Re: [PATCH v2 1/2] iio: adc: Add AD7768-1 ADC basic support

[Popa, Stefan Serban]

On Sb, 2019-01-19 at 17:55 +0000, Jonathan Cameron wrote:
> Use caution when clicking links or attachments as this email originated
> outside of Analog Devices.
> 
> 
> On Tue, 15 Jan 2019 14:33:11 +0200
> Stefan Popa <stefan.popa@xxxxxxxxxx> 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-shee
> > ts/ad7768-1.pdf
> > 
> > Signed-off-by: Stefan Popa <stefan.popa@xxxxxxxxxx>
> Hi Stefan,
> 
> Driver is fine, but the licensing needs clarification.
> "GPL" in module license means GPL v2 or later, but the SPDX is GPL v2
> only.
> 
> I had a question out to Michael for some of his older drivers on
> exactly this.ÂÂWe need to fix this one and tidy those up to
> be clear one way or the other.
> If you just let me know which one is right, I'll fix it up rather than
> you having
> to send a v3.
> 
> Thanks,
> 
> Jonathan
> 
Hi Jonathan,

Thank you for your review. Michael informed me that our drivers are
typically GPL v2 only.

I will check the other drivers that we've sent upstream and provide a patch
to fix the wrong licenses.Â

-Stefan

> > 
> > ---
> > Changes in v2:
> > ÂÂÂÂÂÂ- Added values to all the elements of ad7768_pwrmode enum.
> > ÂÂÂÂÂÂ- Removed the ad7768_ids enum, as the driver supports only one
> > device.
> > ÂÂÂÂÂÂ- Added a new data union which is part of the ad7768_state
> > struct. This
> > ÂÂÂÂÂÂÂÂunion, now includes a d8 field.
> > ÂÂÂÂÂÂ- Used spi_write_then_read() in ad7768_spi_reg_read().
> > ÂÂÂÂÂÂ- Called spi_read() instead of spi_sync_transfer() in
> > ad7768_trigger_handler().
> > ÂÂÂÂÂÂ- Used the devm_request_irq() instead of
> > devm_request_threaded_irq(); called
> > ÂÂÂÂÂÂÂÂiio_trigger_poll() instead of iio_trigger_poll_chained().
> > 
> > ÂMAINTAINERSÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ|ÂÂÂ7 +
> > Âdrivers/iio/adc/KconfigÂÂÂÂ|ÂÂ13 ++
> > Âdrivers/iio/adc/MakefileÂÂÂ|ÂÂÂ1 +
> > Âdrivers/iio/adc/ad7768-1.c | 459
> > +++++++++++++++++++++++++++++++++++++++++++++
> > Â4 files changed, 480 insertions(+)
> > Âcreate 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:ÂÂÂÂÂÂÂSupported
> > ÂF:ÂÂÂdrivers/iio/adc/ad7606.c
> > ÂF:ÂÂÂDocumentation/devicetree/bindings/iio/adc/ad7606.txt
> > 
> > +ANALOG DEVICES INC AD7768-1 DRIVER
> > +M:ÂÂÂStefan Popa <stefan.popa@xxxxxxxxxx>
> > +L:ÂÂÂlinux-iio@xxxxxxxxxxxxxxx
> > +W:ÂÂÂhttp://ez.analog.com/community/linux-device-drivers
> > +S:ÂÂÂSupported
> > +F:ÂÂÂdrivers/iio/adc/ad7768-1.c
> > +
> > ÂANALOG DEVICES INC AD9389B DRIVER
> > ÂM:ÂÂÂHans Verkuil <hans.verkuil@xxxxxxxxx>
> > ÂL:ÂÂÂlinux-media@xxxxxxxxxxxxxxx
> > 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
> > ÂÂÂÂÂÂÂÂTo compile this driver as a module, choose M here: the module
> > will be
> > ÂÂÂÂÂÂÂÂcalled ad7766.
