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References: <20220628070553.3933748-1-cosmin.tanislav@analog.com> <20220628070553.3933748-3-cosmin.tanislav@analog.com>
In-Reply-To: <20220628070553.3933748-3-cosmin.tanislav@analog.com>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Tue, 28 Jun 2022 14:32:39 +0200
Message-ID: <CAHp75VdZd3+GFhSotUDSpycPXSGVk5vQXbik-ngJEJFiFe-UhQ@mail.gmail.com>
Subject: Re: [PATCH v6 2/2] iio: adc: ad4130: add AD4130 driver
To:     Cosmin Tanislav <demonsingur@gmail.com>
Cc:     Jonathan Cameron <jic23@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Cosmin Tanislav <cosmin.tanislav@analog.com>
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Precedence: bulk

On Tue, Jun 28, 2022 at 9:08 AM Cosmin Tanislav <demonsingur@gmail.com> wrote:
>
> AD4130-8 is an ultra-low power, high precision, measurement solution for
> low bandwidth battery operated applications.
>
> The fully integrated AFE (Analog Front-End) includes a multiplexer for up
> to 16 single-ended or 8 differential inputs, PGA (Programmable Gain
> Amplifier), 24-bit Sigma-Delta ADC, on-chip reference and oscillator,
> selectable filter options, smart sequencer, sensor biasing and excitation
> options, diagnostics, and a FIFO buffer.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

I think it's in a good enough shape, but the version of the ABI should
be bumped to 5.20. I think Jonathan may tweak it when applying if
neither requires to resend, otherwise, please update in next version.

> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
> ---
>  .../ABI/testing/sysfs-bus-iio-adc-ad4130      |   36 +
>  MAINTAINERS                                   |    8 +
>  drivers/iio/adc/Kconfig                       |   13 +
>  drivers/iio/adc/Makefile                      |    1 +
>  drivers/iio/adc/ad4130.c                      | 2014 +++++++++++++++++
>  5 files changed, 2072 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130
>  create mode 100644 drivers/iio/adc/ad4130.c
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130 b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130
> new file mode 100644
> index 000000000000..90aa50cecfd1
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130
> @@ -0,0 +1,36 @@
> +What:          /sys/bus/iio/devices/iio:deviceX/in_voltage-voltage_filter_mode_available
> +KernelVersion: 5.19
> +Contact:       linux-iio@vger.kernel.org
> +Description:
> +               Reading returns a list with the possible filter modes.
> +               "sinc4"       - Sinc 4. Excellent noise performance. Long 1st
> +                               conversion time. No natural 50/60Hz rejection.
> +               "sinc4+sinc1" - Sinc4 + averaging by 8. Low 1st conversion time.
> +               "sinc3"       - Sinc3. Moderate 1st conversion time. Good noise
> +                               performance.
> +               "sinc3+rej60" - Sinc3 + 60Hz rejection. At a sampling frequency
> +                               of 50Hz, achieves simultaneous 50Hz and 60Hz
> +                               rejection.
> +               "sinc3+sinc1" - Sinc3 + averaging by 8. Low 1st conversion time.
> +                               Best used with a sampling frequency of at least
> +                               216.19Hz.
> +               "sinc3+pf1"   - Sinc3 + Post Filter 1.
> +                               53dB rejection @ 50Hz, 58dB rejection @ 60Hz.
> +               "sinc3+pf2"   - Sinc3 + Post Filter 2.
> +                               70dB rejection @ 50Hz, 70dB rejection @ 60Hz.
> +               "sinc3+pf3"   - Sinc3 + Post Filter 3.
> +                               99dB rejection @ 50Hz, 103dB rejection @ 60Hz.
> +               "sinc3+pf4"   - Sinc3 + Post Filter 4.
> +                               103dB rejection @ 50Hz, 109dB rejection @ 60Hz.
> +
> +What:          /sys/bus/iio/devices/iio:deviceX/in_voltageY-voltageZ_filter_mode
> +KernelVersion: 5.19
> +Contact:       linux-iio@vger.kernel.org
> +Description:
> +               Set the filter mode of the differential channel. When the filter
> +               mode changes, the in_voltageY-voltageZ_sampling_frequency and
> +               in_voltageY-voltageZ_sampling_frequency_available attributes
> +               might also change to accommodate the new filter mode.
> +               If the current sampling frequency is out of range for the new
> +               filter mode, the sampling frequency will be changed to the
> +               closest valid one.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a6d3bd9d2a8d..2981968260be 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1074,6 +1074,14 @@ T:       git git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git
>  T:     git git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
>  F:     drivers/net/amt.c
>
> +ANALOG DEVICES INC AD4130 DRIVER
> +M:     Cosmin Tanislav <cosmin.tanislav@analog.com>
> +L:     linux-iio@vger.kernel.org
> +S:     Supported
> +W:     http://ez.analog.com/community/linux-device-drivers
> +F:     Documentation/devicetree/bindings/iio/adc/adi,ad4130.yaml
> +F:     drivers/iio/adc/ad4130.c
> +
>  ANALOG DEVICES INC AD7192 DRIVER
>  M:     Alexandru Tachici <alexandru.tachici@analog.com>
>  L:     linux-iio@vger.kernel.org
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 7fe5930891e0..52387925e41f 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -21,6 +21,19 @@ config AD_SIGMA_DELTA
>         select IIO_BUFFER
>         select IIO_TRIGGERED_BUFFER
>
> +config AD4130
> +       tristate "Analog Device AD4130 ADC Driver"
> +       depends on SPI
> +       select IIO_BUFFER
> +       select IIO_KFIFO_BUF
> +       select REGMAP_SPI
> +       help
> +         Say yes here to build support for Analog Devices AD4130-8 SPI analog
> +         to digital converters (ADC).
> +
> +         To compile this driver as a module, choose M here: the module will be
> +         called ad4130.
> +
>  config AD7091R5
>         tristate "Analog Devices AD7091R5 ADC Driver"
>         depends on I2C
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 1772a549a3c8..9d8619753b39 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -6,6 +6,7 @@
>  # When adding new entries keep the list in alphabetical order
>  obj-$(CONFIG_AB8500_GPADC) += ab8500-gpadc.o
>  obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
> +obj-$(CONFIG_AD4130) += ad4130.o
>  obj-$(CONFIG_AD7091R5) += ad7091r5.o ad7091r-base.o
>  obj-$(CONFIG_AD7124) += ad7124.o
>  obj-$(CONFIG_AD7192) += ad7192.o
> diff --git a/drivers/iio/adc/ad4130.c b/drivers/iio/adc/ad4130.c
> new file mode 100644
> index 000000000000..b907f8b8eec8
> --- /dev/null
> +++ b/drivers/iio/adc/ad4130.c
> @@ -0,0 +1,2014 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2022 Analog Devices, Inc.
> + * Author: Cosmin Tanislav <cosmin.tanislav@analog.com>
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +#include <linux/units.h>
> +
> +#include <asm/div64.h>
> +#include <asm/unaligned.h>
> +
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/kfifo_buf.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define AD4130_NAME                            "ad4130"
> +
> +#define AD4130_COMMS_READ_MASK                 BIT(6)
> +
> +#define AD4130_STATUS_REG                      0x00
> +#define AD4130_STATUS_POR_FLAG_MASK            BIT(4)
> +
> +#define AD4130_ADC_CONTROL_REG                 0x01
> +#define AD4130_ADC_CONTROL_BIPOLAR_MASK                BIT(14)
> +#define AD4130_ADC_CONTROL_INT_REF_VAL_MASK    BIT(13)
> +#define AD4130_INT_REF_2_5V                    2500000
> +#define AD4130_INT_REF_1_25V                   1250000
> +#define AD4130_ADC_CONTROL_CSB_EN_MASK         BIT(9)
> +#define AD4130_ADC_CONTROL_INT_REF_EN_MASK     BIT(8)
> +#define AD4130_ADC_CONTROL_MODE_MASK           GENMASK(5, 2)
> +#define AD4130_ADC_CONTROL_MCLK_SEL_MASK       GENMASK(1, 0)
> +#define AD4130_MCLK_FREQ_76_8KHZ               76800
> +#define AD4130_MCLK_FREQ_153_6KHZ              153600
> +
> +#define AD4130_DATA_REG                                0x02
> +
> +#define AD4130_IO_CONTROL_REG                  0x03
> +#define AD4130_IO_CONTROL_INT_PIN_SEL_MASK     GENMASK(9, 8)
> +#define AD4130_IO_CONTROL_GPIO_DATA_MASK       GENMASK(7, 4)
> +#define AD4130_IO_CONTROL_GPIO_CTRL_MASK       GENMASK(3, 0)
> +
> +#define AD4130_VBIAS_REG                       0x04
> +
> +#define AD4130_ID_REG                          0x05
> +
> +#define AD4130_ERROR_REG                       0x06
> +
> +#define AD4130_ERROR_EN_REG                    0x07
> +
> +#define AD4130_MCLK_COUNT_REG                  0x08
> +
> +#define AD4130_CHANNEL_X_REG(x)                        (0x09 + (x))
> +#define AD4130_CHANNEL_EN_MASK                 BIT(23)
> +#define AD4130_CHANNEL_SETUP_MASK              GENMASK(22, 20)
> +#define AD4130_CHANNEL_AINP_MASK               GENMASK(17, 13)
> +#define AD4130_CHANNEL_AINM_MASK               GENMASK(12, 8)
