drivers/iio/dac/ad5504.c

Source file repositories/reference/linux-study-clean/drivers/iio/dac/ad5504.c

File Facts

System
Linux kernel
Corpus path
drivers/iio/dac/ad5504.c
Extension
.c
Size
8123 bytes
Lines
339
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 ad5504_state {
	struct spi_device		*spi;
	struct regulator		*reg;
	unsigned short			vref_mv;
	unsigned			pwr_down_mask;
	unsigned			pwr_down_mode;

	__be16				data[2] __aligned(IIO_DMA_MINALIGN);
};

/*
 * ad5504_supported_device_ids:
 */
enum ad5504_supported_device_ids {
	ID_AD5504,
	ID_AD5501,
};

static int ad5504_spi_write(struct ad5504_state *st, u8 addr, u16 val)
{
	st->data[0] = cpu_to_be16(AD5504_CMD_WRITE | AD5504_ADDR(addr) |
			      (val & AD5504_RES_MASK));

	return spi_write(st->spi, &st->data[0], 2);
}

static int ad5504_spi_read(struct ad5504_state *st, u8 addr)
{
	int ret;
	struct spi_transfer t = {
	    .tx_buf = &st->data[0],
	    .rx_buf = &st->data[1],
	    .len = 2,
	};

	st->data[0] = cpu_to_be16(AD5504_CMD_READ | AD5504_ADDR(addr));
	ret = spi_sync_transfer(st->spi, &t, 1);
	if (ret < 0)
		return ret;

	return be16_to_cpu(st->data[1]) & AD5504_RES_MASK;
}

static int ad5504_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val,
			   int *val2,
			   long m)
{
	struct ad5504_state *st = iio_priv(indio_dev);
	int ret;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
		ret = ad5504_spi_read(st, chan->address);
		if (ret < 0)
			return ret;

		*val = ret;

		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		*val = st->vref_mv;
		*val2 = chan->scan_type.realbits;
		return IIO_VAL_FRACTIONAL_LOG2;
	}
	return -EINVAL;
}

static int ad5504_write_raw(struct iio_dev *indio_dev,
			       struct iio_chan_spec const *chan,
			       int val,
			       int val2,
			       long mask)
{
	struct ad5504_state *st = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		if (val >= (1 << chan->scan_type.realbits) || val < 0)
			return -EINVAL;

		return ad5504_spi_write(st, chan->address, val);
	default:
		return -EINVAL;
	}
}

static const char * const ad5504_powerdown_modes[] = {
	"20kohm_to_gnd",

Annotation

Implementation Notes