Re: [PATCH v3 2/3] iio: adc: Add the TI ads124s08 ADC code

From: Jonathan Cameron
Date: Sat Jan 19 2019 - 11:55:54 EST

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On Mon, 14 Jan 2019 15:31:13 -0600
Dan Murphy <dmurphy@xxxxxx> wrote:

> Jonathan
>
> On 1/12/19 12:43 PM, Jonathan Cameron wrote:
> > On Sat, 12 Jan 2019 18:42:49 +0000
> > Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> >
> >> On Fri, 11 Jan 2019 13:57:06 -0600
> >> Dan Murphy <dmurphy@xxxxxx> wrote:
> >>
> >>> Introduce the TI ADS124S08 and the ADS124S06 ADC
> >>> devices from TI. The ADS124S08 is the 12 channel ADC
> >>> and the ADS124S06 is the 6 channel ADC device
> >>>
> >>> These devices share a common datasheet:
> >>> http://www.ti.com/lit/gpn/ads124s08
> >>>
> >>> Signed-off-by: Dan Murphy <dmurphy@xxxxxx>
> >> Hi Dan,
> >>
> >> The only real change in here (there is another nitpick) that I think
> >> needs to be made is that the buffer length in the private stucture is
> >> not longer connected to the number of channels. You effectively use it
> >> as a bounce buffer now and I think the maximum is 5.
> >>
> >> As that's it I'll just clean it up whilst applying. If you could
> >> confirm I'm not crazy and didn't mess it up that would be great!
> > Probably would help if I added.
> >
> > Applied to the togreg branch of iio.git but for now just pushed out
> > as testing for the autobuilders to play with it.
>
>
> Thank you. I assume if there are no issue then this will be in a PR for 5.1 then?
Yes. For mostly historical reasons (and because he's really nice)
IIO goes through Greg's staging tree and tends to end up in a joint
staging/iio pull request from him. I'll send Greg a pull request
either this weekend or next depending on what else is in the queue
and after he pulls that it'll show up in Linux next.

Thanks,

Jonathan

>
> Dan
>
> >
> > Thanks,
> >
> > Jonathan
> >
> >>
> >> Thanks,
> >>
> >> Jonathan
> >>
> >>> ---
> >>> v3 - Fixed the IIO channel definition, reduce long line in probe and
> >>> fixed the buffer allocation definition - https://lore.kernel.org/patchwork/patch/1023970/
> >>>
> >>> v2 - Removed the fill_noop call, updated probe to use device managed calls,
> >>> removed regulator support, fixed the buffer to allow 64 bit timestamp, changed
> >>> all the defines from S0X to S08, added an enum for the IDs and updated copyright
> >>> header format. I may have missed a few summary changes here but here is the
> >>> review reference - https://lore.kernel.org/patchwork/patch/1021048/
> >>>
> >>> drivers/iio/adc/Kconfig | 10 +
> >>> drivers/iio/adc/Makefile | 1 +
> >>> drivers/iio/adc/ti-ads124s08.c | 375 +++++++++++++++++++++++++++++++++
> >>> 3 files changed, 386 insertions(+)
> >>> create mode 100644 drivers/iio/adc/ti-ads124s08.c
> >>>
> >>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> >>> index 7a3ca4ec0cb7..8cf9e007ea76 100644
> >>> --- a/drivers/iio/adc/Kconfig
> >>> +++ b/drivers/iio/adc/Kconfig
> >>> @@ -908,6 +908,16 @@ config TI_ADS8688
> >>> This driver can also be built as a module. If so, the module will be
> >>> called ti-ads8688.
> >>>
> >>> +config TI_ADS124S08
> >>> + tristate "Texas Instruments ADS124S08"
> >>> + depends on SPI && OF
> >>> + help
> >>> + If you say yes here you get support for Texas Instruments ADS124S08
> >>> + and ADS124S06 ADC chips
> >>> +
> >>> + This driver can also be built as a module. If so, the module will be
> >>> + called ti-ads124s08.