> +#define AD4130_CHANNEL_IOUT1_MASK              GENMASK(7, 4)
> +#define AD4130_CHANNEL_IOUT2_MASK              GENMASK(3, 0)
> +
> +#define AD4130_CONFIG_X_REG(x)                 (0x19 + (x))
> +#define AD4130_CONFIG_IOUT1_VAL_MASK           GENMASK(15, 13)
> +#define AD4130_CONFIG_IOUT2_VAL_MASK           GENMASK(12, 10)
> +#define AD4130_CONFIG_BURNOUT_MASK             GENMASK(9, 8)
> +#define AD4130_CONFIG_REF_BUFP_MASK            BIT(7)
> +#define AD4130_CONFIG_REF_BUFM_MASK            BIT(6)
> +#define AD4130_CONFIG_REF_SEL_MASK             GENMASK(5, 4)
> +#define AD4130_CONFIG_PGA_MASK                 GENMASK(3, 1)
> +
> +#define AD4130_FILTER_X_REG(x)                 (0x21 + (x))
> +#define AD4130_FILTER_MODE_MASK                        GENMASK(15, 12)
> +#define AD4130_FILTER_SELECT_MASK              GENMASK(10, 0)
> +#define AD4130_FILTER_SELECT_MIN               1
> +
> +#define AD4130_OFFSET_X_REG(x)                 (0x29 + (x))
> +
> +#define AD4130_GAIN_X_REG(x)                   (0x31 + (x))
> +
> +#define AD4130_MISC_REG                                0x39
> +
> +#define AD4130_FIFO_CONTROL_REG                        0x3a
> +#define AD4130_FIFO_CONTROL_HEADER_MASK                BIT(18)
> +#define AD4130_FIFO_CONTROL_MODE_MASK          GENMASK(17, 16)
> +#define AD4130_FIFO_CONTROL_WM_INT_EN_MASK     BIT(9)
> +#define AD4130_FIFO_CONTROL_WM_MASK            GENMASK(7, 0)
> +#define AD4130_WATERMARK_256                   0
> +
> +#define AD4130_FIFO_STATUS_REG                 0x3b
> +
> +#define AD4130_FIFO_THRESHOLD_REG              0x3c
> +
> +#define AD4130_FIFO_DATA_REG                   0x3d
> +#define AD4130_FIFO_SIZE                       256
> +#define AD4130_FIFO_MAX_SAMPLE_SIZE            3
> +
> +#define AD4130_MAX_ANALOG_PINS                 16
> +#define AD4130_MAX_CHANNELS                    16
> +#define AD4130_MAX_DIFF_INPUTS                 30
> +#define AD4130_MAX_GPIOS                       4
> +#define AD4130_MAX_ODR                         2400
> +#define AD4130_MAX_PGA                         8
> +#define AD4130_MAX_SETUPS                      8
> +
> +#define AD4130_AIN2_P1                         0x2
> +#define AD4130_AIN3_P2                         0x3
> +
> +#define AD4130_RESET_BUF_SIZE                  8
> +#define AD4130_RESET_SLEEP_US                  (160 * MICRO / AD4130_MCLK_FREQ_76_8KHZ)
> +
> +#define AD4130_INVALID_SLOT                    -1
> +
> +static const unsigned int ad4130_reg_size[] = {
> +       [AD4130_STATUS_REG] = 1,
> +       [AD4130_ADC_CONTROL_REG] = 2,
> +       [AD4130_DATA_REG] = 3,
> +       [AD4130_IO_CONTROL_REG] = 2,
> +       [AD4130_VBIAS_REG] = 2,
> +       [AD4130_ID_REG] = 1,
> +       [AD4130_ERROR_REG] = 2,
> +       [AD4130_ERROR_EN_REG] = 2,
> +       [AD4130_MCLK_COUNT_REG] = 1,
> +       [AD4130_CHANNEL_X_REG(0) ... AD4130_CHANNEL_X_REG(AD4130_MAX_CHANNELS)] = 3,
> +       [AD4130_CONFIG_X_REG(0) ... AD4130_CONFIG_X_REG(AD4130_MAX_SETUPS)] = 2,
> +       [AD4130_FILTER_X_REG(0) ... AD4130_FILTER_X_REG(AD4130_MAX_SETUPS)] = 3,
> +       [AD4130_OFFSET_X_REG(0) ... AD4130_OFFSET_X_REG(AD4130_MAX_SETUPS)] = 3,
> +       [AD4130_GAIN_X_REG(0) ... AD4130_GAIN_X_REG(AD4130_MAX_SETUPS)] = 3,
> +       [AD4130_MISC_REG] = 2,
> +       [AD4130_FIFO_CONTROL_REG] = 3,
> +       [AD4130_FIFO_STATUS_REG] = 1,
> +       [AD4130_FIFO_THRESHOLD_REG] = 3,
> +       [AD4130_FIFO_DATA_REG] = 3,
> +};
> +
> +enum ad4130_id {
> +       ID_AD4130_8_24_WLCSP,
> +       ID_AD4130_8_24_LFCSP,
> +       ID_AD4130_8_16_WLCSP,
> +       ID_AD4130_8_16_LFCSP,
> +};
> +
> +enum ad4130_int_ref_val {
> +       AD4130_INT_REF_VAL_2_5V,
> +       AD4130_INT_REF_VAL_1_25V,
> +};
> +
> +enum ad4130_mclk_sel {
> +       AD4130_MCLK_76_8KHZ,
> +       AD4130_MCLK_76_8KHZ_OUT,
> +       AD4130_MCLK_76_8KHZ_EXT,
> +       AD4130_MCLK_153_6KHZ_EXT,
> +       AD4130_MCLK_SEL_MAX
> +};
> +
> +enum ad4130_int_pin_sel {
> +       AD4130_INT_PIN_INT,
> +       AD4130_INT_PIN_CLK,
> +       AD4130_INT_PIN_P2,
> +       AD4130_INT_PIN_DOUT,
> +};
> +
> +enum ad4130_iout {
> +       AD4130_IOUT_OFF,
> +       AD4130_IOUT_10000NA,
> +       AD4130_IOUT_20000NA,
> +       AD4130_IOUT_50000NA,
> +       AD4130_IOUT_100000NA,
> +       AD4130_IOUT_150000NA,
> +       AD4130_IOUT_200000NA,
> +       AD4130_IOUT_100NA,
> +       AD4130_IOUT_MAX
> +};
> +
> +enum ad4130_burnout {
> +       AD4130_BURNOUT_OFF,
> +       AD4130_BURNOUT_500NA,
> +       AD4130_BURNOUT_2000NA,
> +       AD4130_BURNOUT_4000NA,
> +       AD4130_BURNOUT_MAX
> +};
> +
> +enum ad4130_ref_sel {
> +       AD4130_REF_REFIN1,
> +       AD4130_REF_REFIN2,
> +       AD4130_REF_REFOUT_AVSS,
> +       AD4130_REF_AVDD_AVSS,
> +       AD4130_REF_SEL_MAX
> +};
> +
> +enum ad4130_fifo_mode {
> +       AD4130_FIFO_MODE_DISABLED = 0b00,
> +       AD4130_FIFO_MODE_WM = 0b01,
> +};
> +
> +enum ad4130_mode {
> +       AD4130_MODE_CONTINUOUS = 0b0000,
> +       AD4130_MODE_IDLE = 0b0100,
> +};
> +
> +enum ad4130_filter_mode {
> +       AD4130_FILTER_SINC4,
> +       AD4130_FILTER_SINC4_SINC1,
> +       AD4130_FILTER_SINC3,
> +       AD4130_FILTER_SINC3_REJ60,
> +       AD4130_FILTER_SINC3_SINC1,
> +       AD4130_FILTER_SINC3_PF1,
> +       AD4130_FILTER_SINC3_PF2,
> +       AD4130_FILTER_SINC3_PF3,
> +       AD4130_FILTER_SINC3_PF4,
> +};
> +
> +enum ad4130_pin_function {
> +       AD4130_PIN_FN_NONE,
> +       AD4130_PIN_FN_SPECIAL = BIT(0),
> +       AD4130_PIN_FN_DIFF = BIT(1),
> +       AD4130_PIN_FN_EXCITATION = BIT(2),
> +       AD4130_PIN_FN_VBIAS = BIT(3),
> +};
> +
> +struct ad4130_setup_info {
> +       unsigned int                    iout0_val;
> +       unsigned int                    iout1_val;
> +       unsigned int                    burnout;
> +       unsigned int                    pga;
> +       unsigned int                    fs;
> +       u32                             ref_sel;
> +       enum ad4130_filter_mode         filter_mode;
> +       bool                            ref_bufp;
> +       bool                            ref_bufm;
> +};
> +
> +struct ad4130_slot_info {
> +       struct ad4130_setup_info        setup;
> +       unsigned int                    enabled_channels;
> +       unsigned int                    channels;
> +};
> +
> +struct ad4130_chan_info {
> +       struct ad4130_setup_info        setup;
> +       u32                             iout0;
> +       u32                             iout1;
> +       int                             slot;
> +       bool                            enabled;
> +       bool                            initialized;
> +};
> +
> +struct ad4130_filter_config {
> +       enum ad4130_filter_mode         filter_mode;
> +       unsigned int                    odr_div;
> +       unsigned int                    fs_max;
> +       enum iio_available_type         samp_freq_avail_type;
> +       int                             samp_freq_avail_len;
> +       int                             samp_freq_avail[3][2];
> +};
> +
> +struct ad4130_state {
> +       struct regmap                   *regmap;
> +       struct spi_device               *spi;
> +       struct clk                      *mclk;
> +       struct regulator_bulk_data      regulators[4];
> +       u32                             irq_trigger;
> +       u32                             inv_irq_trigger;
> +
> +       /*
> +        * Synchronize access to members the of driver state, and ensure
> +        * atomicity of consecutive regmap operations.
> +        */
> +       struct mutex                    lock;
> +       struct completion               completion;
> +
> +       struct iio_chan_spec            chans[AD4130_MAX_CHANNELS];
> +       struct ad4130_chan_info         chans_info[AD4130_MAX_CHANNELS];
> +       struct ad4130_slot_info         slots_info[AD4130_MAX_SETUPS];
> +       enum ad4130_pin_function        pins_fn[AD4130_MAX_ANALOG_PINS];
> +       u32                             vbias_pins[AD4130_MAX_ANALOG_PINS];
> +       u32                             num_vbias_pins;
> +       int                             scale_tbls[AD4130_REF_SEL_MAX][AD4130_MAX_PGA][2];
> +       struct gpio_chip                gc;
> +
> +       u32                     int_pin_sel;
> +       u32                     int_ref_uv;
> +       u32                     mclk_sel;
> +       bool                    int_ref_en;
> +       bool                    bipolar;
> +
> +       unsigned int            num_enabled_channels;
> +       unsigned int            effective_watermark;
> +       unsigned int            watermark;
> +
> +       struct spi_message      fifo_msg;
> +       struct spi_transfer     fifo_xfer[2];
> +
> +       /*
> +        * DMA (thus cache coherency maintenance) requires any transfer
> +        * buffers to live in their own cache lines. As the use of these
> +        * buffers is synchronous, all of the buffers used for DMA in this
> +        * driver may share a cache line.
