| Message ID | 20240216-ad7944-mainline-v2-0-7eb69651e592@baylibre.com |
|---|---|
| Headers | show |
| Series | iio: adc: ad7944: new driver | expand |
On Fri, Feb 16, 2024 at 1:47 PM David Lechner <dlechner@baylibre.com> wrote: ... > + > +#define AD7944_DEFINE_CHIP_INFO(_name, _t, _bits, _sign) \ > +static const struct ad7944_chip_info _name##_chip_info = { \ > + .name = #_name, \ > + .t = &_t##_timing_spec, \ > + .channels = { \ > + { \ > + .type = IIO_VOLTAGE, \ > + .indexed = 1, \ > + .differential = 1, \ > + .channel = 0, \ > + .channel2 = 1, \ > + .scan_index = 0, \ > + .scan_type.sign = _sign, \ > + .scan_type.realbits = _bits, \ > + .scan_type.storagebits = _bits > 16 ? 32 : 16, \ > + .scan_type.endianness = IIO_CPU, \ > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \ > + | BIT(IIO_CHAN_INFO_SCALE), \ > + }, \ > + IIO_CHAN_SOFT_TIMESTAMP(1), \ > + }, \ > +} > + > +AD7944_DEFINE_CHIP_INFO(ad7944, ad7944, 14, 'u'); > +AD7944_DEFINE_CHIP_INFO(ad7985, ad7944, 16, 'u'); > +AD7944_DEFINE_CHIP_INFO(ad7986, ad7986, 18, 's'); Now that I have been enlightened [1] about pseudo-differntial inputs, I'm thinking that AD7944 and AD7985 should not have the .differential = 1 flag set since they are pseudo-differential inputs with a ground sense on the negative input (and no extra supply needed since it is always ground). Does that sound right? AD7986 is true differential though, so should be correct already. [1]: https://lore.kernel.org/linux-iio/CAMknhBF5mAsN1c-194Qwa5oKmqKzef2khXnqA1cSdKpWHKWp0w@mail.gmail.com/
On Mon, 19 Feb 2024 13:13:35 -0600 David Lechner <dlechner@baylibre.com> wrote: > On Fri, Feb 16, 2024 at 1:47 PM David Lechner <dlechner@baylibre.com> wrote: > > ... > > > + > > +#define AD7944_DEFINE_CHIP_INFO(_name, _t, _bits, _sign) \ > > +static const struct ad7944_chip_info _name##_chip_info = { \ > > + .name = #_name, \ > > + .t = &_t##_timing_spec, \ > > + .channels = { \ > > + { \ > > + .type = IIO_VOLTAGE, \ > > + .indexed = 1, \ > > + .differential = 1, \ > > + .channel = 0, \ > > + .channel2 = 1, \ > > + .scan_index = 0, \ > > + .scan_type.sign = _sign, \ > > + .scan_type.realbits = _bits, \ > > + .scan_type.storagebits = _bits > 16 ? 32 : 16, \ > > + .scan_type.endianness = IIO_CPU, \ > > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \ > > + | BIT(IIO_CHAN_INFO_SCALE), \ > > + }, \ > > + IIO_CHAN_SOFT_TIMESTAMP(1), \ > > + }, \ > > +} > > + > > +AD7944_DEFINE_CHIP_INFO(ad7944, ad7944, 14, 'u'); > > +AD7944_DEFINE_CHIP_INFO(ad7985, ad7944, 16, 'u'); > > +AD7944_DEFINE_CHIP_INFO(ad7986, ad7986, 18, 's'); > > Now that I have been enlightened [1] about pseudo-differntial inputs, > I'm thinking that AD7944 and AD7985 should not have the .differential > = 1 flag set since they are pseudo-differential inputs with a ground > sense on the negative input (and no extra supply needed since it is > always ground). Does that sound right? yes > > AD7986 is true differential though, so should be correct already. > > [1]: https://lore.kernel.org/linux-iio/CAMknhBF5mAsN1c-194Qwa5oKmqKzef2khXnqA1cSdKpWHKWp0w@mail.gmail.com/
This is a new driver for the Analog Devices AD7944/AD7985/AD7986 family of ADCs. These are fairly simple chips (e.g. no configuration registers). The initial driver is only supporting the 'multi' (4-wire) SPI mode. We plan to follow up with support for the 'single' (3-wire) SPI mode. This work is done on behalf of Analog Devices, Inc., hence the MAINTAINERS are @analog.com folks. --- Changes in v2: - Added limit to spi-max-frequency for chain mode in DT bindings - Added spi-cpol property to DT bindings - Renamed '3-wire' mode to 'single' mode (to avoid confusion with spi-3wire) - Renamed '4-wire' mode to 'multi' mode - Dropped adi,reference property - now using only ref-supply and refin-supply to determine the reference voltage source - Fixed spelling of TURBO - Renamed t_cnv to t_conv to match datasheet name and fixed comment - Fixed wrong timestamp pushed to buffer - Fixed scaling for chips with signed data - Make use of sysfs_match_string() function - Link to v1: https://lore.kernel.org/r/20240206-ad7944-mainline-v1-0-bf115fa9474f@baylibre.com --- David Lechner (2): dt-bindings: iio: adc: add ad7944 ADCs iio: adc: ad7944: add driver for AD7944/AD7985/AD7986 .../devicetree/bindings/iio/adc/adi,ad7944.yaml | 204 ++++++++++ MAINTAINERS | 9 + drivers/iio/adc/Kconfig | 10 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/ad7944.c | 427 +++++++++++++++++++++ 5 files changed, 651 insertions(+) --- base-commit: bd2f1ed8873d4bbb2798151bbe28c86565251cfb change-id: 20240206-ad7944-mainline-17c968aa0967