> >>> +
> >>> config TI_AM335X_ADC
> >>> tristate "TI's AM335X ADC driver"
> >>> depends on MFD_TI_AM335X_TSCADC && HAS_DMA
> >>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> >>> index 07df37f621bd..49b203bf4e0e 100644
> >>> --- a/drivers/iio/adc/Makefile
> >>> +++ b/drivers/iio/adc/Makefile
> >>> @@ -81,6 +81,7 @@ obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
> >>> obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
> >>> obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
> >>> obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
> >>> +obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
> >>> obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
> >>> obj-$(CONFIG_TI_TLC4541) += ti-tlc4541.o
> >>> obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
> >>> diff --git a/drivers/iio/adc/ti-ads124s08.c b/drivers/iio/adc/ti-ads124s08.c
> >>> new file mode 100644
> >>> index 000000000000..3d7f2300e0f6
> >>> --- /dev/null
> >>> +++ b/drivers/iio/adc/ti-ads124s08.c
> >>> @@ -0,0 +1,375 @@
> >>> +// SPDX-License-Identifier: GPL-2.0
> >>> +/* TI ADS124S0X chip family driver
> >>> + * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
> >>> + */
> >>> +
> >>> +#include <linux/err.h>
> >>> +#include <linux/delay.h>
> >>> +#include <linux/device.h>
> >>> +#include <linux/kernel.h>
> >>> +#include <linux/module.h>
> >>> +#include <linux/of.h>
> >>> +#include <linux/of_gpio.h>
> >>> +#include <linux/slab.h>
> >>> +#include <linux/sysfs.h>
> >>> +
> >>> +#include <linux/gpio/consumer.h>
> >>> +#include <linux/spi/spi.h>
> >>> +
> >>> +#include <linux/iio/iio.h>
> >>> +#include <linux/iio/buffer.h>
> >>> +#include <linux/iio/trigger_consumer.h>
> >>> +#include <linux/iio/triggered_buffer.h>
> >>> +#include <linux/iio/sysfs.h>
> >>> +
> >>> +/* Commands */
> >>> +#define ADS124S08_CMD_NOP 0x00
> >>> +#define ADS124S08_CMD_WAKEUP 0x02
> >>> +#define ADS124S08_CMD_PWRDWN 0x04
> >>> +#define ADS124S08_CMD_RESET 0x06
> >>> +#define ADS124S08_CMD_START 0x08
> >>> +#define ADS124S08_CMD_STOP 0x0a
> >>> +#define ADS124S08_CMD_SYOCAL 0x16
> >>> +#define ADS124S08_CMD_SYGCAL 0x17
> >>> +#define ADS124S08_CMD_SFOCAL 0x19
> >>> +#define ADS124S08_CMD_RDATA 0x12
> >>> +#define ADS124S08_CMD_RREG 0x20
> >>> +#define ADS124S08_CMD_WREG 0x40
> >>> +
> >>> +/* Registers */
> >>> +#define ADS124S08_ID_REG 0x00
> >>> +#define ADS124S08_STATUS 0x01
> >>> +#define ADS124S08_INPUT_MUX 0x02
> >>> +#define ADS124S08_PGA 0x03
> >>> +#define ADS124S08_DATA_RATE 0x04
> >>> +#define ADS124S08_REF 0x05
> >>> +#define ADS124S08_IDACMAG 0x06
> >>> +#define ADS124S08_IDACMUX 0x07
> >>> +#define ADS124S08_VBIAS 0x08
> >>> +#define ADS124S08_SYS 0x09
> >>> +#define ADS124S08_OFCAL0 0x0a
> >>> +#define ADS124S08_OFCAL1 0x0b
> >>> +#define ADS124S08_OFCAL2 0x0c
> >>> +#define ADS124S08_FSCAL0 0x0d
> >>> +#define ADS124S08_FSCAL1 0x0e
> >>> +#define ADS124S08_FSCAL2 0x0f
> >>> +#define ADS124S08_GPIODAT 0x10
> >>> +#define ADS124S08_GPIOCON 0x11
> >>> +
> >>> +/* ADS124S0x common channels */
> >>> +#define ADS124S08_AIN0 0x00
> >>> +#define ADS124S08_AIN1 0x01
> >>> +#define ADS124S08_AIN2 0x02
> >>> +#define ADS124S08_AIN3 0x03
> >>> +#define ADS124S08_AIN4 0x04
> >>> +#define ADS124S08_AIN5 0x05
> >>> +#define ADS124S08_AINCOM 0x0c
> >>> +/* ADS124S08 only channels */
> >>> +#define ADS124S08_AIN6 0x06
> >>> +#define ADS124S08_AIN7 0x07
> >>> +#define ADS124S08_AIN8 0x08
> >>> +#define ADS124S08_AIN9 0x09
> >>> +#define ADS124S08_AIN10 0x0a
> >>> +#define ADS124S08_AIN11 0x0b
> >>> +#define ADS124S08_MAX_CHANNELS 12
> >>> +
> >>> +#define ADS124S08_POS_MUX_SHIFT 0x04
> >>> +#define ADS124S08_INT_REF 0x09
> >>> +
> >>> +#define ADS124S08_START_REG_MASK 0x1f
> >>> +#define ADS124S08_NUM_BYTES_MASK 0x1f
> >>> +
> >>> +#define ADS124S08_START_CONV 0x01
> >>> +#define ADS124S08_STOP_CONV 0x00
> >>> +
> >>> +enum ads124s_id {
> >>> + ADS124S08_ID,
> >>> + ADS124S06_ID,
> >>> +};
> >>> +
> >>> +struct ads124s_chip_info {
> >>> + const struct iio_chan_spec *channels;
> >>> + unsigned int num_channels;
> >>> +};
> >>> +
> >>> +struct ads124s_private {
> >>> + const struct ads124s_chip_info *chip_info;
> >>> + struct gpio_desc *reset_gpio;
> >>> + struct spi_device *spi;
> >>> + struct mutex lock;
> >>> + u8 data[ADS124S08_MAX_CHANNELS] ____cacheline_aligned;
> >>
> >> I'm fairly sure this only needs to be 5 not MAX_CHANNELS as you use
> >> another buffer to build up the full set of readouts.
