> This patch adds support for the Texas Intruments ADS868x ADC.
looks good, some minor comments below
maybe add link to datasheet
> Signed-off-by: Sean Nyekjaer <sean.nyekjaer@xxxxxxxxx>
> Reviewed-by: Martin Hundebøll <martin.hundeboll@xxxxxxxxx>
> ---
> Changes since v1:
> - Now possible to read and write the actual offset and scale values
> - Removed unused includes
> - Removed unused buffer references
>
> drivers/iio/adc/Kconfig | 10 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/ti-ads868x.c | 456 +++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 467 insertions(+)
> create mode 100644 drivers/iio/adc/ti-ads868x.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index deea62c..39924d5 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -322,6 +322,16 @@ config TI_ADC128S052
> This driver can also be built as a module. If so, the module will be
> called ti-adc128s052.
>
> +config TI_ADS868X
> + tristate "Texas Instruments ADS8684/8"
> + depends on SPI && OF
> + help
> + If you say yes here you get support for Texas Instruments ADS8684 and
> + and ADS8688 ADC chips
> +
> + This driver can also be built as a module. If so, the module will be
> + called ti-ads868x.
> +
> config TI_AM335X_ADC
> tristate "TI's AM335X ADC driver"
> depends on MFD_TI_AM335X_TSCADC
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index fa5723a..75170d2 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -31,6 +31,7 @@ obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
> obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
> obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
> obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
> +obj-$(CONFIG_TI_ADS868X) += ti-ads868x.o
> obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
> obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
> obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
> diff --git a/drivers/iio/adc/ti-ads868x.c b/drivers/iio/adc/ti-ads868x.c
> new file mode 100644
> index 0000000..66d9b64
> --- /dev/null
> +++ b/drivers/iio/adc/ti-ads868x.c
> @@ -0,0 +1,456 @@
> +/*
> + * Copyright (C) 2015 Prevas A/S
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +#include <linux/spi/spi.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define ADS868X_CMD_REG(x) (x << 8)
> +#define ADS868X_CMD_REG_NOOP 0x00
> +#define ADS868X_CMD_REG_RST 0x85
> +#define ADS868X_CMD_REG_MAN_CH(chan) (0xC0 | (4 * chan))
> +#define ADS868X_CMD_DONT_CARE_BITS 16
> +
> +#define ADS868X_PROG_REG(x) (x << 9)
> +#define ADS868X_PROG_REG_RANGE_CH(chan) (0x05 + chan)
> +#define ADS868X_PROG_WR_BIT BIT(8)
> +#define ADS868X_PROG_DONT_CARE_BITS 8
> +
> +#define ADS868X_VREF_MV 4096
> +#define ADS868X_REALBITS 16
> +
> +struct ads868x_chip_info {
> + unsigned int id;
> + const struct iio_chan_spec *channels;
> + unsigned int num_channels;
> + unsigned int flags;
> + const struct iio_info *iio_info;
> +};
> +
> +struct ads868x_state {
> + const struct ads868x_chip_info *chip_info;
> + struct spi_device *spi;
> + struct regulator *reg;
> + unsigned int vref_mv;
> + char range[8];
> + union {
> + __be32 d32;
> + u8 d8[4];
> + } data[2] ____cacheline_aligned;
> +};
> +
> +enum ads868x_id {
> + ID_ADS8684,
> + ID_ADS8688,
> +};
> +
> +enum ads868x_range {
> + ADS868X_PLUSMINUS25VREF = 0x00,
> + ADS868X_PLUSMINUS125VREF = 0x01,
> + ADS868X_PLUSMINUS0625VREF = 0x02,
> + ADS868X_PLUS25VREF = 0x05,
> + ADS868X_PLUS125VREF = 0x06,
> +};
> +
> +struct ads868x_ranges {
> + enum ads868x_range range;
> + unsigned int scale;
> + int offset;
> +};
> +
> +static struct ads868x_ranges ads868x_range_def[5] = {
can be const?