> +        */
> +       u8                      reset_buf[AD4130_RESET_BUF_SIZE] __aligned(IIO_DMA_MINALIGN);
> +       u8                      reg_write_tx_buf[4];
> +       u8                      reg_read_tx_buf[1];
> +       u8                      reg_read_rx_buf[3];
> +       u8                      fifo_tx_buf[2];
> +       u8                      fifo_rx_buf[AD4130_FIFO_SIZE *
> +                                           AD4130_FIFO_MAX_SAMPLE_SIZE];
> +};
> +
> +static const char * const ad4130_int_pin_names[] = {
> +       [AD4130_INT_PIN_INT] = "int",
> +       [AD4130_INT_PIN_CLK] = "clk",
> +       [AD4130_INT_PIN_P2] = "p2",
> +       [AD4130_INT_PIN_DOUT] = "dout",
> +};
> +
> +static const unsigned int ad4130_iout_current_na_tbl[AD4130_IOUT_MAX] = {
> +       [AD4130_IOUT_OFF] = 0,
> +       [AD4130_IOUT_100NA] = 100,
> +       [AD4130_IOUT_10000NA] = 10000,
> +       [AD4130_IOUT_20000NA] = 20000,
> +       [AD4130_IOUT_50000NA] = 50000,
> +       [AD4130_IOUT_100000NA] = 100000,
> +       [AD4130_IOUT_150000NA] = 150000,
> +       [AD4130_IOUT_200000NA] = 200000,
> +};
> +
> +static const unsigned int ad4130_burnout_current_na_tbl[AD4130_BURNOUT_MAX] = {
> +       [AD4130_BURNOUT_OFF] = 0,
> +       [AD4130_BURNOUT_500NA] = 500,
> +       [AD4130_BURNOUT_2000NA] = 2000,
> +       [AD4130_BURNOUT_4000NA] = 4000,
> +};
> +
> +#define AD4130_VARIABLE_ODR_CONFIG(_filter_mode, _odr_div, _fs_max)    \
> +{                                                                      \
> +               .filter_mode = (_filter_mode),                          \
> +               .odr_div = (_odr_div),                                  \
> +               .fs_max = (_fs_max),                                    \
> +               .samp_freq_avail_type = IIO_AVAIL_RANGE,                \
> +               .samp_freq_avail = {                                    \
> +                       { AD4130_MAX_ODR, (_odr_div) * (_fs_max) },     \
> +                       { AD4130_MAX_ODR, (_odr_div) * (_fs_max) },     \
> +                       { AD4130_MAX_ODR, (_odr_div) },                 \
> +               },                                                      \
> +}
> +
> +#define AD4130_FIXED_ODR_CONFIG(_filter_mode, _odr_div)                        \
> +{                                                                      \
> +               .filter_mode = (_filter_mode),                          \
> +               .odr_div = (_odr_div),                                  \
> +               .fs_max = AD4130_FILTER_SELECT_MIN,                     \
> +               .samp_freq_avail_type = IIO_AVAIL_LIST,                 \
> +               .samp_freq_avail_len = 1,                               \
> +               .samp_freq_avail = {                                    \
> +                       { AD4130_MAX_ODR, (_odr_div) },                 \
> +               },                                                      \
> +}
> +
> +static const struct ad4130_filter_config ad4130_filter_configs[] = {
> +       AD4130_VARIABLE_ODR_CONFIG(AD4130_FILTER_SINC4,       1,  10),
> +       AD4130_VARIABLE_ODR_CONFIG(AD4130_FILTER_SINC4_SINC1, 11, 10),
> +       AD4130_VARIABLE_ODR_CONFIG(AD4130_FILTER_SINC3,       1,  2047),
> +       AD4130_VARIABLE_ODR_CONFIG(AD4130_FILTER_SINC3_REJ60, 1,  2047),
> +       AD4130_VARIABLE_ODR_CONFIG(AD4130_FILTER_SINC3_SINC1, 10, 2047),
> +       AD4130_FIXED_ODR_CONFIG(AD4130_FILTER_SINC3_PF1,      92),
> +       AD4130_FIXED_ODR_CONFIG(AD4130_FILTER_SINC3_PF2,      100),
> +       AD4130_FIXED_ODR_CONFIG(AD4130_FILTER_SINC3_PF3,      124),
> +       AD4130_FIXED_ODR_CONFIG(AD4130_FILTER_SINC3_PF4,      148),
> +};
> +
> +static const char * const ad4130_filter_modes_str[] = {
> +       [AD4130_FILTER_SINC4] = "sinc4",
> +       [AD4130_FILTER_SINC4_SINC1] = "sinc4+sinc1",
> +       [AD4130_FILTER_SINC3] = "sinc3",
> +       [AD4130_FILTER_SINC3_REJ60] = "sinc3+rej60",
> +       [AD4130_FILTER_SINC3_SINC1] = "sinc3+sinc1",
> +       [AD4130_FILTER_SINC3_PF1] = "sinc3+pf1",
> +       [AD4130_FILTER_SINC3_PF2] = "sinc3+pf2",
> +       [AD4130_FILTER_SINC3_PF3] = "sinc3+pf3",
> +       [AD4130_FILTER_SINC3_PF4] = "sinc3+pf4",
> +};
> +
> +static int ad4130_get_reg_size(struct ad4130_state *st, unsigned int reg,
> +                              unsigned int *size)
> +{
> +       if (reg >= ARRAY_SIZE(ad4130_reg_size))
> +               return -EINVAL;
> +
> +       *size = ad4130_reg_size[reg];
> +
> +       return 0;
> +}
> +
> +static unsigned int ad4130_data_reg_size(struct ad4130_state *st)
> +{
> +       unsigned int data_reg_size;
> +       int ret;
> +
> +       ret = ad4130_get_reg_size(st, AD4130_DATA_REG, &data_reg_size);
> +       if (ret)
> +               return 0;
> +
> +       return data_reg_size;
> +}
> +
> +static unsigned int ad4130_resolution(struct ad4130_state *st)
> +{
> +       return ad4130_data_reg_size(st) * BITS_PER_BYTE;
> +}
> +
> +static int ad4130_reg_write(void *context, unsigned int reg, unsigned int val)
> +{
> +       struct ad4130_state *st = context;
> +       unsigned int size;
> +       int ret;
> +
> +       ret = ad4130_get_reg_size(st, reg, &size);
> +       if (ret)
> +               return ret;
> +
> +       st->reg_write_tx_buf[0] = reg;
> +
> +       switch (size) {
> +       case 3:
> +               put_unaligned_be24(val, &st->reg_write_tx_buf[1]);
> +               break;
> +       case 2:
> +               put_unaligned_be16(val, &st->reg_write_tx_buf[1]);
> +               break;
> +       case 1:
> +               st->reg_write_tx_buf[1] = val;
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
> +
> +       return spi_write(st->spi, st->reg_write_tx_buf, size + 1);
> +}
> +
> +static int ad4130_reg_read(void *context, unsigned int reg, unsigned int *val)
> +{
> +       struct ad4130_state *st = context;
> +       struct spi_transfer t[] = {
> +               {
> +                       .tx_buf = st->reg_read_tx_buf,
> +                       .len = sizeof(st->reg_read_tx_buf),
> +               },
> +               {
> +                       .rx_buf = st->reg_read_rx_buf,
> +               },
> +       };
> +       unsigned int size;
> +       int ret;
> +
> +       ret = ad4130_get_reg_size(st, reg, &size);
> +       if (ret)
> +               return ret;
> +
> +       st->reg_read_tx_buf[0] = AD4130_COMMS_READ_MASK | reg;
> +       t[1].len = size;
> +
> +       ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
> +       if (ret)
> +               return ret;
> +
> +       switch (size) {
> +       case 3:
> +               *val = get_unaligned_be24(st->reg_read_rx_buf);
> +               break;
> +       case 2:
> +               *val = get_unaligned_be16(st->reg_read_rx_buf);
> +               break;
> +       case 1:
> +               *val = st->reg_read_rx_buf[0];
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct regmap_config ad4130_regmap_config = {
> +       .reg_read = ad4130_reg_read,
> +       .reg_write = ad4130_reg_write,
> +};
> +
> +static int ad4130_gpio_init_valid_mask(struct gpio_chip *gc,
> +                                      unsigned long *valid_mask,
> +                                      unsigned int ngpios)
> +{
> +       struct ad4130_state *st = gpiochip_get_data(gc);
> +       unsigned int i;
> +
> +       /*
> +        * Output-only GPIO functionality is available on pins AIN2 through
> +        * AIN5. If these pins are used for anything else, do not expose them.
