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iio: adc: mcp3911: add support for oversampling ratio 

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

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220815061625.35568-9-marcus.folkesson@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Marcus Folkesson 2022-08-15 08:16:24 +02:00 committed by Jonathan Cameron
parent 1a84fa695c
commit 6d965885f4
1 changed files with 58 additions and 0 deletions
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58
drivers/iio/adc/mcp3911.c
View File

@ -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 @@ out:
.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 @@ out:
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)