> + {
> + .range = ADS868X_PLUSMINUS25VREF,
> + .scale = 76295,
> + .offset = -(1 << (ADS868X_REALBITS - 1)),
> + }, {
> + .range = ADS868X_PLUSMINUS125VREF,
> + .scale = 38148,
> + .offset = -(1 << (ADS868X_REALBITS - 1)),
> + }, {
> + .range = ADS868X_PLUSMINUS0625VREF,
> + .scale = 19074,
> + .offset = -(1 << (ADS868X_REALBITS - 1)),
> + }, {
> + .range = ADS868X_PLUS25VREF,
> + .scale = 38148,
> + .offset = 0,
> + }, {
> + .range = ADS868X_PLUS125VREF,
> + .scale = 19074,
> + .offset = 0,
> + }
> +};
> +
> +static ssize_t ads868x_show_scales(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct ads868x_state *st = iio_priv(dev_to_iio_dev(dev));
> +
> + return sprintf(buf, "0.%09u 0.%09u 0.%09u\n",
> + ads868x_range_def[0].scale * st->vref_mv,
> + ads868x_range_def[1].scale * st->vref_mv,
> + ads868x_range_def[2].scale * st->vref_mv);
> +}
> +
> +static ssize_t ads868x_show_offsets(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return sprintf(buf, "%d %d\n", ads868x_range_def[0].offset,
> + ads868x_range_def[3].offset);
> +}
> +
> +static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
> + ads868x_show_scales, NULL, 0);
> +static IIO_DEVICE_ATTR(in_voltage_offset_available, S_IRUGO,
> + ads868x_show_offsets, NULL, 0);
> +
> +static struct attribute *ads868x_attributes[] = {
> + &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
> + &iio_dev_attr_in_voltage_offset_available.dev_attr.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group ads868x_attribute_group = {
> + .attrs = ads868x_attributes,
> +};
> +
> +#define ADS868X_CHAN(index) \
> +{ \
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .channel = index, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
> + | BIT(IIO_CHAN_INFO_SCALE) \
> + | BIT(IIO_CHAN_INFO_OFFSET), \
> +}
> +
> +static const struct iio_chan_spec ads8684_channels[] = {
> + ADS868X_CHAN(0),
> + ADS868X_CHAN(1),
> + ADS868X_CHAN(2),
> + ADS868X_CHAN(3),
> +};
> +
> +static const struct iio_chan_spec ads8688_channels[] = {
> + ADS868X_CHAN(0),
> + ADS868X_CHAN(1),
> + ADS868X_CHAN(2),
> + ADS868X_CHAN(3),
> + ADS868X_CHAN(4),
> + ADS868X_CHAN(5),
> + ADS868X_CHAN(6),
> + ADS868X_CHAN(7),
> +};
> +
> +static int ads868x_prog_write(struct iio_dev *indio_dev, unsigned int addr,
> + unsigned int val)
> +{
> + struct ads868x_state *st = iio_priv(indio_dev);
> + unsigned int tmp;
tmp could be u32 to make it clear that it is turned into a 32-bit values
> +
> + tmp = ADS868X_PROG_REG(addr) | ADS868X_PROG_WR_BIT | val;
> + tmp <<= ADS868X_PROG_DONT_CARE_BITS;
> + st->data[0].d32 = cpu_to_be32(tmp);
> +
> + return spi_write(st->spi, &st->data[0].d8[1], 3);
> +}
> +
> +static int ads868x_reset(struct iio_dev *indio_dev)
> +{
> + struct ads868x_state *st = iio_priv(indio_dev);
> + unsigned int tmp;
> +
> + tmp = ADS868X_CMD_REG(ADS868X_CMD_REG_RST);
> + tmp <<= ADS868X_CMD_DONT_CARE_BITS;
> + st->data[0].d32 = cpu_to_be32(tmp);
> +
> + return spi_write(st->spi, &st->data[0].d8[0], 4);
> +}
> +
> +static int ads868x_read(struct iio_dev *indio_dev, unsigned int chan)
> +{
> + struct ads868x_state *st = iio_priv(indio_dev);
> + int ret;
> + unsigned int tmp;
> + struct spi_transfer t[] = {
> + {
> + .tx_buf = &st->data[0].d8[0],
> + .len = 4,
> + .cs_change = 1,
> + }, {
> + .tx_buf = &st->data[1].d8[0],
> + .rx_buf = &st->data[1].d8[0],
> + .len = 4,
> + },
> + };
> +
> + tmp = ADS868X_CMD_REG(ADS868X_CMD_REG_MAN_CH(chan));
