mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-29 05:44:11 +00:00
iio: adc: mcp3911: add support to set PGA
Add support for setting the Programmable Gain Amplifiers by adjust the scale value. Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220922194639.1118971-1-marcus.folkesson@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Marcus Folkesson
Jonathan Cameron
parent
4e61514036
commit
8cf5f03291
1 changed files with 80 additions and 24 deletions
|
|
@ -29,6 +29,8 @@
|
|||
#define MCP3911_REG_MOD 0x06
|
||||
#define MCP3911_REG_PHASE 0x07
|
||||
#define MCP3911_REG_GAIN 0x09
|
||||
#define MCP3911_GAIN_MASK(ch) (GENMASK(2, 0) << 3 * ch)
|
||||
#define MCP3911_GAIN_VAL(ch, val) ((val << 3 * ch) & MCP3911_GAIN_MASK(ch))
|
||||
|
||||
#define MCP3911_REG_STATUSCOM 0x0a
|
||||
#define MCP3911_STATUSCOM_DRHIZ BIT(12)
|
||||
|
|
@ -60,8 +62,10 @@
|
|||
#define MCP3911_REG_MASK GENMASK(4, 1)
|
||||
|
||||
#define MCP3911_NUM_CHANNELS 2
|
||||
#define MCP3911_NUM_SCALES 6
|
||||
|
||||
static const int mcp3911_osr_table[] = { 32, 64, 128, 256, 512, 1024, 2048, 4096 };
|
||||
static u32 mcp3911_scale_table[MCP3911_NUM_SCALES][2];
|
||||
|
||||
struct mcp3911 {
|
||||
struct spi_device *spi;
|
||||
|
|
@ -70,6 +74,7 @@ struct mcp3911 {
|
|||
struct clk *clki;
|
||||
u32 dev_addr;
|
||||
struct iio_trigger *trig;
|
||||
u32 gain[MCP3911_NUM_CHANNELS];
|
||||
struct {
|
||||
u32 channels[MCP3911_NUM_CHANNELS];
|
||||
s64 ts __aligned(8);
|
||||
|
|
@ -146,6 +151,11 @@ static int mcp3911_read_avail(struct iio_dev *indio_dev,
|
|||
*vals = mcp3911_osr_table;
|
||||
*length = ARRAY_SIZE(mcp3911_osr_table);
|
||||
return IIO_AVAIL_LIST;
|
||||
case IIO_CHAN_INFO_SCALE:
|
||||
*type = IIO_VAL_INT_PLUS_NANO;
|
||||
*vals = (int *)mcp3911_scale_table;
|
||||
*length = ARRAY_SIZE(mcp3911_scale_table) * 2;
|
||||
return IIO_AVAIL_LIST;
|
||||
default:
|
||||
return -EINVAL;
|
||||
}
|
||||
|
|
@ -190,29 +200,9 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
|
|||
break;
|
||||
|
||||
case IIO_CHAN_INFO_SCALE:
|
||||
if (adc->vref) {
|
||||
ret = regulator_get_voltage(adc->vref);
|
||||
if (ret < 0) {
|
||||
dev_err(indio_dev->dev.parent,
|
||||
"failed to get vref voltage: %d\n",
|
||||
ret);
|
||||
goto out;
|
||||
}
|
||||
|
||||
*val = ret / 1000;
|
||||
} else {
|
||||
*val = MCP3911_INT_VREF_MV;
|
||||
}
|
||||
|
||||
/*
|
||||
* For 24bit Conversion
|
||||
* Raw = ((Voltage)/(Vref) * 2^23 * Gain * 1.5
|
||||
* Voltage = Raw * (Vref)/(2^23 * Gain * 1.5)
|
||||
*/
|
||||
|
||||
/* val2 = (2^23 * 1.5) */
|
||||
*val2 = 12582912;
|
||||
ret = IIO_VAL_FRACTIONAL;
|
||||
*val = mcp3911_scale_table[ilog2(adc->gain[channel->channel])][0];
|
||||
*val2 = mcp3911_scale_table[ilog2(adc->gain[channel->channel])][1];
|
||||
ret = IIO_VAL_INT_PLUS_NANO;
|
||||
break;
|
||||
}
|
||||
|
||||
|
|
@ -230,6 +220,18 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
