summaryrefslogtreecommitdiff
path: root/drivers/iio/adc/mcp320x.c
AgeCommit message (Collapse)Author
2017-10-09iio: adc: mcp320x: Add support for mcp3550/1/3Lukas Wunner
These ADCs are marketed as single-channel 22 bit delta-sigma ADCs, but in reality their resolution is 21 bit with an overrange or underrange of 12% beyond Vref. In other words, "full scale" means +/- 2^20. This driver does not explicitly signal back to the user when an overrange or underrange occurs, but the user can detect it by comparing the raw value to +/- 2^20 (or the scaled value to Vref). The chips feature an extended temperature range and high accuracy, low noise characteristics, but their conversion times are slow with up to 80 ms +/- 2% (on the MCP3550-50). Hence, unlike the other ADCs supported by the driver, conversion does not take place in realtime upon lowering CS. Instead, CS is asserted for 8 usec to start the conversion. After waiting for the duration of the conversion, the result can be fetched. While waiting, control of the bus is ceased so it may be used by a different device. After the result has been fetched and 10 us have passed, the chip goes into shutdown and an additional power-up delay of 144 clock periods is then required to wake the analog circuitry upon the next conversion (footnote below table 4-1, page 16 in the spec). Optionally, the chips can be used in so-called "continuous conversion mode": Conversions then take place continuously and the last result may be fetched at any time without observing a delay. The mode is enabled by permanently driving CS low, e.g. by wiring it to ground. The driver only supports "single conversion mode" for now but should be adaptable to "continuous conversion mode" with moderate effort. The chips clock out a 3 byte word, unlike the other ADCs supported by the driver which all have a lower resolution than 16 bit and thus make do with 2 bytes. Calculate the word length on probe by rounding up the resolution to full bytes. Crucially, if the clock idles low, the transfer is preceded by a useless Data Ready bit which increases its length from 24 bit to 25 bit = 4 bytes (section 5.5 in the spec). Autosense this based on the SPI slave's configuration. Cc: Mathias Duckeck <m.duckeck@kunbus.de> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-10-09Merge 4.14-rc4 into staging-nextGreg Kroah-Hartman
We want the staging/iio fixes in here as well to handle merge issues. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-24iio: adc: mcp320x: Fix readout of negative voltagesLukas Wunner
Commit f686a36b4b79 ("iio: adc: mcp320x: Add support for mcp3301") returns a signed voltage from mcp320x_adc_conversion() but neglects that the caller interprets a negative return value as failure. Only mcp3301 (and the upcoming mcp3550/1/3) is affected as the other chips are incapable of measuring negative voltages. Fix and while at it, add mcp3301 to the list of supported chips at the top of the file. Fixes: f686a36b4b79 ("iio: adc: mcp320x: Add support for mcp3301") Cc: Andrea Galbusera <gizero@gmail.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-09-24iio: adc: mcp320x: Fix oops on module unloadLukas Wunner
The driver calls spi_get_drvdata() in its ->remove hook even though it has never called spi_set_drvdata(). Stack trace for posterity: Unable to handle kernel NULL pointer dereference at virtual address 00000220 Internal error: Oops: 5 [#1] SMP ARM [<8072f564>] (mutex_lock) from [<7f1400d0>] (iio_device_unregister+0x24/0x7c [industrialio]) [<7f1400d0>] (iio_device_unregister [industrialio]) from [<7f15e020>] (mcp320x_remove+0x20/0x30 [mcp320x]) [<7f15e020>] (mcp320x_remove [mcp320x]) from [<8055a8cc>] (spi_drv_remove+0x2c/0x44) [<8055a8cc>] (spi_drv_remove) from [<805087bc>] (__device_release_driver+0x98/0x134) [<805087bc>] (__device_release_driver) from [<80509180>] (driver_detach+0xdc/0xe0) [<80509180>] (driver_detach) from [<8050823c>] (bus_remove_driver+0x5c/0xb0) [<8050823c>] (bus_remove_driver) from [<80509ab0>] (driver_unregister+0x38/0x58) [<80509ab0>] (driver_unregister) from [<7f15e69c>] (mcp320x_driver_exit+0x14/0x1c [mcp320x]) [<7f15e69c>] (mcp320x_driver_exit [mcp320x]) from [<801a78d0>] (SyS_delete_module+0x184/0x1d0) [<801a78d0>] (SyS_delete_module) from [<80108100>] (ret_fast_syscall+0x0/0x1c) Fixes: f5ce4a7a9291 ("iio: adc: add driver for MCP3204/08 12-bit ADC") Cc: Oskar Andero <oskar.andero@gmail.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-09-24iio: adc: mcp320x: Document struct mcp320xLukas Wunner
Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-09-24iio: adc: mcp320x: Drop unnecessary of_device_id attributesLukas Wunner