> + tmp <<= ADS868X_CMD_DONT_CARE_BITS;
> + st->data[0].d32 = cpu_to_be32(tmp);
> +
> + tmp = ADS868X_CMD_REG(ADS868X_CMD_REG_NOOP);
> + tmp <<= ADS868X_CMD_DONT_CARE_BITS;
> + st->data[1].d32 = cpu_to_be32(tmp);
> +
> + ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
> + if (ret < 0)
> + return ret;
> +
> + return be32_to_cpu(st->data[1].d32) & 0xffff;
> +}
> +
> +static int ads868x_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long m)
> +{
> + int ret, offset, i;
> + unsigned long scale_mv;
> +
> + struct ads868x_state *st = iio_priv(indio_dev);
> +
> + switch (m) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&indio_dev->mlock);
> + ret = ads868x_read(indio_dev, chan->channel);
> + mutex_unlock(&indio_dev->mlock);
> + if (ret < 0)
> + return ret;
> + *val = ret;
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + scale_mv = st->vref_mv;
> + for (i = 0; i < ARRAY_SIZE(ads868x_range_def); i++) {
> + if (st->range[chan->channel] == ads868x_range_def[i].range)
> + scale_mv *= ads868x_range_def[i].scale;
> + }
> + *val = 0;
> + *val2 = scale_mv;
> + return IIO_VAL_INT_PLUS_NANO;
> + case IIO_CHAN_INFO_OFFSET:
> + for (i = 0; i < ARRAY_SIZE(ads868x_range_def); i++) {
> + if (st->range[chan->channel] == ads868x_range_def[i].range)
> + offset = ads868x_range_def[i].offset;
> + }
> + *val = offset;
> + return IIO_VAL_INT;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int ads868x_write_reg_range(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + enum ads868x_range range)
> +{
> + unsigned int tmp;
> + int ret;
> +
> + tmp = ADS868X_PROG_REG_RANGE_CH(chan->channel);
> + mutex_lock(&indio_dev->mlock);
> + ret = ads868x_prog_write(indio_dev, tmp, range);
> + mutex_unlock(&indio_dev->mlock);
> +
> + return ret;
> +}
> +
> +static int ads868x_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long mask)
> +{
> + struct ads868x_state *st = iio_priv(indio_dev);
> + unsigned int scale = 0;
> + int ret = -EINVAL, i, offset = 0;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_SCALE:
> + for (i = 0; i < ARRAY_SIZE(ads868x_range_def); i++)
> + if (st->range[chan->channel] ==
> + ads868x_range_def[i].range) {
> + offset = ads868x_range_def[i].offset;
> + if (offset == 0 &&
> + val2 == ads868x_range_def[0].scale *
> + st->vref_mv / 1000)
> + return ret;
> + break;
> + }
> + for (i = 0; i < ARRAY_SIZE(ads868x_range_def); i++)
> + if (val2 ==
> + ads868x_range_def[i].scale * st->vref_mv / 1000 &&
> + offset == ads868x_range_def[i].offset) {
> + ret = ads868x_write_reg_range(indio_dev, chan,
> + ads868x_range_def[i].range);
> + }
> + break;
> + case IIO_CHAN_INFO_OFFSET:
> + if (!(ads868x_range_def[0].offset == val ||
> + ads868x_range_def[3].offset == val))
> + return ret;
> + if (0 == val &&
> + st->range[chan->channel] == ADS868X_PLUSMINUS25VREF)
> + return ret;
> + for (i = 0; i < ARRAY_SIZE(ads868x_range_def); i++)
> + if (st->range[chan->channel] ==
> + ads868x_range_def[i].range)
> + scale = ads868x_range_def[i].scale;
> + for (i = 0; i < ARRAY_SIZE(ads868x_range_def); i++)
> + if (val == ads868x_range_def[i].offset &&
> + scale == ads868x_range_def[i].scale) {
> + ret = ads868x_write_reg_range(indio_dev, chan,
> + ads868x_range_def[i].range);
> + }
> + break;
> + default:
> + ret = -EINVAL;
ret already is -EINVAL
> + }
> +
> + if (!ret)
> + st->range[chan->channel] = ads868x_range_def[i].range;
