Re: [PATCH v3 2/2] iio: adc: Add driver for the TI ADS8344 A/DC chips

[Jonathan Cameron <jic23@jic23.retrosnub.co.uk>]

On Sun, 14 Apr 2019 14:51:52 +0100
Jonathan Cameron <jic23@kernel.org> wrote:

> On Fri, 12 Apr 2019 11:15:37 +0200
> Gregory CLEMENT <gregory.clement@bootlin.com> wrote:
> 
> > This adds support for the Texas Instruments ADS8344 ADC chip. This chip
> > has a 16-bit 8-Channel ADC and is access directly through SPI.
> > 
> > Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>  
> Applied to the togreg branch of iio.git and pushed out as testing
> for the autobuilders to play with it.
I spoke too soon. See below.

Fixed up.

Jonathan

> 
> Thanks,
> 
> Jonathan
> 
> > ---
> >  drivers/iio/adc/Kconfig      |  10 ++
> >  drivers/iio/adc/Makefile     |   1 +
> >  drivers/iio/adc/ti-ads8344.c | 204 +++++++++++++++++++++++++++++++++++
> >  3 files changed, 215 insertions(+)
> >  create mode 100644 drivers/iio/adc/ti-ads8344.c
> > 
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 76db6e5cc296..447d3a871746 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -967,6 +967,16 @@ config TI_ADS7950
> >  	  To compile this driver as a module, choose M here: the
> >  	  module will be called ti-ads7950.
> >  
> > +config TI_ADS8344
> > +	tristate "Texas Instruments ADS8344"
> > +	depends on SPI && OF
> > +	help
> > +	  If you say yes here you get support for Texas Instruments ADS8344
> > +	  ADC chips
> > +
> > +	  This driver can also be built as a module. If so, the module will be
> > +	  called ti-ads8344.
> > +
> >  config TI_ADS8688
> >  	tristate "Texas Instruments ADS8688"
> >  	depends on SPI && OF
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index 6fcebd167524..1f3ae934111d 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -87,6 +87,7 @@ obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
> >  obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
> >  obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
> >  obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
> > +obj-$(CONFIG_TI_ADS8344) += ti-ads8344.o
> >  obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
> >  obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
> >  obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
> > diff --git a/drivers/iio/adc/ti-ads8344.c b/drivers/iio/adc/ti-ads8344.c
> > new file mode 100644
> > index 000000000000..e1649e237edc
> > --- /dev/null
> > +++ b/drivers/iio/adc/ti-ads8344.c
> > @@ -0,0 +1,204 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * ADS8344 16-bit 8-Channel ADC driver
> > + *
> > + * Author: Gregory CLEMENT <gregory.clement@bootlin.com>
> > + *
> > + * Datasheet: http://www.ti.com/lit/ds/symlink/ads8344.pdf
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/iio/buffer.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/module.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/spi/spi.h>
> > +
> > +#define ADS8344_START BIT(7)
> > +#define ADS8344_SINGLE_END BIT(2)
> > +#define ADS8344_CHANNEL(channel) ((channel) << 4)
> > +#define ADS8344_CLOCK_INTERNAL 0x2 /* PD1 = 1 and PD0 = 0 */
> > +
> > +struct ads8344 {
> > +	struct spi_device *spi;
> > +	struct regulator *reg;
> > +	/*
> > +	 * Lock protecting access to adc->tx_buff and rx_buff,
> > +	 * especially from concurrent read on sysfs file.
> > +	 */
> > +	struct mutex lock;
> > +
> > +	u8 tx_buf ____cacheline_aligned;
> > +	u16 rx_buf;
> > +};
> > +
> > +#define ADS8344_VOLTAGE_CHANNEL(chan, si)				\
> > +	{								\
> > +		.type = IIO_VOLTAGE,					\
> > +		.indexed = 1,						\
> > +		.channel = chan,					\
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
> > +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> > +	}
> > +
> > +#define ADS8344_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)			\
> > +	{								\
> > +		.type = IIO_VOLTAGE,					\
> > +		.indexed = 1,						\
> > +		.channel = (chan1),					\
> > +		.channel2 = (chan2),					\
> > +		.differential = 1,					\
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
> > +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> > +	}
> > +
> > +static const struct iio_chan_spec ads8344_channels[] = {
> > +	ADS8344_VOLTAGE_CHANNEL(0, 0),