The driver sets a .data pointer for each .compatible string but never calls of_device_get_match_data(). Instead, ADC properties are looked up with spi_get_device_id(). The .data pointer is therefore unnecessary, so drop it. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-09-24iio: adc: mcp320x: Speed up readout of single-channel ADCsLukas Wunner
Single-channel converters such as mcp3001, mcp3201, mcp3301 and the upcoming mcp3550/1/3 lack a MOSI pin, so there's no need to call mcp320x_channel_to_tx_data() for them. Moreover, instead of calling spi_read() for these converters, which generates an spi_message and spi_transfer on the stack on every readout, it's more efficient to use the spi_message and spi_transfer[] included in struct mcp320x (as we do for multi-channel ADCs), but initialize the spi_message only with the receive transfer. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-08-22iio:adc: drop assign iio_info.driver_module and iio_trigger_ops.ownerJonathan Cameron
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>
2016-07-03iio: adc: add missing of_node references to iio_devMatt Ranostay
Adding missing indio_dev->dev.of_node references to allow iio consumers to access the device channels. Signed-off-by: Matt Ranostay <mranostay@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2016-01-16iio: adc: mcp320x: support more differential voltage measurementAkinobu Mita
mcp320x driver supports the pseudo-differential mode by in_voltage'IN+'-voltage'IN-'_raw where (IN+, IN-) = (0, 1), (2, 3), ... mcp320x chips except MCP3X01 can also select swapped IN+ and IN- pairs in the pseudo-differential mode. i.e. in_voltage'IN+'-voltage'IN-'_raw where (IN+, IN-) = (1, 0), (3, 2), ... If the voltage level of IN+ is equal to or less than IN-, the resultant code will be 000h. So it is useful to provide these, too. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Oskar Andero <oskar.andero@gmail.com> Cc: Jonathan Cameron <jic23@kernel.org> Cc: Hartmut Knaack <knaack.h@gmx.de> Cc: Lars-Peter Clausen <lars@metafoo.de> Cc: Peter Meerwald <pmeerw@pmeerw.net> Cc: linux-iio@vger.kernel.org Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-12-01Merge tag 'iio-for-4.5a' of ↵Greg Kroah-Hartman
git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next Jonathan writes: First set of new device support, features and cleanups for IIO in the 4.5 cycle Usual mixed bag, but the big item perhaps in this series is the DMA buffer support added by Lars-Peter Clausen. It's been in the works for a long time and it will be interesting to see what hardware support shows up now that this is available. New core features + associate cleanup. * Add generic DMA buffer infrastructure * Add a DMAengine framework based buffer Also associated minor changes. - Set the device buffer watermark based on the minimum watermark for all attached buffers rather than just the 'primary' one. - iio_buffer_init - only set the watermark default if one hasn't already been provided. This allows simple support for devices with a fixed watermark. - read only attribute for watermark on fixed watermark devices. - add explicit buffer enable/disable callbacks to allow the buffer to do more than trivial actions when it is being turned on and off. * IIO_VAL_INT support in write_raw_get_fmt function. New device support * Freescale MMA7455/7456L accelerometers * Memsic MXC6255XC accelerometer * ST lis2dh12 accelerometer * TI ADS8688 ADC * TI Palamas (twl6035/7) gpadc New driver features * mma8452 - support either of the available interrupt pins to cope with the case where board layout has lead to a particular one being connected. Staging graduation * Dummy driver - this driver acts as both an example and a test device for those with out hardware to develop userspace code against. Cleanups and minor bits and bobs. * treewide - Sort out the ordering of iio_device_register/unregister vs runtime pm function calls so that it's all nice and consistent and not race prone. - Check sscanf return values. None of the cases will actually happen as the strings are supplied internally, but best to be consistent on this. * ad7780 - switch over to the gpio descriptor interface and remove the now unused platform data which gets rid of a header entirely. * ad7793 - drop a pointless else statement. * at91_adc - Swap kmalloc_array in for a kmalloc doing the same job. * dummy - get rid of some commented out lines that snuck in during the move of the driver. * lm3533-als - Print an error message on provision of an invalid resistance. * mcp320x - Add compatible strings with vendor prefix and deprecate those with no vendor prefix. * mxs-lradc - Use BIT macro in various places rather than shifted ones. * pa12203001 - Power off the chip if the registration fails. * pulsedlight-lidar-lite - add runtime PM support. * xilinx XADC - constify an iio_buffer_setup_ops structure.
