On 01/13/2017 10:50 AM, Jacopo Mondi wrote: > From: Jacopo Mondi <[email protected]> > > Add iio driver for Maxim MAX11100 single-channel ADC. > > Signed-off-by: Jacopo Mondi <[email protected]> > Tested-by: Marek Vasut <[email protected]> > > --- > drivers/iio/adc/Kconfig | 9 +++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/max11100.c | 187 > +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 197 insertions(+) > create mode 100644 drivers/iio/adc/max11100.c > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index 38bc319..c32bc7a 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -307,6 +307,15 @@ config MAX1027 > To compile this driver as a module, choose M here: the module will be > called max1027. > > +config MAX11100 > + tristate "Maxim max11100 ADC driver" > + depends on SPI_MASTER > + help > + Say yes here to build support for Maxim max11100 SPI ADC > + > + To compile this driver as a module, choose M here: the module will be > + called max11100. > + > config MAX1363 > tristate "Maxim max1363 ADC driver" > depends on I2C > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index d36c4be..5684369 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -31,6 +31,7 @@ obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o > obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o > obj-$(CONFIG_LTC2485) += ltc2485.o > obj-$(CONFIG_MAX1027) += max1027.o > +obj-$(CONFIG_MAX11100) += max11100.o > obj-$(CONFIG_MAX1363) += max1363.o > obj-$(CONFIG_MCP320X) += mcp320x.o > obj-$(CONFIG_MCP3422) += mcp3422.o > diff --git a/drivers/iio/adc/max11100.c b/drivers/iio/adc/max11100.c > new file mode 100644 > index 0000000..78e2a45 > --- /dev/null > +++ b/drivers/iio/adc/max11100.c > @@ -0,0 +1,187 @@ > +/* > + * iio/adc/max11100.c > + * Maxim max11100 ADC Driver with IIO interface > + * > + * Copyright (C) 2016 Renesas Electronics Corporation > + * Copyright (C) 2016 Jacopo Mondi > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + */ > +#include <linux/delay.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/regulator/consumer.h> > +#include <linux/spi/spi.h> > + > +#include <linux/iio/iio.h> > +#include <linux/iio/buffer.h> > +#include <linux/iio/driver.h> > + > +/* > + * LSB is the ADC single digital step > + * 1 LSB = (vref_mv / 2 ^ 16) > + * > + * LSB is used to calculate analog voltage value > + * from the number of ADC steps count > + * > + * Ain = (count * LSB) > + */ > +#define MAX11100_LSB_DIV (1 << 16) > + > +struct max11100_state { > + const struct max11100_chip_desc *desc; > + struct regulator *vref_reg; > + struct spi_device *spi; > +}; > + > +static struct iio_chan_spec max11100_channels[] = { > + { /* [0] */ > + .type = IIO_VOLTAGE, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > + BIT(IIO_CHAN_INFO_SCALE), > + }, > +}; > + > +static struct max11100_chip_desc { > + unsigned int num_chan; > + const struct iio_chan_spec *channels; > +} max11100_desc = { > + .num_chan = ARRAY_SIZE(max11100_channels), > + .channels = max11100_channels, > +}; > + > +static int max11100_read_single(struct iio_dev *indio_dev, int *val) > +{ > + int ret; > + struct max11100_state *state = iio_priv(indio_dev); > + uint8_t buffer[3]; > + > + ret = spi_read(state->spi, buffer, sizeof(buffer)); > + if (ret) { > + dev_err(&indio_dev->dev, "SPI transfer failed\n"); > + return ret; > + } > + > + /* the first 8 bits sent out from ADC must be 0s */ > + if (buffer[0]) { > + dev_err(&indio_dev->dev, "Invalid value: buffer[0] != 0\n"); > + return -EINVAL; > + } > + > + *val = (buffer[1] << 8) | buffer[2]; > + > + return 0; > +} > + > +static int max11100_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long info) > +{ > + int ret, vref_uv; > + struct max11100_state *state = iio_priv(indio_dev); > + > + switch (info) { > + case IIO_CHAN_INFO_RAW: > + ret = max11100_read_single(indio_dev, val); > + if (ret) > + return ret; > + > + return IIO_VAL_INT; > + > + case IIO_CHAN_INFO_SCALE: > + vref_uv = regulator_get_voltage(state->vref_reg); > + if (vref_uv < 0) > + /* dummy regulator "get_voltage" returns -EINVAL */ > + return -EINVAL; > + > + *val = vref_uv / 1000; > + *val2 = MAX11100_LSB_DIV; > + return IIO_VAL_FRACTIONAL; > + } > + > + return -EINVAL; > +} > + > +static const struct iio_info max11100_info = { > + .driver_module = THIS_MODULE, > + .read_raw = max11100_read_raw, > +}; > + > +static int max11100_probe(struct spi_device *spi) > +{ > + int ret; > + struct iio_dev *indio_dev; > + struct max11100_state *state; > + > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); > + if (!indio_dev) > + return -ENOMEM; > + > + spi_set_drvdata(spi, indio_dev); > + > + state = iio_priv(indio_dev); > + state->spi = spi; > + state->desc = &max11100_desc; > + > + indio_dev->dev.parent = &spi->dev; > + indio_dev->dev.of_node = spi->dev.of_node; > + indio_dev->info = &max11100_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = state->desc->channels; > + indio_dev->num_channels = state->desc->num_chan;
Consider setting indio_dev->name= "max11100"; so userspace can identify the type of the device.
