Add support for the AD7766, AD7766-1, AD7766-2, AD7767, AD7767-1, AD7767-2 Analog to Digital converters. It's a family of single channel 24-bit SAR ADCs. They are all digital interface compatible and the main difference is the internal decimation rate and analog performance. For communication with the host processor a SPI interface is used. In addition the part has a data ready pin that is pulsed for one MCLK cycle when a conversion has completed and can be used as a IIO trigger. Datasheets: http://www.analog.com/media/en/technical-documentation/data-sheets/AD7766.pdf http://www.analog.com/media/en/technical-documentation/data-sheets/AD7767.pdf Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx> --- Changes since v2: (Thanks to Jonathan for the review) * More aggressive devm usage * Restrict trigger to this device * select IIO_BUFFER and IIO_TRIGGERED_BYFFER Kconfig symbols Changes since v1: (Thanks to Peter Meerwald-Stadler for the review) * Whitespace cleanup * Introduce symbolic constants for regulator indices * Document in the driver that AD7766 and AD7767 are fully register map compatible and only differ in analog performance --- drivers/iio/adc/Kconfig | 12 ++ drivers/iio/adc/Makefile | 1 + drivers/iio/adc/ad7766.c | 330 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 343 insertions(+) create mode 100644 drivers/iio/adc/ad7766.c diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index 7edcf32..6042668 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -58,6 +58,18 @@ config AD7476 To compile this driver as a module, choose M here: the module will be called ad7476. +config AD7766 + tristate "Analog Devices AD7766/AD7767 ADC driver" + depends on SPI_MASTER + select IIO_BUFFER + select IIO_TRIGGERED_BUFFER + help + Say yes here to build support for Analog Devices AD7766, AD7766-1, + AD7766-2, AD7767, AD7767-1, AD7767-2 SPI analog to digital converters. + + To compile this driver as a module, choose M here: the module will be + called ad7766. + config AD7791 tristate "Analog Devices AD7791 ADC driver" depends on SPI diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index 7a40c04..96894b3 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -9,6 +9,7 @@ obj-$(CONFIG_AD7291) += ad7291.o obj-$(CONFIG_AD7298) += ad7298.o obj-$(CONFIG_AD7923) += ad7923.o obj-$(CONFIG_AD7476) += ad7476.o +obj-$(CONFIG_AD7766) += ad7766.o obj-$(CONFIG_AD7791) += ad7791.o obj-$(CONFIG_AD7793) += ad7793.o obj-$(CONFIG_AD7887) += ad7887.o diff --git a/drivers/iio/adc/ad7766.c b/drivers/iio/adc/ad7766.c new file mode 100644 index 0000000..d906686 --- /dev/null +++ b/drivers/iio/adc/ad7766.c @@ -0,0 +1,330 @@ +/* + * AD7766/AD7767 SPI ADC driver + * + * Copyright 2016 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> + +#include <linux/iio/iio.h> +#include <linux/iio/buffer.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> + +struct ad7766_chip_info { + unsigned int decimation_factor; +}; + +enum { + AD7766_SUPPLY_AVDD = 0, + AD7766_SUPPLY_DVDD = 1, + AD7766_SUPPLY_VREF = 2, + AD7766_NUM_SUPPLIES = 3 +}; + +struct ad7766 { + const struct ad7766_chip_info *chip_info; + struct spi_device *spi; + struct clk *mclk; + struct gpio_desc *pd_gpio; + struct regulator_bulk_data reg[AD7766_NUM_SUPPLIES]; + + struct iio_trigger *trig; + + struct spi_transfer xfer; + struct spi_message msg; + + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + * Make the buffer large enough for one 24 bit sample and one 64 bit + * aligned 64 bit timestamp. + */ + unsigned char data[ALIGN(3, sizeof(s64)) + sizeof(s64)] + ____cacheline_aligned; +}; + +/* + * AD7766 and AD7767 variations are interface compatible, the main difference is + * analog performance. Both parts will use the same ID. + */ +enum ad7766_device_ids { + ID_AD7766, + ID_AD7766_1, + ID_AD7766_2, +}; + +static irqreturn_t ad7766_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct ad7766 *ad7766 = iio_priv(indio_dev); + int ret; + + ret = spi_sync(ad7766->spi, &ad7766->msg); + if (ret < 0) + goto done; + + iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data, + pf->timestamp); +done: + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static int ad7766_preenable(struct iio_dev *indio_dev) +{ + struct ad7766 *ad7766 = iio_priv(indio_dev); + int ret; + + ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg); + if (ret < 0) { + dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n", + ret); + return ret; + } + + ret = clk_prepare_enable(ad7766->mclk); + if (ret < 0) { + dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret); + regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg); + return ret; + } + + if (ad7766->pd_gpio) + gpiod_set_value(ad7766->pd_gpio, 0); + + return 0; +} + +static int ad7766_postdisable(struct iio_dev *indio_dev) +{ + struct ad7766 *ad7766 = iio_priv(indio_dev); + + if (ad7766->pd_gpio) + gpiod_set_value(ad7766->pd_gpio, 1); + + /* + * The PD pin is synchronous to the clock, so give it some time to + * notice the change before we disable the clock. + */ + msleep(20); + + clk_disable_unprepare(ad7766->mclk); + regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg); + + return 