> +        */
> +       for (i = 0; i < ngpios; i++) {
> +               unsigned int pin = i + AD4130_AIN2_P1;
> +               bool valid = st->pins_fn[pin] == AD4130_PIN_FN_NONE;
> +
> +               __assign_bit(i, valid_mask, valid);
> +       }
> +
> +
> +       return 0;
> +}
> +
> +static int ad4130_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
> +{
> +       return GPIO_LINE_DIRECTION_OUT;
> +}
> +
> +static void ad4130_gpio_set(struct gpio_chip *gc, unsigned int offset,
> +                           int value)
> +{
> +       struct ad4130_state *st = gpiochip_get_data(gc);
> +       unsigned int mask = FIELD_PREP(AD4130_IO_CONTROL_GPIO_DATA_MASK,
> +                                      BIT(offset));
> +
> +       regmap_update_bits(st->regmap, AD4130_IO_CONTROL_REG, mask,
> +                          value ? mask : 0);
> +}
> +
> +static int ad4130_set_mode(struct ad4130_state *st, enum ad4130_mode mode)
> +{
> +       return regmap_update_bits(st->regmap, AD4130_ADC_CONTROL_REG,
> +                                 AD4130_ADC_CONTROL_MODE_MASK,
> +                                 FIELD_PREP(AD4130_ADC_CONTROL_MODE_MASK, mode));
> +}
> +
> +static int ad4130_set_watermark_interrupt_en(struct ad4130_state *st, bool en)
> +{
> +       return regmap_update_bits(st->regmap, AD4130_FIFO_CONTROL_REG,
> +                                 AD4130_FIFO_CONTROL_WM_INT_EN_MASK,
> +                                 FIELD_PREP(AD4130_FIFO_CONTROL_WM_INT_EN_MASK, en));
> +}
> +
> +static unsigned int ad4130_watermark_reg_val(unsigned int val)
> +{
> +       if (val == AD4130_FIFO_SIZE)
> +               val = AD4130_WATERMARK_256;
> +
> +       return val;
> +}
> +
> +static int ad4130_set_fifo_mode(struct ad4130_state *st,
> +                               enum ad4130_fifo_mode mode)
> +{
> +       return regmap_update_bits(st->regmap, AD4130_FIFO_CONTROL_REG,
> +                                 AD4130_FIFO_CONTROL_MODE_MASK,
> +                                 FIELD_PREP(AD4130_FIFO_CONTROL_MODE_MASK, mode));
> +}
> +
> +static void ad4130_push_fifo_data(struct iio_dev *indio_dev)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int data_reg_size = ad4130_data_reg_size(st);
> +       unsigned int transfer_len = st->effective_watermark * data_reg_size;
> +       unsigned int set_size = st->num_enabled_channels * data_reg_size;
> +       unsigned int i;
> +       int ret;
> +
> +       st->fifo_tx_buf[1] = ad4130_watermark_reg_val(st->effective_watermark);
> +       st->fifo_xfer[1].len = transfer_len;
> +
> +       ret = spi_sync(st->spi, &st->fifo_msg);
> +       if (ret)
> +               return;
> +
> +       for (i = 0; i < transfer_len; i += set_size)
> +               iio_push_to_buffers(indio_dev, &st->fifo_rx_buf[i]);
> +}
> +
> +static irqreturn_t ad4130_irq_handler(int irq, void *private)
> +{
> +       struct iio_dev *indio_dev = private;
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +
> +       if (iio_buffer_enabled(indio_dev))
> +               ad4130_push_fifo_data(indio_dev);
> +       else
> +               complete(&st->completion);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static int ad4130_find_slot(struct ad4130_state *st,
> +                           struct ad4130_setup_info *target_setup_info,
> +                           unsigned int *slot, bool *overwrite)
> +{
> +       unsigned int i;
> +
> +       *slot = AD4130_INVALID_SLOT;
> +       *overwrite = false;
> +
> +       for (i = 0; i < AD4130_MAX_SETUPS; i++) {
> +               struct ad4130_slot_info *slot_info = &st->slots_info[i];
> +
> +               /* Immediately accept a matching setup info. */
> +               if (!memcmp(target_setup_info, &slot_info->setup,
> +                           sizeof(*target_setup_info))) {
> +                       *slot = i;
> +                       return 0;
> +               }
> +
> +               /* Ignore all setups which are used by enabled channels. */
> +               if (slot_info->enabled_channels)
> +                       continue;
> +
> +               /* Find the least used slot. */
> +               if (*slot == AD4130_INVALID_SLOT ||
> +                   slot_info->channels < st->slots_info[*slot].channels)
> +                       *slot = i;
> +       }
> +
> +       if (*slot == AD4130_INVALID_SLOT)
> +               return -EINVAL;
> +
> +       *overwrite = true;
> +
> +       return 0;
> +}
> +
> +static void ad4130_unlink_channel(struct ad4130_state *st, unsigned int channel)
> +{
> +       struct ad4130_chan_info *chan_info = &st->chans_info[channel];
> +       struct ad4130_slot_info *slot_info = &st->slots_info[chan_info->slot];
> +
> +       chan_info->slot = AD4130_INVALID_SLOT;
> +       slot_info->channels--;
> +}
> +
> +static int ad4130_unlink_slot(struct ad4130_state *st, unsigned int slot)
> +{
> +       unsigned int i;
> +
> +       for (i = 0; i < AD4130_MAX_CHANNELS; i++) {
> +               struct ad4130_chan_info *chan_info = &st->chans_info[i];
> +
> +               if (!chan_info->initialized || chan_info->slot != slot)
> +                       continue;
> +
> +               ad4130_unlink_channel(st, i);
> +       }
> +
> +       return 0;
> +}
> +
> +static int ad4130_link_channel_slot(struct ad4130_state *st,
> +                                   unsigned int channel, unsigned int slot)
> +{
> +       struct ad4130_slot_info *slot_info = &st->slots_info[slot];
> +       struct ad4130_chan_info *chan_info = &st->chans_info[channel];
> +       int ret;
> +
> +       ret = regmap_update_bits(st->regmap, AD4130_CHANNEL_X_REG(channel),
> +                                AD4130_CHANNEL_SETUP_MASK,
> +                                FIELD_PREP(AD4130_CHANNEL_SETUP_MASK, slot));
> +       if (ret)
> +               return ret;
> +
> +       chan_info->slot = slot;
> +       slot_info->channels++;
> +
> +       return 0;
> +}
> +
> +static int ad4130_write_slot_setup(struct ad4130_state *st,
> +                                  unsigned int slot,
> +                                  struct ad4130_setup_info *setup_info)
> +{
> +       unsigned int val;
> +       int ret;
> +
> +       val = FIELD_PREP(AD4130_CONFIG_IOUT1_VAL_MASK, setup_info->iout0_val) |
> +             FIELD_PREP(AD4130_CONFIG_IOUT1_VAL_MASK, setup_info->iout1_val) |
> +             FIELD_PREP(AD4130_CONFIG_BURNOUT_MASK, setup_info->burnout) |
> +             FIELD_PREP(AD4130_CONFIG_REF_BUFP_MASK, setup_info->ref_bufp) |
> +             FIELD_PREP(AD4130_CONFIG_REF_BUFM_MASK, setup_info->ref_bufm) |
> +             FIELD_PREP(AD4130_CONFIG_REF_SEL_MASK, setup_info->ref_sel) |
> +             FIELD_PREP(AD4130_CONFIG_PGA_MASK, setup_info->pga);
> +
> +       ret = regmap_write(st->regmap, AD4130_CONFIG_X_REG(slot), val);
> +       if (ret)
> +               return ret;
> +
> +       val = FIELD_PREP(AD4130_FILTER_MODE_MASK, setup_info->filter_mode) |
> +             FIELD_PREP(AD4130_FILTER_SELECT_MASK, setup_info->fs);
> +
> +       ret = regmap_write(st->regmap, AD4130_FILTER_X_REG(slot), val);
> +       if (ret)
> +               return ret;
> +
> +       memcpy(&st->slots_info[slot].setup, setup_info, sizeof(*setup_info));
> +
> +       return 0;
> +}
> +
> +static int ad4130_write_channel_setup(struct ad4130_state *st,
> +                                     unsigned int channel, bool on_enable)
> +{
> +       struct ad4130_chan_info *chan_info = &st->chans_info[channel];
> +       struct ad4130_setup_info *setup_info = &chan_info->setup;
> +       bool overwrite;
> +       int slot;
> +       int ret;
> +
> +       /*
> +        * The following cases need to be handled.
> +        *
> +        * 1. Enabled and linked channel with setup changes:
> +        *    - Find a slot. If not possible, return error.
> +        *    - Unlink channel from current slot.
> +        *    - If the slot has channels linked to it, unlink all channels, and
> +        *      write the new setup to it.
> +        *    - Link channel to new slot.
> +        *
> +        * 2. Soon to be enabled and unlinked channel:
> +        *    - Find a slot. If not possible, return error.
> +        *    - If the slot has channels linked to it, unlink all channels, and
> +        *      write the new setup to it.
> +        *    - Link channel to the slot.
> +        *
> +        * 3. Disabled and linked channel with setup changes:
> +        *    - Unlink channel from current slot.
> +        *
> +        * 4. Soon to be enabled and linked channel:
> +        * 5. Disabled and unlinked channel with setup changes:
> +        *    - Do nothing.
> +        */
> +
> +       /* Case 4 */
> +       if (on_enable && chan_info->slot != AD4130_INVALID_SLOT)
> +               return 0;
> +
> +       if (!on_enable && !chan_info->enabled) {
> +               if (chan_info->slot != AD4130_INVALID_SLOT)
> +                       /* Case 3 */
> +                       ad4130_unlink_channel(st, channel);
> +
> +               /* Cases 3 & 5 */
> +               return 0;
> +       }
> +
> +       /* Cases 1 & 2 */
> +       ret = ad4130_find_slot(st, setup_info, &slot, &overwrite);
> +       if (ret)
> +               return ret;
> +
> +       if (chan_info->slot != AD4130_INVALID_SLOT)
> +               /* Case 1 */
> +               ad4130_unlink_channel(st, channel);
> +
> +       if (overwrite) {
> +               ret = ad4130_unlink_slot(st, slot);
> +               if (ret)
> +                       return ret;
> +
> +               ret = ad4130_write_slot_setup(st, slot, setup_info);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       return ad4130_link_channel_slot(st, channel, slot);
> +}
> +
> +static int ad4130_set_channel_enable(struct ad4130_state *st,
> +                                    unsigned int channel, bool status)
> +{
> +       struct ad4130_chan_info *chan_info = &st->chans_info[channel];
> +       struct ad4130_slot_info *slot_info;
> +       int ret;
> +
> +       if (chan_info->enabled == status)
> +               return 0;
> +
> +       if (status) {
> +               ret = ad4130_write_channel_setup(st, channel, true);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       slot_info = &st->slots_info[chan_info->slot];
> +
> +       ret = regmap_update_bits(st->regmap, AD4130_CHANNEL_X_REG(channel),
> +                                AD4130_CHANNEL_EN_MASK,
> +                                FIELD_PREP(AD4130_CHANNEL_EN_MASK, status));
> +       if (ret)
> +               return ret;
> +
> +       slot_info->enabled_channels += status ? 1 : -1;
> +       chan_info->enabled = status;
> +
> +       return 0;
> +}
> +
> +/*
> + * Table 58. FILTER_MODE_n bits and Filter Types of the datasheet describes
> + * the relation between filter mode, ODR and FS.
> + *
> + * Notice that the max ODR of each filter mode is not necessarily the
> + * absolute max ODR supported by the chip.
> + *
> + * The ODR divider is not explicitly specified, but it can be deduced based
> + * on the ODR range of each filter mode.
> + *
> + * For example, for Sinc4+Sinc1, max ODR is 218.18. That means that the
> + * absolute max ODR is divided by 11 to achieve the max ODR of this filter
> + * mode.
> + *
> + * The formulas for converting between ODR and FS for a specific filter
> + * mode can be deduced from the same table.
> + *
> + * Notice that FS = 1 actually means max ODR, and that ODR decreases by
> + * (maximum ODR / maximum FS) for each increment of FS.
> + *
> + * odr = MAX_ODR / odr_div * (1 - (fs - 1) / fs_max) <=>
> + * odr = MAX_ODR * (1 - (fs - 1) / fs_max) / odr_div <=>
> + * odr = MAX_ODR * (1 - (fs - 1) / fs_max) / odr_div <=>
> + * odr = MAX_ODR * (fs_max - fs + 1) / (fs_max * odr_div)
> + * (used in ad4130_fs_to_freq)
> + *
> + * For the opposite formula, FS can be extracted from the last one.
