| Message ID | 20240304-ad7944-mainline-v5-0-f0a38cea8901@baylibre.com |
|---|---|
| Headers | show |
| Series | iio: adc: ad7944: new driver | expand |
On Mon, 2024-03-04 at 13:48 -0600, David Lechner wrote: > This adds a driver for the Analog Devices Inc. AD7944, AD7985, and > AD7986 ADCs. These are a family of pin-compatible ADCs that can sample > at rates up to 2.5 MSPS. > > The initial driver adds support for sampling at lower rates using the > usual IIO triggered buffer and can handle all 3 possible reference > voltage configurations. > > Signed-off-by: David Lechner <dlechner@baylibre.com> > --- LGTM: Reviewed-by: Nuno Sa <nuno.sa@analog.com> > v5 changes: > - Dropped "nanoseconds" from comments. > - Renamed "t" to "timing_spec" > - Replaced "&spi->dev" with "dev" > - Fixed logic on optional "ref" regulator > - Added comment explaining why "cnv" gpio is required > - Simplified always_turbo assignment > > v4 changes: none > > v3 changes: > - Replaced _sign with _diff in chip info struct to properly handle > pseudo-differential vs. true differential chips. Pseudo-differential chips > now just have a voltage0 channel instead of voltage0-voltage1. > - Fixed not resetting the CNV gpio on error return. > - Simplified check of adi,spi-mode property now that "multi" is no longer a > valid option. > --- > MAINTAINERS | 1 + > drivers/iio/adc/Kconfig | 10 ++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/ad7944.c | 416 > +++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 428 insertions(+) > > diff --git a/MAINTAINERS b/MAINTAINERS > index 35f27504632d..7b1a6f2d0c9c 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -448,6 +448,7 @@ R: David Lechner <dlechner@baylibre.com> > S: Supported > W: https://ez.analog.com/linux-software-drivers > F: Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml > +F: drivers/iio/adc/ad7944.c > > ADAFRUIT MINI I2C GAMEPAD > M: Anshul Dalal <anshulusr@gmail.com> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index 0d9282fa67f5..555ac74889f3 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -264,6 +264,16 @@ config AD7923 > To compile this driver as a module, choose M here: the > module will be called ad7923. > > +config AD7944 > + tristate "Analog Devices AD7944 and similar ADCs driver" > + depends on SPI > + help > + Say yes here to build support for Analog Devices > + AD7944, AD7985, AD7986 ADCs. > + > + To compile this driver as a module, choose M here: the > + module will be called ad7944 > + > config AD7949 > tristate "Analog Devices AD7949 and similar ADCs driver" > depends on SPI > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index b3c434722364..a0d69b452cca 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -28,6 +28,7 @@ obj-$(CONFIG_AD7780) += ad7780.o > obj-$(CONFIG_AD7791) += ad7791.o > obj-$(CONFIG_AD7793) += ad7793.o > obj-$(CONFIG_AD7887) += ad7887.o > +obj-$(CONFIG_AD7944) += ad7944.o > obj-$(CONFIG_AD7949) += ad7949.o > obj-$(CONFIG_AD799X) += ad799x.o > obj-$(CONFIG_AD9467) += ad9467.o > diff --git a/drivers/iio/adc/ad7944.c b/drivers/iio/adc/ad7944.c > new file mode 100644 > index 000000000000..adb007cdd287 > --- /dev/null > +++ b/drivers/iio/adc/ad7944.c > @@ -0,0 +1,416 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Analog Devices AD7944/85/86 PulSAR ADC family driver. > + * > + * Copyright 2024 Analog Devices, Inc. > + * Copyright 2024 BayLibre, SAS > + */ > + > +#include <linux/bitfield.h> > +#include <linux/bitops.h> > +#include <linux/delay.h> > +#include <linux/device.h> > +#include <linux/err.h> > +#include <linux/gpio/consumer.h> > +#include <linux/module.h> > +#include <linux/property.h> > +#include <linux/regulator/consumer.h> > +#include <linux/spi/spi.h> > +#include <linux/string_helpers.h> > + > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > +#include <linux/iio/trigger_consumer.h> > +#include <linux/iio/triggered_buffer.h> > + > +#define AD7944_INTERNAL_REF_MV 4096 > + > +struct ad7944_timing_spec { > + /* Normal mode max conversion time (t_{CONV}). */ > + unsigned int conv_ns; > + /* TURBO mode max conversion time (t_{CONV}). */ > + unsigned int turbo_conv_ns; > +}; > + > +struct ad7944_adc { > + struct spi_device *spi; > + /* Chip-specific timing specifications. */ > + const struct ad7944_timing_spec *timing_spec; > + /* GPIO connected to CNV pin. */ > + struct gpio_desc *cnv; > + /* Optional GPIO to enable turbo mode. */ > + struct gpio_desc *turbo; > + /* Indicates TURBO is hard-wired to be always enabled. */ > + bool always_turbo; > + /* Reference voltage (millivolts). */ > + unsigned int ref_mv; > + > + /* > + * DMA (thus cache coherency maintenance) requires the > + * transfer buffers to live in their own cache lines. > + */ > + struct { > + union { > + u16 u16; > + u32 u32; > + } raw; > + u64 timestamp __aligned(8); > + } sample __aligned(IIO_DMA_MINALIGN); > +}; > + > +static const struct ad7944_timing_spec ad7944_timing_spec = { > + .conv_ns = 420, > + .turbo_conv_ns = 320, > +}; > + > +static const struct ad7944_timing_spec ad7986_timing_spec = { > + .conv_ns = 500, > + .turbo_conv_ns = 400, > +}; > + > +struct ad7944_chip_info { > + const char *name; > + const struct ad7944_timing_spec *timing_spec; > + const struct iio_chan_spec channels[2]; > +}; > + > +/* > + * AD7944_DEFINE_CHIP_INFO - Define a chip info structure for a specific chip > + * @_name: The name of the chip > + * @_ts: The timing specification for the chip > + * @_bits: The number of bits in the conversion result > + * @_diff: Whether the chip is true differential or not > + */ > +#define AD7944_DEFINE_CHIP_INFO(_name, _ts, _bits, _diff) \ > +static const struct ad7944_chip_info _name##_chip_info = { \ > + .name = > #_name, \ > + .timing_spec = &_ts##_timing_spec, \ > + .channels = { \ > + { \ > + .type = IIO_VOLTAGE, \ > + .indexed = 1, \ > + .differential = _diff, \ > + .channel = 0, \ > + .channel2 = _diff ? 1 : 0, \ > + .scan_index = 0, \ > + .scan_type.sign = _diff ? 's' : 'u', \ > + .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), \ > + }, \ > +} > + > +/* pseudo-differential with ground sense */ > +AD7944_DEFINE_CHIP_INFO(ad7944, ad7944, 14, 0); > +AD7944_DEFINE_CHIP_INFO(ad7985, ad7944, 16, 0); > +/* fully differential */ > +AD7944_DEFINE_CHIP_INFO(ad7986, ad7986, 18, 1); > + > +/* > + * ad7944_4wire_mode_conversion - Perform a 4-wire mode conversion and > acquisition > + * @adc: The ADC device structure > + * @chan: The channel specification > + * Return: 0 on success, a negative error code on failure > + * > + * Upon successful return adc->sample.raw will contain the conversion result. > + */ > +static int ad7944_4wire_mode_conversion(struct ad7944_adc *adc, > + const struct iio_chan_spec *chan) > +{ > + unsigned int t_conv_ns = adc->always_turbo ? adc->timing_spec- > >turbo_conv_ns > + : adc->timing_spec- > >conv_ns; > + struct