> > 
> > +config AD7768_1
> > +ÂÂÂÂÂtristate "Analog Devices AD7768-1 ADC driver"
> > +ÂÂÂÂÂdepends on SPI
> > +ÂÂÂÂÂselect IIO_BUFFER
> > +ÂÂÂÂÂselect IIO_TRIGGER
> > +ÂÂÂÂÂselect IIO_TRIGGERED_BUFFER
> > +ÂÂÂÂÂhelp
> > +ÂÂÂÂÂÂÂSay yes here to build support for Analog Devices AD7768-1 SPI
> > +ÂÂÂÂÂÂÂsimultaneously sampling sigma-delta analog to digital converter
> > (ADC).
> > +
> > +ÂÂÂÂÂÂÂTo compile this driver as a module, choose M here: the module
> > will be
> > +ÂÂÂÂÂÂÂcalled ad7768-1.
> > +
> > Âconfig AD7791
> > ÂÂÂÂÂÂtristate "Analog Devices AD7791 ADC driver"
> > ÂÂÂÂÂÂdepends 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-$(CONFIG_AD7606_IFACE_PARALLEL) += ad7606_par.o
> > Âobj-$(CONFIG_AD7606_IFACE_SPI) += ad7606_spi.o
> > Âobj-$(CONFIG_AD7606) += ad7606.o
> > Âobj-$(CONFIG_AD7766) += ad7766.o
> > +obj-$(CONFIG_AD7768_1) += ad7768-1.o
> > Âobj-$(CONFIG_AD7791) += ad7791.o
> > Âobj-$(CONFIG_AD7793) += ad7793.o
> > Âobj-$(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..fdcb966
> > --- /dev/null
> > +++ b/drivers/iio/adc/ad7768-1.c
> > @@ -0,0 +1,459 @@
> > +// SPDX-License-Identifier: GPL-2.0
> This is GPl v2 only.ÂÂThe MODULE_LICENSE is GPL v2 or later.
> 
> > 
> > +/*
> > + * 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_TYPEÂÂÂÂÂÂÂÂÂ0x3
> > +#define AD7768_REG_PROD_ID_LÂÂÂÂÂÂÂÂÂ0x4
> > +#define AD7768_REG_PROD_ID_HÂÂÂÂÂÂÂÂÂ0x5
> > +#define AD7768_REG_CHIP_GRADEÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x6
> > +#define AD7768_REG_SCRATCH_PADÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x0A
> > +#define AD7768_REG_VENDOR_LÂÂÂÂÂÂÂÂÂÂ0x0C
> > +#define AD7768_REG_VENDOR_HÂÂÂÂÂÂÂÂÂÂ0x0D
> > +#define AD7768_REG_INTERFACE_FORMATÂÂ0x14
> > +#define AD7768_REG_POWER_CLOCKÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x15
> > +#define AD7768_REG_ANALOGÂÂÂÂÂÂÂÂÂÂÂÂ0x16
> > +#define AD7768_REG_ANALOG2ÂÂÂÂÂÂÂÂÂÂÂ0x17
> > +#define AD7768_REG_CONVERSIONÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x18
> > +#define AD7768_REG_DIGITAL_FILTERÂÂÂÂ0x19
> > +#define AD7768_REG_SINC3_DEC_RATE_MSBÂÂÂÂÂÂÂÂ0x1A
> > +#define AD7768_REG_SINC3_DEC_RATE_LSBÂÂÂÂÂÂÂÂ0x1B
> > +#define AD7768_REG_DUTY_CYCLE_RATIOÂÂ0x1C
> > +#define AD7768_REG_SYNC_RESETÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x1D
> > +#define AD7768_REG_GPIO_CONTROLÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x1E
> > +#define AD7768_REG_GPIO_WRITEÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x1F
> > +#define AD7768_REG_GPIO_READÂÂÂÂÂÂÂÂÂ0x20
> > +#define AD7768_REG_OFFSET_HIÂÂÂÂÂÂÂÂÂ0x21