> + *
> + * MAX_ODR * (fs_max - fs + 1) = fs_max * odr_div * odr <=>
> + * fs_max - fs + 1 = fs_max * odr_div * odr / MAX_ODR <=>
> + * fs = 1 + fs_max - fs_max * odr_div * odr / MAX_ODR
> + * (used in ad4130_fs_to_freq)
> + */
> +
> +static void ad4130_freq_to_fs(enum ad4130_filter_mode filter_mode,
> +                             int val, int val2, unsigned int *fs)
> +{
> +       const struct ad4130_filter_config *filter_config =
> +               &ad4130_filter_configs[filter_mode];
> +       u64 dividend, divisor;
> +       int temp;
> +
> +       dividend = filter_config->fs_max * filter_config->odr_div *
> +                  ((u64)val * NANO + val2);
> +       divisor = (u64)AD4130_MAX_ODR * NANO;
> +
> +       temp = AD4130_FILTER_SELECT_MIN + filter_config->fs_max -
> +              DIV64_U64_ROUND_CLOSEST(dividend, divisor);
> +
> +       if (temp < AD4130_FILTER_SELECT_MIN)
> +               temp = AD4130_FILTER_SELECT_MIN;
> +       else if (temp > filter_config->fs_max)
> +               temp = filter_config->fs_max;
> +
> +       *fs = temp;
> +}
> +
> +static void ad4130_fs_to_freq(enum ad4130_filter_mode filter_mode,
> +                             unsigned int fs, int *val, int *val2)
> +{
> +       const struct ad4130_filter_config *filter_config =
> +               &ad4130_filter_configs[filter_mode];
> +       unsigned int dividend, divisor;
> +       u64 temp;
> +
> +       dividend = (filter_config->fs_max - fs + AD4130_FILTER_SELECT_MIN) *
> +                  AD4130_MAX_ODR;
> +       divisor = filter_config->fs_max * filter_config->odr_div;
> +
> +       temp = div_u64((u64)dividend * NANO, divisor);
> +       *val = div_u64_rem(temp, NANO, val2);
> +}
> +
> +static int ad4130_set_filter_mode(struct iio_dev *indio_dev,
> +                                 const struct iio_chan_spec *chan,
> +                                 unsigned int val)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int channel = chan->scan_index;
> +       struct ad4130_chan_info *chan_info = &st->chans_info[channel];
> +       struct ad4130_setup_info *setup_info = &chan_info->setup;
> +       enum ad4130_filter_mode old_filter_mode;
> +       int freq_val, freq_val2;
> +       unsigned int old_fs;
> +       int ret = 0;
> +
> +       mutex_lock(&st->lock);
> +       if (setup_info->filter_mode == val)
> +               goto out;
> +
> +       old_fs = setup_info->fs;
> +       old_filter_mode = setup_info->filter_mode;
> +
> +       /*
> +        * When switching between filter modes, try to match the ODR as
> +        * close as possible. To do this, convert the current FS into ODR
> +        * using the old filter mode, then convert it back into FS using
> +        * the new filter mode.
> +        */
> +       ad4130_fs_to_freq(setup_info->filter_mode, setup_info->fs,
> +                         &freq_val, &freq_val2);
> +
> +       ad4130_freq_to_fs(val, freq_val, freq_val2, &setup_info->fs);
> +
> +       setup_info->filter_mode = val;
> +
> +       ret = ad4130_write_channel_setup(st, channel, false);
> +       if (ret) {
> +               setup_info->fs = old_fs;
> +               setup_info->filter_mode = old_filter_mode;
> +       }
> +
> + out:
> +       mutex_unlock(&st->lock);
> +
> +       return ret;
> +}
> +
> +static int ad4130_get_filter_mode(struct iio_dev *indio_dev,
> +                                 const struct iio_chan_spec *chan)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int channel = chan->scan_index;
> +       struct ad4130_setup_info *setup_info = &st->chans_info[channel].setup;
> +       enum ad4130_filter_mode filter_mode;
> +
> +       mutex_lock(&st->lock);
> +       filter_mode = setup_info->filter_mode;
> +       mutex_unlock(&st->lock);
> +
> +       return filter_mode;
> +}
> +
> +static const struct iio_enum ad4130_filter_mode_enum = {
> +       .items = ad4130_filter_modes_str,
> +       .num_items = ARRAY_SIZE(ad4130_filter_modes_str),
> +       .set = ad4130_set_filter_mode,
> +       .get = ad4130_get_filter_mode,
> +};
> +
> +static const struct iio_chan_spec_ext_info ad4130_filter_mode_ext_info[] = {
> +       IIO_ENUM("filter_mode", IIO_SEPARATE, &ad4130_filter_mode_enum),
> +       IIO_ENUM_AVAILABLE("filter_mode", IIO_SHARED_BY_TYPE,
> +                          &ad4130_filter_mode_enum),
> +       { }
> +};
> +
> +static const struct iio_chan_spec ad4130_channel_template = {
> +       .type = IIO_VOLTAGE,
> +       .indexed = 1,
> +       .differential = 1,
> +       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +                             BIT(IIO_CHAN_INFO_SCALE) |
> +                             BIT(IIO_CHAN_INFO_OFFSET) |
> +                             BIT(IIO_CHAN_INFO_SAMP_FREQ),
> +       .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE) |
> +                                       BIT(IIO_CHAN_INFO_SAMP_FREQ),
> +       .ext_info = ad4130_filter_mode_ext_info,
> +       .scan_type = {
> +               .sign = 'u',
> +               .endianness = IIO_BE,
> +       },
> +};
> +
> +static int ad4130_set_channel_pga(struct ad4130_state *st, unsigned int channel,
> +                                 int val, int val2)
> +{
> +       struct ad4130_chan_info *chan_info = &st->chans_info[channel];
> +       struct ad4130_setup_info *setup_info = &chan_info->setup;
> +       unsigned int pga, old_pga;
> +       int ret = 0;
> +
> +       for (pga = 0; pga < AD4130_MAX_PGA; pga++)
> +               if (val == st->scale_tbls[setup_info->ref_sel][pga][0] &&
> +                   val2 == st->scale_tbls[setup_info->ref_sel][pga][1])
> +                       break;
> +
> +       if (pga == AD4130_MAX_PGA)
> +               return -EINVAL;
> +
> +       mutex_lock(&st->lock);
> +       if (pga == setup_info->pga)
> +               goto out;
> +
> +       old_pga = setup_info->pga;
> +       setup_info->pga = pga;
> +
> +       ret = ad4130_write_channel_setup(st, channel, false);
> +       if (ret)
> +               setup_info->pga = old_pga;
> +
> +out:
> +       mutex_unlock(&st->lock);
> +
> +       return ret;
> +}
> +
> +static int ad4130_set_channel_freq(struct ad4130_state *st,
> +                                  unsigned int channel, int val, int val2)
> +{
> +       struct ad4130_chan_info *chan_info = &st->chans_info[channel];
> +       struct ad4130_setup_info *setup_info = &chan_info->setup;
> +       unsigned int fs, old_fs;
> +       int ret = 0;
> +
> +       mutex_lock(&st->lock);
> +       old_fs = setup_info->fs;
> +
> +       ad4130_freq_to_fs(setup_info->filter_mode, val, val2, &fs);
> +
> +       if (fs == setup_info->fs)
> +               goto out;
> +
> +       setup_info->fs = fs;
> +
> +       ret = ad4130_write_channel_setup(st, channel, false);
> +       if (ret)
> +               setup_info->fs = old_fs;
> +
> +out:
> +       mutex_unlock(&st->lock);
> +
> +       return ret;
> +}
> +
> +static int _ad4130_read_sample(struct iio_dev *indio_dev, unsigned int channel,
> +                              int *val)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       int ret;
> +
> +       ret = ad4130_set_channel_enable(st, channel, true);
> +       if (ret)
> +               return ret;
> +
> +       reinit_completion(&st->completion);
> +
> +       ret = ad4130_set_mode(st, AD4130_MODE_CONTINUOUS);
> +       if (ret)
> +               return ret;
> +
> +       ret = wait_for_completion_timeout(&st->completion,
> +                                         msecs_to_jiffies(1000));
> +       if (!ret)
> +               return -ETIMEDOUT;
> +
> +       ret = ad4130_set_mode(st, AD4130_MODE_IDLE);
> +       if (ret)
> +               return ret;
> +
> +       ret = regmap_read(st->regmap, AD4130_DATA_REG, val);
> +       if (ret)
> +               return ret;
> +
> +       ret = ad4130_set_channel_enable(st, channel, false);
> +       if (ret)
> +               return ret;
> +
> +       return IIO_VAL_INT;
> +}
> +
> +static int ad4130_read_sample(struct iio_dev *indio_dev, unsigned int channel,
> +                             int *val)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       int ret;
> +
> +       ret = iio_device_claim_direct_mode(indio_dev);
> +       if (ret)
> +               return ret;
> +
> +       mutex_lock(&st->lock);
> +       ret = _ad4130_read_sample(indio_dev, channel, val);
> +       mutex_unlock(&st->lock);
> +
> +       iio_device_release_direct_mode(indio_dev);
> +
> +       return ret;
> +}
> +
> +static int ad4130_read_raw(struct iio_dev *indio_dev,
> +                          struct iio_chan_spec const *chan,
> +                          int *val, int *val2, long info)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int channel = chan->scan_index;
> +       struct ad4130_setup_info *setup_info = &st->chans_info[channel].setup;
> +
> +       switch (info) {
> +       case IIO_CHAN_INFO_RAW:
> +               return ad4130_read_sample(indio_dev, channel, val);
> +       case IIO_CHAN_INFO_SCALE:
> +               mutex_lock(&st->lock);
> +               *val = st->scale_tbls[setup_info->ref_sel][setup_info->pga][0];
> +               *val2 = st->scale_tbls[setup_info->ref_sel][setup_info->pga][1];
> +               mutex_unlock(&st->lock);
> +
> +               return IIO_VAL_INT_PLUS_NANO;
> +       case IIO_CHAN_INFO_OFFSET:
> +               *val = st->bipolar ? -BIT(chan->scan_type.realbits - 1) : 0;
> +
> +               return IIO_VAL_INT;
> +       case IIO_CHAN_INFO_SAMP_FREQ:
> +               mutex_lock(&st->lock);
> +               ad4130_fs_to_freq(setup_info->filter_mode, setup_info->fs,
> +                                 val, val2);
> +               mutex_unlock(&st->lock);
> +
> +               return IIO_VAL_INT_PLUS_NANO;
> +       default:
> +               return -EINVAL;
> +       }
> +}
> +
> +static int ad4130_read_avail(struct iio_dev *indio_dev,
> +                            struct iio_chan_spec const *chan,
> +                            const int **vals, int *type, int *length,
> +                            long info)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int channel = chan->scan_index;
> +       struct ad4130_setup_info *setup_info = &st->chans_info[channel].setup;
> +       const struct ad4130_filter_config *filter_config;
> +
> +       switch (info) {
> +       case IIO_CHAN_INFO_SCALE:
> +               *vals = (int *)st->scale_tbls[setup_info->ref_sel];
> +               *length = ARRAY_SIZE(st->scale_tbls[setup_info->ref_sel]) * 2;
> +
> +               *type = IIO_VAL_INT_PLUS_NANO;
> +
> +               return IIO_AVAIL_LIST;
> +       case IIO_CHAN_INFO_SAMP_FREQ:
> +               mutex_lock(&st->lock);
> +               filter_config = &ad4130_filter_configs[setup_info->filter_mode];
> +               mutex_unlock(&st->lock);
> +
> +               *vals = (int *)filter_config->samp_freq_avail;
> +               *length = filter_config->samp_freq_avail_len * 2;
> +               *type = IIO_VAL_FRACTIONAL;
> +
> +               return filter_config->samp_freq_avail_type;
> +       default:
> +               return -EINVAL;
> +       }
> +}
> +
> +static int ad4130_write_raw_get_fmt(struct iio_dev *indio_dev,
> +                                   struct iio_chan_spec const *chan,
> +                                   long info)
> +{
> +       switch (info) {
> +       case IIO_CHAN_INFO_SCALE:
> +       case IIO_CHAN_INFO_SAMP_FREQ:
> +               return IIO_VAL_INT_PLUS_NANO;
> +       default:
> +               return -EINVAL;
> +       }
> +}
> +
> +static int ad4130_write_raw(struct iio_dev *indio_dev,
> +                           struct iio_chan_spec const *chan,
> +                           int val, int val2, long info)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int channel = chan->scan_index;
> +
> +       switch (info) {
> +       case IIO_CHAN_INFO_SCALE:
> +               return ad4130_set_channel_pga(st, channel, val, val2);
> +       case IIO_CHAN_INFO_SAMP_FREQ:
> +               return ad4130_set_channel_freq(st, channel, val, val2);
> +       default:
> +               return -EINVAL;
> +       }
> +}
> +
> +static int ad4130_reg_access(struct iio_dev *indio_dev, unsigned int reg,
> +                            unsigned int writeval, unsigned int *readval)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +
> +       if (readval)
> +               return regmap_read(st->regmap, reg, readval);
> +
> +       return regmap_write(st->regmap, reg, writeval);
> +}
> +
> +static int ad4130_update_scan_mode(struct iio_dev *indio_dev,
> +                                  const unsigned long *scan_mask)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int channel;
> +       unsigned int val = 0;
> +       int ret;
> +
> +       mutex_lock(&st->lock);
> +
> +       for_each_set_bit(channel, scan_mask, indio_dev->num_channels) {
> +               ret = ad4130_set_channel_enable(st, channel, true);
> +               if (ret)
> +                       goto out;
> +
> +               val++;
> +       }
> +
> +       st->num_enabled_channels = val;
> +
> +out:
> +       mutex_unlock(&st->lock);
> +
> +       return 0;
> +}
> +
> +static int ad4130_set_fifo_watermark(struct iio_dev *indio_dev, unsigned int val)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int eff;
> +       int ret;
> +
> +       if (val > AD4130_FIFO_SIZE)
> +               return -EINVAL;
> +
> +       eff = val * st->num_enabled_channels;
> +       if (eff > AD4130_FIFO_SIZE)
> +               /*
> +                * Always set watermark to a multiple of the number of
> +                * enabled channels to avoid making the FIFO unaligned.