2015-11-05Merge tag 'spi-v4.4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi Pull spi updates from Mark Brown: "Quite a lot of activity in SPI this cycle, almost all of it in drivers with a few minor improvements and tweaks in the core. - Updates to pxa2xx to support Intel Broxton and multiple chip selects. - Support for big endian in the bcm63xx driver. - Multiple slave support for the mt8173 - New driver for the auxiliary SPI controller in bcm2835 SoCs. - Support for Layerscale SoCs in the Freescale DSPI driver" * tag 'spi-v4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (87 commits) spi: pxa2xx: Rework self-initiated platform data creation for non-ACPI spi: pxa2xx: Add support for Intel Broxton spi: pxa2xx: Detect number of enabled Intel LPSS SPI chip select signals spi: pxa2xx: Add output control for multiple Intel LPSS chip selects spi: pxa2xx: Use LPSS prefix for defines that are Intel LPSS specific spi: Add DSPI support for layerscape family spi: ti-qspi: improve ->remove() callback spi/spi-xilinx: Fix race condition on last word read spi: Drop owner assignment from spi_drivers spi: Add THIS_MODULE to spi_driver in SPI core spi: Setup the master controller driver before setting the chipselect spi: dw: replace magic constant by DW_SPI_DR spi: mediatek: mt8173 spi multiple devices support spi: mediatek: handle controller_data in mtk_spi_setup spi: mediatek: remove mtk_spi_config spi: mediatek: Update document devicetree bindings to support multiple devices spi: fix kernel-doc warnings about missing return desc in spi.c spi: fix kernel-doc warnings about missing return desc in spi.h spi: pxa2xx: Align a few defines spi: pxa2xx: Save other reg_cs_ctrl bits when configuring chip select ...
2015-10-28spi: Drop owner assignment from spi_driversAndrew F. Davis
An spi_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Andrew F. Davis <afd@ti.com> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-10-25iio: adc: mcp320x: Add compatible with vendor prefix to OF tableJavier Martinez Canillas
The driver Device Tree binding now documents compatible strings that have a vendor prefix, so add these to the OF device ID table to match and mark the old ones as deprecated explaining that should not be used anymore. Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Michael Welling <mwelling@ieee.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-08-22iio: adc: mcp320x: Set struct spi_driver .of_match_tableJavier Martinez Canillas
The driver has an OF id table but the .of_match_table is not set so the SPI core can't do an OF style match and the table was unused. Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Michael Welling <mwelling@ieee.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-08-12Merge tag 'iio-for-4.3b-2' of ↵Greg Kroah-Hartman
git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next Jonathan writes: Second set of new device support, features and cleanup for the 4.3 cycle. Take 2 also includes a fix set that was too late for the 4.2 cycle. As we had a lot of tools and docs work in this set, I have broken those out into their own categories in this description. Fixes from the pull request '4th set of IIO fixes for the 4.2 cycle'. * Poll functions for both event chardev and the buffer one were returning negative error codes (via a positive value). * A recent change to lsiio adding some error handling that was wrong and stopped the tool working. * bmg160 was missing some dependencies in Kconfig * berlin2-adc had a misshandled register (wrote a value rather than a bitmap) New device support * TI opt3001 light sensor * TXC PA12 ALS and proximity sensor. * mcp3301 ADC support (in mcp320x driver) * ST lsm303agr accelerometer and magnetometer drivers (plus some st-sensors common support to allow different WHOAMI register addresses, devices with fixed scale and allow interrupt equiped magnetometers). * ADIS16305, ADIS16367, ADIS16445IMUs (in the adis16400 driver) * ADIS16266 gyro (in the adis16260 driver) * ADIS16137 gyro (in the adis16136 driver) New functionality * mmc35240 DT bindings. * Inverse unit conversion macros to aid handing of values written to sysfs attributes. Core cleanup * Forward declaration of struct iio_trigger to avoid a compile warning. Driver cleanup / fixes * mxs-lradc - Clarify which parts are supported. - Fix spelling erorrs. - Missing/extra includes - reorder includes - add datasheet name listings for all usable channels (to allow them to be bound by name from consumer drivers) * acpi-als - add some function prefixes as per general iio style. * bmc150_magn - replace a magic value with the existing define. * vf610 - determine possible sample frequencies taking into account the electrical characteristics (defining a minimum sample time) * dht11 - whitespace - additional docs - avoid mulitple assignments in one line - Use the new funciton ktime_get_resolution_ns to cleanup