> +
> + return ret;
> +}
> +
> +static const struct iio_info ads868x_info = {
> + .read_raw = &ads868x_read_raw,
> + .write_raw = &ads868x_write_raw,
> + .attrs = &ads868x_attribute_group,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static const struct ads868x_chip_info ads868x_chip_info_tbl[] = {
> + [ID_ADS8684] = {
> + .channels = ads8684_channels,
> + .num_channels = ARRAY_SIZE(ads8684_channels),
> + .iio_info = &ads868x_info,
> + },
> + [ID_ADS8688] = {
> + .channels = ads8688_channels,
> + .num_channels = ARRAY_SIZE(ads8688_channels),
> + .iio_info = &ads868x_info,
> + },
> +};
> +
> +static int ads868x_probe(struct spi_device *spi)
> +{
> + struct ads868x_state *st;
> + struct iio_dev *indio_dev;
> + bool ext_ref;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> + if (indio_dev == NULL)
> + return -ENOMEM;
> +
> + st = iio_priv(indio_dev);
> +
> + if (spi->dev.of_node)
> + ext_ref = of_property_read_bool(spi->dev.of_node,
> + "vref-supply");
> + else
> + ext_ref = false;
> +
> + if (ext_ref) {
> + st->reg = devm_regulator_get(&spi->dev, "vref");
> + if (!IS_ERR(st->reg)) {
> + ret = regulator_enable(st->reg);
> + if (ret)
> + return ret;
> +
> + ret = regulator_get_voltage(st->reg);
> + if (ret < 0)
> + goto error_out;
> + st->vref_mv = ret / 1000;
indentation
> + }
> + } else {
> + /* Use internal reference */
> + st->vref_mv = ADS868X_VREF_MV;
> + }
> +
> + st->chip_info = &ads868x_chip_info_tbl[spi_get_device_id(spi)->driver_data];
> +
> + spi->mode = SPI_MODE_1;
> +
> + spi_set_drvdata(spi, indio_dev);
> +
> + st->spi = spi;
> +
> + indio_dev->name = spi_get_device_id(spi)->name;
> + indio_dev->dev.parent = &spi->dev;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = st->chip_info->channels;
> + indio_dev->num_channels = st->chip_info->num_channels;
> + indio_dev->info = st->chip_info->iio_info;
> +
> + /* Reset ADS868x */
drop comment, pretty obvious what's going on next :)
locking is probably not needed in _probe()
> + mutex_lock(&indio_dev->mlock);
> + ads868x_reset(indio_dev);
> + mutex_unlock(&indio_dev->mlock);
> +
> + ret = iio_device_register(indio_dev);
> + if (ret)
> + goto error_out;
> +
> + return 0;
> +
> +error_out:
> + if (!IS_ERR_OR_NULL(st->reg))
> + regulator_disable(st->reg);
> +
> + return ret;
> +}
> +
> +static int ads868x_remove(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct ads868x_state *st = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> +
> + if (!IS_ERR_OR_NULL(st->reg))
> + regulator_disable(st->reg);
> +
> + return 0;
> +}
> +
> +static const struct spi_device_id ads868x_id[] = {
> + {"ads8684", ID_ADS8684},
> + {"ads8688", ID_ADS8688},
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, ads868x_id);
> +
> +static const struct of_device_id ads868x_of_match[] = {
> + { .compatible = "ti,ads8684" },
> + { .compatible = "ti,ads8688" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, ads868x_of_match);
> +
> +static struct spi_driver ads868x_driver = {
> + .driver = {
> + .name = "ads868x",
> + .owner = THIS_MODULE,
> + },
> + .probe = ads868x_probe,
> + .remove = ads868x_remove,
> + .id_table = ads868x_id,
> +};
> +module_spi_driver(ads868x_driver);
> +
> +MODULE_AUTHOR("Sean Nyekjaer <sean.nyekjaer@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Texas Instruments ADS868x driver");
> +MODULE_LICENSE("GPL v2");
>
--
Peter Meerwald
+43-664-2444418 (mobile)