> +                */
> +               eff = rounddown(AD4130_FIFO_SIZE, st->num_enabled_channels);
> +
> +       mutex_lock(&st->lock);
> +
> +       ret = regmap_update_bits(st->regmap, AD4130_FIFO_CONTROL_REG,
> +                                AD4130_FIFO_CONTROL_WM_MASK,
> +                                FIELD_PREP(AD4130_FIFO_CONTROL_WM_MASK,
> +                                           ad4130_watermark_reg_val(eff)));
> +       if (ret)
> +               goto out;
> +
> +       st->effective_watermark = eff;
> +       st->watermark = val;
> +
> +out:
> +       mutex_unlock(&st->lock);
> +
> +       return ret;
> +}
> +
> +static const struct iio_info ad4130_info = {
> +       .read_raw = ad4130_read_raw,
> +       .read_avail = ad4130_read_avail,
> +       .write_raw_get_fmt = ad4130_write_raw_get_fmt,
> +       .write_raw = ad4130_write_raw,
> +       .update_scan_mode = ad4130_update_scan_mode,
> +       .hwfifo_set_watermark = ad4130_set_fifo_watermark,
> +       .debugfs_reg_access = ad4130_reg_access,
> +};
> +
> +static int ad4130_buffer_postenable(struct iio_dev *indio_dev)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       int ret;
> +
> +       mutex_lock(&st->lock);
> +
> +       ret = ad4130_set_watermark_interrupt_en(st, true);
> +       if (ret)
> +               goto out;
> +
> +       ret = irq_set_irq_type(st->spi->irq, st->inv_irq_trigger);
> +       if (ret)
> +               goto out;
> +
> +       ret = ad4130_set_fifo_mode(st, AD4130_FIFO_MODE_WM);
> +       if (ret)
> +               goto out;
> +
> +       ret = ad4130_set_mode(st, AD4130_MODE_CONTINUOUS);
> +
> +out:
> +       mutex_unlock(&st->lock);
> +
> +       return ret;
> +}
> +
> +static int ad4130_buffer_predisable(struct iio_dev *indio_dev)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int i;
> +       int ret;
> +
> +       mutex_lock(&st->lock);
> +
> +       ret = ad4130_set_mode(st, AD4130_MODE_IDLE);
> +       if (ret)
> +               goto out;
> +
> +       ret = irq_set_irq_type(st->spi->irq, st->irq_trigger);
> +       if (ret)
> +               goto out;
> +
> +       ret = ad4130_set_fifo_mode(st, AD4130_FIFO_MODE_DISABLED);
> +       if (ret)
> +               goto out;
> +
> +       ret = ad4130_set_watermark_interrupt_en(st, false);
> +       if (ret)
> +               goto out;
> +
> +       /*
> +        * update_scan_mode() is not called in the disable path, disable all
> +        * channels here.
> +        */
> +       for (i = 0; i < indio_dev->num_channels; i++) {
> +               ret = ad4130_set_channel_enable(st, i, false);
> +               if (ret)
> +                       goto out;
> +       }
> +
> +out:
> +       mutex_unlock(&st->lock);
> +
> +       return ret;
> +}
> +
> +static const struct iio_buffer_setup_ops ad4130_buffer_ops = {
> +       .postenable = ad4130_buffer_postenable,
> +       .predisable = ad4130_buffer_predisable,
> +};
> +
> +static ssize_t hwfifo_watermark_show(struct device *dev,
> +                                    struct device_attribute *attr, char *buf)
> +{
> +       struct ad4130_state *st = iio_priv(dev_to_iio_dev(dev));
> +       unsigned int val;
> +
> +       mutex_lock(&st->lock);
> +       val = st->watermark;
> +       mutex_unlock(&st->lock);
> +
> +       return sysfs_emit(buf, "%d\n", val);
> +}
> +
> +static ssize_t hwfifo_enabled_show(struct device *dev,
> +                                  struct device_attribute *attr, char *buf)
> +{
> +       struct ad4130_state *st = iio_priv(dev_to_iio_dev(dev));
> +       unsigned int val;
> +       int ret;
> +
> +       ret = regmap_read(st->regmap, AD4130_FIFO_CONTROL_REG, &val);
> +       if (ret)
> +               return ret;
> +
> +       val = FIELD_GET(AD4130_FIFO_CONTROL_MODE_MASK, val);
> +
> +       return sysfs_emit(buf, "%d\n", val != AD4130_FIFO_MODE_DISABLED);
> +}
> +
> +static IIO_CONST_ATTR(hwfifo_watermark_min, "1");
> +static IIO_CONST_ATTR(hwfifo_watermark_max, __stringify(AD4130_FIFO_SIZE));
> +static IIO_DEVICE_ATTR_RO(hwfifo_watermark, 0);
> +static IIO_DEVICE_ATTR_RO(hwfifo_enabled, 0);
> +
> +static const struct attribute *ad4130_fifo_attributes[] = {
> +       &iio_const_attr_hwfifo_watermark_min.dev_attr.attr,
> +       &iio_const_attr_hwfifo_watermark_max.dev_attr.attr,
> +       &iio_dev_attr_hwfifo_watermark.dev_attr.attr,
> +       &iio_dev_attr_hwfifo_enabled.dev_attr.attr,
> +       NULL
> +};
> +
> +static int _ad4130_find_table_index(const unsigned int *tbl, size_t len,
> +                                   unsigned int val)
> +{
> +       unsigned int i;
> +
> +       for (i = 0; i < len; i++)
> +               if (tbl[i] == val)
> +                       return i;
> +
> +       return -EINVAL;
> +}
> +
> +#define ad4130_find_table_index(table, val) \
> +       _ad4130_find_table_index(table, ARRAY_SIZE(table), val)
> +
> +static int ad4130_get_ref_voltage(struct ad4130_state *st,
> +                                 enum ad4130_ref_sel ref_sel)
> +{
> +       switch (ref_sel) {
> +       case AD4130_REF_REFIN1:
> +               return regulator_get_voltage(st->regulators[2].consumer);
> +       case AD4130_REF_REFIN2:
> +               return regulator_get_voltage(st->regulators[3].consumer);
> +       case AD4130_REF_AVDD_AVSS:
> +               return regulator_get_voltage(st->regulators[0].consumer);
> +       case AD4130_REF_REFOUT_AVSS:
> +               return st->int_ref_uv;
> +       default:
> +               return -EINVAL;
> +       }
> +}
> +
> +static int ad4130_parse_fw_setup(struct ad4130_state *st,
> +                                struct fwnode_handle *child,
> +                                struct ad4130_setup_info *setup_info)
> +{
> +       struct device *dev = &st->spi->dev;
> +       u32 tmp;
> +       int ret;
> +
> +       tmp = 0;
> +       fwnode_property_read_u32(child, "adi,excitation-current-0-nanoamp", &tmp);
> +       ret = ad4130_find_table_index(ad4130_iout_current_na_tbl, tmp);
> +       if (ret < 0)
> +               return dev_err_probe(dev, ret,
> +                                    "Invalid excitation current %unA\n", tmp);
> +       setup_info->iout0_val = ret;
> +
> +       tmp = 0;
> +       fwnode_property_read_u32(child, "adi,excitation-current-1-nanoamp", &tmp);
> +       ret = ad4130_find_table_index(ad4130_iout_current_na_tbl, tmp);
> +       if (ret < 0)
> +               return dev_err_probe(dev, ret,
> +                                    "Invalid excitation current %unA\n", tmp);
> +       setup_info->iout1_val = ret;
> +
> +       tmp = 0;
> +       fwnode_property_read_u32(child, "adi,burnout-current-nanoamp", &tmp);
> +       ret = ad4130_find_table_index(ad4130_burnout_current_na_tbl, tmp);
> +       if (ret < 0)
> +               return dev_err_probe(dev, ret,
> +                                    "Invalid burnout current %unA\n", tmp);
> +       setup_info->burnout = ret;
> +
> +       setup_info->ref_bufp = fwnode_property_read_bool(child, "adi,buffered-positive");
> +       setup_info->ref_bufm = fwnode_property_read_bool(child, "adi,buffered-negative");
> +
> +       setup_info->ref_sel = AD4130_REF_REFIN1;
> +       fwnode_property_read_u32(child, "adi,reference-select",
> +                                &setup_info->ref_sel);
> +       if (setup_info->ref_sel >= AD4130_REF_SEL_MAX)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Invalid reference selected %u\n",
> +                                    setup_info->ref_sel);
> +
> +       if (setup_info->ref_sel == AD4130_REF_REFOUT_AVSS)
> +               st->int_ref_en = true;
> +
> +       ret = ad4130_get_ref_voltage(st, setup_info->ref_sel);
> +       if (ret < 0)
> +               return dev_err_probe(dev, ret, "Cannot use reference %u\n",
> +                                    setup_info->ref_sel);
> +
> +       return 0;
> +}
> +
