Re: [PATCH] iio: Add IIO support for the Measurement Computing CIO-DAC family

From: Peter Meerwald-Stadler
Date: Mon Jul 11 2016 - 14:18:39 EST



> The Measurement Computing CIO-DAC is a family of 12-bit analog output
> devices. The analog outputs are from AD660BNs with each output buffered
> by an OP-27. Voltage ranges are configured via physical jumpers on the
> device.
>
> This driver does not support the devices' simulataneous update mode; the
> XFER jumper option should be deselected for all analog output channels.

out of curiosity: what is CIO?
comments below, looks nice & tidy

I guess devicetree config is not fashionable for ISA devices :)

> This driver provides IIO support for the Measurement Computing CIO-DAC
> family: CIO-DAC16, CIO-DAC08, and PC104-DAC06. The base port addresses
> for the devices may be configured via the base array module parameter.
>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
> ---
> MAINTAINERS | 6 ++
> drivers/iio/dac/Kconfig | 9 +++
> drivers/iio/dac/Makefile | 1 +
> drivers/iio/dac/cio-dac.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 156 insertions(+)
> create mode 100644 drivers/iio/dac/cio-dac.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 345e757..7280259 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7318,6 +7318,12 @@ L: linux-iio@xxxxxxxxxxxxxxx
> S: Maintained
> F: drivers/iio/potentiometer/mcp4531.c
>
> +MEASUREMENT COMPUTING CIO-DAC DAC DRIVER

maybe it is more informative to state
MEASUREMENT COMPUTING CIO-DAC IIO DRIVER
(here and below)

> +M: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
> +L: linux-iio@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: drivers/iio/dac/cio-dac.c
> +
> MEDIA DRIVERS FOR RENESAS - VSP1
> M: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> L: linux-media@xxxxxxxxxxxxxxx
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index ca81447..38ea272 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -181,6 +181,15 @@ config AD7303
> To compile this driver as module choose M here: the module will be called
> ad7303.
>
> +config CIO_DAC
> + tristate "Measurement Computing CIO-DAC DAC driver"
> + depends on X86 && ISA_BUS_API
> + help
> + Say yes here to build support for the Measurement Computing CIO-DAC
> + analog output device family (CIO-DAC16, CIO-DAC08, PC104-DAC06). The
> + base port addresses for the devices may be configured via the base
> + array module parameter.
> +
> 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..b1a1206 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-$(CONFIG_CIO_DAC) += cio-dac.o
> obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
> obj-$(CONFIG_M62332) += m62332.o
> obj-$(CONFIG_MAX517) += max517.o
> diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
> new file mode 100644
> index 0000000..eb52819
> --- /dev/null
> +++ b/drivers/iio/dac/cio-dac.c
> @@ -0,0 +1,140 @@
> +/*
> + * DAC driver for the Measurement Computing CIO-DAC
> + * Copyright (C) 2016 William Breathitt Gray
> + *
> + * 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.
> + *
> + * This driver supports the following Measurement Computing devices: CIO-DAC16,
> + * CIO-DAC06, and PC104-DAC06.
> + */
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/types.h>
> +#include <linux/io.h>
> +#include <linux/ioport.h>
> +#include <linux/isa.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +
> +#define CIO_DAC_NUM_CHAN 16
> +
> +#define CIO_DAC_CHAN(chan) { \
> + .type = IIO_VOLTAGE, \
> + .channel = chan, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .indexed = 1, \
> + .output = 1 \
> +}
> +
> +#define CIO_DAC_EXTENT 32
> +
> +static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
> +static unsigned int num_cio_dac;
> +module_param_array(base, uint, &num_cio_dac, 0);
> +MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
> +
> +/**
> + * struct cio_dac_iio - IIO device private data structure
> + * @chan_out_states: channels' output states
> + * @base: base port address of the IIO device
> + */
> +struct cio_dac_iio {
> + unsigned int chan_out_states[CIO_DAC_NUM_CHAN];
> + unsigned int base;
> +};
> +
> +static int cio_dac_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val, int *val2, long mask)
> +{
> + struct cio_dac_iio *const priv = iio_priv(indio_dev);
> +
> + if (mask != IIO_CHAN_INFO_RAW)
> + return -EINVAL;
> +
> + *val = priv->chan_out_states[chan->channel];
> +
> + return IIO_VAL_INT;
> +}
> +
> +static int cio_dac_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int val, int val2, long mask)
> +{
> + struct cio_dac_iio *const priv = iio_priv(indio_dev);
> + const unsigned int chan_addr_offset = 2 * chan->channel;
> +
> + if (mask != IIO_CHAN_INFO_RAW)
> + return -EINVAL;
> +

what unit applies to val? milli volts?
any range checking?

> + priv->chan_out_states[chan->channel] = val;
> + outw(val, priv->base + chan_addr_offset);
> +
> + return 0;
> +}
> +
> +static const struct iio_info cio_dac_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = cio_dac_read_raw,
> + .write_raw = cio_dac_write_raw
> +};
> +
> +static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
> + CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
> + CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
> + CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
> + CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
> +};
> +
> +static int cio_dac_probe(struct device *dev, unsigned int id)
> +{
> + struct iio_dev *indio_dev;
> + struct cio_dac_iio *priv;
> + unsigned int i;
> +
> + indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
> + dev_name(dev))) {
> + dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",

maybe 'request' instead of 'lock' (maximum nitpick)

> + base[id], base[id] + CIO_DAC_EXTENT);
> + return -EBUSY;
> + }
> +
> + indio_dev->info = &cio_dac_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = cio_dac_channels;
> + indio_dev->num_channels = CIO_DAC_NUM_CHAN;
> + indio_dev->name = dev_name(dev);
> +
> + priv = iio_priv(indio_dev);
> + priv->base = base[id];
> +
> + /* initialize DAC outputs to 0V */
> + for (i = 0; i < 32; i += 2)
> + outw(0, base[id] + i);
> +
> + return devm_iio_device_register(dev, indio_dev);
> +}
> +
> +static struct isa_driver cio_dac_driver = {
> + .probe = cio_dac_probe,
> + .driver = {
> + .name = "cio-dac"
> + }
> +};
> +
> +module_isa_driver(cio_dac_driver, num_cio_dac);
> +
> +MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Measurement Computing CIO-DAC DAC driver");
> +MODULE_LICENSE("GPL v2");
>

--

Peter Meerwald-Stadler
+43-664-2444418 (mobile)