0; +} + +static int ad7766_read_raw(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, int *val, int *val2, long info) +{ + struct ad7766 *ad7766 = iio_priv(indio_dev); + struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer; + int scale_uv; + + switch (info) { + case IIO_CHAN_INFO_SCALE: + scale_uv = regulator_get_voltage(vref); + if (scale_uv < 0) + return scale_uv; + *val = scale_uv / 1000; + *val2 = chan->scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; + case IIO_CHAN_INFO_SAMP_FREQ: + *val = clk_get_rate(ad7766->mclk) / + ad7766->chip_info->decimation_factor; + return IIO_VAL_INT; + } + return -EINVAL; +} + +static const struct iio_chan_spec ad7766_channels[] = { + { + .type = IIO_VOLTAGE, + .indexed = 1, + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), + .scan_type = { + .sign = 's', + .realbits = 24, + .storagebits = 32, + .endianness = IIO_BE, + }, + }, + IIO_CHAN_SOFT_TIMESTAMP(1), +}; + +static const struct ad7766_chip_info ad7766_chip_info[] = { + [ID_AD7766] = { + .decimation_factor = 8, + }, + [ID_AD7766_1] = { + .decimation_factor = 16, + }, + [ID_AD7766_2] = { + .decimation_factor = 32, + }, +}; + +static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = { + .preenable = &ad7766_preenable, + .postenable = &iio_triggered_buffer_postenable, + .predisable = &iio_triggered_buffer_predisable, + .postdisable = &ad7766_postdisable, +}; + +static const struct iio_info ad7766_info = { + .driver_module = THIS_MODULE, + .read_raw = &ad7766_read_raw, +}; + +static irqreturn_t ad7766_irq(int irq, void *private) +{ + iio_trigger_poll(private); + return IRQ_HANDLED; +} + +static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable) +{ + struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig); + + if (enable) + enable_irq(ad7766->spi->irq); + else + disable_irq(ad7766->spi->irq); + + return 0; +} + +static const struct iio_trigger_ops ad7766_trigger_ops = { + .owner = THIS_MODULE, + .set_trigger_state = ad7766_set_trigger_state, + .validate_device = iio_trigger_validate_own_device, +}; + +static int ad7766_probe(struct spi_device *spi) +{ + const struct spi_device_id *id = spi_get_device_id(spi); + struct iio_dev *indio_dev; + struct ad7766 *ad7766; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766)); + if (!indio_dev) + return -ENOMEM; + + ad7766 = iio_priv(indio_dev); + ad7766->chip_info = &ad7766_chip_info[id->driver_data]; + + ad7766->mclk = devm_clk_get(&spi->dev, "mclk"); + if (IS_ERR(ad7766->mclk)) + return PTR_ERR(ad7766->mclk); + + ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd"; + ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd"; + ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref"; + + ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg), + ad7766->reg); + if (IS_ERR(ad7766->reg)) + return PTR_ERR(ad7766->reg); + + ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown", + GPIOD_OUT_HIGH); + if (IS_ERR(ad7766->pd_gpio)) + return PTR_ERR(ad7766->pd_gpio); + + indio_dev->dev.parent = &spi->dev; + indio_dev->name = spi_get_device_id(spi)->name; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = ad7766_channels; + indio_dev->num_channels = ARRAY_SIZE(ad7766_channels); + indio_dev->info = &ad7766_info; + + if (spi->irq > 0) { + ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d", + indio_dev->name, indio_dev->id); + if (!ad7766->trig) + return -ENOMEM; + + ad7766->trig->ops = &ad7766_trigger_ops; + ad7766->trig->dev.parent = &spi->dev; + iio_trigger_set_drvdata(ad7766->trig, ad7766); + + ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq, + IRQF_TRIGGER_FALLING, dev_name(&spi->dev), + ad7766->trig); + if (ret < 0) + return ret; + + /* + * The device generates interrupts as long as it is powered up. + * Some platforms might not allow the option to power it down so + * disable the interrupt to avoid extra load on the system + */ + disable_irq(spi->irq); + + ret = devm_iio_trigger_register(&spi->dev, ad7766->trig); + if (ret) + return ret; + } + + spi_set_drvdata(spi, indio_dev); + + ad7766->spi = spi; + + /* First byte always 0 */ + ad7766->xfer.rx_buf = &ad7766->data[1]; + ad7766->xfer.len = 3; + + spi_message_init(&ad7766->msg); + spi_message_add_tail(&ad7766->xfer, &ad7766->msg); + + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, + &iio_pollfunc_store_time, &ad7766_trigger_handler, + &ad7766_buffer_setup_ops); + if (ret) + return ret; + + ret = devm_iio_device_register(&spi->dev, indio_dev); + if (ret) + return ret; + return 0; +} + +static const struct spi_device_id ad7766_id[] = { + {"ad7766", ID_AD7766}, + {"ad7766-1", ID_AD7766_1}, + {"ad7766-2", ID_AD7766_2}, + {"ad7767", ID_AD7766}, + {"ad7767-1", ID_AD7766_1}, + {"ad7767-2", ID_AD7766_2}, + {} +}; +MODULE_DEVICE_TABLE(spi, ad7766_id); + +static struct spi_driver ad7766_driver = { + .driver = { + .name = "ad7766", + }, + .probe = ad7766_probe, + .id_table = ad7766_id, +}; +module_spi_driver(ad7766_driver); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@xxxxxxxxxx>"); +MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support"); +MODULE_LICENSE("GPL v2"); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
