On Wed, 17 Oct 2018 22:39:53 +0200 Charles-Antoine Couret <charles-antoine.couret@xxxxxxxxxxxxx> wrote: > Add AD7949 ADC driver family > > Compatible with AD7682 and AD7689 chips. > It is a Analog Devices ADC driver 14/16 bits 4/8 channels > with SPI protocol > > Datasheet of the device: > http://www.analog.com/media/en/technical-documentation/data-sheets/AD7949.pdf > > Signed-off-by: Charles-Antoine Couret <charles-antoine.couret@xxxxxxxxxxxxx> Hi Charles-Antoine Please a prefix to the patch description to describe roughly where in the kernel a patch applies. The precise convention varies rather more than it probably should, but in iio we usually use. iio:adc:ad7949: Add AD79759 ADC driver family. A few minor bits and pieces inline to add to Alex's comments. I missed some of these on V1, so sorry about that! Thanks, Jonathan > --- > drivers/iio/adc/Kconfig | 10 ++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/ad7949.c | 352 +++++++++++++++++++++++++++++++++++++++ > 3 files changed, 363 insertions(+) > create mode 100644 drivers/iio/adc/ad7949.c > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index 4a754921fb6f..42e66efff6c0 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -116,6 +116,16 @@ config AD7923 > To compile this driver as a module, choose M here: the > module will be called ad7923. > > +config AD7949 > + tristate "Analog Devices AD7949 and similar ADCs driver" > + depends on SPI > + help > + Say yes here to build support for Analog Devices > + AD7949, AD7682, AD7689 8 Channel ADCs. > + > + To compile this driver as a module, choose M here: the > + module will be called ad7949. > + > config AD799X > tristate "Analog Devices AD799x ADC driver" > depends on I2C > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index 03db7b578f9c..88804c867aa9 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -14,6 +14,7 @@ obj-$(CONFIG_AD7766) += ad7766.o > obj-$(CONFIG_AD7791) += ad7791.o > obj-$(CONFIG_AD7793) += ad7793.o > obj-$(CONFIG_AD7887) += ad7887.o > +obj-$(CONFIG_AD7949) += ad7949.o > obj-$(CONFIG_AD799X) += ad799x.o > obj-$(CONFIG_ASPEED_ADC) += aspeed_adc.o > obj-$(CONFIG_AT91_ADC) += at91_adc.o > diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c > new file mode 100644 > index 000000000000..da5082e80317 > --- /dev/null > +++ b/drivers/iio/adc/ad7949.c > @@ -0,0 +1,352 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* ad7949.c - Analog Devices ADC driver 14/16 bits 4/8 channels > + * > + * Copyright (C) 2018 CMC NV > + * > + * http://www.analog.com/media/en/technical-documentation/data-sheets/AD7949.pdf > + */ > + > +#include <linux/delay.h> > +#include <linux/iio/iio.h> > +#include <linux/module.h> > +#include <linux/regulator/consumer.h> > +#include <linux/spi/spi.h> > + > +#define AD7949_MASK_CHANNEL_SEL GENMASK(9, 7) > +#define AD7949_MASK_TOTAL GENMASK(13, 0) > +#define AD7949_OFFSET_CHANNEL_SEL 7 > +#define AD7949_CFG_READ_BACK 0x1 > +#define AD7949_CFG_REG_SIZE_BITS 14 > + > +enum { > + ID_AD7949 = 0, > + ID_AD7682, > + ID_AD7689, > +}; > + > +struct ad7949_adc_spec { > + u8 num_channels; > + u8 resolution; > +}; > + > +static const struct ad7949_adc_spec ad7949_adc_spec[] = { > + [ID_AD7949] = { .num_channels = 8, .resolution = 14 }, > + [ID_AD7682] = { .num_channels = 4, .resolution = 16 }, > + [ID_AD7689] = { .num_channels = 8, .resolution = 16 }, > +}; > + > +/** > + * struct ad7949_adc_chip - AD ADC chip > + * @lock: protects write sequences > + * @vref: regulator generating Vref > + * @iio_dev: reference to iio structure > + * @spi: reference to spi structure > + * @resolution: resolution of the chip > + * @cfg: copy of the configuration register > + * @current_channel: current channel in use > + * @buffer: buffer to send / receive data to / from device > + */ > +struct ad7949_adc_chip { > + struct mutex lock; > + struct regulator *vref; > + struct iio_dev *indio_dev; > + struct spi_device *spi; > + u8 resolution; > + u16 cfg; > + unsigned int current_channel; > + u32 buffer ____cacheline_aligned; > +}; > + > +static bool ad7949_spi_cfg_is_read_back(struct ad7949_adc_chip *ad7949_adc) > +{ > + if (!