On Tue, 13 Nov 2018 13:21:32 +0200
Stefan Popa <stefan.p...@analog.com> wrote:

> The ad7124-4 and ad7124-8 are a family of 4 and 8 channel sigma-delta ADCs
> with 24-bit precision and reference.
> 
> Three power modes are available which in turn affect the output data rate:
>  * Full power: 9.38 SPS to 19,200 SPS
>  * Mid power: 2.34 SPS to 4800 SPS
>  * Low power: 1.17 SPS to 2400 SPS
> 
> The ad7124-4 can be configured to have four differential inputs, while
> ad7124-8 can have 8. Moreover, ad7124 also supports per channel
> configuration. Each configuration consists of gain, reference source,
> output data rate and bipolar/unipolar configuration.
> 
> Datasheets:
> Link: 
> http://www.analog.com/media/en/technical-documentation/data-sheets/AD7124-4.pdf
> Link: 
> http://www.analog.com/media/en/technical-documentation/data-sheets/ad7124-8.pdf
> 
> Signed-off-by: Stefan Popa <stefan.p...@analog.com>
Nice driver.  One totally trivial thing I noted inline, but I'll just
fix that up when applying once we have the binding acked.

Give me a poke if I seem to have forgotten this (it's been known to happen :(

Thanks,

Jonathan

> ---
> Changes in v2:
>       - Nothing changed.
> Changes in v3:
>       - Removed channel, address, scan_index and shift fields from
>         ad7124_channel_template.
>       - Added a sanity check for val2 in ad7124_write_raw().
>       - Used the "reg" property to get the channel address and 
> "adi,diff-channels"
>         for the differential pins. The "adi,channel-number" property was 
> removed.
>       - When calling regulator_get_optional, the probe is given up in case of 
> error,
>         but continues in case of -ENODEV.
>       - clk_disable_unprepare() is called before 
> ad_sd_cleanup_buffer_and_trigger
>         in ad7124_remove().
> Changes in v4:
>       - Added the .shift and .endianness fields as part of the 
> ad7124_channel_template.
>       - Made the gain configurable from the user space.
>       - Removed the odr_hz and gain properties from the DT.
>       - Used the bipolar and diff-channels properties defined in the new 
> adc.txt doc.
>       - Misc style fixes.
> Changes in v5:
>       - Fixed the way the offset is determined.
>       - Dropped the hardware gain.
>       - Added a scale_available attribute.
>       - The scale can be set from user space.
>       - In ad7124_read_raw(), the gain in applied to *val2.
>   
>  MAINTAINERS              |   7 +
>  drivers/iio/adc/Kconfig  |  11 +
>  drivers/iio/adc/Makefile |   1 +
>  drivers/iio/adc/ad7124.c | 686 
> +++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 705 insertions(+)
>  create mode 100644 drivers/iio/adc/ad7124.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f642044..3a1bfcb 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -839,6 +839,13 @@ S:       Supported
>  F:   drivers/iio/dac/ad5758.c
>  F:   Documentation/devicetree/bindings/iio/dac/ad5758.txt
>  
> +ANALOG DEVICES INC AD7124 DRIVER
> +M:   Stefan Popa <stefan.p...@analog.com>
> +L:   linux-...@vger.kernel.org
> +W:   http://ez.analog.com/community/linux-device-drivers
> +S:   Supported
> +F:   drivers/iio/adc/ad7124.c
> +
>  ANALOG DEVICES INC AD9389B DRIVER
>  M:   Hans Verkuil <hans.verk...@cisco.com>
>  L:   linux-me...@vger.kernel.org
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index a52fea8..148a10f 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -10,6 +10,17 @@ config AD_SIGMA_DELTA
>       select IIO_BUFFER
>       select IIO_TRIGGERED_BUFFER
>  
> +config AD7124
> +     tristate "Analog Devices AD7124 and similar sigma-delta ADCs driver"
> +     depends on SPI_MASTER
> +     select AD_SIGMA_DELTA
> +     help
> +       Say yes here to build support for Analog Devices AD7124-4 and AD7124-8
> +       SPI analog to digital converters (ADC).
