| Message ID | 20230929-ad2s1210-mainline-v3-14-fa4364281745@baylibre.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | iio: resolver: move ad2s1210 out of staging | expand |
On Fri, Sep 29, 2023 at 12:25 PM David Lechner <dlechner@baylibre.com> wrote: > > The AD2S1210 resolver has a hysteresis feature that can be used to > prevent flicker in the LSB of the position register. This can be either > enabled or disabled. Disabling hysteresis is useful for increasing > precision by oversampling. > > Signed-off-by: David Lechner <dlechner@baylibre.com> > --- ... > +static int ad2s1210_read_avail(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + const int **vals, int *type, > + int *length, long mask) > +{ > + static const int hysteresis_available[] = { 0, 1 }; This is basically an enable/disable. Should the 1 value be changed to the appropriate radians value since this is hysteresis on the position (angle) channel? > + > + switch (mask) { > + case IIO_CHAN_INFO_HYSTERESIS: > + switch (chan->type) { > + case IIO_ANGL: > + *vals = hysteresis_available; > + *type = IIO_VAL_INT; > + *length = ARRAY_SIZE(hysteresis_available); > + return IIO_AVAIL_LIST; > + default: > + return -EINVAL; > + } > + default: > + return -EINVAL; > + } > +} >
On Fri, 29 Sep 2023 12:53:00 -0500 David Lechner <dlechner@baylibre.com> wrote: > On Fri, Sep 29, 2023 at 12:25 PM David Lechner <dlechner@baylibre.com> wrote: > > > > The AD2S1210 resolver has a hysteresis feature that can be used to > > prevent flicker in the LSB of the position register. This can be either > > enabled or disabled. Disabling hysteresis is useful for increasing > > precision by oversampling. > > > > Signed-off-by: David Lechner <dlechner@baylibre.com> > > --- > > ... > > > +static int ad2s1210_read_avail(struct iio_dev *indio_dev, > > + struct iio_chan_spec const *chan, > > + const int **vals, int *type, > > + int *length, long mask) > > +{ > > + static const int hysteresis_available[] = { 0, 1 }; > > This is basically an enable/disable. Should the 1 value be changed to the > appropriate radians value since this is hysteresis on the position > (angle) channel? Good point. However it should be in the _raw units. The text is slightly more explicit on this for the variant of hysteresis applied to threshold events as it's added or substracted from a threshold (and thresholds are in _raw readings unless only _processed is available). Does that make 0, 1 correct as we are talking about LSB only? Jonathan > > > + > > + switch (mask) { > > + case IIO_CHAN_INFO_HYSTERESIS: > > + switch (chan->type) { > > + case IIO_ANGL: > > + *vals = hysteresis_available; > > + *type = IIO_VAL_INT; > > + *length = ARRAY_SIZE(hysteresis_available); > > + return IIO_AVAIL_LIST; > > + default: > > + return -EINVAL; > > + } > > + default: > > + return -EINVAL; > > + } > > +} > >
On Fri, 29 Sep 2023 12:23:19 -0500 David Lechner <dlechner@baylibre.com> wrote: > From: David Lechner <david@lechnology.com> > > From: David Lechner <dlechner@baylibre.com> > > The AD2S1210 resolver has a hysteresis feature that can be used to > prevent flicker in the LSB of the position register. This can be either > enabled or disabled. Disabling hysteresis is useful for increasing > precision by oversampling. > > Signed-off-by: David Lechner <dlechner@baylibre.com> One trivial thing inline. Thanks, Jonathan > --- > > v3 changes: > * Refactored into more functions to reduce complexity of switch statements. > * Use early return instead of break in switch statements. > > drivers/staging/iio/resolver/ad2s1210.c | 86 +++++++++++++++++++++++++++++++-- > 1 file changed, 83 insertions(+), 3 deletions(-) > > diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c > index 0ec3598b600a..a82cb124a12f 100644 > --- a/drivers/staging/iio/resolver/ad2s1210.c > +++ b/drivers/staging/iio/resolver/ad2s1210.c > @@ -78,7 +78,6 @@ struct ad2s1210_state { > /** The external oscillator frequency in Hz. */ > unsigned long clkin_hz; > unsigned int fexcit; > - bool hysteresis; > u8 resolution; > /** For reading raw sample value via SPI. */ > __be16 sample __aligned(IIO_DMA_MINALIGN); > @@ -430,6 +429,35 @@ static int ad2s1210_single_conversion(struct ad2s1210_state *st, > return ret; > } > > +static int ad2s1210_get_hysteresis(struct ad2s1210_state *st, int *val) > +{ > + int ret; > + > + mutex_lock(&st->lock); > + ret = regmap_test_bits(st->regmap, AD2S1210_REG_CONTROL, > + AD2S1210_ENABLE_HYSTERESIS); > + mutex_unlock(&st->lock); > + > + if (ret < 0) > + return ret; > + > + *val = !!ret; regmap_test_bits() is documented as returning 1 or 0 anyway. So this !! isn't necessary.. > + return IIO_VAL_INT; > +} > + > +static int ad2s1210_set_hysteresis(struct ad2s1210_state *st, int val) > +{ > + int ret; > + > + mutex_lock(&st->lock); > + ret = regmap_update_bits(st->regmap, AD2S1210_REG_CONTROL, > + AD2S1210_ENABLE_HYSTERESIS, > + val ? AD2S1210_ENABLE_HYSTERESIS : 0); > + mutex_unlock(&st->lock); > + > + return ret; > +} > + > static const int ad2s1210_velocity_scale[] = { > 17089132, /* 8.192MHz / (2*pi * 2500 / 2^15) */ > 42722830, /* 8.192MHz / (2*pi * 1000 / 2^15) */ > @@ -462,7 +490,55 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev, > default: > return -EINVAL; > } > + case IIO_CHAN_INFO_HYSTERESIS: > + switch (chan->type) { > + case IIO_ANGL: > + return ad2s1210_get_hysteresis(st, val); > + default: > + return -EINVAL; > + } > + default: > + return -EINVAL; > + } > +} > + > +static int ad2s1210_read_avail(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + const int **vals, int *type, > + int *length, long mask) > +{ > + static const int hysteresis_available[] = { 0, 1 }; > + > + switch (mask) { > + case IIO_CHAN_INFO_HYSTERESIS: > + switch (chan->type) { > + case IIO_ANGL: > + *vals = hysteresis_available; > + *type = IIO_VAL_INT; > + *length = ARRAY_SIZE(hysteresis_available); > + return IIO_AVAIL_LIST; > + default: > + return -EINVAL; > + } > + default: > + return -EINVAL; > + } > +} > > +static int ad2s1210_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct ad2s1210_state *st = iio_priv(indio_dev); > + > + switch (mask) { > + case IIO_CHAN_INFO_HYSTERESIS: > + switch (chan->type) { > + case IIO_ANGL: > + return ad2s1210_set_hysteresis(st, val); > + default: > + return -EINVAL; > + } > default: > return -EINVAL; > } > @@ -503,7 +579,10 @@ static const struct iio_chan_spec ad2s1210_channels[] = { > .indexed = 1, > .channel = 0, > .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > - BIT(IIO_CHAN_INFO_SCALE), > + BIT(IIO_CHAN_INFO_SCALE) | > + BIT(IIO_CHAN_INFO_HYSTERESIS), > + .info_mask_separate_available = > + BIT(IIO_CHAN_INFO_HYSTERESIS), > }, { > .type = IIO_ANGL_VEL, > .indexed = 1, > @@ -581,6 +660,8 @@ static int ad2s1210_debugfs_reg_access(struct iio_dev *indio_dev, > > static const struct iio_info ad2s1210_info = { > .read_raw = ad2s1210_read_raw, > + .read_avail = ad2s1210_read_avail, > + .write_raw = ad2s1210_write_raw, > .attrs = &ad2s1210_attribute_group, > .debugfs_reg_access = &ad2s1210_debugfs_reg_access, > }; > @@ -696,7 +777,6 @@ static int ad2s1210_probe(struct spi_device *spi) > > mutex_init(&st->lock); > st->sdev = spi; > - st->hysteresis = true; > st->resolution = 12; > st->fexcit = AD2S1210_DEF_EXCIT; > >
On Sat, Sep 30, 2023 at 10:00 AM Jonathan Cameron <jic23@kernel.org> wrote: > > On Fri, 29 Sep 2023 12:53:00 -0500 > David Lechner <dlechner@baylibre.com> wrote: > > > On Fri, Sep 29, 2023 at 12:25 PM David Lechner <dlechner@baylibre.com> wrote: > > > > > > The AD2S1210 resolver has a hysteresis feature that can be used to > > > prevent flicker in the LSB of the position register. This can be either > > > enabled or disabled. Disabling hysteresis is useful for increasing > > > precision by oversampling. > > > > > > Signed-off-by: David Lechner <dlechner@baylibre.com> > > > --- > > > > ... > > > > > +static int ad2s1210_read_avail(struct iio_dev *indio_dev, > > > + struct iio_chan_spec const *chan, > > > + const int **vals, int *type, > > > + int *length, long mask) > > > +{ > > > + static const int hysteresis_available[] = { 0, 1 }; > > > > This is basically an enable/disable. Should the 1 value be changed to the > > appropriate radians value since this is hysteresis on the position > > (angle) channel? > > Good point. However it should be in the _raw units. The text is > slightly more explicit on this for > the variant of hysteresis applied to threshold events as it's > added or substracted from a threshold (and thresholds are in > _raw readings unless only _processed is available). > > Does that make 0, 1 correct as we are talking about LSB only? > It is currently only correct (as a raw value) if the selected resolution is 16-bit. So I will need to fix this so the value is `1 << (16 - resolution)`.
diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c index 0ec3598b600a..a82cb124a12f 100644 --- a/drivers/staging/iio/resolver/ad2s1210.c +++ b/drivers/staging/iio/resolver/ad2s1210.c @@ -78,7 +78,6 @@ struct ad2s1210_state { /** The external oscillator frequency in Hz. */ unsigned long clkin_hz; unsigned int fexcit; - bool hysteresis; u8 resolution; /** For reading raw sample value via SPI. */ __be16 sample __aligned(IIO_DMA_MINALIGN); @@ -430,6 +429,35 @@ static int ad2s1210_single_conversion(struct ad2s1210_state *st, return ret; } +static int ad2s1210_get_hysteresis(struct ad2s1210_state *st, int *val) +{ + int ret; + + mutex_lock(&st->lock); + ret = regmap_test_bits(st->regmap, AD2S1210_REG_CONTROL, + AD2S1210_ENABLE_HYSTERESIS); + mutex_unlock(&st->lock); + + if (ret < 0) + return ret; + + *val = !!ret; + return IIO_VAL_INT; +} + +static int ad2s1210_set_hysteresis(struct ad2s1210_state *st, int val) +{ + int ret; + + mutex_lock(&st->lock); + ret = regmap_update_bits(st->regmap, AD2S1210_REG_CONTROL, + AD2S1210_ENABLE_HYSTERESIS, + val ? AD2S1210_ENABLE_HYSTERESIS : 0); + mutex_unlock(&st->lock); + + return ret; +} + static const int ad2s1210_velocity_scale[] = { 17089132, /* 8.192MHz / (2*pi * 2500 / 2^15) */ 42722830, /* 8.192MHz / (2*pi * 1000 / 2^15) */ @@ -462,7 +490,55 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev, default: return -EINVAL; } + case IIO_CHAN_INFO_HYSTERESIS: + switch (chan->type) { + case IIO_ANGL: + return ad2s1210_get_hysteresis(st, val); + default: + return -EINVAL; + } + default: + return -EINVAL; + } +} + +static int ad2s1210_read_avail(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int **vals, int *type, + int *length, long mask) +{ + static const int hysteresis_available[] = { 0, 1 }; + + switch (mask) { + case IIO_CHAN_INFO_HYSTERESIS: + switch (chan->type) { + case IIO_ANGL: + *vals = hysteresis_available; + *type = IIO_VAL_INT; + *length = ARRAY_SIZE(hysteresis_available); + return IIO_AVAIL_LIST; + default: + return -EINVAL; + } + default: + return -EINVAL; + } +} +static int ad2s1210_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct ad2s1210_state *st = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_HYSTERESIS: + switch (chan->type) { + case IIO_ANGL: + return ad2s1210_set_hysteresis(st, val); + default: + return -EINVAL; + } default: return -EINVAL; } @@ -503,7 +579,10 @@ static const struct iio_chan_spec ad2s1210_channels[] = { .indexed = 1, .channel = 0, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | - BIT(IIO_CHAN_INFO_SCALE), + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_HYSTERESIS), + .info_mask_separate_available = + BIT(IIO_CHAN_INFO_HYSTERESIS), }, { .type = IIO_ANGL_VEL, .indexed = 1, @@ -581,6 +660,8 @@ static int ad2s1210_debugfs_reg_access(struct iio_dev *indio_dev, static const struct iio_info ad2s1210_info = { .read_raw = ad2s1210_read_raw, + .read_avail = ad2s1210_read_avail, + .write_raw = ad2s1210_write_raw, .attrs = &ad2s1210_attribute_group, .debugfs_reg_access = &ad2s1210_debugfs_reg_access, }; @@ -696,7 +777,6 @@ static int ad2s1210_probe(struct spi_device *spi) mutex_init(&st->lock); st->sdev = spi; - st->hysteresis = true; st->resolution = 12; st->fexcit = AD2S1210_DEF_EXCIT;