|
|||
|
||||
mutex_lock(&adc->lock);
|
||||
switch (mask) {
|
||||
case IIO_CHAN_INFO_SCALE:
|
||||
for (int i = 0; i < MCP3911_NUM_SCALES; i++) {
|
||||
if (val == mcp3911_scale_table[i][0] &&
|
||||
val2 == mcp3911_scale_table[i][1]) {
|
||||
|
||||
adc->gain[channel->channel] = BIT(i);
|
||||
ret = mcp3911_update(adc, MCP3911_REG_GAIN,
|
||||
MCP3911_GAIN_MASK(channel->channel),
|
||||
MCP3911_GAIN_VAL(channel->channel, i), 1);
|
||||
}
|
||||
}
|
||||
break;
|
||||
case IIO_CHAN_INFO_OFFSET:
|
||||
if (val2 != 0) {
|
||||
ret = -EINVAL;
|
||||
|
|
@ -265,6 +267,44 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
|
|||
return ret;
|
||||
}
|
||||
|
||||
static int mcp3911_calc_scale_table(struct mcp3911 *adc)
|
||||
{
|
||||
u32 ref = MCP3911_INT_VREF_MV;
|
||||
u32 div;
|
||||
int ret;
|
||||
u64 tmp;
|
||||
|
||||
if (adc->vref) {
|
||||
ret = regulator_get_voltage(adc->vref);
|
||||
if (ret < 0) {
|
||||
dev_err(&adc->spi->dev,
|
||||
"failed to get vref voltage: %d\n",
|
||||
ret);
|
||||
return ret;
|
||||
}
|
||||
|
||||
ref = ret / 1000;
|
||||
}
|
||||
|
||||
/*
|
||||
* For 24-bit Conversion
|
||||
* Raw = ((Voltage)/(Vref) * 2^23 * Gain * 1.5
|
||||
* Voltage = Raw * (Vref)/(2^23 * Gain * 1.5)
|
||||
*
|
||||
* ref = Reference voltage
|
||||
* div = (2^23 * 1.5 * gain) = 12582912 * gain
|
||||
*/
|
||||
for (int i = 0; i < MCP3911_NUM_SCALES; i++) {
|
||||
div = 12582912 * BIT(i);
|
||||
tmp = div_s64((s64)ref * 1000000000LL, div);
|
||||
|
||||
mcp3911_scale_table[i][0] = 0;
|
||||
mcp3911_scale_table[i][1] = tmp;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#define MCP3911_CHAN(idx) { \
|
||||
.type = IIO_VOLTAGE, \
|
||||
.indexed = 1, \
|
||||
|
|
@ -274,8 +314,10 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
|
|||
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
|
||||
BIT(IIO_CHAN_INFO_OFFSET) | \
|
||||
BIT(IIO_CHAN_INFO_SCALE), \
|
||||
.info_mask_shared_by_type_available = \
|
||||
.info_mask_shared_by_type_available = \
|
||||
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
|
||||
.info_mask_separate_available = \
|
||||
BIT(IIO_CHAN_INFO_SCALE), \
|
||||
.scan_type = { \
|
||||
.sign = 's', \
|
||||
.realbits = 24, \
|
||||
|
|
@ -482,6 +524,20 @@ static int mcp3911_probe(struct spi_device *spi)
|
|||
if (ret)
|
||||
return ret;
|
||||
|
||||
ret = mcp3911_calc_scale_table(adc);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
/* Set gain to 1 for all channels */
|
||||
for (int i = 0; i < MCP3911_NUM_CHANNELS; i++) {
|
||||
adc->gain[i] = 1;
|
||||
ret = mcp3911_update(adc, MCP3911_REG_GAIN,
|
||||
MCP3911_GAIN_MASK(i),
|
||||
MCP3911_GAIN_VAL(i, 0), 1);
|
||||
if (ret)
|
||||
return ret;
|
||||
}
|
||||
|
||||
indio_dev->name = spi_get_device_id(spi)->name;
|
||||
indio_dev->modes = INDIO_DIRECT_MODE;
|
||||
indio_dev->info = &mcp3911_info;
|
||||
|
|
|
|||
Loading…
Reference in a new issue