> > +#define AD7768_REG_OFFSET_MIDÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x22
> > +#define AD7768_REG_OFFSET_LOÂÂÂÂÂÂÂÂÂ0x23
> > +#define AD7768_REG_GAIN_HIÂÂÂÂÂÂÂÂÂÂÂ0x24
> > +#define AD7768_REG_GAIN_MIDÂÂÂÂÂÂÂÂÂÂ0x25
> > +#define AD7768_REG_GAIN_LOÂÂÂÂÂÂÂÂÂÂÂ0x26
> > +#define AD7768_REG_SPI_DIAG_ENABLEÂÂÂ0x28
> > +#define AD7768_REG_ADC_DIAG_ENABLEÂÂÂ0x29
> > +#define AD7768_REG_DIG_DIAG_ENABLEÂÂÂ0x2A
> > +#define AD7768_REG_ADC_DATAÂÂÂÂÂÂÂÂÂÂ0x2C
> > +#define AD7768_REG_MASTER_STATUSÂÂÂÂÂ0x2D
> > +#define AD7768_REG_SPI_DIAG_STATUSÂÂÂ0x2E
> > +#define AD7768_REG_ADC_DIAG_STATUSÂÂÂ0x2F
> > +#define AD7768_REG_DIG_DIAG_STATUSÂÂÂ0x30
> > +#define AD7768_REG_MCLK_COUNTERÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x31
> > +
> > +/* AD7768_REG_CONVERSION */
> > +#define AD7768_CONV_MODE_MSKÂÂÂÂÂÂÂÂÂGENMASK(2, 0)
> > +#define AD7768_CONV_MODE(x)ÂÂÂÂÂÂÂÂÂÂFIELD_PREP(AD7768_CONV_MODE_MSK,
> > x)
> > +
> > +#define AD7768_RD_FLAG_MSK(x)ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ(BIT(6) | ((x) & 0x3F))
> > +#define AD7768_WR_FLAG_MSK(x)ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ((x) & 0x3F)
> > +
> > +enum ad7768_conv_mode {
> > +ÂÂÂÂÂAD7768_CONTINUOUS,
> > +ÂÂÂÂÂAD7768_ONE_SHOT,
> > +ÂÂÂÂÂAD7768_SINGLE,
> > +ÂÂÂÂÂAD7768_PERIODIC,
> > +ÂÂÂÂÂAD7768_STANDBY
> > +};
> > +
> > +enum ad7768_pwrmode {
> > +ÂÂÂÂÂAD7768_ECO_MODE = 0,
> > +ÂÂÂÂÂAD7768_MED_MODE = 2,
> > +ÂÂÂÂÂAD7768_FAST_MODE = 3
> > +};
> > +
> > +static const struct iio_chan_spec ad7768_channels[] = {
> > +ÂÂÂÂÂ{
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.type = IIO_VOLTAGE,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.indexed = 1,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.channel = 0,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.scan_index = 0,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.scan_type = {
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ.sign = 'u',
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ.realbits = 24,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ.storagebits = 32,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ.shift = 8,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ.endianness = IIO_BE,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ},
> > +ÂÂÂÂÂ},
> > +};
> > +
> > +struct ad7768_state {
> > +ÂÂÂÂÂstruct spi_device *spi;
> > +ÂÂÂÂÂstruct regulator *vref;
> > +ÂÂÂÂÂstruct mutex lock;
> > +ÂÂÂÂÂstruct completion completion;
> > +ÂÂÂÂÂstruct iio_trigger *trig;
> > +ÂÂÂÂÂ/*
> > +ÂÂÂÂÂÂ* DMA (thus cache coherency maintenance) requires the
> > +ÂÂÂÂÂÂ* transfer buffers to live in their own cache lines.
