diff options
Diffstat (limited to 'drivers/iio/adc/mcp3911.c')
| -rw-r--r-- | drivers/iio/adc/mcp3911.c | 104 |
1 files changed, 80 insertions, 24 deletions
diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c index 76b334f5ac61..974c5bd923a6 100644 --- a/drivers/iio/adc/mcp3911.c +++ b/drivers/iio/adc/mcp3911.c @@ -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 @@ out: 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 @@ out: .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; |