drivers/iio/adc/lpc18xx_adc.c

Source file repositories/reference/linux-study-clean/drivers/iio/adc/lpc18xx_adc.c

File Facts

System
Linux kernel
Corpus path
drivers/iio/adc/lpc18xx_adc.c
Extension
.c
Size
5006 bytes
Lines
207
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 lpc18xx_adc {
	struct regulator *vref;
	void __iomem *base;
	struct device *dev;
	struct mutex lock;
	struct clk *clk;
	u32 cr_reg;
};

#define LPC18XX_ADC_CHAN(_idx) {				\
	.type = IIO_VOLTAGE,					\
	.indexed = 1,						\
	.channel = _idx,					\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
}

static const struct iio_chan_spec lpc18xx_adc_iio_channels[] = {
	LPC18XX_ADC_CHAN(0),
	LPC18XX_ADC_CHAN(1),
	LPC18XX_ADC_CHAN(2),
	LPC18XX_ADC_CHAN(3),
	LPC18XX_ADC_CHAN(4),
	LPC18XX_ADC_CHAN(5),
	LPC18XX_ADC_CHAN(6),
	LPC18XX_ADC_CHAN(7),
};

static int lpc18xx_adc_read_chan(struct lpc18xx_adc *adc, unsigned int ch)
{
	int ret;
	u32 reg;

	reg = adc->cr_reg | BIT(ch) | LPC18XX_ADC_CR_START_NOW;
	writel(reg, adc->base + LPC18XX_ADC_CR);

	ret = readl_poll_timeout(adc->base + LPC18XX_ADC_GDR, reg,
				 reg & LPC18XX_ADC_CONV_DONE, 3, 9);
	if (ret) {
		dev_warn(adc->dev, "adc read timed out\n");
		return ret;
	}

	return (reg >> LPC18XX_ADC_SAMPLE_SHIFT) & LPC18XX_ADC_SAMPLE_MASK;
}

static int lpc18xx_adc_read_raw(struct iio_dev *indio_dev,
				struct iio_chan_spec const *chan,
				int *val, int *val2, long mask)
{
	struct lpc18xx_adc *adc = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&adc->lock);
		*val = lpc18xx_adc_read_chan(adc, chan->channel);
		mutex_unlock(&adc->lock);
		if (*val < 0)
			return *val;

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:
		*val = regulator_get_voltage(adc->vref) / 1000;
		*val2 = 10;

		return IIO_VAL_FRACTIONAL_LOG2;
	}

	return -EINVAL;
}

static const struct iio_info lpc18xx_adc_info = {
	.read_raw = lpc18xx_adc_read_raw,
};

static void lpc18xx_clear_cr_reg(void *data)
{
	struct lpc18xx_adc *adc = data;

	writel(0, adc->base + LPC18XX_ADC_CR);
}

static void lpc18xx_regulator_disable(void *vref)
{
	regulator_disable(vref);
}

static int lpc18xx_adc_probe(struct platform_device *pdev)
{

Annotation

Implementation Notes