> > +ÂÂÂÂÂÂ*/
> > +ÂÂÂÂÂunion {
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ__be32 d32;
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂu8 d8[2];
> > +ÂÂÂÂÂ} data ____cacheline_aligned;
> > +};
> > +
> > +static int ad7768_spi_reg_read(struct ad7768_state *st, unsigned int
> > addr,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂunsigned int len)
> > +{
> > +ÂÂÂÂÂunsigned int shift;
> > +ÂÂÂÂÂint ret;
> > +
> > +ÂÂÂÂÂshift = 32 - (8 * len);
> > +ÂÂÂÂÂst->data.d8[0] = AD7768_RD_FLAG_MSK(addr);
> > +
> > +ÂÂÂÂÂret = spi_write_then_read(st->spi, st->data.d8, 1,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ&st->data.d32, len);
> > +ÂÂÂÂÂif (ret < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂreturn (be32_to_cpu(st->data.d32) >> shift);
> > +}
> > +
> > +static int ad7768_spi_reg_write(struct ad7768_state *st,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂunsigned int addr,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂunsigned int val)
> > +{
> > +ÂÂÂÂÂst->data.d8[0] = AD7768_WR_FLAG_MSK(addr);
> > +ÂÂÂÂÂst->data.d8[1] = val & 0xFF;
> > +
> > +ÂÂÂÂÂreturn spi_write(st->spi, st->data.d8, 2);
> > +}
> > +
> > +static int ad7768_set_mode(struct ad7768_state *st,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂenum ad7768_conv_mode mode)
> > +{
> > +ÂÂÂÂÂint regval;
> > +
> > +ÂÂÂÂÂregval = ad7768_spi_reg_read(st, AD7768_REG_CONVERSION, 1);
> > +ÂÂÂÂÂif (regval < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn regval;
> > +
> > +ÂÂÂÂÂregval &= ~AD7768_CONV_MODE_MSK;
> > +ÂÂÂÂÂregval |= AD7768_CONV_MODE(mode);
> > +
> > +ÂÂÂÂÂreturn ad7768_spi_reg_write(st, AD7768_REG_CONVERSION, regval);
> > +}
> > +
> > +static int ad7768_scan_direct(struct iio_dev *indio_dev)
> > +{
> > +ÂÂÂÂÂstruct ad7768_state *st = iio_priv(indio_dev);
> > +ÂÂÂÂÂint readval, ret;
> > +
> > +ÂÂÂÂÂreinit_completion(&st->completion);
> > +
> > +ÂÂÂÂÂret = ad7768_set_mode(st, AD7768_ONE_SHOT);
> > +ÂÂÂÂÂif (ret < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂret = wait_for_completion_timeout(&st->completion,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂmsecs_to_jiffies(1000));
> > +ÂÂÂÂÂif (!ret)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn -ETIMEDOUT;
> > +
> > +ÂÂÂÂÂreadval = ad7768_spi_reg_read(st, AD7768_REG_ADC_DATA, 3);
> > +ÂÂÂÂÂif (readval < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn readval;
> > +ÂÂÂÂÂ/*
> > +ÂÂÂÂÂÂ* Any SPI configuration of the AD7768-1 can only be
> > +ÂÂÂÂÂÂ* performed in continuous conversion mode.
