On Thu, 31 Jan 2019 18:20:51 +0200 Stefan Popa <stefan.p...@analog.com> wrote:
> The ad7768-1 is a single channel, precision 24-bit analog to digital > converter (ADC). > > This basic patch configures the device in fast mode, with 32 kSPS and > leaves the default sinc5 filter. > > Two data conversion modes are made available. When data is retrieved by > using the read_raw attribute, one shot single conversion mode is set. > The continuous conversion mode is enabled when the triggered buffer > mechanism is used. To assure correct data retrieval, the driver waits > for the interrupt triggered by the low to high transition of the DRDY > pin. > > Datasheets: > Link: > https://www.analog.com/media/en/technical-documentation/data-sheets/ad7768-1.pdf > > Signed-off-by: Stefan Popa <stefan.p...@analog.com> Applied to the togreg branch of iio.git and pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > --- > Changes in v2: > - Added values to all the elements of ad7768_pwrmode enum. > - Removed the ad7768_ids enum, as the driver supports only one device. > - Added a new data union which is part of the ad7768_state struct. This > union, now includes a d8 field. > - Used spi_write_then_read() in ad7768_spi_reg_read(). > - Called spi_read() instead of spi_sync_transfer() in > ad7768_trigger_handler(). > - Used the devm_request_irq() instead of devm_request_threaded_irq(); > called > iio_trigger_poll() instead of iio_trigger_poll_chained(). > Changes in v3: > - Changed module license from GPL to GPL v2 > > MAINTAINERS | 7 + > drivers/iio/adc/Kconfig | 13 ++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/ad7768-1.c | 459 > +++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 480 insertions(+) > create mode 100644 drivers/iio/adc/ad7768-1.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index d039f66..3ba3811 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -862,6 +862,13 @@ S: Supported > F: drivers/iio/adc/ad7606.c > F: Documentation/devicetree/bindings/iio/adc/ad7606.txt > > +ANALOG DEVICES INC AD7768-1 DRIVER > +M: Stefan Popa <stefan.p...@analog.com> > +L: linux-...@vger.kernel.org > +W: http://ez.analog.com/community/linux-device-drivers > +S: Supported > +F: drivers/iio/adc/ad7768-1.c > + > ANALOG DEVICES INC AD9389B DRIVER > M: Hans Verkuil <hans.verk...@cisco.com> > L: linux-me...@vger.kernel.org > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index f3cc7a3..6c19dfe 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -108,6 +108,19 @@ config AD7766 > To compile this driver as a module, choose M here: the module will be > called ad7766. > > +config AD7768_1 > + tristate "Analog Devices AD7768-1 ADC driver" > + depends on SPI > + select IIO_BUFFER > + select IIO_TRIGGER > + select IIO_TRIGGERED_BUFFER > + help > + Say yes here to build support for Analog Devices AD7768-1 SPI > + simultaneously sampling sigma-delta analog to digital converter (ADC). > + > + To compile this driver as a module, choose M here: the module will be > + called ad7768-1. > + > config AD7791 > tristate "Analog Devices AD7791 ADC driver" > depends on SPI > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index ea50313..9d50f7b 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -15,6 +15,7 @@ obj-$(CONFIG_AD7606_IFACE_PARALLEL) += ad7606_par.o > obj-$(CONFIG_AD7606_IFACE_SPI) += ad7606_spi.o > obj-$(CONFIG_AD7606) += ad7606.o > obj-$(CONFIG_AD7766) += ad7766.o > +obj-$(CONFIG_AD7768_1) += ad7768-1.o > obj-$(CONFIG_AD7791) += ad7791.o > obj-$(CONFIG_AD7793) += ad7793.o > obj-$(CONFIG_AD7887) += ad7887.o > diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c > new file mode 100644 > index 0000000..78449e9 > --- /dev/null > +++ b/drivers/iio/adc/ad7768-1.c > @@ -0,0 +1,459 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Analog Devices AD7768-1 SPI ADC driver > + * > + * Copyright 2017 Analog Devices Inc. > + */ > +#include <linux/bitfield.h> > +#include <linux/clk.h> > +#include <linux/delay.h> > +#include <linux/device.h> > +#include <linux/err.