> +
> +       To compile this driver as a module, choose M here: the module will be
> +       called ad7124.
> +
>  config AD7266
>       tristate "Analog Devices AD7265/AD7266 ADC driver"
>       depends on SPI_MASTER
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index a6e6a0b..76168b2 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -5,6 +5,7 @@
>  
>  # When adding new entries keep the list in alphabetical order
>  obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
> +obj-$(CONFIG_AD7124) += ad7124.o
>  obj-$(CONFIG_AD7266) += ad7266.o
>  obj-$(CONFIG_AD7291) += ad7291.o
>  obj-$(CONFIG_AD7298) += ad7298.o
> diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
> new file mode 100644
> index 0000000..187675e
> --- /dev/null
> +++ b/drivers/iio/adc/ad7124.c
> @@ -0,0 +1,686 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * AD7124 SPI ADC driver
> + *
> + * Copyright 2018 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/spi/spi.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/adc/ad_sigma_delta.h>
> +#include <linux/iio/sysfs.h>
> +
> +/* AD7124 registers */
> +#define AD7124_COMMS                 0x00
> +#define AD7124_STATUS                        0x00
> +#define AD7124_ADC_CONTROL           0x01
> +#define AD7124_DATA                  0x02
> +#define AD7124_IO_CONTROL_1          0x03
> +#define AD7124_IO_CONTROL_2          0x04
> +#define AD7124_ID                    0x05
> +#define AD7124_ERROR                 0x06
> +#define AD7124_ERROR_EN              0x07
> +#define AD7124_MCLK_COUNT            0x08
> +#define AD7124_CHANNEL(x)            (0x09 + (x))
> +#define AD7124_CONFIG(x)             (0x19 + (x))
> +#define AD7124_FILTER(x)             (0x21 + (x))
> +#define AD7124_OFFSET(x)             (0x29 + (x))
> +#define AD7124_GAIN(x)                       (0x31 + (x))
> +
> +/* AD7124_STATUS */
> +#define AD7124_STATUS_POR_FLAG_MSK   BIT(4)
> +
> +/* AD7124_ADC_CONTROL */
> +#define AD7124_ADC_CTRL_PWR_MSK      GENMASK(7, 6)
> +#define AD7124_ADC_CTRL_PWR(x)               
> FIELD_PREP(AD7124_ADC_CTRL_PWR_MSK, x)
> +#define AD7124_ADC_CTRL_MODE_MSK     GENMASK(5, 2)
> +#define AD7124_ADC_CTRL_MODE(x)      FIELD_PREP(AD7124_ADC_CTRL_MODE_MSK, x)
> +
> +/* AD7124_CHANNEL_X */
> +#define AD7124_CHANNEL_EN_MSK                BIT(15)
> +#define AD7124_CHANNEL_EN(x)         FIELD_PREP(AD7124_CHANNEL_EN_MSK, x)
> +#define AD7124_CHANNEL_SETUP_MSK     GENMASK(14, 12)
> +#define AD7124_CHANNEL_SETUP(x)      FIELD_PREP(AD7124_CHANNEL_SETUP_MSK, x)
> +#define AD7124_CHANNEL_AINP_MSK      GENMASK(9, 5)
> +#define AD7124_CHANNEL_AINP(x)               
> FIELD_PREP(AD7124_CHANNEL_AINP_MSK, x)
> +#define AD7124_CHANNEL_AINM_MSK      GENMASK(4, 0)
> +#define AD7124_CHANNEL_AINM(x)               
> FIELD_PREP(AD7124_CHANNEL_AINM_MSK, x)
> +
> +/* AD7124_CONFIG_X */
> +#define AD7124_CONFIG_BIPOLAR_MSK    BIT(11)
> +#define AD7124_CONFIG_BIPOLAR(x)     FIELD_PREP(AD7124_CONFIG_BIPOLAR_MSK, x)
> +#define AD7124_CONFIG_REF_SEL_MSK    GENMASK(4, 3)
> +#define AD7124_CONFIG_REF_SEL(x)     FIELD_PREP(AD7124_CONFIG_REF_SEL_MSK, x)
> +#define AD7124_CONFIG_PGA_MSK                GENMASK(2, 0)
> +#define AD7124_CONFIG_PGA(x)         FIELD_PREP(AD7124_CONFIG_PGA_MSK, x)
> +
> +/* AD7124_FILTER_X */
> +#define AD7124_FILTER_FS_MSK         GENMASK(10, 0)
> +#define AD7124_FILTER_FS(x)          FIELD_PREP(AD7124_FILTER_FS_MSK, x)
