> Add IIO driver for Maxim MAX11100 single-channel ADC. > Add DT bindings documentation. some more comments > Signed-off-by: Jacopo Mondi <jacopo@xxxxxxxxxx> > --- > > v1 -> v2: > - incorporated pmeerw's review comments > - retrieve vref from dts and use that to convert read_raw result > to mV > - add device tree bindings documentation > > --- > .../devicetree/bindings/iio/adc/max11100.txt | 17 +++ > drivers/iio/adc/Kconfig | 9 ++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/max11100.c | 166 +++++++++++++++++++++ > 4 files changed, 193 insertions(+) > create mode 100644 Documentation/devicetree/bindings/iio/adc/max11100.txt > create mode 100644 drivers/iio/adc/max11100.c > > diff --git a/Documentation/devicetree/bindings/iio/adc/max11100.txt b/Documentation/devicetree/bindings/iio/adc/max11100.txt > new file mode 100644 > index 0000000..6877c11 > --- /dev/null > +++ b/Documentation/devicetree/bindings/iio/adc/max11100.txt > @@ -0,0 +1,17 @@ > +* Maxim max11100 Analog to Digital Converter (ADC) > + > +Required properties: > + - compatible: Should be "maxim,max11100" > + - vref-supply: phandle to the regulator that provides reference voltage > + > +Optional properties: > + - spi-max-frequency: SPI maximum frequency > + > +Example: > + > +adc0: max11100@0 { > + compatible = "maxim,max11100"; > + vref-supply = <&adc0_vref>; > + spi-max-frequency = <240000>; > +}; > + > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index 99c0514..a909484 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -285,6 +285,15 @@ 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 SPI_MASTER is more precise I think > + 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 7a40c04..1463044 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -29,6 +29,7 @@ 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..f372ad8 > --- /dev/null > +++ b/drivers/iio/adc/max11100.c > @@ -0,0 +1,166 @@ > +/* > + * 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 / 2 ^ 16) > + * AIN = (DIN * LSB) > + */ > +#define MAX11100_LSB_DIV (1 << 16) > +#define MAX11100_LSB(vref) (vref / MAX11100_LSB_DIV) maybe parenthesis around vref > + > +struct max11100_state { > + const struct max11100_chip_desc *desc; > + struct spi_device *spi; > + int vref_uv; > + struct mutex lock; > +}; > + > +static struct iio_chan_spec max11100_channels[] = { > + { /* [0] */ > + .type = IIO_VOLTAGE, > + .scan_type = { scan_type not needed since driver does not support buffered reads > + .sign = 'u', > + .realbits = 16, > + .storagebits = 24, > + .shift = 8, > + .repeat = 1, > + .endianness = IIO_BE, > + }, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), > + }, > +}; > + > +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_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + int ret; > + struct max11100_state *state = iio_priv(indio_dev); > + uint8_t buffer[3]; > + > + mutex_lock(&state->lock); > + > + ret = spi_read(state->spi, buffer, sizeof(buffer)); > + if (ret) { > + mutex_unlock(&state->lock); > + dev_err(&indio_dev->dev, "SPI transfer failed\n"); > + return ret; > + } > + mutex_unlock(&state->lock); > + > + /* 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 = be16_to_cpu(*(uint16_t *)&buffer[1]); > + *val = *val * MAX11100_LSB(state->vref_uv) / 1000; no, INFO_RAW shall not perform such scaling, use _PROCESSED or add an INFO_SCALE to indicate the scaling > + > + return IIO_VAL_INT; > +} > + > +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 regulator *vref_reg; > + 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; > + > + mutex_init(&state->lock); > + > + 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; > + > + vref_reg = devm_regulator_get(&spi->dev, "vref"); > + if (IS_ERR(vref_reg)) > + return PTR_ERR(vref_reg); > + > + ret = regulator_enable(vref_reg); > + if (ret) > + return ret; > + > + state->vref_uv = regulator_get_voltage(vref_reg); > + if (state->vref_uv < 0) { > + /* dummy regulator "get_voltage" returns -EINVAL as well */ > + ret = -EINVAL; > + goto disable_regulator; > + } > + > + ret = devm_iio_device_register(&spi->dev, indio_dev); the regulator needs to be disabled in a _remove() function and since you need a remove function, devm_iio_device_register() should not be used > + if (ret) > + goto disable_regulator; > + > + return 0; > + > +disable_regulator: > + regulator_disable(vref_reg); > + return ret; > +} > + > +static const struct of_device_id max11100_ids[] = { > + {.compatible = "maxim,max11100"}, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, max11100_ids); > + > +static struct spi_driver max11100_driver = { > + .driver = { > + .name = "max11100", > + .owner = THIS_MODULE, > + .of_match_table = of_match_ptr(max11100_ids), > + }, > + .probe = max11100_probe, > +}; > + > +module_spi_driver(max11100_driver); > + > +MODULE_AUTHOR("Jacopo Mondi <jacopo@xxxxxxxxxx>"); > +MODULE_DESCRIPTION("Maxim max11100 ADC Driver"); > +MODULE_LICENSE("GPL v2"); > -- Peter Meerwald-Stadler +43-664-2444418 (mobile) -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html