diff options
Diffstat (limited to 'drivers/iio/dac/cio-dac.c')
| -rw-r--r-- | drivers/iio/dac/cio-dac.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c new file mode 100644 index 000000000..77a6916b3 --- /dev/null +++ b/drivers/iio/dac/cio-dac.c @@ -0,0 +1,135 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * IIO driver for the Measurement Computing CIO-DAC + * Copyright (C) 2016 William Breathitt Gray + * + * 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_hw_array(base, uint, ioport, &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 { + 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; + + /* DAC can only accept up to a 12-bit value */ + if ((unsigned int)val > 4095) + return -EINVAL; + + priv->chan_out_states[chan->channel] = val; + outw(val, priv->base + chan_addr_offset); + + return 0; +} + +static const struct iio_info cio_dac_info = { + .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 request port addresses (0x%X-0x%X)\n", + 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@gmail.com>"); +MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver"); +MODULE_LICENSE("GPL v2"); |