> +
> +enum ad7124_ids {
> +     ID_AD7124_4,
> +     ID_AD7124_8,
> +};
> +
> +enum ad7124_ref_sel {
> +     AD7124_REFIN1,
> +     AD7124_REFIN2,
> +     AD7124_INT_REF,
> +     AD7124_AVDD_REF,
> +};
> +
> +enum ad7124_power_mode {
> +     AD7124_LOW_POWER,
> +     AD7124_MID_POWER,
> +     AD7124_FULL_POWER,
> +};
> +
> +static const unsigned int ad7124_gain[8] = {
> +     1, 2, 4, 8, 16, 32, 64, 128
> +};
> +
> +static const int ad7124_master_clk_freq_hz[3] = {
> +     [AD7124_LOW_POWER] = 76800,
> +     [AD7124_MID_POWER] = 153600,
> +     [AD7124_FULL_POWER] = 614400,
> +};
> +
> +static const char * const ad7124_ref_names[] = {
> +     [AD7124_REFIN1] = "refin1",
> +     [AD7124_REFIN2] = "refin2",
> +     [AD7124_INT_REF] = "int",
> +     [AD7124_AVDD_REF] = "avdd",
> +};
> +
> +struct ad7124_chip_info {
> +     unsigned int num_inputs;
> +};
> +
> +struct ad7124_channel_config {
> +     enum ad7124_ref_sel refsel;
> +     bool bipolar;
> +     unsigned int ain;
> +     unsigned int vref_mv;
> +     unsigned int pga_bits;
> +     unsigned int odr;
> +};
> +
> +struct ad7124_state {
> +     const struct ad7124_chip_info *chip_info;
> +     struct ad_sigma_delta sd;
> +     struct ad7124_channel_config channel_config[4];
> +     struct regulator *vref[4];
> +     struct clk *mclk;
> +     unsigned int adc_control;
> +     unsigned int num_channels;
> +};
> +
> +static const struct iio_chan_spec ad7124_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),
> +     .scan_type = {
> +             .sign = 'u',
> +             .realbits = 24,
> +             .storagebits = 32,
> +             .shift = 8,
> +             .endianness = IIO_BE,
> +     },
> +};
> +
> +static struct ad7124_chip_info ad7124_chip_info_tbl[] = {
> +     [ID_AD7124_4] = {
> +             .num_inputs = 8,
> +     },
> +     [ID_AD7124_8] = {
> +             .num_inputs = 16,
> +     },
> +};
> +
> +static int ad7124_find_closest_match(const int *array,
> +                                  unsigned int size, int val)
> +{
> +     int i, idx;
> +     unsigned int diff_new, diff_old;
> +
> +     diff_old = U32_MAX;
> +     idx = 0;
> +
> +     for (i = 0; i < size; i++) {
> +             diff_new = abs(val - array[i]);
> +             if (diff_new < diff_old) {
> +                     diff_old = diff_new;
> +                     idx = i;
> +             }
> +     }
> +
> +     return idx;
> +}
> +
> +static int ad7124_spi_write_mask(struct ad7124_state *st,
> +                              unsigned int addr,
> +                              unsigned long mask,
> +                              unsigned int val,
> +                              unsigned int bytes)
> +{
> +     unsigned int readval;
> +     int ret;
> +
> +     ret = ad_sd_read_reg(&st->sd, addr, bytes, &readval);
> +     if (ret < 0)
> +             return ret;
> +
> +     readval &= ~mask;
> +     readval |= val;
> +
> +     return ad_sd_write_reg(&st->sd, addr, bytes, readval);
> +}
> +
> +static int ad7124_set_mode(struct ad_sigma_delta *sd,
> +                        enum ad_sigma_delta_mode mode)
> +{
> +     struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
> +
> +     st->adc_control &= ~AD7124_ADC_CTRL_MODE_MSK;
> +     st->adc_control |= AD7124_ADC_CTRL_MODE(mode);
> +
> +     return ad_sd_write_reg(&st->sd, AD7124_ADC_CONTROL, 2, st->adc_control);
