> Add support for Analog Devices AD8801/AD8803, 8 channels 8bits, Digital to
> Analog converters.
comments below, looks good
> Signed-off-by: Gwenhael <gwe@xxxxxxxxxxxxxx>
> ---
> drivers/iio/dac/Kconfig | 10 ++
> drivers/iio/dac/Makefile | 1 +
> drivers/iio/dac/ad8801.c | 244 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 255 insertions(+)
> create mode 100644 drivers/iio/dac/ad8801.c
>
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index ca81447..af0e684 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -181,6 +181,16 @@ config AD7303
> To compile this driver as module choose M here: the module will be called
> ad7303.
>
> +config AD8801
> + tristate "Analog Devices AD8801/AD8803 DAC driver"
> + depends on SPI
> + help
> + Say yes here to build support for Analog Devices AD8801, ad8803 Digital to
AD8803 (uppercase)
> + Analog Converters (DAC).
> +
> + To compile this driver as module choose M here: the module will be called
as _a_ module
> + ad8801.
> +
> config LPC18XX_DAC
> tristate "NXP LPC18xx DAC driver"
> depends on ARCH_LPC18XX || COMPILE_TEST
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index 8b78d5c..c5767b8 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -20,6 +20,7 @@ obj-$(CONFIG_AD5764) += ad5764.o
> obj-$(CONFIG_AD5791) += ad5791.o
> obj-$(CONFIG_AD5686) += ad5686.o
> obj-$(CONFIG_AD7303) += ad7303.o
> +obj-$(CONFIG_AD8801) += ad8801.o
> obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
> obj-$(CONFIG_M62332) += m62332.o
> obj-$(CONFIG_MAX517) += max517.o
> diff --git a/drivers/iio/dac/ad8801.c b/drivers/iio/dac/ad8801.c
> new file mode 100644
> index 0000000..4e1891c
> --- /dev/null
> +++ b/drivers/iio/dac/ad8801.c
> @@ -0,0 +1,244 @@
> +/*
> + * IIO DAC driver for Analog Devices AD8801 DAC
> + *
> + * Copyright (C) 2016 Gwenhael Goavec-Merou
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + *
> + */
> +
> +#include <linux/iio/iio.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +#include <linux/sysfs.h>
> +
> +
> +#define AD8801_CFG_ADDR_OFFSET 8
> +
> +enum ad8801_device_ids {
> + ID_AD8801,
> + ID_AD8803,
> +};
> +
> +struct ad8801_state {
> + struct spi_device *spi;
> + unsigned char dac_cache[8]; /* Value write on each channel */
> + unsigned int vrefh_mv;
> + unsigned int vrefl_mv;
> + struct regulator *vrefh_reg;
> + struct regulator *vrefl_reg;
> +
> + __be16 data ____cacheline_aligned;
> +};
> +
> +static int ad8801_spi_write(struct ad8801_state *state,
> + u8 channel, unsigned char value)
> +{
> + state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value);
> + return spi_write(state->spi, &state->data, sizeof(state->data));
> +}
> +
> +static int ad8801_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int val, int val2, long mask)
> +{
> + struct ad8801_state *state = iio_priv(indio_dev);
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + if (val >= 256 || val < 0)
> + return -EINVAL;
> +
> + ret = ad8801_spi_write(state, chan->channel, val);
> + if (ret == 0)
> + state->dac_cache[chan->channel] = val;
> + break;
> + default:
> + ret = -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static int ad8801_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val, int *val2, long info)
> +{
> + struct ad8801_state *state = iio_priv(indio_dev);
> +
> + switch (info) {
> + case IIO_CHAN_INFO_RAW:
> + *val = state->dac_cache[chan->channel];
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + *val = (state->vrefh_mv - state->vrefl_mv);
parenthesis not needed
> + *val2 = 8;
> + return IIO_VAL_FRACTIONAL_LOG2;
> + case IIO_CHAN_INFO_OFFSET:
> + *val = state->vrefl_mv;
> + return IIO_VAL_INT;
> + default:
> + break;
just
return -EINVAL;
here
> + }
> +
> + return -EINVAL;
> +}
> +
> +static const struct iio_info ad8801_info = {
> + .read_raw = ad8801_read_raw,
> + .write_raw = ad8801_write_raw,
> + .driver_module = THIS_MODULE,
> +};
> +