> > +	ADS8344_VOLTAGE_CHANNEL(1, 4),
> > +	ADS8344_VOLTAGE_CHANNEL(2, 1),
> > +	ADS8344_VOLTAGE_CHANNEL(3, 5),
> > +	ADS8344_VOLTAGE_CHANNEL(4, 2),
> > +	ADS8344_VOLTAGE_CHANNEL(5, 6),
> > +	ADS8344_VOLTAGE_CHANNEL(6, 3),
> > +	ADS8344_VOLTAGE_CHANNEL(7, 7),
> > +	ADS8344_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
> > +	ADS8344_VOLTAGE_CHANNEL_DIFF(2, 3, 9),
> > +	ADS8344_VOLTAGE_CHANNEL_DIFF(4, 5, 10),
> > +	ADS8344_VOLTAGE_CHANNEL_DIFF(6, 7, 11),
> > +	ADS8344_VOLTAGE_CHANNEL_DIFF(1, 0, 12),
> > +	ADS8344_VOLTAGE_CHANNEL_DIFF(3, 2, 13),
> > +	ADS8344_VOLTAGE_CHANNEL_DIFF(5, 4, 14),
> > +	ADS8344_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
> > +};
> > +
> > +static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
> > +				  bool differential)
> > +{
> > +	struct spi_device *spi = adc->spi;
> > +	int ret;
> > +
> > +	adc->tx_buf = ADS8344_START;
> > +	if (!differential)
> > +		adc->tx_buf |= ADS8344_SINGLE_END;
> > +	adc->tx_buf |= ADS8344_CHANNEL(channel);
> > +	adc->tx_buf |= ADS8344_CLOCK_INTERNAL;
> > +
> > +	ret = spi_write(spi, &adc->tx_buf, 1);
> > +	if (ret)
> > +		return ret;
> > +
> > +	udelay(9);
> > +
> > +	ret = spi_read(spi, &adc->rx_buf, 2);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return adc->rx_buf;
> > +}
> > +
> > +static int ads8344_read_raw(struct iio_dev *iio,
> > +			    struct iio_chan_spec const *channel, int *value,
> > +			    int *shift, long mask)
> > +{
> > +	struct ads8344 *adc = iio_priv(iio);
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_RAW:
> > +		mutex_lock(&adc->lock);
> > +		*value = ads8344_adc_conversion(adc, channel->scan_index,
> > +						channel->differential);
> > +		mutex_unlock(&adc->lock);
> > +		if (*value < 0)
> > +			return *value;
> > +
> > +		return IIO_VAL_INT;
> > +	case IIO_CHAN_INFO_SCALE:
> > +		*value = regulator_get_voltage(adc->reg);
> > +		if (*value < 0)
> > +			return *value;
> > +
> > +		/* convert regulator output voltage to mV */
> > +		*value /= 1000;
> > +		*shift = 16;
> > +
> > +		return IIO_VAL_FRACTIONAL_LOG2;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +}
> > +
> > +static const struct iio_info ads8344_info = {
> > +	.read_raw = ads8344_read_raw,
> > +};
> > +
> > +static int ads8344_probe(struct spi_device *spi)
> > +{
> > +	struct iio_dev *indio_dev;
> > +	struct ads8344 *adc;
> > +	int ret;
> > +
> > +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
> > +	if (!indio_dev)
> > +		return -ENOMEM;
> > +
> > +	adc = iio_priv(indio_dev);
> > +	adc->spi = spi;
> > +	mutex_init(&adc->lock);
> > +
> > +	indio_dev->name = dev_name(&spi->dev);
> > +	indio_dev->dev.parent = &spi->dev;
> > +	indio_dev->dev.of_node = spi->dev.of_node;
> > +	indio_dev->info = &ads8344_info;
> > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > +	indio_dev->channels = ads8344_channels;
> > +	indio_dev->num_channels = ARRAY_SIZE(ads8344_channels);
> > +
> > +	adc->reg = devm_regulator_get(&spi->dev, "vref");
> > +	if (IS_ERR(adc->reg))
> > +		return PTR_ERR(adc->reg);
> > +
> > +	ret = regulator_enable(adc->reg);
> > +	if (ret)
> > +		return ret;
> > +
> > +	spi_set_drvdata(spi, indio_dev);
> > +
> > +	ret = iio_device_register(indio_dev);
> > +	if (ret) {
> > +		regulator_disable(adc->reg);
> > +		return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int ads8344_remove(struct spi_device *spi)
> > +{
> > +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> > +	struct ads8344 *adc = iio_priv(indio_dev);
> > +
> > +	iio_device_unregister(indio_dev);
> > +	regulator_disable(adc->reg);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id ads8344_of_match[] = {
> > +	{ .compatible = "ti,ads8344", },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(of, ads8344_dt_ids);
no such variable... fixed as ads8344_of_match.

> > +
> > +static struct spi_driver ads8344_driver = {
> > +	.driver = {
> > +		.name = "ads8344",
> > +		.of_match_table = ads8344_of_match,
> > +	},
> > +	.probe = ads8344_probe,
> > +	.remove = ads8344_remove,
> > +};
> > +module_spi_driver(ads8344_driver);
> > +
> > +MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@bootlin.com>");
> > +MODULE_DESCRIPTION("ADS8344 driver");
> > +MODULE_LICENSE("GPL");  
>