> >>
> >>> +};
> >>> +
> >>> +#define ADS124S08_CHAN(index) \
> >>> +{ \
> >>> + .type = IIO_VOLTAGE, \
> >>> + .indexed = 1, \
> >>> + .channel = index, \
> >>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> >>> + .scan_index = index, \
> >>> + .scan_type = { \
> >>> + .sign = 'u', \
> >>> + .realbits = 32, \
> >>> + .storagebits = 32, \
> >>> + }, \
> >>> +}
> >>> +
> >>> +static const struct iio_chan_spec ads124s06_channels[] = {
> >>> + ADS124S08_CHAN(0),
> >>> + ADS124S08_CHAN(1),
> >>> + ADS124S08_CHAN(2),
> >>> + ADS124S08_CHAN(3),
> >>> + ADS124S08_CHAN(4),
> >>> + ADS124S08_CHAN(5),
> >>> +};
> >>> +
> >>> +static const struct iio_chan_spec ads124s08_channels[] = {
> >>> + ADS124S08_CHAN(0),
> >>> + ADS124S08_CHAN(1),
> >>> + ADS124S08_CHAN(2),
> >>> + ADS124S08_CHAN(3),
> >>> + ADS124S08_CHAN(4),
> >>> + ADS124S08_CHAN(5),
> >>> + ADS124S08_CHAN(6),
> >>> + ADS124S08_CHAN(7),
> >>> + ADS124S08_CHAN(8),
> >>> + ADS124S08_CHAN(9),
> >>> + ADS124S08_CHAN(10),
> >>> + ADS124S08_CHAN(11),
> >>> +};
> >>> +
> >>> +static const struct ads124s_chip_info ads124s_chip_info_tbl[] = {
> >>> + [ADS124S08_ID] = {
> >>> + .channels = ads124s08_channels,
> >>> + .num_channels = ARRAY_SIZE(ads124s08_channels),
> >>> + },
> >>> + [ADS124S06_ID] = {
> >>> + .channels = ads124s06_channels,
> >>> + .num_channels = ARRAY_SIZE(ads124s06_channels),
> >>> + },
> >>> +};
> >>> +
> >>> +static int ads124s_write_cmd(struct iio_dev *indio_dev, u8 command)
> >>> +{
> >>> + struct ads124s_private *priv = iio_priv(indio_dev);
> >>> +
> >>> + priv->data[0] = command;
> >>> +
> >>> + return spi_write(priv->spi, &priv->data[0], 1);
> >>> +}
> >>> +
> >>> +static int ads124s_write_reg(struct iio_dev *indio_dev, u8 reg, u8 data)
> >>> +{
> >>> + struct ads124s_private *priv = iio_priv(indio_dev);
> >>> +
> >>> + priv->data[0] = ADS124S08_CMD_WREG | reg;
> >>> + priv->data[1] = 0x0;
> >>> + priv->data[2] = data;
> >>> +
> >>> + return spi_write(priv->spi, &priv->data[0], 3);
> >>> +}
> >>> +
> >>> +static int ads124s_reset(struct iio_dev *indio_dev)
> >>> +{
> >>> + struct ads124s_private *priv = iio_priv(indio_dev);
> >>> +
> >>> + if (priv->reset_gpio) {
> >>> + gpiod_set_value(priv->reset_gpio, 0);
> >>> + udelay(200);
> >>> + gpiod_set_value(priv->reset_gpio, 1);
> >>> + } else {
> >>> + return ads124s_write_cmd(indio_dev, ADS124S08_CMD_RESET);
> >>> + }
> >>> +
> >>> + return 0;
> >>> +};
> >>> +
> >>> +static int ads124s_read(struct iio_dev *indio_dev, unsigned int chan)
> >>> +{
> >>> + struct ads124s_private *priv = iio_priv(indio_dev);
> >>> + int ret;
> >>> + u32 tmp;
> >>> + struct spi_transfer t[] = {
> >>> + {
> >>> + .tx_buf = &priv->data[0],
> >>> + .len = 4,
> >>> + .cs_change = 1,
> >>> + }, {
> >>> + .tx_buf = &priv->data[1],
> >>> + .rx_buf = &priv->data[1],
> >>> + .len = 4,
