From: Rodrigo Alencar <[email protected]> Most of the supported devices rely on a GAIN pin to control a 2x multiplier applied to the output voltage. Other devices, e.g. the single-channel ones, provides a gain control through a bit field in the control register. Some designs might have the GAIN pin hardwired to VDD/VLOGIC or GND, which would still be fine for this patch, that allows the scale property to be configurable with two available options.
Signed-off-by: Rodrigo Alencar <[email protected]> --- drivers/iio/dac/ad5686.c | 96 +++++++++++++++++++++++++++++++++++++++++++++--- drivers/iio/dac/ad5686.h | 8 ++++ 2 files changed, 99 insertions(+), 5 deletions(-) diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c index 54b953018cfa..fabe967c5225 100644 --- a/drivers/iio/dac/ad5686.c +++ b/drivers/iio/dac/ad5686.c @@ -13,10 +13,12 @@ #include <linux/errno.h> #include <linux/export.h> #include <linux/kstrtox.h> +#include <linux/math64.h> #include <linux/module.h> #include <linux/regulator/consumer.h> #include <linux/reset.h> #include <linux/sysfs.h> +#include <linux/units.h> #include <linux/wordpart.h> #include <linux/iio/buffer.h> @@ -39,7 +41,8 @@ static int ad5310_control_sync(struct ad5686_state *st) return ad5686_write(st, AD5686_CMD_CONTROL_REG, 0, FIELD_PREP(AD5310_PD_MSK, pd_val & AD5686_PD_MSK) | - FIELD_PREP(AD5310_REF_BIT_MSK, st->use_internal_vref ? 0 : 1)); + FIELD_PREP(AD5310_REF_BIT_MSK, st->use_internal_vref ? 0 : 1) | + FIELD_PREP(AD5310_GAIN_BIT_MSK, st->double_scale ? 1 : 0)); } static int ad5683_control_sync(struct ad5686_state *st) @@ -48,7 +51,8 @@ static int ad5683_control_sync(struct ad5686_state *st) return ad5686_write(st, AD5686_CMD_CONTROL_REG, 0, FIELD_PREP(AD5683_PD_MSK, pd_val & AD5686_PD_MSK) | - FIELD_PREP(AD5683_REF_BIT_MSK, st->use_internal_vref ? 0 : 1)); + FIELD_PREP(AD5683_REF_BIT_MSK, st->use_internal_vref ? 0 : 1) | + FIELD_PREP(AD5683_GAIN_BIT_MSK, st->double_scale ? 1 : 0)); } static inline unsigned int ad5686_pd_mask_shift(const struct iio_chan_spec *chan) @@ -191,9 +195,14 @@ static int ad5686_read_raw(struct iio_dev *indio_dev, GENMASK(chan->scan_type.realbits - 1, 0); return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: - *val = st->vref_mv; - *val2 = chan->scan_type.realbits; - return IIO_VAL_FRACTIONAL_LOG2; + if (st->double_scale) { + *val = st->scale_avail[2]; + *val2 = st->scale_avail[3]; + } else { + *val = st->scale_avail[0]; + *val2 = st->scale_avail[1]; + } + return IIO_VAL_INT_PLUS_NANO; } return -EINVAL; } @@ -215,6 +224,63 @@ static int ad5686_write_raw(struct iio_dev *indio_dev, return ad5686_write(st, AD5686_CMD_WRITE_INPUT_N_UPDATE_N, chan->address, val << chan->scan_type.shift); + case IIO_CHAN_INFO_SCALE: + if (val == st->scale_avail[0] && val2 == st->scale_avail[1]) + st->double_scale = false; + else if (val == st->scale_avail[2] && val2 == st->scale_avail[3]) + st->double_scale = true; + else + return -EINVAL; + + switch (st->chip_info->regmap_type) { + case AD5310_REGMAP: + return ad5310_control_sync(st); + case AD5683_REGMAP: + return ad5683_control_sync(st); + case AD5686_REGMAP: + /* + * even if the gain pin is hardwired on the board, the + * user is able to control the scale such that it + * matches the actual gain setting. + */ + gpiod_set_value_cansleep(st->gain_gpio, + st->double_scale ? 