> +#define AD8801_CHANNEL(chan) { \
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .output = 1, \
> + .channel = (chan + 1), \
parenthesis not needed, or rather put it around (chan)
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_OFFSET), \
> + .address = chan, \
> +}
> +
> +const struct iio_chan_spec ad8801_channels[] = {
> + AD8801_CHANNEL(0),
> + AD8801_CHANNEL(1),
> + AD8801_CHANNEL(2),
> + AD8801_CHANNEL(3),
> + AD8801_CHANNEL(4),
> + AD8801_CHANNEL(5),
> + AD8801_CHANNEL(6),
> + AD8801_CHANNEL(7),
> +};
> +
> +static int ad8801_probe(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev;
> + struct ad8801_state *state;
> + const struct spi_device_id *id;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
> + if (indio_dev == NULL)
> + return -ENOMEM;
> +
> + state = iio_priv(indio_dev);
> + state->spi = spi;
> + id = spi_get_device_id(spi);
> +
> + state->vrefh_reg = devm_regulator_get(&spi->dev, "vrefh");
> + if (IS_ERR(state->vrefh_reg)) {
> + dev_err(&spi->dev, "Vrefh regulator not specified\n");
> + return PTR_ERR(state->vrefh_reg);
> + }
> +
> + ret = regulator_enable(state->vrefh_reg);
> + if (ret) {
> + dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = regulator_get_voltage(state->vrefh_reg);
> + if (ret < 0) {
> + dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n",
> + ret);
> + goto error_disable_vrefh_reg;
> + }
> + state->vrefh_mv = ret / 1000;
> +
> + if (id->driver_data == ID_AD8803) {
> + state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl");
maybe could split out code to get/enable/read regulator into a function to
avoid duplication, not sure if worth it
> + if (IS_ERR(state->vrefl_reg)) {
> + dev_err(&spi->dev, "Vrefl regulator not specified\n");
> + ret = PTR_ERR(state->vrefl_reg);
> + goto error_disable_vrefh_reg;
> + }
> +
> + ret = regulator_enable(state->vrefl_reg);
> + if (ret) {
> + dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n",
> + ret);
> + goto error_disable_vrefh_reg;
> + }
> +
> + ret = regulator_get_voltage(state->vrefl_reg);
> + if (ret < 0) {
> + dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n",
> + ret);
> + goto error_disable_vrefl_reg;
> + }
> + state->vrefl_mv = ret / 1000;
> + } else {
> + state->vrefl_mv = 0;
> + state->vrefl_reg = NULL;
> + }
> +
> + spi_set_drvdata(spi, indio_dev);
> + indio_dev->dev.parent = &spi->dev;
> + indio_dev->info = &ad8801_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = ad8801_channels;
> + indio_dev->num_channels = ARRAY_SIZE(ad8801_channels);
> + indio_dev->name = id->name;
> +
> + ret = iio_device_register(indio_dev);
> + if (ret) {
> + dev_err(&spi->dev, "Failed to register iio device: %d\n",
> + ret);
> + goto error_disable_vrefl_reg;
> + }
> +
> + return 0;
> +
> +error_disable_vrefl_reg:
> + if (state->vrefl_reg)
> + regulator_disable(state->vrefl_reg);
> +error_disable_vrefh_reg:
> + regulator_disable(state->vrefh_reg);
> + return ret;
> +}
> +
> +static int ad8801_remove(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct ad8801_state *state = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> + if (state->vrefl_reg)
> + regulator_disable(state->vrefl_reg);
> + regulator_disable(state->vrefh_reg);
> +
> + return 0;
> +}
> +
> +static const struct spi_device_id ad8801_ids[] = {
> + {"ad8801", ID_AD8801},
> + {"ad8803", ID_AD8803},
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, ad8801_ids);
> +
> +static struct spi_driver ad8801_driver = {
> + .driver = {
> + .name = "ad8801",
> + },
> + .probe = ad8801_probe,
> + .remove = ad8801_remove,
> + .id_table = ad8801_ids,
> +};
> +module_spi_driver(ad8801_driver);
> +
> +MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@xxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC");
> +MODULE_LICENSE("GPL v2");
> +
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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