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/regulator/consumer.h> > +#include <linux/sysfs.h> > +#include <linux/spi/spi.h> > + > +#include <linux/iio/buffer.h> > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > +#include <linux/iio/trigger.h> > +#include <linux/iio/triggered_buffer.h> > +#include <linux/iio/trigger_consumer.h> > + > +/* AD7768 registers definition */ > +#define AD7768_REG_CHIP_TYPE 0x3 > +#define AD7768_REG_PROD_ID_L 0x4 > +#define AD7768_REG_PROD_ID_H 0x5 > +#define AD7768_REG_CHIP_GRADE 0x6 > +#define AD7768_REG_SCRATCH_PAD 0x0A > +#define AD7768_REG_VENDOR_L 0x0C > +#define AD7768_REG_VENDOR_H 0x0D > +#define AD7768_REG_INTERFACE_FORMAT 0x14 > +#define AD7768_REG_POWER_CLOCK 0x15 > +#define AD7768_REG_ANALOG 0x16 > +#define AD7768_REG_ANALOG2 0x17 > +#define AD7768_REG_CONVERSION 0x18 > +#define AD7768_REG_DIGITAL_FILTER 0x19 > +#define AD7768_REG_SINC3_DEC_RATE_MSB 0x1A > +#define AD7768_REG_SINC3_DEC_RATE_LSB 0x1B > +#define AD7768_REG_DUTY_CYCLE_RATIO 0x1C > +#define AD7768_REG_SYNC_RESET 0x1D > +#define AD7768_REG_GPIO_CONTROL 0x1E > +#define AD7768_REG_GPIO_WRITE 0x1F > +#define AD7768_REG_GPIO_READ 0x20 > +#define AD7768_REG_OFFSET_HI 0x21 > +#define AD7768_REG_OFFSET_MID 0x22 > +#define AD7768_REG_OFFSET_LO 0x23 > +#define AD7768_REG_GAIN_HI 0x24 > +#define AD7768_REG_GAIN_MID 0x25 > +#define AD7768_REG_GAIN_LO 0x26 > +#define AD7768_REG_SPI_DIAG_ENABLE 0x28 > +#define AD7768_REG_ADC_DIAG_ENABLE 0x29 > +#define AD7768_REG_DIG_DIAG_ENABLE 0x2A > +#define AD7768_REG_ADC_DATA 0x2C > +#define AD7768_REG_MASTER_STATUS 0x2D > +#define AD7768_REG_SPI_DIAG_STATUS 0x2E > +#define AD7768_REG_ADC_DIAG_STATUS 0x2F > +#define AD7768_REG_DIG_DIAG_STATUS 0x30 > +#define AD7768_REG_MCLK_COUNTER 0x31 > + > +/* AD7768_REG_CONVERSION */ > +#define AD7768_CONV_MODE_MSK GENMASK(2, 0) > +#define AD7768_CONV_MODE(x) FIELD_PREP(AD7768_CONV_MODE_MSK, x) > + > +#define AD7768_RD_FLAG_MSK(x) (BIT(6) | ((x) & 0x3F)) > +#define AD7768_WR_FLAG_MSK(x) ((x) & 0x3F) > + > +enum ad7768_conv_mode { > + AD7768_CONTINUOUS, > + AD7768_ONE_SHOT, > + AD7768_SINGLE, > + AD7768_PERIODIC, > + AD7768_STANDBY > +}; > + > +enum ad7768_pwrmode { > + AD7768_ECO_MODE = 0, > + AD7768_MED_MODE = 2, > + AD7768_FAST_MODE = 3 > +}; > + > +static const struct iio_chan_spec ad7768_channels[] = { > + { > + .type = IIO_VOLTAGE, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), > + .indexed = 1, > + .channel = 0, > + .scan_index = 0, > + .scan_type = { > + .sign = 'u', > + .realbits = 24, > + .storagebits = 32, > + .shift = 8, > + .endianness = IIO_BE, > + }, > + }, > +}; > + > +struct ad7768_state { > + struct spi_device *spi; > + struct regulator *vref; > + struct mutex lock; > + struct completion completion; > + struct iio_trigger *trig; > + /* > + * DMA (thus cache coherency maintenance) requires the > + * transfer buffers to live in their own cache lines. > + */ > + union { > + __be32 d32; > + u8 d8[2]; > + } data ____cacheline_aligned; > +}; > + > +static int ad7768_spi_reg_read(struct ad7768_state *st, unsigned int addr, > + unsigned int len) > +{ > + unsigned int shift; > + int ret; > + > + shift = 32 - (8 * len); > + st->data.d8[0] = AD7768_RD_FLAG_MSK(addr); > + > + ret = spi_write_then_read(st->spi, st->data.d8, 1, > + &st->data.d32, len); > + if (ret < 0) > + return ret; > + > + return (be32_to_cpu(st->data.d32) >> shift); > +} > + > +static int ad7768_spi_reg_write(struct ad7768_state *st, > + unsigned int addr, > + unsigned int val) > +{ > + st->data.d8[0] = AD7768_WR_FLAG_MSK(addr); > + st->data.d8[1] = val & 0xFF; > + > + return spi_write(st->spi, st->data.d8, 2); > +} > + > +static int ad7768_set_mode(struct ad7768_state *st, > + enum ad7768_conv_mode mode) > +{ > + int regval; > + > + regval = ad7768_spi_reg_read(st, AD7768_REG_CONVERSION, 1); > + if (regval < 0) > + return regval; > + > + regval &= ~AD7768_CONV_MODE_MSK; > + regval |= AD7768_CONV_MODE(mode); > + > + return ad7768_spi_reg_write(st, AD7768_REG_CONVERSION, regval); > +} > + > +static int ad7768_scan_direct(struct iio_dev *indio_dev) > +{ > + struct ad7768_state *st = iio_priv(indio_dev); > + int readval, ret; > + > + reinit_completion(&st->completion); > + > + ret = ad7768_set_mode(st, AD7768_ONE_SHOT); > + if (ret < 0) > + return ret; > + > + ret = wait_for_completion_timeout(&st->completion, > + msecs_to_jiffies(1000)); > + if (!ret) > + return -ETIMEDOUT; > + > + readval = ad7768_spi_reg_read(st, AD7768_REG_ADC_DATA, 3); > + if (readval < 0) > + return readval; > + /* > + * Any SPI configuration of the AD7768-1 can only be > + * performed in continuous conversion mode. > + */ > + ret = ad7768_set_mode(st, AD7768_CONTINUOUS); > + if (ret < 0) > + return ret; > + > + return readval; > +} > + > +static int ad7768_reg_access(struct iio_dev *indio_dev, > + unsigned int reg, > + unsigned int writeval, > + unsigned int *readval) > +{ > + struct ad7768_state *st = iio_priv(indio_dev); > + int ret; > + > + mutex_lock(&st->lock); > + if (readval) { > + ret = ad7768_spi_reg_read(st, reg, 1); > + if (ret < 0) > + goto err_unlock; > + *readval = ret; > + ret = 0; > + } else { > + ret = ad7768_spi_reg_write(st, reg, writeval); > + } > +err_unlock: > + mutex_unlock(&st->lock); > + > + return ret; > +} > + > +static int ad7768_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long info) > +{ > + struct ad7768_state *st = iio_priv(indio_dev); > + int scale_uv, ret; > + > + switch (info) { > + case IIO_CHAN_INFO_RAW: > + ret = iio_device_claim_direct_mode(indio_dev); > + if (ret) > + return ret; > + > + ret = ad7768_scan_direct(indio_dev); > + if (ret >= 0) > + *val = ret; > + > + iio_device_release_direct_mode(indio_dev); > + if (ret < 0) > + return ret; > + > + return IIO_VAL_INT; > + > + case IIO_CHAN_INFO_SCALE: > + scale_uv = regulator_get_voltage(st->vref); > + if (scale_uv < 0) > + return scale_uv; > + > + *val = (scale_uv * 2) / 1000; > + *val2 = chan->scan_type.realbits; > + > + return IIO_VAL_FRACTIONAL_LOG2; > + } > + > + return -EINVAL; > +} > + > +static const struct iio_info ad7768_info = { > + .read_raw = &ad7768_read_raw, > + .debugfs_reg_access = &ad7768_reg_access, > +}; > + > +static int ad7768_setup(struct ad7768_state *st) > +{ > + int ret; > + > + /* > + * Two writes to the SPI_RESET[1:0] bits are required to initiate > + * a software reset. The bits must first be set to 11, and then > + * to 10. When the sequence is detected, the reset occurs. > + * See the datasheet, page 70. > + */ > + ret = ad7768_spi_reg_write(st, AD7768_REG_SYNC_RESET, 0x3); > + if (ret) > + return ret; > + > + ret = ad7768_spi_reg_write(st, AD7768_REG_SYNC_RESET, 0x2); > + if (ret) > + return ret; > + > + /* Set power mode to fast */ > + return ad7768_spi_reg_write(st, AD7768_REG_POWER_CLOCK, > + AD7768_FAST_MODE); > +} > + > +static irqreturn_t ad7768_trigger_handler(int irq, void *p) > +{ > + struct iio_poll_func *pf = p; > + struct iio_dev *indio_dev = pf->indio_dev; > + struct ad7768_state *st = iio_priv(indio_dev); > + int ret; > + > + mutex_lock(&st->lock); > + > + ret = spi_read(st->spi, &st->data.d32, 3); > + if (ret < 0) > + goto err_unlock; > + > + iio_push_to_buffers_with_timestamp(indio_dev, &st->data.d32, > + iio_get_time_ns(indio_dev)); > + > + iio_trigger_notify_done(indio_dev->trig); > +err_unlock: > + mutex_unlock(&st->lock); > + > + return IRQ_HANDLED; > +} > + > +static irqreturn_t ad7768_interrupt(int irq, void *dev_id) > +{ > + struct iio_dev *indio_dev = dev_id; > + struct ad7768_state *st = iio_priv(indio_dev); > + > + if (iio_buffer_enabled(indio_dev)) > + iio_trigger_poll(st->trig); > + else > + complete(&st->completion); > + > + return IRQ_HANDLED; > +}; > + > +static int ad7768_buffer_postenable(struct iio_dev *indio_dev) > +{ > + struct ad7768_state *st = iio_priv(indio_dev); > + > + iio_triggered_buffer_postenable(indio_dev); > + /* > + * Write a 1 to the LSB of the INTERFACE_FORMAT register to enter > + * continuous read mode. Subsequent data reads do not require an > + * initial 8-bit write to query the ADC_DATA register. > + */ > + return ad7768_spi_reg_write(st, AD7768_REG_INTERFACE_FORMAT, 0x01); > +} > + > +static int ad7768_buffer_predisable(struct iio_dev *indio_dev) > +{ > + struct ad7768_state *st = iio_priv(indio_dev); > + int ret; > + > + /* > + * To exit continuous read mode, perform a single read of the ADC_DATA > + * reg (0x2C), which allows further configuration of the device. > + */ > + ret = ad7768_spi_reg_read(st, AD7768_REG_ADC_DATA, 3); > + if (ret < 0) > + return ret; > + > + return iio_triggered_buffer_predisable(indio_dev); > +} > + > +static const struct iio_buffer_setup_ops ad7768_buffer_ops = { > + .postenable = &ad7768_buffer_postenable, > + .predisable = &ad7768_buffer_predisable, > +}; > + > +static const struct iio_trigger_ops ad7768_trigger_ops = { > + .validate_device = iio_trigger_validate_own_device, > +}; > + > +static void ad7768_regulator_disable(void *data) > +{ > + struct ad7768_state *st = data; > + > + regulator_disable(st->vref); > +} > + > +static int ad7768_probe(struct spi_device *spi) > +{ > + struct ad7768_state *st; > + struct iio_dev *indio_dev; > + int ret; > + > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); > + if (!indio_dev) > + return -ENOMEM; > + > + st = iio_priv(indio_dev); > + st->spi = spi; > + > + st->vref = devm_regulator_get(&spi->dev, "vref"); > + if (IS_ERR(st->vref)) > + return PTR_ERR(st->vref); > + > + ret = regulator_enable(st->vref); > + if (ret) { > + dev_err(&spi->dev, "Failed to enable specified vref supply\n"); > + return ret; > + } > + > + ret = devm_add_action_or_reset(&spi->dev, ad7768_regulator_disable, st); > + if (ret) > + return ret; > + > + spi_set_drvdata(spi, indio_dev); > + mutex_init(&st->lock); > + > + indio_dev->channels = ad7768_channels; > + indio_dev->num_channels = ARRAY_SIZE(ad7768_channels); > + indio_dev->dev.parent = &spi->dev; > + indio_dev->name = spi_get_device_id(spi)->name; > + indio_dev->info = &ad7768_info; > + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED; > + > + ret = ad7768_setup(st); > + if (ret < 0) { > + dev_err(&spi->dev, "AD7768 setup failed\n"); > + return ret; > + } > + > + st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d", > + indio_dev->name, indio_dev->id); > + if (!st->trig) > + return -ENOMEM; > + > + st->trig->ops = &ad7768_trigger_ops; > + st->trig->dev.parent = &spi->dev; > + iio_trigger_set_drvdata(st->trig, indio_dev); > + ret = devm_iio_trigger_register(&spi->dev, st->trig); > + if (ret) > + return ret; > + > + indio_dev->trig = iio_trigger_get(st->trig); > + > + init_completion(&st->completion); > + > + ret = devm_request_irq(&spi->dev, spi->irq, > + &ad7768_interrupt, > + IRQF_TRIGGER_RISING | IRQF_ONESHOT, > + indio_dev->name, indio_dev); > + if (ret) > + return ret; > + > + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, > + &iio_pollfunc_store_time, > + &ad7768_trigger_handler, > + &ad7768_buffer_ops); > + if (ret) > + return ret; > + > + return devm_iio_device_register(&spi->dev, indio_dev); > +} > + > +static const struct spi_device_id ad7768_id_table[] = { > + { "ad7768-1", 0 }, > + {} > +}; > +MODULE_DEVICE_TABLE(spi, ad7768_id_table); > + > +static const struct of_device_id ad7768_of_match[] = { > + { .compatible = "adi,ad7768-1" }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, ad7768_of_match); > + > +static struct spi_driver ad7768_driver = { > + .driver = { > + .name = "ad7768-1", > + .of_match_table = ad7768_of_match, > + }, > + .probe = ad7768_probe, > + .id_table = ad7768_id_table, > +}; > +module_spi_driver(ad7768_driver); > + > +MODULE_AUTHOR("Stefan Popa <stefan.p...@analog.com>"); > +MODULE_DESCRIPTION("Analog Devices AD7768-1 ADC driver"); > +MODULE_LICENSE("GPL v2");