spi_transfer xfers[] = { > + { > + /* > + * NB: can get better performance from some SPI > + * controllers if we use the same bits_per_word > + * in every transfer. > + */ > + .bits_per_word = chan->scan_type.realbits, > + /* > + * CS has to be high for full conversion time to > avoid > + * triggering the busy indication. > + */ > + .cs_off = 1, > + .delay = { > + .value = t_conv_ns, > + .unit = SPI_DELAY_UNIT_NSECS, > + }, > + > + }, > + { > + .rx_buf = &adc->sample.raw, > + .len = BITS_TO_BYTES(chan->scan_type.storagebits), > + .bits_per_word = chan->scan_type.realbits, > + }, > + }; > + int ret; > + > + /* > + * In 4-wire mode, the CNV line is held high for the entire > conversion > + * and acquisition process. > + */ > + gpiod_set_value_cansleep(adc->cnv, 1); > + ret = spi_sync_transfer(adc->spi, xfers, ARRAY_SIZE(xfers)); > + gpiod_set_value_cansleep(adc->cnv, 0); > + > + return ret; > +} > + > +static int ad7944_single_conversion(struct ad7944_adc *adc, > + const struct iio_chan_spec *chan, > + int *val) > +{ > + int ret; > + > + ret = ad7944_4wire_mode_conversion(adc, chan); > + if (ret) > + return ret; > + > + if (chan->scan_type.storagebits > 16) > + *val = adc->sample.raw.u32; > + else > + *val = adc->sample.raw.u16; > + > + if (chan->scan_type.sign == 's') > + *val = sign_extend32(*val, chan->scan_type.realbits - 1); > + > + return IIO_VAL_INT; > +} > + > +static int ad7944_read_raw(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + int *val, int *val2, long info) > +{ > + struct ad7944_adc *adc = iio_priv(indio_dev); > + int ret; > + > + switch (info) { > + case IIO_CHAN_INFO_RAW: > + ret = iio_device_claim_direct_mode(indio_dev); > + if (ret) > + return ret; > + > + ret = ad7944_single_conversion(adc, chan, val); > + iio_device_release_direct_mode(indio_dev); > + return ret; > + > + case IIO_CHAN_INFO_SCALE: > + switch (chan->type) { > + case IIO_VOLTAGE: > + *val = adc->ref_mv; > + > + if (chan->scan_type.sign == 's') > + *val2 = chan->scan_type.realbits - 1; > + else > + *val2 = chan->scan_type.realbits; > + > + return IIO_VAL_FRACTIONAL_LOG2; > + default: > + return -EINVAL; > + } > + > + default: > + return -EINVAL; > + } > +} > + > +static const struct iio_info ad7944_iio_info = { > + .read_raw = &ad7944_read_raw, > +}; > + > +static irqreturn_t ad7944_trigger_handler(int irq, void *p) > +{ > + struct iio_poll_func *pf = p; > + struct iio_dev *indio_dev = pf->indio_dev; > + struct ad7944_adc *adc = iio_priv(indio_dev); > + int ret; > + > + ret = ad7944_4wire_mode_conversion(adc, &indio_dev->channels[0]); > + if (ret) > + goto out; > + > + iio_push_to_buffers_with_timestamp(indio_dev, &adc->sample.raw, > + pf->timestamp); > + > +out: > + iio_trigger_notify_done(indio_dev->trig); > + > + return IRQ_HANDLED; > +} > + > +static const char * const ad7944_power_supplies[] = { > + "avdd", "dvdd", "bvdd", "vio" > +}; > + > +static void ad7944_ref_disable(void *ref) > +{ > + regulator_disable(ref); > +} > + > +static int ad7944_probe(struct spi_device *spi) > +{ > + const struct ad7944_chip_info *chip_info; > + struct device *dev = &spi->dev; > + struct iio_dev *indio_dev; > + struct ad7944_adc *adc; > + bool have_refin = false; > + struct regulator *ref; > + int ret; > + > + /* > + * driver currently only supports the conventional "4-wire" mode and > + * not other special wiring configurations. > + */ > + if (device_property_present(dev, "adi,spi-mode")) > + return