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Extend the device driver, handling the internal reference and input signal attenuation, enabling it to also support LTC2338-18. Signed-off-by: Marcelo Schmitt --- New patch mainly extracted from the base driver patch with the addition of input attenuation handling for LTC2338-18. drivers/iio/adc/ltc2378.c | 44 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 43 insertions(+), 1 deletion(-) diff --git a/drivers/iio/adc/ltc2378.c b/drivers/iio/adc/ltc2378.c index 146eaadbeb6c..689fa5419faf 100644 --- a/drivers/iio/adc/ltc2378.c +++ b/drivers/iio/adc/ltc2378.c @@ -107,6 +107,8 @@ struct ltc2378_chip_info { const char *name; + unsigned int internal_ref_uV; + struct u32_fract internal_div; struct iio_chan_spec chan[2]; /* 1 physical chan + 1 timestamp chan */ struct iio_chan_spec offload_chan; unsigned int max_sample_rate_Hz; @@ -145,6 +147,16 @@ struct ltc2378_state { } scan __aligned(IIO_DMA_MINALIGN); }; +static const struct ltc2378_chip_info ltc2338_18_chip_info = { + .name = "ltc2338-18", + .internal_ref_uV = 2048000, + .internal_div = { .numerator = 5, .denominator = 2 }, + .chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) }, + .offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18), + .max_sample_rate_Hz = 1 * HZ_PER_MHZ, + .tconv_ns = 527, +}; + static const struct ltc2378_chip_info ltc2364_16_chip_info = { .name = "ltc2364-16", .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) }, @@ -383,7 +395,10 @@ static int ltc2378_read_raw(struct iio_dev *indio_dev, return IIO_VAL_INT; } case IIO_CHAN_INFO_SCALE: + struct u32_fract fract = st->info->internal_div; *val = st->ref_uV / MILLI; + if (fract.numerator && fract.denominator) + *val = mult_frac(*val, fract.numerator, fract.denominator); /* * For all LTC2378-like devices, the amount of bits that express * voltage magnitude depend on the polarity / output code format: @@ -641,6 +656,28 @@ static const struct spi_offload_config ltc2378_offload_config = { SPI_OFFLOAD_CAP_RX_STREAM_DMA, }; +static int ltc2378_refin_setup(struct device *dev, struct ltc2378_state *st) +{ + int ret; + + /* + * The internal reference buffer amplifies both the internal reference + * and REFIN by a factor of 2. + */ + ret = devm_regulator_get_enable_read_voltage(dev, "refin"); + if (ret == -ENODEV) { /* refin is optional */ + st->ref_uV = st->info->internal_ref_uV * 2; + return 0; + } + + if (ret < 0) + return dev_err_probe(dev, ret, "failed to read refin regulator\n"); + + st->ref_uV = ret * 2; + + return 0; +} + static int ltc2378_ref_setup(struct device *dev, struct ltc2378_state *st) { int ret; @@ -676,7 +713,10 @@ static int ltc2378_probe(struct spi_device *spi) if (!st->info) return -EINVAL; - ret = ltc2378_ref_setup(dev, st); + if (st->info->internal_ref_uV) + ret = ltc2378_refin_setup(dev, st); + else + ret = ltc2378_ref_setup(dev, st); if (ret) return ret; @@ -750,6 +790,7 @@ static int ltc2378_probe(struct spi_device *spi) } static const struct of_device_id ltc2378_of_match[] = { + { .compatible = "adi,ltc2338-18", .data = <c2338_18_chip_info }, { .compatible = "adi,ltc2364-16", .data = <c2364_16_chip_info }, { .compatible = "adi,ltc2364-18", .data = <c2364_18_chip_info }, { .compatible = "adi,ltc2367-16", .data = <c2367_16_chip_info }, @@ -774,6 +815,7 @@ static const struct of_device_id ltc2378_of_match[] = { MODULE_DEVICE_TABLE(of, ltc2378_of_match); static const struct spi_device_id ltc2378_spi_id[] = { + { .name = "ltc2338-18", .driver_data = (kernel_ulong_t)<c2338_18_chip_info }, { .name = "ltc2364-16", .driver_data = (kernel_ulong_t)<c2364_16_chip_info }, { .name = "ltc2364-18", .driver_data = (kernel_ulong_t)<c2364_18_chip_info }, { .name = "ltc2367-16", .driver_data = (kernel_ulong_t)<c2367_16_chip_info }, -- 2.53.0