drivers/iio/dac/cio-dac.c

Source file repositories/reference/linux-study-clean/drivers/iio/dac/cio-dac.c

File Facts

System
Linux kernel
Corpus path
drivers/iio/dac/cio-dac.c
Extension
.c
Size
4318 bytes
Lines
162
Domain
Driver Families
Bucket
drivers/iio
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct cio_dac_iio {
	struct regmap *map;
};

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);
	const unsigned int offset = chan->channel * CIO_DAC_CHANNEL_STRIDE;
	int err;
	unsigned int dac_val;

	if (mask != IIO_CHAN_INFO_RAW)
		return -EINVAL;

	err = regmap_read(priv->map, CIO_DAC_BASE + offset, &dac_val);
	if (err)
		return err;

	*val = dac_val;

	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 offset = chan->channel * CIO_DAC_CHANNEL_STRIDE;

	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;

	return regmap_write(priv->map, CIO_DAC_BASE + offset, val);
}

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;
	void __iomem *regs;

	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;
	}

	regs = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
	if (!regs)
		return -ENOMEM;

	priv = iio_priv(indio_dev);
	priv->map = devm_regmap_init_mmio(dev, regs, &cio_dac_regmap_config);
	if (IS_ERR(priv->map))
		return dev_err_probe(dev, PTR_ERR(priv->map),
				     "Unable to initialize register map\n");

	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);

	return devm_iio_device_register(dev, indio_dev);
}

static struct isa_driver cio_dac_driver = {
	.probe = cio_dac_probe,

Annotation

Implementation Notes