> +}
> +
> +static int ad7124_set_channel(struct ad_sigma_delta *sd, unsigned int 
> channel)
> +{
> +     struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
> +     unsigned int val;
> +
> +     val = st->channel_config[channel].ain | AD7124_CHANNEL_EN(1) |
> +           AD7124_CHANNEL_SETUP(channel);
> +
> +     return ad_sd_write_reg(&st->sd, AD7124_CHANNEL(channel), 2, val);
> +}
> +
> +static const struct ad_sigma_delta_info ad7124_sigma_delta_info = {
> +     .set_channel = ad7124_set_channel,
> +     .set_mode = ad7124_set_mode,
> +     .has_registers = true,
> +     .addr_shift = 0,
> +     .read_mask = BIT(6),
> +     .data_reg = AD7124_DATA,
> +};
> +
> +static int ad7124_set_channel_odr(struct ad7124_state *st,
> +                               unsigned int channel,
> +                               unsigned int odr)
> +{
> +     unsigned int fclk, odr_sel_bits;
> +     int ret;
> +
> +     fclk = clk_get_rate(st->mclk);
> +     /*
> +      * FS[10:0] = fCLK / (fADC x 32) where:
> +      * fADC is the output data rate
> +      * fCLK is the master clock frequency
> +      * FS[10:0] are the bits in the filter register
> +      * FS[10:0] can have a value from 1 to 2047
> +      */
> +     odr_sel_bits = DIV_ROUND_CLOSEST(fclk, odr * 32);
> +     if (odr_sel_bits < 1)
> +             odr_sel_bits = 1;
> +     else if (odr_sel_bits > 2047)
> +             odr_sel_bits = 2047;
> +
> +     ret = ad7124_spi_write_mask(st, AD7124_FILTER(channel),
> +                                 AD7124_FILTER_FS_MSK,
> +                                 AD7124_FILTER_FS(odr_sel_bits), 3);
> +     if (ret < 0)
> +             return ret;
> +     /* fADC = fCLK / (FS[10:0] x 32) */
> +     st->channel_config[channel].odr =
> +             DIV_ROUND_CLOSEST(fclk, odr_sel_bits * 32);
> +
> +     return 0;
> +}
> +
> +static int ad7124_set_channel_gain(struct ad7124_state *st,
> +                                unsigned int channel,
> +                                unsigned int gain)
> +{
> +     unsigned int res;
> +     int ret;
> +
> +     res = ad7124_find_closest_match(ad7124_gain,
> +                                     ARRAY_SIZE(ad7124_gain), gain);
> +     ret = ad7124_spi_write_mask(st, AD7124_CONFIG(channel),
> +                                 AD7124_CONFIG_PGA_MSK,
> +                                 AD7124_CONFIG_PGA(res), 2);
> +     if (ret < 0)
> +             return ret;
> +
> +     st->channel_config[channel].pga_bits = res;
> +
> +     return 0;
> +}
> +
> +static int ad7124_read_raw(struct iio_dev *indio_dev,
> +                        struct iio_chan_spec const *chan,
> +                        int *val, int *val2, long info)
> +{
> +     struct ad7124_state *st = iio_priv(indio_dev);
> +     int idx, ret;
> +
> +     switch (info) {
> +     case IIO_CHAN_INFO_RAW:
> +             ret = ad_sigma_delta_single_conversion(indio_dev, chan, val);
> +             if (ret < 0)
> +                     return ret;
> +
> +             /* After the conversion is performed, disable the channel */
> +             ret = ad_sd_write_reg(&st->sd,
> +                                   AD7124_CHANNEL(chan->address), 2,
> +                                   st->channel_config[chan->address].ain |
> +                                   AD7124_CHANNEL_EN(0));
> +             if (ret < 0)
> +                     return ret;
> +