> > +ÂÂÂÂÂÂ*/
> > +ÂÂÂÂÂret = ad7768_set_mode(st, AD7768_CONTINUOUS);
> > +ÂÂÂÂÂif (ret < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂreturn readval;
> > +}
> > +
> > +static int ad7768_reg_access(struct iio_dev *indio_dev,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂunsigned int reg,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂunsigned int writeval,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂunsigned int *readval)
> > +{
> > +ÂÂÂÂÂstruct ad7768_state *st = iio_priv(indio_dev);
> > +ÂÂÂÂÂint ret;
> > +
> > +ÂÂÂÂÂmutex_lock(&st->lock);
> > +ÂÂÂÂÂif (readval) {
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂret = ad7768_spi_reg_read(st, reg, 1);
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂif (ret < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂgoto err_unlock;
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ*readval = ret;
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂret = 0;
> > +ÂÂÂÂÂ} else {
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂret = ad7768_spi_reg_write(st, reg, writeval);
> > +ÂÂÂÂÂ}
> > +err_unlock:
> > +ÂÂÂÂÂmutex_unlock(&st->lock);
> > +
> > +ÂÂÂÂÂreturn ret;
> > +}
> > +
> > +static int ad7768_read_raw(struct iio_dev *indio_dev,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂstruct iio_chan_spec const *chan,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂint *val, int *val2, long info)
> > +{
> > +ÂÂÂÂÂstruct ad7768_state *st = iio_priv(indio_dev);
> > +ÂÂÂÂÂint scale_uv, ret;
> > +
> > +ÂÂÂÂÂswitch (info) {
> > +ÂÂÂÂÂcase IIO_CHAN_INFO_RAW:
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂret = iio_device_claim_direct_mode(indio_dev);
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂif (ret)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂret = ad7768_scan_direct(indio_dev);
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂif (ret >= 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ*val = ret;
> > +
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂiio_device_release_direct_mode(indio_dev);
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂif (ret < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn IIO_VAL_INT;
> > +
> > +ÂÂÂÂÂcase IIO_CHAN_INFO_SCALE:
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂscale_uv = regulator_get_voltage(st->vref);
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂif (scale_uv < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂreturn scale_uv;
> > +
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ*val = (scale_uv * 2) / 1000;
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ*val2 = chan->scan_type.realbits;
> > +
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn IIO_VAL_FRACTIONAL_LOG2;
> > +ÂÂÂÂÂ}
> > +
> > +ÂÂÂÂÂreturn -EINVAL;
> > +}
> > +
> > +static const struct iio_info ad7768_info = {
> > +ÂÂÂÂÂ.read_raw = &ad7768_read_raw,
> > +ÂÂÂÂÂ.debugfs_reg_access = &ad7768_reg_access,
> > +};
> > +
> > +static int ad7768_setup(struct ad7768_state *st)
> > +{
> > +ÂÂÂÂÂint ret;
> > +
> > +ÂÂÂÂÂ/*
> > +ÂÂÂÂÂÂ* Two writes to the SPI_RESET[1:0] bits are required to initiate
> > +ÂÂÂÂÂÂ* a software reset. The bits must first be set to 11, and then
> > +ÂÂÂÂÂÂ* to 10. When the sequence is detected, the reset occurs.
> > +ÂÂÂÂÂÂ* See the datasheet, page 70.
> > +ÂÂÂÂÂÂ*/
> > +ÂÂÂÂÂret = ad7768_spi_reg_write(st, AD7768_REG_SYNC_RESET, 0x3);