a nasty trick previously used for timing. * Fix all drivers that consider 0 a valid IRQ for historical reasons. * Export I2C module alias info where previously missing (to allow autoprobing) * Export OF module alias info where previously missing. * mmc35240 - switch some variables into arrays to improve readability. * mlx90614 - define some magic numbers for readability. * bmc150_magn - expand area locked by a mutex to cover all the use of the data->buffer. - use descriptive naming for a mask instead of a magic value. * berin2-adc - pass up an error code rather that a generic error - constify the iio_chan_spec - some other little tidy ups. * stk8312 - fix a dependency on triggered buffers in kconfig - add a check for invalid attribute values - improve error handling by returning error codes where possible and return immediately where relevant - rework macro defs to use GENMASK etc - change some variable types to reduce unnecessary casting - clean up code style - drop a local buffer copy for bulk reads and use the one in data->buffer instead. * adis16400 - the adis16448 gyroscope scale was wrong. * adis16480 - some more wrong scales for various parts. * adis16300 - has an undocumented product id and serial number registers so use them. * iio_simple_dummy - fix some wrong code indentation. * bmc150-accel - use the chip ID to detect the chip present rather than verifying the expected part was there. This was in response to a wrong ACPI entry on the WinBook TW100. * mma8452 - fix _get_hp_filter_index - drop a double include - pass up an error code rather than rewriting it - range check input values to attribute writes - register defs tidy up using GENMASK and reordering them to be easier to follow. - various coding style cleanups - put the Kconfig entry in the write place (alphabetically). Tools related * Tools cleanup - drop an explicity NULL comparison, some unnecessary braces, use the ARRAY_SIZE macro, send error messages to stderr instead of dropping them in the middle of normal output. * Fix tools to allow that scale and offset attributes are optional. * More tools fixes including allowing true 32bit data (previously an overflow prevented more than 31bits) * Drop a stray header guard that ended up in a c file. * Make calc_digits static as it isn't exported or in the header. * Set ci_array pointer to NULL after free as a protection against non safe usage of the tools core code. Also convert a double pointer to a single one as the extra level of indirection was unnecessary. Docs * DocBook introduction by Daniel Baluta. Glad we are beginning to draw together some more introductory docs to suplement the various tools / examples. * Drop bytes_per_datum sysfs attribute docs as it no longer exists. * A whole load of missing / fixing of kernel-doc for the core of IIO. * Document the trigger name sysfs attribute in the ABI docs. * Minor typos in the ABI docs related to power down modes.
2015-07-20iio: adc: mcp320x: Add support for mcp3301Andrea Galbusera
This adds support for Microchip's 13 bit 1 channel AD converter MCP3301 Signed-off-by: Andrea Galbusera <gizero@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-07-19iio: mcp320x: Fix NULL pointer dereferenceManfred Schlaegl
On reading in_voltage_scale of we got an NULL pointer dereference Oops. The reason for this is, that mcp320x_read_raw tries to access chip_info->resolution from struct mcp320x, but chip_info is never set. chip_info was never set since the driver was added, but there was no acute problem, because it was not referenced. The acute problem exists since b12206e917ac34bec41b9ff93d37d8bd53a2b3bc iio: adc: mcp320x. Add support for more ADCs This patch fixes the issue by setting chip_info in mcp320x_probe. Signed-off-by: Manfred Schlaegl <manfred.schlaegl@gmx.at> Reviewed-by: Michael Welling <mwelling@ieee.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-05-07iio: mcp320x: Fix occasional incorrect readingsMichael Welling
Without the cacheline alignment, the readings will occasionally incorrectly return 0. Signed-off-by: Michael Welling <mwelling@ieee.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-10-09iio: adc: mcp320x. Add support for more ADCsSøren Andersen
Signed-off-by: Soeren Andersen <san at rosetechnology.dk> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-08-03iio: adc: mcp320x: Use devm_* APIsSachin Kamat
devm_* APIs are device managed and make code simpler. Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Cc: Oskar Andero <oskar.andero@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-05-22iio: adc: add driver for MCP3204/08 12-bit ADCOskar Andero
This adds support for Microchip's 12 bit AD converters MCP3204 and MCP3208. These chips communicates over SPI and supports single-ended and pseudo-differential configurations. Signed-off-by: Oskar Andero <oskar.andero@gmail.com> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>