> +             return IIO_VAL_INT;
> +     case IIO_CHAN_INFO_SCALE:
> +             idx = st->channel_config[chan->address].pga_bits;
> +             *val = st->channel_config[chan->address].vref_mv;
> +             if (st->channel_config[chan->address].bipolar)
> +                     *val2 = chan->scan_type.realbits - 1 + idx;
> +             else
> +                     *val2 = chan->scan_type.realbits + idx;
> +
> +             return IIO_VAL_FRACTIONAL_LOG2;
> +     case IIO_CHAN_INFO_OFFSET:
> +             if (st->channel_config[chan->address].bipolar)
> +                     *val = -(1 << (chan->scan_type.realbits - 1));
> +             else
> +                     *val = 0;
> +
> +             return IIO_VAL_INT;
> +     case IIO_CHAN_INFO_SAMP_FREQ:
> +             *val = st->channel_config[chan->address].odr;
> +
> +             return IIO_VAL_INT;
> +     default:
> +             return -EINVAL;
> +     }
> +}
> +
> +static int ad7124_write_raw(struct iio_dev *indio_dev,
> +                         struct iio_chan_spec const *chan,
> +                         int val, int val2, long info)
> +{
> +     struct ad7124_state *st = iio_priv(indio_dev);
> +     unsigned int res, gain, full_scale, vref;
> +
> +     switch (info) {
> +     case IIO_CHAN_INFO_SAMP_FREQ:
> +             if (val2 != 0)
> +                     return -EINVAL;
> +
> +             return ad7124_set_channel_odr(st, chan->address, val);
> +     case IIO_CHAN_INFO_SCALE:
> +             if (val != 0)
> +                     return -EINVAL;
> +
> +             if (st->channel_config[chan->address].bipolar)
> +                     full_scale = 1 << (chan->scan_type.realbits - 1);
> +             else
> +                     full_scale = 1 << chan->scan_type.realbits;
> +
> +             vref = st->channel_config[chan->address].vref_mv * 1000000LL;
> +             res = DIV_ROUND_CLOSEST(vref, full_scale);
> +             gain = DIV_ROUND_CLOSEST(res, val2);
> +
> +             return ad7124_set_channel_gain(st, chan->address, gain);
> +     default:
> +             return -EINVAL;
> +     }
> +}
> +
> +static IIO_CONST_ATTR(in_voltage_scale_available,
> +     "0.000001164 0.000002328 0.000004656 0.000009313 0.000018626 
> 0.000037252 0.000074505 0.000149011 0.000298023");
> +
> +static struct attribute *ad7124_attributes[] = {
> +     &iio_const_attr_in_voltage_scale_available.dev_attr.attr,
> +     NULL,
> +};
> +
> +static const struct attribute_group ad7124_attrs_group = {
> +     .attrs = ad7124_attributes,
> +};
> +
> +static const struct iio_info ad7124_info = {
> +     .read_raw = ad7124_read_raw,
> +     .write_raw = ad7124_write_raw,
> +     .validate_trigger = ad_sd_validate_trigger,
> +     .attrs = &ad7124_attrs_group,
> +};
> +
> +static int ad7124_soft_reset(struct ad7124_state *st)
> +{
> +     unsigned int readval, timeout;
> +     int ret;
> +
> +     ret = ad_sd_reset(&st->sd, 64);
> +     if (ret < 0)
> +             return ret;
> +
> +     timeout = 100;
> +     do {
> +             ret = ad_sd_read_reg(&st->sd, AD7124_STATUS, 1, &readval);
> +             if (ret < 0)
> +                     return ret;
> +
> +             if (!(readval & AD7124_STATUS_POR_FLAG_MSK))
> +                     return 0;
> +
> +             /* The AD7124 requires typically 2ms to power up and settle */
> +             usleep_range(100, 2000);
