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

From: Jonathan Cameron
Date: Sat Jan 12 2019 - 13:42:57 EST

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In reply to: Dan Murphy: "[PATCH v3 2/3] iio: adc: Add the TI ads124s08 ADC code"
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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!

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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