Message-ID: <20190112184357.506c485a@archlinux>
Date:   Sat, 12 Jan 2019 18:43:57 +0000
From:   Jonathan Cameron <jic23@...23.retrosnub.co.uk>
To:     Dan Murphy <dmurphy@...com>
Cc:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <robh+dt@...nel.org>
Subject: Re: [PATCH v3 2/3] iio: adc: Add the TI ads124s08 ADC code

On Sat, 12 Jan 2019 18:42:49 +0000
Jonathan Cameron <jic23@...nel.org> wrote:

> On Fri, 11 Jan 2019 13:57:06 -0600
> Dan Murphy <dmurphy@...com> 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@...com>  
> 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.

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@...com>");
> > +MODULE_DESCRIPTION("TI TI_ADS12S0X ADC");
> > +MODULE_LICENSE("GPL v2");  
> 

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