> +     } while (--timeout);
> +
> +     dev_err(&st->sd.spi->dev, "Soft reset failed\n");
> +
> +     return -EIO;
> +}
> +
> +static int ad7124_init_channel_vref(struct ad7124_state *st,
> +                                 unsigned int channel_number)
> +{
> +     unsigned int refsel = st->channel_config[channel_number].refsel;
> +
> +     switch (refsel) {
> +     case AD7124_REFIN1:
> +     case AD7124_REFIN2:
> +     case AD7124_AVDD_REF:
> +             if (IS_ERR(st->vref[refsel])) {
> +                     dev_err(&st->sd.spi->dev,
> +                             "Error, trying to use external voltage 
> reference without a %s regulator.\n",
> +                             ad7124_ref_names[refsel]);
> +                             return PTR_ERR(st->vref[refsel]);
> +             }
> +             st->channel_config[channel_number].vref_mv =
> +                     regulator_get_voltage(st->vref[refsel]);
> +             /* Conversion from uV to mV */
> +             st->channel_config[channel_number].vref_mv /= 1000;
> +             break;
> +     case AD7124_INT_REF:
> +             st->channel_config[channel_number].vref_mv = 2500;
> +             break;
> +     default:
> +             dev_err(&st->sd.spi->dev, "Invalid reference %d\n", refsel);
> +             return -EINVAL;
> +     }
> +
> +     return 0;
> +}
> +
> +static int ad7124_of_parse_channel_config(struct iio_dev *indio_dev,
> +                                       struct device_node *np)
> +{
> +     struct ad7124_state *st = iio_priv(indio_dev);
> +     struct device_node *child;
> +     struct iio_chan_spec *chan;
> +     unsigned int ain[2], channel = 0, tmp;
> +     int ret;
> +
> +     st->num_channels = of_get_available_child_count(np);
> +     if (!st->num_channels) {
> +             dev_err(indio_dev->dev.parent, "no channel children\n");
> +             return -ENODEV;
> +     }
> +
> +     chan = devm_kcalloc(indio_dev->dev.parent, st->num_channels,
> +                         sizeof(*chan), GFP_KERNEL);
> +     if (!chan)
> +             return -ENOMEM;
> +
> +     indio_dev->channels = chan;
> +     indio_dev->num_channels = st->num_channels;
> +
> +     for_each_available_child_of_node(np, child) {
> +             ret = of_property_read_u32(child, "reg", &channel);
> +             if (ret)
> +                     goto err;
> +
> +             ret = of_property_read_u32_array(child, "diff-channels",
> +                                              ain, 2);
> +             if (ret)
> +                     goto err;
> +
> +             if (ain[0] >= st->chip_info->num_inputs ||
> +                 ain[1] >= st->chip_info->num_inputs) {
> +                     dev_err(indio_dev->dev.parent,
> +                             "Input pin number out of range.\n");
> +                     ret = -EINVAL;
> +                     goto err;
> +             }
> +             st->channel_config[channel].ain = AD7124_CHANNEL_AINP(ain[0]) |
> +                                               AD7124_CHANNEL_AINM(ain[1]);
> +             st->channel_config[channel].bipolar =
> +                     of_property_read_bool(child, "bipolar");
> +
> +             ret = of_property_read_u32(child, "adi,reference-select", &tmp);
> +             if (ret)
> +                     st->channel_config[channel].refsel = AD7124_INT_REF;
> +             else
