Commit 6d965885 authored by Marcus Folkesson's avatar Marcus Folkesson Committed by Jonathan Cameron
Browse files

iio: adc: mcp3911: add support for oversampling ratio 



The chip supports oversampling ratio, so expose it to userspace.

Signed-off-by: default avatarMarcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220815061625.35568-9-marcus.folkesson@gmail.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 1a84fa69

drivers/iio/adc/mcp3911.c

+58 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#define MCP3911_REG_CONFIG		0x0c

#define MCP3911_CONFIG_CLKEXT		BIT(1)

#define MCP3911_CONFIG_VREFEXT		BIT(2)

#define MCP3911_CONFIG_OSR		GENMASK(13, 11)



#define MCP3911_REG_OFFCAL_CH0		0x0e

#define MCP3911_REG_GAINCAL_CH0		0x11
@@ -59,6 +60,8 @@ 


#define MCP3911_NUM_CHANNELS		2



static const int mcp3911_osr_table[] = { 32, 64, 128, 256, 512, 1024, 2048, 4096 };



struct mcp3911 {

	struct spi_device *spi;

	struct mutex lock;
@@ -117,6 +120,36 @@ static int mcp3911_update(struct mcp3911 *adc, u8 reg, u32 mask, 
	return mcp3911_write(adc, reg, val, len);

}



static int mcp3911_write_raw_get_fmt(struct iio_dev *indio_dev,

					struct iio_chan_spec const *chan,

					long mask)

{

	switch (mask) {

	case IIO_CHAN_INFO_SCALE:

		return IIO_VAL_INT_PLUS_NANO;

	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:

		return IIO_VAL_INT;

	default:

		return IIO_VAL_INT_PLUS_NANO;

	}

}



static int mcp3911_read_avail(struct iio_dev *indio_dev,

			     struct iio_chan_spec const *chan,

			     const int **vals, int *type, int *length,

			     long info)

{

	switch (info) {

	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:

		*type = IIO_VAL_INT;

		*vals = mcp3911_osr_table;

		*length = ARRAY_SIZE(mcp3911_osr_table);

		return IIO_AVAIL_LIST;

	default:

		return -EINVAL;

	}

}



static int mcp3911_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *channel, int *val,

			    int *val2, long mask)
@@ -145,6 +178,15 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev, 


		ret = IIO_VAL_INT;

		break;

	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:

		ret = mcp3911_read(adc, MCP3911_REG_CONFIG, val, 2);

		if (ret)

			goto out;



		*val = FIELD_GET(MCP3911_CONFIG_OSR, *val);

		*val = 32 << *val;

		ret = IIO_VAL_INT;

		break;



	case IIO_CHAN_INFO_SCALE:

		if (adc->vref) {
@@ -204,6 +246,17 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev, 
				MCP3911_STATUSCOM_EN_OFFCAL,

				MCP3911_STATUSCOM_EN_OFFCAL, 2);

		break;



	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:

		for (int i = 0; i < sizeof(mcp3911_osr_table); i++) {

			if (val == mcp3911_osr_table[i]) {

				val = FIELD_PREP(MCP3911_CONFIG_OSR, i);

				ret = mcp3911_update(adc, MCP3911_REG_CONFIG, MCP3911_CONFIG_OSR,

						val, 2);

				break;

			}

		}

		break;

	}



out:
@@ -216,9 +269,12 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev, 
		.indexed = 1,					\

		.channel = idx,					\

		.scan_index = idx,				\

		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\

			BIT(IIO_CHAN_INFO_OFFSET) |		\

			BIT(IIO_CHAN_INFO_SCALE),		\

		.info_mask_shared_by_type_available =		\

			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),	\

		.scan_type = {					\

			.sign = 's',				\

			.realbits = 24,				\
@@ -278,6 +334,8 @@ static irqreturn_t mcp3911_trigger_handler(int irq, void *p) 
static const struct iio_info mcp3911_info = {

	.read_raw = mcp3911_read_raw,

	.write_raw = mcp3911_write_raw,

	.read_avail = mcp3911_read_avail,

	.write_raw_get_fmt = mcp3911_write_raw_get_fmt,

};



static int mcp3911_config(struct mcp3911 *adc)