(ad7949_adc->cfg & AD7949_CFG_READ_BACK)) > + return true; return !(ad7949_adc->cfg & AD7949_CFG_READ_BACK); > + > + return false; > +} > + > +static int ad7949_spi_bits_per_word(struct ad7949_adc_chip *ad7949_adc) > +{ > + int ret = ad7949_adc->resolution; > + > + if (ad7949_spi_cfg_is_read_back(ad7949_adc)) > + ret += AD7949_CFG_REG_SIZE_BITS; > + > + return ret; > +} > + > +static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc, u16 val, > + u16 mask) > +{ > + int ret; > + int bits_per_word = ad7949_spi_bits_per_word(ad7949_adc); > + int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS; > + struct spi_message msg; > + struct spi_transfer tx[] = { > + { > + .tx_buf = &ad7949_adc->buffer, > + .len = 4, > + .bits_per_word = bits_per_word, > + }, > + }; > + > + ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask); > + ad7949_adc->buffer = ad7949_adc->cfg << shift; > + spi_message_init(&msg); > + spi_message_add_tail(&tx[0], &msg); spi_message_init_with_transfers (saves a line ;) > + ret = spi_sync(ad7949_adc->spi, &msg); > + > + /* This delay is to avoid a new request before the required time to Multiline comment style (see below). > + * send a new command to the device > + */ > + udelay(2); > + return ret; > +} > + > +static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, > + unsigned int channel) > +{ > + int ret; > + int bits_per_word = ad7949_spi_bits_per_word(ad7949_adc); > + int mask = GENMASK(ad7949_adc->resolution, 0); > + struct spi_message msg; > + struct spi_transfer tx[] = { > + { > + .rx_buf = &ad7949_adc->buffer, > + .len = 4, > + .bits_per_word = bits_per_word, > + }, > + }; > + > + ret = ad7949_spi_write_cfg(ad7949_adc, > + channel << AD7949_OFFSET_CHANNEL_SEL, > + AD7949_MASK_CHANNEL_SEL); > + if (ret) > + return ret; > + > + ad7949_adc->buffer = 0; > + spi_message_init(&msg); > + spi_message_add_tail(&tx[0], &msg); spi_message_init_with_transfers. > + ret = spi_sync(ad7949_adc->spi, &msg); > + if (ret) > + return ret; > + > + /* This delay is to avoid a new request before the required time to Multiline comment style. /* * This * ... */ > + * send a new command to the device > + */ > + udelay(2); > + > + ad7949_adc->current_channel = channel; > + > + if (ad7949_spi_cfg_is_read_back(ad7949_adc)) > + *val = (ad7949_adc->buffer >> AD7949_CFG_REG_SIZE_BITS) & mask; > + else > + *val = ad7949_adc->buffer & mask; > + > + return 0; > +} > + > +#define AD7949_ADC_CHANNEL(chan) { \ > + .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), \ > +} > + > +static const struct iio_chan_spec ad7949_adc_channels[] = { > + AD7949_ADC_CHANNEL(0), > + AD7949_ADC_CHANNEL(1), > + AD7949_ADC_CHANNEL(2), > + AD7949_ADC_CHANNEL(3), > + AD7949_ADC_CHANNEL(4), > + AD7949_ADC_CHANNEL(5), > + AD7949_ADC_CHANNEL(6), > + AD7949_ADC_CHANNEL(7), > +}; > + > +static int ad7949_spi_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev); > + int ret; > + > + if (!val) > + return -EINVAL; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + mutex_lock(&ad7949_adc->lock); > + ret = ad7949_spi_read_channel(ad7949_adc, val, chan->channel); > + mutex_unlock(&ad7949_adc->lock); > + > + if (ret < 0) > + return ret; > + > + return IIO_VAL_INT; > + > + case IIO_CHAN_INFO_SCALE: > + ret = regulator_get_voltage(ad7949_adc->vref); > + if (ret < 0) > + return ret; > + > + *val = ret / 5000; > + return IIO_VAL_INT; > + } > + > + return -EINVAL; > +} > + > +static int ad7949_spi_reg_access(struct iio_dev *indio_dev, > + unsigned int reg, unsigned int writeval, > + unsigned int *readval) > +{ > + struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev); > + int ret = 0; > + > + if (readval) > + *readval = ad7949_adc->cfg; > + else > + ret = ad7949_spi_write_cfg(ad7949_adc, > + writeval & AD7949_MASK_TOTAL, AD7949_MASK_TOTAL); > + > + return ret; > +} > + > +static const struct iio_info ad7949_spi_info = { > + .read_raw = ad7949_spi_read_raw, > + .debugfs_reg_access = ad7949_spi_reg_access, > +}; > + > +static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc) > +{ > + int ret; > + int val; > + > + /* Sequencer disabled, CFG readback disabled, IN0 as default channel */ > + ad7949_adc->current_channel = 0; > + ret = ad7949_spi_write_cfg(ad7949_adc, 0x3C79, AD7949_MASK_TOTAL); > + > + /* Do two dummy conversions to apply the first configuration setting. IIO uses the most common kernel multiline comment style. /* * Do two.. */ > + * Required only after the start up of the device. > + */ > + ad7949_spi_read_channel(ad7949_adc, &val, ad7949_adc->current_channel); > + ad7949_spi_read_channel(ad7949_adc, &val, ad7949_adc->current_channel); A blank line here would help readability (a very small amount!) > + return ret; > +} > + > +static int ad7949_spi_probe(struct spi_device *spi) > +{ > + struct device *dev = &spi->dev; > + const struct ad7949_adc_spec *spec; > + struct ad7949_adc_chip *ad7949_adc; > + struct iio_dev *indio_dev; > + int ret; > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(*ad7949_adc)); > + if (!indio_dev) { > + dev_err(dev, "can not allocate iio device\n"); > + return -ENOMEM; > + } > + > + spi->max_speed_hz = 33000000; This one would actually override what you already have in the DT binding. > + spi->mode = SPI_MODE_0; This one is the default (I think....) > + spi->bits_per_word = 8; This is the default so doesn't need to be set. > + spi_setup(spi); > + > + indio_dev->dev.parent = dev; > + indio_dev->dev.of_node = dev->of_node; > + indio_dev->info = &ad7949_spi_info; > + indio_dev->name = spi_get_device_id(spi)->name; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = ad7949_adc_channels; > + spi_set_drvdata(spi, indio_dev); > + > + ad7949_adc = iio_priv(indio_dev); > + ad7949_adc->indio_dev = indio_dev; > + ad7949_adc->spi = spi; > + > + spec = &ad7949_adc_spec[spi_get_device_id(spi)->driver_data]; > + indio_dev->num_channels = spec->num_channels; > + ad7949_adc->resolution = spec->resolution; > + > + ad7949_adc->vref = devm_regulator_get(dev, "vref"); > + if (IS_ERR(ad7949_adc->vref)) { > + dev_err(dev, "fail to request regulator\n"); > + return PTR_ERR(ad7949_adc->vref); > + } > + > + ret = regulator_enable(ad7949_adc->vref); > + if (ret < 0) { > + dev_err(dev, "fail to enable regulator\n"); > + goto err_regulator; > + } > + > + mutex_init(&ad7949_adc->lock); > + > + ret = ad7949_spi_init(ad7949_adc); > + if (ret) { > + dev_err(dev, "enable to init this device: %d\n", ret); > + goto err; > + } > + > + ret = iio_device_register(indio_dev); > + if (ret) { > + dev_err(dev, "fail to register iio device: %d\n", ret); > + goto err; > + } > + > + return 0; > + > +err: > + mutex_destroy(&ad7949_adc->lock); > + regulator_disable(ad7949_adc->vref); > +err_regulator: > + return ret; > +} > + > +static int ad7949_spi_remove(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev = spi_get_drvdata(spi); > + struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev); > + > + iio_device_unregister(indio_dev); > + mutex_destroy(&ad7949_adc->lock); > + regulator_disable(ad7949_adc->vref); > + > + return 0; > +} > + > +#ifdef CONFIG_OF > +static const struct of_device_id ad7949_spi_of_id[] = { > + { .compatible = "ad7949" }, > + { .compatible = "ad7682" }, > + { .compatible = "ad7689" }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, ad7949_spi_of_id); > +#endif > + > +static const struct spi_device_id ad7949_spi_id[] = { > + { "ad7949", ID_AD7949 }, > + { "ad7682", ID_AD7682 }, > + { "ad7689", ID_AD7689 }, > + { } > +}; > +MODULE_DEVICE_TABLE(spi, ad7949_spi_id); > + > +static struct spi_driver ad7949_spi_driver = { > + .driver = { > + .name = "ad7949", > + .of_match_table = of_match_ptr(ad7949_spi_of_id), > + }, > + .probe = ad7949_spi_probe, > + .remove = ad7949_spi_remove, > + .id_table = ad7949_spi_id, > +}; > +module_spi_driver(ad7949_spi_driver); > + > +MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@xxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("Analog Devices 14/16-bit 8-channel ADC driver"); > +MODULE_LICENSE("GPL v2");