> > +ÂÂÂÂÂif (ret)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂret = ad7768_spi_reg_write(st, AD7768_REG_SYNC_RESET, 0x2);
> > +ÂÂÂÂÂif (ret)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂ/* Set power mode to fast */
> > +ÂÂÂÂÂreturn ad7768_spi_reg_write(st, AD7768_REG_POWER_CLOCK,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂAD7768_FAST_MODE);
> > +}
> > +
> > +static irqreturn_t ad7768_trigger_handler(int irq, void *p)
> > +{
> > +ÂÂÂÂÂstruct iio_poll_func *pf = p;
> > +ÂÂÂÂÂstruct iio_dev *indio_dev = pf->indio_dev;
> > +ÂÂÂÂÂstruct ad7768_state *st = iio_priv(indio_dev);
> > +ÂÂÂÂÂint ret;
> > +
> > +ÂÂÂÂÂmutex_lock(&st->lock);
> > +
> > +ÂÂÂÂÂret = spi_read(st->spi, &st->data.d32, 3);
> > +ÂÂÂÂÂif (ret < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂgoto err_unlock;
> > +
> > +ÂÂÂÂÂiio_push_to_buffers_with_timestamp(indio_dev, &st->data.d32,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂiio_get_time_ns(indio_dev));
> > +
> > +ÂÂÂÂÂiio_trigger_notify_done(indio_dev->trig);
> > +err_unlock:
> > +ÂÂÂÂÂmutex_unlock(&st->lock);
> > +
> > +ÂÂÂÂÂreturn IRQ_HANDLED;
> > +}
> > +
> > +static irqreturn_t ad7768_interrupt(int irq, void *dev_id)
> > +{
> > +ÂÂÂÂÂstruct iio_dev *indio_dev = dev_id;
> > +ÂÂÂÂÂstruct ad7768_state *st = iio_priv(indio_dev);
> > +
> > +ÂÂÂÂÂif (iio_buffer_enabled(indio_dev))
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂiio_trigger_poll(st->trig);
> > +ÂÂÂÂÂelse
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂcomplete(&st->completion);
> > +
> > +ÂÂÂÂÂreturn IRQ_HANDLED;
> > +};
> > +
> > +static int ad7768_buffer_postenable(struct iio_dev *indio_dev)
> > +{
> > +ÂÂÂÂÂstruct ad7768_state *st = iio_priv(indio_dev);
> > +
> > +ÂÂÂÂÂiio_triggered_buffer_postenable(indio_dev);
> > +ÂÂÂÂÂ/*
> > +ÂÂÂÂÂÂ* Write a 1 to the LSB of the INTERFACE_FORMAT register to enter
> > +ÂÂÂÂÂÂ* continuous read mode. Subsequent data reads do not require an
> > +ÂÂÂÂÂÂ* initial 8-bit write to query the ADC_DATA register.
> > +ÂÂÂÂÂÂ*/
> > +ÂÂÂÂÂreturn ad7768_spi_reg_write(st, AD7768_REG_INTERFACE_FORMAT,
> > 0x01);
> > +}
> > +
> > +static int ad7768_buffer_predisable(struct iio_dev *indio_dev)
> > +{
> > +ÂÂÂÂÂstruct ad7768_state *st = iio_priv(indio_dev);
> > +ÂÂÂÂÂint ret;
> > +
> > +ÂÂÂÂÂ/*
> > +ÂÂÂÂÂÂ* To exit continuous read mode, perform a single read of the
> > ADC_DATA
> > +ÂÂÂÂÂÂ* reg (0x2C), which allows further configuration of the device.
> > +ÂÂÂÂÂÂ*/
> > +ÂÂÂÂÂret = ad7768_spi_reg_read(st, AD7768_REG_ADC_DATA, 3);
> > +ÂÂÂÂÂif (ret < 0)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂreturn iio_triggered_buffer_predisable(indio_dev);
> > +}
> > +
> > +static const struct iio_buffer_setup_ops ad7768_buffer_ops = {
> > +ÂÂÂÂÂ.postenable = &ad7768_buffer_postenable,
> > +ÂÂÂÂÂ.predisable = &ad7768_buffer_predisable,
> > +};
> > +
> > +static const struct iio_trigger_ops ad7768_trigger_ops = {
> > +ÂÂÂÂÂ.validate_device = iio_trigger_validate_own_device,
> > +};
> > +
> > +static void ad7768_regulator_disable(void *data)
> > +{
> > +ÂÂÂÂÂstruct ad7768_state *st = data;
> > +
> > +ÂÂÂÂÂregulator_disable(st->vref);
> > +}
> > +
> > +static int ad7768_probe(struct spi_device *spi)
> > +{
> > +ÂÂÂÂÂstruct ad7768_state *st;
> > +ÂÂÂÂÂstruct iio_dev *indio_dev;
> > +ÂÂÂÂÂint ret;
> > +
> > +ÂÂÂÂÂindio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> > +ÂÂÂÂÂif (!indio_dev)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn -ENOMEM;
> > +
> > +ÂÂÂÂÂst = iio_priv(indio_dev);
> > +ÂÂÂÂÂst->spi = spi;