> +                     st->channel_config[channel].refsel = tmp;
> +
> +             *chan = ad7124_channel_template;
> +             chan->address = channel;
> +             chan->scan_index = channel;
> +             chan->channel = ain[0];
> +             chan->channel2 = ain[1];
> +
> +             chan++;
> +     }
> +
> +     return 0;
> +err:
> +     of_node_put(child);
> +
> +     return ret;
> +}
> +
> +static int ad7124_setup(struct ad7124_state *st)
> +{
> +     unsigned int val, fclk, power_mode;
> +     int i, ret;
> +
> +     fclk = clk_get_rate(st->mclk);
> +     if (!fclk)
> +             return -EINVAL;
> +
> +     /* The power mode changes the master clock frequency */
> +     power_mode = ad7124_find_closest_match(ad7124_master_clk_freq_hz,
> +                                     ARRAY_SIZE(ad7124_master_clk_freq_hz),
> +                                     fclk);
> +     if (fclk != ad7124_master_clk_freq_hz[power_mode]) {
> +             ret = clk_set_rate(st->mclk, fclk);
> +             if (ret)
> +                     return ret;
> +     }
> +
> +     /* Set the power mode */
> +     st->adc_control &= ~AD7124_ADC_CTRL_PWR_MSK;
> +     st->adc_control |= AD7124_ADC_CTRL_PWR(power_mode);
> +     ret = ad_sd_write_reg(&st->sd, AD7124_ADC_CONTROL, 2, st->adc_control);
> +     if (ret < 0)
> +             return ret;
> +
> +     for (i = 0; i < st->num_channels; i++) {
> +             val = st->channel_config[i].ain | AD7124_CHANNEL_SETUP(i);
> +             ret = ad_sd_write_reg(&st->sd, AD7124_CHANNEL(i), 2, val);
> +             if (ret < 0)
> +                     return ret;
> +
> +             ret = ad7124_init_channel_vref(st, i);
> +             if (ret < 0)
> +                     return ret;
> +
> +             val = AD7124_CONFIG_BIPOLAR(st->channel_config[i].bipolar) |
> +                   AD7124_CONFIG_REF_SEL(st->channel_config[i].refsel);
> +             ret = ad_sd_write_reg(&st->sd, AD7124_CONFIG(i), 2, val);
> +             if (ret < 0)
> +                     return ret;
> +             /*
> +              * 9.38 SPS is the minimum output data rate supported
> +              * regardless of the selected power mode. Round it up to 10 and
> +              * set all the enabled channels to this default value.
> +              */
> +             ret = ad7124_set_channel_odr(st, i, 10);
> +             if (ret < 0)
> +                     return ret;

It's really trivial and I'll just clean it up, but clearly this return ret
doesn't actually do anything useful given we'll return ret anyway ;)

> +     }
> +
> +     return ret;
> +}
> +
> +static int ad7124_probe(struct spi_device *spi)
> +{
> +     const struct spi_device_id *id;
> +     struct ad7124_state *st;
> +     struct iio_dev *indio_dev;
> +     int i, ret;
> +
> +     indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> +     if (!indio_dev)
> +             return -ENOMEM;
> +
> +     st = iio_priv(indio_dev);
> +
> +     id = spi_get_device_id(spi);
> +     st->chip_info = &ad7124_chip_info_tbl[id->driver_data];
> +
> +     ad_sd_init(&st->sd, indio_dev, spi, &ad7124_sigma_delta_info);
> +
> +     spi_set_drvdata(spi, indio_dev);
> +
> +     indio_dev->dev.parent = &spi->dev;
> +     indio_dev->name = spi_get_device_id(spi)->name;
> +     indio_dev->modes = INDIO_DIRECT_MODE;
> +     indio_dev->info = &ad7124_info;
> +