> >>> + },
> >>> + };
> >>> +
> >>> + priv->data[0] = ADS124S08_CMD_RDATA;
> >>> + memset(&priv->data[1], ADS124S08_CMD_NOP, sizeof(priv->data));
> >>> +
> >>> + ret = spi_sync_transfer(priv->spi, t, ARRAY_SIZE(t));
> >>> + if (ret < 0)
> >>> + return ret;
> >>> +
> >>> + tmp = priv->data[2] << 16 | priv->data[3] << 8 | priv->data[4];
> >>> +
> >>> + return tmp;
> >>> +}
> >>> +
> >>> +static int ads124s_read_raw(struct iio_dev *indio_dev,
> >>> + struct iio_chan_spec const *chan,
> >>> + int *val, int *val2, long m)
> >>> +{
> >>> + struct ads124s_private *priv = iio_priv(indio_dev);
> >>> + int ret;
> >>> +
> >>> + mutex_lock(&priv->lock);
> >>> + switch (m) {
> >>> + case IIO_CHAN_INFO_RAW:
> >>> + ret = ads124s_write_reg(indio_dev, ADS124S08_INPUT_MUX,
> >>> + chan->channel);
> >>> + if (ret) {
> >>> + dev_err(&priv->spi->dev, "Set ADC CH failed\n");
> >>> + goto out;
> >>> + }
> >>> +
> >>> + ret = ads124s_write_cmd(indio_dev, ADS124S08_START_CONV);
> >>> + if (ret) {
> >>> + dev_err(&priv->spi->dev, "Start converions failed\n");
> >>> + goto out;
> >>> + }
> >>> +
> >>> + ret = ads124s_read(indio_dev, chan->channel);
> >>> + if (ret < 0) {
> >>> + dev_err(&priv->spi->dev, "Read ADC failed\n");
> >>> + goto out;
> >>> + } else
> >>> + *val = ret;
> >> Nit pick is that this doesn't benefit from being an else as it's just the normal
> >> flow. Trivial though so lets just leave it!
> >>
> >>> +
> >>> + ret = ads124s_write_cmd(indio_dev, ADS124S08_STOP_CONV);
> >>> + if (ret) {
> >>> + dev_err(&priv->spi->dev, "Stop converions failed\n");
> >>> + goto out;
> >>> + }
> >>> +
> >>> + ret = IIO_VAL_INT;
> >>> + break;
> >>> + default:
> >>> + ret = -EINVAL;
> >>> + break;
> >>> + }
> >>> +out:
> >>> + mutex_unlock(&priv->lock);
> >>> + return ret;
> >>> +}
> >>> +
> >>> +static const struct iio_info ads124s_info = {
> >>> + .read_raw = &ads124s_read_raw,
> >>> +};
> >>> +
> >>> +static irqreturn_t ads124s_trigger_handler(int irq, void *p)
> >>> +{
> >>> + struct iio_poll_func *pf = p;
> >>> + struct iio_dev *indio_dev = pf->indio_dev;
> >>> + struct ads124s_private *priv = iio_priv(indio_dev);
> >>> + u32 buffer[ADS124S08_MAX_CHANNELS + sizeof(s64)/sizeof(u16)];
> >>> + int scan_index, j = 0;
> >>> + int ret;
> >>> +
> >>> + for_each_set_bit(scan_index, indio_dev->active_scan_mask,
> >>> + indio_dev->masklength) {
> >>> + ret = ads124s_write_reg(indio_dev, ADS124S08_INPUT_MUX,
> >>> + scan_index);
> >>> + if (ret)
> >>> + dev_err(&priv->spi->dev, "Set ADC CH failed\n");
> >>> +
> >>> + ret = ads124s_write_cmd(indio_dev, ADS124S08_START_CONV);
> >>> + if (ret)
> >>> + dev_err(&priv->spi->dev, "Start ADC converions failed\n");
> >>> +
> >>> + buffer[j] = ads124s_read(indio_dev, scan_index);
> >>> + ret = ads124s_write_cmd(indio_dev, ADS124S08_STOP_CONV);