1 : 0); + return 0; + default: + return -EINVAL; + } + default: + return -EINVAL; + } +} + +static int ad5686_write_raw_get_fmt(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_RAW: + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + return IIO_VAL_INT_PLUS_NANO; + default: + return -EINVAL; + } +} + +static int ad5686_read_avail(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int **vals, int *type, int *length, + long mask) +{ + struct ad5686_state *st = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_SCALE: + *type = IIO_VAL_INT_PLUS_NANO; + *vals = st->scale_avail; + *length = ARRAY_SIZE(st->scale_avail); + return IIO_AVAIL_LIST; default: return -EINVAL; } @@ -223,6 +289,8 @@ static int ad5686_write_raw(struct iio_dev *indio_dev, static const struct iio_info ad5686_info = { .read_raw = ad5686_read_raw, .write_raw = ad5686_write_raw, + .write_raw_get_fmt = ad5686_write_raw_get_fmt, + .read_avail = ad5686_read_avail, }; static const struct iio_chan_spec_ext_info ad5686_ext_info[] = { @@ -244,6 +312,7 @@ static const struct iio_chan_spec_ext_info ad5686_ext_info[] = { .channel = chan, \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\ + .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE),\ .address = addr, \ .scan_index = chan, \ .scan_type = { \ @@ -470,6 +539,16 @@ const struct ad5686_chip_info ad5679r_chip_info = { }; EXPORT_SYMBOL_NS_GPL(ad5679r_chip_info, "IIO_AD5686"); +static void ad5686_init_scale_avail(struct ad5686_state *st) +{ + int realbits = st->chip_info->channels[0].scan_type.realbits; + s64 tmp; + + tmp = 2ULL * st->vref_mv * NANO >> realbits; + st->scale_avail[2] = div_s64_rem(tmp, NANO, &st->scale_avail[3]); + st->scale_avail[0] = div_s64_rem(tmp >> 1, NANO, &st->scale_avail[1]); +} + static irqreturn_t ad5686_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; @@ -569,6 +648,13 @@ int ad5686_probe(struct device *dev, return dev_err_probe(dev, PTR_ERR(st->ldac_gpio), "Failed to get LDAC GPIO\n"); + st->gain_gpio = devm_gpiod_get_optional(dev, "gain", GPIOD_OUT_LOW); + if (IS_ERR(st->gain_gpio)) + return dev_err_probe(dev, PTR_ERR(st->gain_gpio), + "Failed to get GAIN GPIO\n"); + + ad5686_init_scale_avail(st); + udelay(5); /* power-up time */ reset_control_assert(rstc); udelay(1); /* reset pulse: comfortably bigger than the spec */ diff --git a/drivers/iio/dac/ad5686.h b/drivers/iio/dac/ad5686.h index bc793179db09..455d6bbefdfe 100644 --- a/drivers/iio/dac/ad5686.h +++ b/drivers/iio/dac/ad5686.h @@ -40,9 +40,11 @@ #define AD5686_CMD_CONTROL_REG 0x4 #define AD5686_CMD_READBACK_ENABLE_V2 0x5 +#define AD5310_GAIN_BIT_MSK BIT(7) #define AD5310_REF_BIT_MSK BIT(8) #define AD5310_PD_MSK GENMASK(10, 9) +#define AD5683_GAIN_BIT_MSK BIT(11) #define AD5683_REF_BIT_MSK BIT(12) #define AD5683_PD_MSK GENMASK(14, 13) @@ -124,9 +126,12 @@ extern const struct ad5686_chip_info ad5679r_chip_info; * @chip_info: chip model specific constants, available modes etc * @ops: bus specific operations * @ldac_gpio: LDAC pin GPIO descriptor + * @gain_gpio: GAIN pin GPIO descriptor * @vref_mv: actual reference voltage used * @pwr_down_mask: power down mask * @pwr_down_mode: current power down mode + * @scale_avail: pre-calculated available scale values + * @double_scale: flag to indicate the gain multiplier is applied * @use_internal_vref: set to true if the internal reference voltage is used * @lock: lock to protect access to state fields, which includes * the data buffer during regmap ops @@ -138,9 +143,12 @@ struct ad5686_state { const struct ad5686_chip_info *chip_info; const struct ad5686_bus_ops *ops; struct gpio_desc *ldac_gpio; + struct gpio_desc *gain_gpio; unsigned short vref_mv; unsigned int pwr_down_mask; unsigned int pwr_down_mode; + int scale_avail[4]; + bool double_scale; bool use_internal_vref; struct mutex lock; void *bus_data; -- 2.43.0