> +static int ad4130_validate_diff_channel(struct ad4130_state *st, u32 pin)
> +{
> +       struct device *dev = &st->spi->dev;
> +
> +       if (pin >= AD4130_MAX_DIFF_INPUTS)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Invalid diffreential channel %u\n", pin);
> +
> +       if (pin >= AD4130_MAX_ANALOG_PINS)
> +               return 0;
> +
> +       if (st->pins_fn[pin] == AD4130_PIN_FN_SPECIAL)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Pin %u already used with fn %u\n", pin,
> +                                    st->pins_fn[pin]);
> +
> +       st->pins_fn[pin] |= AD4130_PIN_FN_DIFF;
> +
> +       return 0;
> +}
> +
> +static int ad4130_validate_diff_channels(struct ad4130_state *st,
> +                                        u32 *pins, unsigned int len)
> +{
> +       unsigned int i;
> +       int ret;
> +
> +       for (i = 0; i < len; i++) {
> +               ret = ad4130_validate_diff_channel(st, pins[i]);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int ad4130_validate_excitation_pin(struct ad4130_state *st, u32 pin)
> +{
> +       struct device *dev = &st->spi->dev;
> +
> +       if (pin >= AD4130_MAX_ANALOG_PINS)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Invalid excitation pin %u\n", pin);
> +
> +       if (st->pins_fn[pin] == AD4130_PIN_FN_SPECIAL)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Pin %u already used with fn %u\n", pin,
> +                                    st->pins_fn[pin]);
> +
> +       st->pins_fn[pin] |= AD4130_PIN_FN_EXCITATION;
> +
> +       return 0;
> +}
> +
> +static int ad4130_validate_vbias_pin(struct ad4130_state *st, u32 pin)
> +{
> +       struct device *dev = &st->spi->dev;
> +
> +       if (pin >= AD4130_MAX_ANALOG_PINS)
> +               return dev_err_probe(dev, -EINVAL, "Invalid vbias pin %u\n",
> +                                    pin);
> +
> +       if (st->pins_fn[pin] == AD4130_PIN_FN_SPECIAL)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Pin %u already used with fn %u\n", pin,
> +                                    st->pins_fn[pin]);
> +
> +       st->pins_fn[pin] |= AD4130_PIN_FN_VBIAS;
> +
> +       return 0;
> +}
> +
> +static int ad4130_validate_vbias_pins(struct ad4130_state *st,
> +                                     u32 *pins, unsigned int len)
> +{
> +       unsigned int i;
> +       int ret;
> +
> +       for (i = 0; i < st->num_vbias_pins; i++) {
> +               ret = ad4130_validate_vbias_pin(st, pins[i]);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int ad4130_parse_fw_channel(struct iio_dev *indio_dev,
> +                                  struct fwnode_handle *child)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       unsigned int resolution = ad4130_resolution(st);
> +       unsigned int index = indio_dev->num_channels++;
> +       struct device *dev = &st->spi->dev;
> +       struct ad4130_chan_info *chan_info;
> +       struct iio_chan_spec *chan;
> +       u32 pins[2];
> +       int ret;
> +
> +       if (index >= AD4130_MAX_CHANNELS)
> +               return dev_err_probe(dev, -EINVAL, "Too many channels\n");
> +
> +       chan = &st->chans[index];
> +       chan_info = &st->chans_info[index];
> +
> +       *chan = ad4130_channel_template;
> +       chan->scan_type.realbits = resolution;
> +       chan->scan_type.storagebits = resolution;
> +       chan->scan_index = index;
> +
> +       chan_info->slot = AD4130_INVALID_SLOT;
> +       chan_info->setup.fs = AD4130_FILTER_SELECT_MIN;
> +       chan_info->initialized = true;
> +
> +       ret = fwnode_property_read_u32_array(child, "diff-channels", pins,
> +                                            ARRAY_SIZE(pins));
> +       if (ret)
> +               return ret;
> +
> +       ret = ad4130_validate_diff_channels(st, pins, ARRAY_SIZE(pins));
> +       if (ret)
> +               return ret;
> +
> +       chan->channel = pins[0];
> +       chan->channel2 = pins[1];
> +
> +       ret = ad4130_parse_fw_setup(st, child, &chan_info->setup);
> +       if (ret)
> +               return ret;
> +
> +       fwnode_property_read_u32(child, "adi,excitation-pin-0",
> +                                &chan_info->iout0);
> +       if (chan_info->setup.iout0_val != AD4130_IOUT_OFF) {
> +               ret = ad4130_validate_excitation_pin(st, chan_info->iout0);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       fwnode_property_read_u32(child, "adi,excitation-pin-1",
> +                                &chan_info->iout1);
> +       if (chan_info->setup.iout1_val != AD4130_IOUT_OFF) {
> +               ret = ad4130_validate_excitation_pin(st, chan_info->iout1);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int ad4130_parse_fw_children(struct iio_dev *indio_dev)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       struct device *dev = &st->spi->dev;
> +       struct fwnode_handle *child;
> +       int ret;
> +
> +       indio_dev->channels = st->chans;
> +
> +       device_for_each_child_node(dev, child) {
> +               ret = ad4130_parse_fw_channel(indio_dev, child);
> +               if (ret) {
> +                       fwnode_handle_put(child);
> +                       return ret;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static int ad4310_parse_fw(struct iio_dev *indio_dev)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       struct device *dev = &st->spi->dev;
> +       u32 ext_clk_freq = AD4130_MCLK_FREQ_76_8KHZ;
> +       bool int_clk_out;
> +       unsigned int i;
> +       int avdd_uv;
> +       int irq;
> +       int ret;
> +
> +       st->mclk = devm_clk_get_optional(dev, "mclk");
> +       if (IS_ERR(st->mclk))
> +               return dev_err_probe(dev, PTR_ERR(st->mclk),
> +                                    "Failed to get mclk\n");
> +
> +       st->int_pin_sel = AD4130_INT_PIN_INT;
> +
> +       for (i = 0; i < ARRAY_SIZE(ad4130_int_pin_names); i++) {
> +               irq = fwnode_irq_get_byname(dev_fwnode(dev),
> +                                           ad4130_int_pin_names[i]);
> +               if (irq > 0) {
> +                       st->int_pin_sel = i;
> +                       break;
> +               }
> +       }
> +
> +       if (st->int_pin_sel == AD4130_INT_PIN_DOUT)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Cannot use DOUT as interrupt pin\n");
> +
> +       if (st->int_pin_sel == AD4130_INT_PIN_P2)
> +               st->pins_fn[AD4130_AIN3_P2] = AD4130_PIN_FN_SPECIAL;
> +
> +       int_clk_out = device_property_read_bool(dev, "adi,int-clk-out");
> +       if (st->mclk && int_clk_out)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Cannot expose internal clock\n");
> +
> +       device_property_read_u32(dev, "adi,ext-clk-freq-hz", &ext_clk_freq);
> +       if (ext_clk_freq != AD4130_MCLK_FREQ_153_6KHZ &&
> +           ext_clk_freq != AD4130_MCLK_FREQ_76_8KHZ)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Invalid external clock frequency %u\n",
> +                                    ext_clk_freq);
> +
> +       if (st->mclk && ext_clk_freq == AD4130_MCLK_FREQ_153_6KHZ)
> +               st->mclk_sel = AD4130_MCLK_153_6KHZ_EXT;
> +       else if (st->mclk)
> +               st->mclk_sel = AD4130_MCLK_76_8KHZ_EXT;
> +       else if (int_clk_out)
> +               st->mclk_sel = AD4130_MCLK_76_8KHZ_OUT;
> +       else
> +               st->mclk_sel = AD4130_MCLK_76_8KHZ;
> +
> +       if (st->int_pin_sel == AD4130_INT_PIN_CLK &&
> +           st->mclk_sel != AD4130_MCLK_76_8KHZ)
> +               return dev_err_probe(dev, -EINVAL,
> +                                    "Invalid clock %u for interrupt pin %u\n",
> +                                    st->mclk_sel, st->int_pin_sel);
> +
> +       st->int_ref_uv = AD4130_INT_REF_2_5V;
> +
> +       /*
> +        * When the AVDD supply is set to below 2.5V the internal reference of
> +        * 1.25V should be selected.
> +        * See datasheet page 37, section ADC REFERENCE.
