On Thu, 22 Sep 2022 21:46:39 +0200 Marcus Folkesson <marcus.folkesson@xxxxxxxxx> wrote: > Add support for setting the Programmable Gain Amplifiers by adjust the > scale value. > > Signed-off-by: Marcus Folkesson <marcus.folkesson@xxxxxxxxx> > Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> Applied to the togreg branch of iio.git and pushed out as testing. I considered slipping this into my 2nd IIO pull request for this cycle at the last minute, but wasn't happy skipping normal time being beaten on by 0-day and time in next, so I didn't. Hence this probably won't make 6.1, but Linus did hint he might do an rc8 in which case I may see if GregKH will take a 3rd pull late next week. If not, it'll be 6.2 material. Thanks, Jonathan > --- > > Notes: > Based on > Link: https://lore.kernel.org/all/20220815061625.35568-1-marcus.folkesson@xxxxxxxxx/ > > But with tmp0, tmp1 and tmp2 removed as those are not needed. > Link: https://lore.kernel.org/all/202209220648.Wb6EtPat-lkp@xxxxxxxxx/ > > drivers/iio/adc/mcp3911.c | 104 +++++++++++++++++++++++++++++--------- > 1 file changed, 80 insertions(+), 24 deletions(-) > > diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c > index 0151258b456c..0d768006eabb 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) > @@ -59,8 +61,10 @@ > #define MCP3911_REG_WRITE(reg, id) ((((reg) << 1) | ((id) << 5) | (0 << 0)) & 0xff) > > #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; > @@ -69,6 +73,7 @@ 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); > @@ -145,6 +150,11 @@ 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; > } > @@ -189,29 +199,9 @@ 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; > } > > @@ -229,6 +219,18 @@ 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; > @@ -264,6 +266,44 @@ 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, \ > @@ -273,8 +313,10 @@ 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, \ > @@ -483,6 +525,20 @@ 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;
