diff options
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | drivers/iio/adc/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/iio/adc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/iio/adc/ad7944.c | 416 |
4 files changed, 428 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 6c14216ddb75..eefd1a8906bf 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 91286ab83bd0..8db68b80b391 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -281,6 +281,16 @@ 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 717e964afed9..edb32ce2af02 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -29,6 +29,7 @@ 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"); |