> >>> + if (ret)
> >>> + dev_err(&priv->spi->dev, "Stop ADC converions failed\n");
> >>> +
> >>> + j++;
> >>> + }
> >>> +
> >>> + iio_push_to_buffers_with_timestamp(indio_dev, buffer,
> >>> + pf->timestamp);
> >>> +
> >>> + iio_trigger_notify_done(indio_dev->trig);
> >>> +
> >>> + return IRQ_HANDLED;
> >>> +}
> >>> +
> >>> +static int ads124s_probe(struct spi_device *spi)
> >>> +{
> >>> + struct ads124s_private *ads124s_priv;
> >>> + struct iio_dev *indio_dev;
> >>> + const struct spi_device_id *spi_id = spi_get_device_id(spi);
> >>> + int ret;
> >>> +
> >>> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ads124s_priv));
> >>> + if (indio_dev == NULL)
> >>> + return -ENOMEM;
> >>> +
> >>> + ads124s_priv = iio_priv(indio_dev);
> >>> +
> >>> + ads124s_priv->reset_gpio = devm_gpiod_get_optional(&spi->dev,
> >>> + "reset", GPIOD_OUT_LOW);
> >>> + if (IS_ERR(ads124s_priv->reset_gpio))
> >>> + dev_info(&spi->dev, "Reset GPIO not defined\n");
> >>> +
> >>> + ads124s_priv->chip_info = &ads124s_chip_info_tbl[spi_id->driver_data];
> >>> +
> >>> + spi_set_drvdata(spi, indio_dev);
> >>> +
> >>> + ads124s_priv->spi = spi;
> >>> +
> >>> + indio_dev->name = spi_id->name;
> >>> + indio_dev->dev.parent = &spi->dev;
> >>> + indio_dev->dev.of_node = spi->dev.of_node;
> >>> + indio_dev->modes = INDIO_DIRECT_MODE;
> >>> + indio_dev->channels = ads124s_priv->chip_info->channels;
> >>> + indio_dev->num_channels = ads124s_priv->chip_info->num_channels;
> >>> + indio_dev->info = &ads124s_info;
> >>> +
> >>> + mutex_init(&ads124s_priv->lock);
> >>> +
> >>> + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
> >>> + ads124s_trigger_handler, NULL);
> >>> + if (ret) {
> >>> + dev_err(&spi->dev, "iio triggered buffer setup failed\n");
> >>> + return ret;
> >>> + }
> >>> +
> >>> + ads124s_reset(indio_dev);
> >>> +
> >>> + return devm_iio_device_register(&spi->dev, indio_dev);
> >>> +}
> >>> +
> >>> +static const struct spi_device_id ads124s_id[] = {
> >>> + { "ads124s06", ADS124S06_ID },
> >>> + { "ads124s08", ADS124S08_ID },
> >>> + { }
> >>> +};
> >>> +MODULE_DEVICE_TABLE(spi, ads124s_id);
> >>> +
> >>> +static const struct of_device_id ads124s_of_table[] = {
> >>> + { .compatible = "ti,ads124s06" },
> >>> + { .compatible = "ti,ads124s08" },
> >>> + { },
> >>> +};
> >>> +MODULE_DEVICE_TABLE(of, ads124s_of_table);
> >>> +
> >>> +static struct spi_driver ads124s_driver = {
> >>> + .driver = {
> >>> + .name = "ads124s08",
> >>> + .of_match_table = ads124s_of_table,
> >>> + },
> >>> + .probe = ads124s_probe,
> >>> + .id_table = ads124s_id,
> >>> +};
> >>> +module_spi_driver(ads124s_driver);
> >>> +
> >>> +MODULE_AUTHOR("Dan Murphy <dmuprhy@xxxxxx>");
> >>> +MODULE_DESCRIPTION("TI TI_ADS12S0X ADC");
> >>> +MODULE_LICENSE("GPL v2");
> >>
> >
>
>

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