dev_err_probe(dev, -EINVAL, > + "adi,spi-mode is not currently > supported\n"); > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(*adc)); > + if (!indio_dev) > + return -ENOMEM; > + > + adc = iio_priv(indio_dev); > + adc->spi = spi; > + > + chip_info = spi_get_device_match_data(spi); > + if (!chip_info) > + return dev_err_probe(dev, -EINVAL, "no chip info\n"); > + > + adc->timing_spec = chip_info->timing_spec; > + > + /* > + * Some chips use unusual word sizes, so check now instead of waiting > + * for the first xfer. > + */ > + if (!spi_is_bpw_supported(spi, chip_info- > >channels[0].scan_type.realbits)) > + return dev_err_probe(dev, -EINVAL, > + "SPI host does not support %d bits per > word\n", > + chip_info->channels[0].scan_type.realbits); > + > + ret = devm_regulator_bulk_get_enable(dev, > + > ARRAY_SIZE(ad7944_power_supplies), > + ad7944_power_supplies); > + if (ret) > + return dev_err_probe(dev, ret, > + "failed to get and enable supplies\n"); > + > + /* > + * Sort out what is being used for the reference voltage. Options > are: > + * - internal reference: neither REF or REFIN is connected > + * - internal reference with external buffer: REF not connected, > REFIN > + * is connected > + * - external reference: REF is connected, REFIN is not connected > + */ > + > + ref = devm_regulator_get_optional(dev, "ref"); > + if (IS_ERR(ref)) { > + if (PTR_ERR(ref) != -ENODEV) > + return dev_err_probe(dev, PTR_ERR(ref), > + "failed to get REF supply\n"); > + > + ref = NULL; > + } > + > + ret = devm_regulator_get_enable_optional(dev, "refin"); > + if (ret == 0) > + have_refin = true; > + else if (ret != -ENODEV) > + return dev_err_probe(dev, ret, > + "failed to get and enable REFIN > supply\n"); > + > + if (have_refin && ref) > + return dev_err_probe(dev, -EINVAL, > + "cannot have both refin and ref > supplies\n"); > + > + if (ref) { > + ret = regulator_enable(ref); > + if (ret) > + return dev_err_probe(dev, ret, > + "failed to enable REF > supply\n"); > + > + ret = devm_add_action_or_reset(dev, ad7944_ref_disable, ref); > + if (ret) > + return ret; > + > + ret = regulator_get_voltage(ref); > + if (ret < 0) > + return dev_err_probe(dev, ret, > + "failed to get REF voltage\n"); > + > + /* external reference */ > + adc->ref_mv = ret / 1000; > + } else { > + /* internal reference */ > + adc->ref_mv = AD7944_INTERNAL_REF_MV; > + } > + > + /* > + * CNV gpio is required in 4-wire mode which is the only currently > + * supported mode. > + */ > + adc->cnv = devm_gpiod_get(dev, "cnv", GPIOD_OUT_LOW); > + if (IS_ERR(adc->cnv)) > + return dev_err_probe(dev, PTR_ERR(adc->cnv), > + "failed to get CNV GPIO\n"); > + > + adc->turbo = devm_gpiod_get_optional(dev, "turbo", GPIOD_OUT_LOW); > + if (IS_ERR(adc->turbo)) > + return dev_err_probe(dev, PTR_ERR(adc->turbo), > + "failed to get TURBO GPIO\n"); > + > + adc->always_turbo = device_property_present(dev, "adi,always-turbo"); > + > + if (adc->turbo && adc->always_turbo) > + return dev_err_probe(dev, -EINVAL, > + "cannot have both turbo-gpios and adi,always- > turbo\n"); > + > + indio_dev->name = chip_info->name; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->info = &ad7944_iio_info; > + indio_dev->channels = chip_info->channels; > + indio_dev->num_channels = ARRAY_SIZE(chip_info->channels); > + > + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, > + iio_pollfunc_store_time, > + ad7944_trigger_handler, NULL); > + if (ret) > + return ret; > + > + return devm_iio_device_register(dev, indio_dev); > +} > + > +static const struct of_device_id ad7944_of_match[] = { > + { .compatible = "adi,ad7944", .data = &ad7944_chip_info }, > + { .compatible = "adi,ad7985", .data = &ad7985_chip_info }, > + { .compatible = "adi,ad7986", .data = &ad7986_chip_info }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, ad7944_of_match); > + > +static const struct spi_device_id ad7944_spi_id[] = { > + { "ad7944", (kernel_ulong_t)&ad7944_chip_info }, > + { "ad7985", (kernel_ulong_t)&ad7985_chip_info }, > + { "ad7986", (kernel_ulong_t)&ad7986_chip_info }, > + { } > + > +}; > +MODULE_DEVICE_TABLE(spi, ad7944_spi_id); > + > +static struct spi_driver ad7944_driver = { > + .driver = { > + .name = "ad7944", > + .of_match_table = ad7944_of_match, > + }, > + .probe = ad7944_probe, > + .id_table = ad7944_spi_id, > +}; > +module_spi_driver(ad7944_driver); > + > +MODULE_AUTHOR("David Lechner <dlechner@baylibre.com>"); > +MODULE_DESCRIPTION("Analog Devices AD7944 PulSAR ADC family driver"); > +MODULE_LICENSE("GPL"); >
On Mon, 4 Mar 2024 13:48:45 -0600 David Lechner <dlechner@baylibre.com> wrote: > 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) > but do have some unusual SPI configurations. The initial driver is only > supporting the normal (4-wire) SPI mode. > > This work is done on behalf of Analog Devices, Inc., hence the > MAINTAINERS are @analog.com folks. Series applied to the togreg-normal branch of iio.git and pushed out for 0-day to get a head start. This is now 6.10 material given timing. I'll be rebasing my tree after rc1 at which point I'll fall back to my normal togreg branch naming. Thanks, Jonathan
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) but do have some unusual SPI configurations. The initial driver is only supporting the normal (4-wire) SPI mode. This work is done on behalf of Analog Devices, Inc., hence the MAINTAINERS are @analog.com folks. --- Changes in v5: - DT bindings: - fixed typo - picked up Rob's reviewed-by - Driver: - Dropped "nanoseconds" from comments. - Renamed "t" to "timing_spec" - Replaced "&spi->dev" with "dev" - Fixed logic on optional "ref" regulator - Added comment explaining why "cnv" gpio is required - Simplified always_turbo assignment - Link to v4: https://lore.kernel.org/r/20240229-ad7944-mainline-v4-0-f88b5ec4baed@baylibre.com Changes in v4: - Fixed broken DT patch due to misplaced changelog - Link to v3: https://lore.kernel.org/r/20240228-ad7944-mainline-v3-0-781b922334af@baylibre.com Changes in v3: - Removed 'multi' value from adi,spi-mode property in DT bindings - Modified driver for above change - Fixed spelling of 'conventional' - Added '#daisy-chained-devices' to DT bindings - Added comments explaining that '3-wire' mode is not related to spi-3wire/SPI_3WIRE - Replaced _sign with _diff in chip info struct to properly handle pseudo-differential vs. true differential chips - Link to v2: https://lore.kernel.org/r/20240216-ad7944-mainline-v2-0-7eb69651e592@baylibre.com 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 | 213 +++++++++++ MAINTAINERS | 9 + drivers/iio/adc/Kconfig | 10 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/ad7944.c | 416 +++++++++++++++++++++ 5 files changed, 649 insertions(+) --- base-commit: 74744b27ba8cb8c265263aa0ff0693350a8cbc19 change-id: 20240206-ad7944-mainline-17c968aa0967