> +     ret = ad7124_of_parse_channel_config(indio_dev, spi->dev.of_node);
> +     if (ret < 0)
> +             return ret;
> +
> +     for (i = 0; i < ARRAY_SIZE(st->vref); i++) {
> +             if (i == AD7124_INT_REF)
> +                     continue;
> +
> +             st->vref[i] = devm_regulator_get_optional(&spi->dev,
> +                                             ad7124_ref_names[i]);
> +             if (PTR_ERR(st->vref[i]) == -ENODEV)
> +                     continue;
> +             else if (IS_ERR(st->vref[i]))
> +                     return PTR_ERR(st->vref[i]);
> +
> +             ret = regulator_enable(st->vref[i]);
> +             if (ret)
> +                     return ret;
> +     }
> +
> +     st->mclk = devm_clk_get(&spi->dev, "mclk");
> +     if (IS_ERR(st->mclk)) {
> +             ret = PTR_ERR(st->mclk);
> +             goto error_regulator_disable;
> +     }
> +
> +     ret = clk_prepare_enable(st->mclk);
> +     if (ret < 0)
> +             goto error_regulator_disable;
> +
> +     ret = ad7124_soft_reset(st);
> +     if (ret < 0)
> +             goto error_clk_disable_unprepare;
> +
> +     ret = ad7124_setup(st);
> +     if (ret < 0)
> +             goto error_clk_disable_unprepare;
> +
> +     ret = ad_sd_setup_buffer_and_trigger(indio_dev);
> +     if (ret < 0)
> +             goto error_clk_disable_unprepare;
> +
> +     ret = iio_device_register(indio_dev);
> +     if (ret < 0) {
> +             dev_err(&spi->dev, "Failed to register iio device\n");
> +             goto error_remove_trigger;
> +     }
> +
> +     return 0;
> +
> +error_remove_trigger:
> +     ad_sd_cleanup_buffer_and_trigger(indio_dev);
> +error_clk_disable_unprepare:
> +     clk_disable_unprepare(st->mclk);
> +error_regulator_disable:
> +     for (i = ARRAY_SIZE(st->vref) - 1; i >= 0; i--) {
> +             if (!IS_ERR_OR_NULL(st->vref[i]))
> +                     regulator_disable(st->vref[i]);
> +     }
> +
> +     return ret;
> +}
> +
> +static int ad7124_remove(struct spi_device *spi)
> +{
> +     struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +     struct ad7124_state *st = iio_priv(indio_dev);
> +     int i;
> +
> +     iio_device_unregister(indio_dev);
> +     ad_sd_cleanup_buffer_and_trigger(indio_dev);
> +     clk_disable_unprepare(st->mclk);
> +
> +     for (i = ARRAY_SIZE(st->vref) - 1; i >= 0; i--) {
> +             if (!IS_ERR_OR_NULL(st->vref[i]))
> +                     regulator_disable(st->vref[i]);
> +     }
> +
> +     return 0;
> +}
> +
> +static const struct spi_device_id ad7124_id_table[] = {
> +     { "ad7124-4", ID_AD7124_4 },
> +     { "ad7124-8", ID_AD7124_8 },
> +     {}
> +};
> +MODULE_DEVICE_TABLE(spi, ad7124_id_table);
> +
> +static const struct of_device_id ad7124_of_match[] = {
> +     { .compatible = "adi,ad7124-4" },
> +     { .compatible = "adi,ad7124-8" },
> +     { },
> +};
> +MODULE_DEVICE_TABLE(of, ad7124_of_match);
> +
> +static struct spi_driver ad71124_driver = {
> +     .driver = {
> +             .name = "ad7124",
> +             .of_match_table = ad7124_of_match,
> +     },
> +     .probe = ad7124_probe,
> +     .remove = ad7124_remove,
> +     .id_table = ad7124_id_table,
> +};
> +module_spi_driver(ad71124_driver);
> +
> +MODULE_AUTHOR("Stefan Popa <stefan.p...@analog.com>");
> +MODULE_DESCRIPTION("Analog Devices AD7124 SPI driver");
> +MODULE_LICENSE("GPL");

Reply via email to