On Fri, Mar 22, 2019 at 12:11:08PM +0100, Gregory CLEMENT 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@xxxxxxxxxxx> > --- > drivers/iio/adc/Kconfig | 10 ++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/ti-ads8344.c | 200 +++++++++++++++++++++++++++++++++++ > 3 files changed, 211 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..649ed05bf1c9 > --- /dev/null > +++ b/drivers/iio/adc/ti-ads8344.c > @@ -0,0 +1,200 @@ > +// SPDX-License-Identifier: GPL-2.0+ Inconsistency in License. > > + * ADS8344 16-bit 8-Channel ADC driver > + * > + * Author: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx> > + * > + * 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; > + struct mutex lock; This requires a comment explaining its purpose. checkpatch issues a warning IIRC. > + > + 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); Just curious: What would happen if you don't lock ? I'm interested in looking for whatever happens in such a case and how to exploit it ? Also, bus transactions are often atomic using their locking/unlocking procedures. So, why do we need locking procedures in iio drivers itself ? > + *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; > + } IDK but it is advised not to mix devm_* with regular functions. If there is any possibilty to use `devm_add_action_or_reset` here ? This would help get rid of `ads8344_remove` and help smooth unwinding in failure w/o any race. > + 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); > + > +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@xxxxxxxxxxx>"); > +MODULE_DESCRIPTION("ADS8344 driver"); > +MODULE_LICENSE("GPL v2"); this is a mismatch. -- Himanshu Jha Undergraduate Student Department of Electronics & Communication Guru Tegh Bahadur Institute of Technology