> > +
> > +ÂÂÂÂÂst->vref = devm_regulator_get(&spi->dev, "vref");
> > +ÂÂÂÂÂif (IS_ERR(st->vref))
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn PTR_ERR(st->vref);
> > +
> > +ÂÂÂÂÂret = regulator_enable(st->vref);
> > +ÂÂÂÂÂif (ret) {
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂdev_err(&spi->dev, "Failed to enable specified vref
> > supply\n");
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +ÂÂÂÂÂ}
> > +
> > +ÂÂÂÂÂret = devm_add_action_or_reset(&spi->dev,
> > ad7768_regulator_disable, st);
> > +ÂÂÂÂÂif (ret)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂspi_set_drvdata(spi, indio_dev);
> > +ÂÂÂÂÂmutex_init(&st->lock);
> > +
> > +ÂÂÂÂÂindio_dev->channels = ad7768_channels;
> > +ÂÂÂÂÂindio_dev->num_channels = ARRAY_SIZE(ad7768_channels);
> > +ÂÂÂÂÂindio_dev->dev.parent = &spi->dev;
> > +ÂÂÂÂÂindio_dev->name = spi_get_device_id(spi)->name;
> > +ÂÂÂÂÂindio_dev->info = &ad7768_info;
> > +ÂÂÂÂÂindio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
> > +
> > +ÂÂÂÂÂret = ad7768_setup(st);
> > +ÂÂÂÂÂif (ret < 0) {
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂdev_err(&spi->dev, "AD7768 setup failed\n");
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +ÂÂÂÂÂ}
> > +
> > +ÂÂÂÂÂst->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂindio_dev->name, indio_dev-
> > >id);
> > +ÂÂÂÂÂif (!st->trig)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn -ENOMEM;
> > +
> > +ÂÂÂÂÂst->trig->ops = &ad7768_trigger_ops;
> > +ÂÂÂÂÂst->trig->dev.parent = &spi->dev;
> > +ÂÂÂÂÂiio_trigger_set_drvdata(st->trig, indio_dev);
> > +ÂÂÂÂÂret = devm_iio_trigger_register(&spi->dev, st->trig);
> > +ÂÂÂÂÂif (ret)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂindio_dev->trig = iio_trigger_get(st->trig);
> > +
> > +ÂÂÂÂÂinit_completion(&st->completion);
> > +
> > +ÂÂÂÂÂret = devm_request_irq(&spi->dev, spi->irq,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ&ad7768_interrupt,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂIRQF_TRIGGER_RISING | IRQF_ONESHOT,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂindio_dev->name, indio_dev);
> > +ÂÂÂÂÂif (ret)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ&iio_pollfunc_store_time,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ&ad7768_trigger_handler,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ&ad7768_buffer_ops);
> > +ÂÂÂÂÂif (ret)
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂreturn ret;
> > +
> > +ÂÂÂÂÂreturn devm_iio_device_register(&spi->dev, indio_dev);
> > +}
> > +
> > +static const struct spi_device_id ad7768_id_table[] = {
> > +ÂÂÂÂÂ{ "ad7768-1", 0 },
> > +ÂÂÂÂÂ{}
> > +};
> > +MODULE_DEVICE_TABLE(spi, ad7768_id_table);
> > +
> > +static const struct of_device_id ad7768_of_match[] = {
> > +ÂÂÂÂÂ{ .compatible = "adi,ad7768-1" },
> > +ÂÂÂÂÂ{ },
> > +};
> > +MODULE_DEVICE_TABLE(of, ad7768_of_match);
> > +
> > +static struct spi_driver ad7768_driver = {
> > +ÂÂÂÂÂ.driver = {
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.name = "ad7768-1",
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ.of_match_table = ad7768_of_match,
> > +ÂÂÂÂÂ},
> > +ÂÂÂÂÂ.probe = ad7768_probe,
> > +ÂÂÂÂÂ.id_table = ad7768_id_table,
> > +};
> > +module_spi_driver(ad7768_driver);
> > +
> > +MODULE_AUTHOR("Stefan Popa <stefan.popa@xxxxxxxxxx>");
> > +MODULE_DESCRIPTION("Analog Devices AD7768-1 ADC driver");
> > +MODULE_LICENSE("GPL");
> Mixed license. This is GPL v2 or later according to module.h.
>