> +        */
> +       avdd_uv = regulator_get_voltage(st->regulators[0].consumer);
> +       if (avdd_uv > 0 && avdd_uv < AD4130_INT_REF_2_5V)
> +               st->int_ref_uv = AD4130_INT_REF_1_25V;
> +
> +       st->bipolar = device_property_read_bool(dev, "adi,bipolar");
> +
> +       ret = device_property_count_u32(dev, "adi,vbias-pins");
> +       if (ret > 0) {
> +               if (ret > AD4130_MAX_ANALOG_PINS)
> +                       return dev_err_probe(dev, -EINVAL,
> +                                            "Too many vbias pins %u\n", ret);
> +
> +               st->num_vbias_pins = ret;
> +
> +               ret = device_property_read_u32_array(dev, "adi,vbias-pins",
> +                                                    st->vbias_pins,
> +                                                    st->num_vbias_pins);
> +               if (ret)
> +                       return dev_err_probe(dev, ret,
> +                                            "Failed to read vbias pins\n");
> +
> +               ret = ad4130_validate_vbias_pins(st, st->vbias_pins,
> +                                                st->num_vbias_pins);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       ret = ad4130_parse_fw_children(indio_dev);
> +       if (ret)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +static void ad4130_fill_scale_tbls(struct ad4130_state *st)
> +{
> +       unsigned int pow = ad4130_resolution(st) - st->bipolar;
> +       unsigned int i, j;
> +
> +       for (i = 0; i < AD4130_REF_SEL_MAX; i++) {
> +               int ret;
> +               u64 nv;
> +
> +               ret = ad4130_get_ref_voltage(st, i);
> +               if (ret < 0)
> +                       continue;
> +
> +               nv = (u64)ret * NANO;
> +
> +               for (j = 0; j < AD4130_MAX_PGA; j++)
> +                       st->scale_tbls[i][j][1] = div_u64(nv >> (pow + j), MILLI);
> +       }
> +}
> +
> +static void ad4130_clk_disable_unprepare(void *clk)
> +{
> +       clk_disable_unprepare(clk);
> +}
> +
> +static int ad4130_setup(struct iio_dev *indio_dev)
> +{
> +       struct ad4130_state *st = iio_priv(indio_dev);
> +       struct device *dev = &st->spi->dev;
> +       unsigned int int_ref_val;
> +       unsigned long rate = AD4130_MCLK_FREQ_76_8KHZ;
> +       unsigned int val;
> +       unsigned int i;
> +       int ret;
> +
> +       if (st->mclk_sel == AD4130_MCLK_153_6KHZ_EXT)
> +               rate = AD4130_MCLK_FREQ_153_6KHZ;
> +
> +       ret = clk_set_rate(st->mclk, rate);
> +       if (ret)
> +               return ret;
> +
> +       ret = clk_prepare_enable(st->mclk);
> +       if (ret)
> +               return ret;
> +
> +       ret = devm_add_action_or_reset(dev, ad4130_clk_disable_unprepare,
> +                                      st->mclk);
> +       if (ret)
> +               return ret;
> +
> +       if (st->int_ref_uv == AD4130_INT_REF_2_5V)
> +               int_ref_val = AD4130_INT_REF_VAL_2_5V;
> +       else
> +               int_ref_val = AD4130_INT_REF_VAL_1_25V;
> +
> +       /* Switch to SPI 4-wire mode. */
> +       val =  FIELD_PREP(AD4130_ADC_CONTROL_CSB_EN_MASK, 1);
> +       val |= FIELD_PREP(AD4130_ADC_CONTROL_BIPOLAR_MASK, st->bipolar);
> +       val |= FIELD_PREP(AD4130_ADC_CONTROL_INT_REF_EN_MASK, st->int_ref_en);
> +       val |= FIELD_PREP(AD4130_ADC_CONTROL_MODE_MASK, AD4130_MODE_IDLE);
> +       val |= FIELD_PREP(AD4130_ADC_CONTROL_MCLK_SEL_MASK, st->mclk_sel);
> +       val |= FIELD_PREP(AD4130_ADC_CONTROL_INT_REF_VAL_MASK, int_ref_val);
> +
> +       ret = regmap_write(st->regmap, AD4130_ADC_CONTROL_REG, val);
> +       if (ret)
> +               return ret;
> +
> +       /*
> +        * Configure all GPIOs for output. If configured, the interrupt function
> +        * of P2 takes priority over the GPIO out function.
> +        */
> +       val =  AD4130_IO_CONTROL_GPIO_CTRL_MASK;
> +       val |= FIELD_PREP(AD4130_IO_CONTROL_INT_PIN_SEL_MASK, st->int_pin_sel);
> +
> +       ret = regmap_write(st->regmap, AD4130_IO_CONTROL_REG, val);
> +       if (ret)
> +               return ret;
> +
> +       val = 0;
> +       for (i = 0; i < st->num_vbias_pins; i++)
> +               val |= BIT(st->vbias_pins[i]);
> +
> +       ret = regmap_write(st->regmap, AD4130_VBIAS_REG, val);
> +       if (ret)
> +               return ret;
> +
> +       ret = regmap_update_bits(st->regmap, AD4130_FIFO_CONTROL_REG,
> +                                AD4130_FIFO_CONTROL_HEADER_MASK, 0);
> +       if (ret)
> +               return ret;
> +
> +       /* FIFO watermark interrupt starts out as enabled, disable it. */
> +       ret = ad4130_set_watermark_interrupt_en(st, false);
> +       if (ret)
> +               return ret;
> +
> +       /* Setup channels. */
> +       for (i = 0; i < indio_dev->num_channels; i++) {
> +               struct ad4130_chan_info *chan_info = &st->chans_info[i];
> +               struct iio_chan_spec *chan = &st->chans[i];
> +               unsigned int val;
> +
> +               val = FIELD_PREP(AD4130_CHANNEL_AINP_MASK, chan->channel) |
> +                     FIELD_PREP(AD4130_CHANNEL_AINM_MASK, chan->channel2) |
> +                     FIELD_PREP(AD4130_CHANNEL_IOUT1_MASK, chan_info->iout0) |
> +                     FIELD_PREP(AD4130_CHANNEL_IOUT2_MASK, chan_info->iout1);
> +
> +               ret = regmap_write(st->regmap, AD4130_CHANNEL_X_REG(i), val);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int ad4130_soft_reset(struct ad4130_state *st)
> +{
> +       int ret;
> +
> +       ret = spi_write(st->spi, st->reset_buf, sizeof(st->reset_buf));
> +       if (ret)
> +               return ret;
> +
> +       fsleep(AD4130_RESET_SLEEP_US);
> +
> +       return 0;
> +}
> +
> +static void ad4130_disable_regulators(void *data)
> +{
> +       struct ad4130_state *st = data;
> +
> +       regulator_bulk_disable(ARRAY_SIZE(st->regulators), st->regulators);
> +}
> +
> +static int ad4130_probe(struct spi_device *spi)
> +{
> +       struct device *dev = &spi->dev;
> +       struct iio_dev *indio_dev;
> +       struct ad4130_state *st;
> +       int ret;
> +
> +       indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
> +       if (!indio_dev)
> +               return -ENOMEM;
> +
> +       st = iio_priv(indio_dev);
> +
> +       memset(st->reset_buf, 0xff, sizeof(st->reset_buf));
> +       init_completion(&st->completion);
> +       mutex_init(&st->lock);
> +       st->spi = spi;
> +
> +       /*
> +        * Xfer:   [ XFR1 ] [         XFR2         ]
> +        * Master:  0x7D N   ......................
> +        * Slave:   ......   DATA1 DATA2 ... DATAN
> +        */
> +       st->fifo_tx_buf[0] = AD4130_COMMS_READ_MASK | AD4130_FIFO_DATA_REG;
> +       st->fifo_xfer[0].tx_buf = st->fifo_tx_buf;
> +       st->fifo_xfer[0].len = sizeof(st->fifo_tx_buf);
> +       st->fifo_xfer[1].rx_buf = st->fifo_rx_buf;
> +       spi_message_init_with_transfers(&st->fifo_msg, st->fifo_xfer,
> +                                       ARRAY_SIZE(st->fifo_xfer));
> +
> +       indio_dev->name = AD4130_NAME;
> +       indio_dev->modes = INDIO_DIRECT_MODE;
> +       indio_dev->info = &ad4130_info;
> +
> +       st->regmap = devm_regmap_init(dev, NULL, st, &ad4130_regmap_config);
> +       if (IS_ERR(st->regmap))
> +               return PTR_ERR(st->regmap);
> +
> +       st->regulators[0].supply = "avdd";
> +       st->regulators[1].supply = "iovdd";
> +       st->regulators[2].supply = "refin1";
> +       st->regulators[3].supply = "refin2";
> +
> +       ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(st->regulators),
> +                                     st->regulators);
> +       if (ret)
> +               return dev_err_probe(dev, ret, "Failed to get regulators\n");
> +
> +       ret = regulator_bulk_enable(ARRAY_SIZE(st->regulators), st->regulators);
> +       if (ret)
> +               return dev_err_probe(dev, ret, "Failed to enable regulators\n");
> +
> +       ret = devm_add_action_or_reset(dev, ad4130_disable_regulators, st);
> +       if (ret)
> +               return dev_err_probe(dev, ret,
> +                                    "Failed to add regulators disable action\n");
> +
> +       ret = ad4130_soft_reset(st);
> +       if (ret)
> +               return ret;
> +
> +       ret = ad4310_parse_fw(indio_dev);
> +       if (ret)
> +               return ret;
> +
> +       ret = ad4130_setup(indio_dev);
> +       if (ret)
> +               return ret;
> +
> +       ad4130_fill_scale_tbls(st);
> +
> +       st->gc.owner = THIS_MODULE;
> +       st->gc.label = AD4130_NAME;
> +       st->gc.base = -1;
> +       st->gc.ngpio = AD4130_MAX_GPIOS;
> +       st->gc.parent = dev;
> +       st->gc.can_sleep = true;
> +       st->gc.init_valid_mask = ad4130_gpio_init_valid_mask;
> +       st->gc.get_direction = ad4130_gpio_get_direction;
> +       st->gc.set = ad4130_gpio_set;
> +
> +       ret = devm_gpiochip_add_data(dev, &st->gc, st);
> +       if (ret)
> +               return ret;
> +
> +       ret = devm_iio_kfifo_buffer_setup_ext(dev, indio_dev,
> +                                             &ad4130_buffer_ops,
> +                                             ad4130_fifo_attributes);
> +       if (ret)
> +               return ret;
> +
> +       ret = devm_request_threaded_irq(dev, spi->irq, NULL,
> +                                       ad4130_irq_handler, IRQF_ONESHOT,
> +                                       indio_dev->name, indio_dev);
> +       if (ret)
> +               return dev_err_probe(dev, ret, "Failed to request irq\n");
> +
> +       /*
> +        * When the chip enters FIFO mode, IRQ polarity is inverted.
> +        * When the chip exits FIFO mode, IRQ polarity returns to normal.
> +        * See datasheet pages: 65, FIFO Watermark Interrupt section,
> +        * and 71, Bit Descriptions for STATUS Register, RDYB.
> +        * Cache the normal and inverted IRQ triggers to set them when
> +        * entering and exiting FIFO mode.
> +        */
> +       st->irq_trigger = irq_get_trigger_type(spi->irq);
> +       if (st->irq_trigger & IRQF_TRIGGER_RISING)
> +               st->inv_irq_trigger = IRQF_TRIGGER_FALLING;
> +       else if (st->irq_trigger & IRQF_TRIGGER_FALLING)
> +               st->inv_irq_trigger = IRQF_TRIGGER_RISING;
> +       else
> +               return dev_err_probe(dev, -EINVAL, "Invalid irq flags: %u\n",
> +                                    st->irq_trigger);
> +
> +       return devm_iio_device_register(dev, indio_dev);
> +}
> +
> +static const struct of_device_id ad4130_of_match[] = {
> +       {
> +               .compatible = "adi,ad4130",
> +       },
> +       { }
> +};
> +MODULE_DEVICE_TABLE(of, ad4130_of_match);
> +
> +static struct spi_driver ad4130_driver = {
> +       .driver = {
> +               .name = AD4130_NAME,
> +               .of_match_table = ad4130_of_match,
> +       },
> +       .probe = ad4130_probe,
> +};
> +module_spi_driver(ad4130_driver);
> +
> +MODULE_AUTHOR("Cosmin Tanislav <cosmin.tanislav@analog.com>");
> +MODULE_DESCRIPTION("Analog Devices AD4130 SPI driver");
> +MODULE_LICENSE("GPL");
> --
> 2.36.1
>


-- 
With Best Regards,
Andy Shevchenko