if the devices are registered via OF.

Tested-by: David Lechner <david@lechnology.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-08-09 14:26:28 +01:00
David Lechner 0bf1a2aac6 iio: adc: ti-ads7950: Change regulator matching string to "vref"
This changes the reference voltage regulator matching string from "refin"
to "vref". This is to be consistent with other A/DC chips that also use
"vref-supply" in their device tree bindings.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2017-01-15 13:56:08 +00:00
David Lechner 2b84f4ded4 iio: adc: ti-ads7950: Drop "ti-" prefix from module name
This drops the "ti-" prefix from the module name. It makes the module name
consistent with other iio ti-ads* drivers and it makes the driver work
with device tree (the spi subsystem drops the "ti," prefix when matching
compatible strings from device tree).

Tested working on LEGO MINDSTORMS EV3 with the following device tree node:

	adc@3 {
		compatible = "ti,ads7957";
		reg = <3>;
		#io-channel-cells = <1>;
		spi-max-frequency = <10000000>;
		vref-supply = <&adc_ref>;
	};

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2017-01-15 13:52:51 +00:00
David Lechner 902c4b2446 iio: adc: New driver for TI ADS7950 chips
This adds a new driver for the TI ADS7950 family of ADC chips. These
communicate using SPI and come in 8/10/12-bit and 4/8/12/16 channel
varieties.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2016-12-03 09:57:21 +00:00