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iio: adc: ad4630: update to use pwm waveforms API
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Also change AD4630_TQUIET_CNV_DELAY_PS to AD4630_TQUIET_CNV_DELAY_NS and
the nearest appropriate value, so that we don't have to round when
calculating PWM offsets now.

Signed-off-by: Trevor Gamblin <[email protected]>
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@threexc
threexc committed Nov 21, 2024
1 parent fbeec8a commit e01069d
Showing 1 changed file with 50 additions and 31 deletions.
81 changes: 50 additions & 31 deletions drivers/iio/adc/ad4630.c
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Original file line number Diff line number Diff line change
Expand Up @@ -94,9 +94,10 @@
/* sequence starting with "1 0 1" to enable reg access */
#define AD4630_REG_ACCESS 0x2000
/* Sampling timing */
#define AD4630_TQUIET_CNV_DELAY_PS 9800
#define AD4630_MAX_RATE_1_LANE 1750000
#define AD4630_MAX_RATE 2000000
/* Datasheet says 9.8ns, so use the closest integer value */
#define AD4630_TQUIET_CNV_DELAY_NS 10

#define AD4630_MAX_CHANNEL_NR 3
#define AD4630_VREF_MIN (4096 * MILLI)
Expand Down Expand Up @@ -192,6 +193,8 @@ struct ad4630_state {
struct regulator_bulk_data regulators[3];
struct pwm_device *conv_trigger;
struct pwm_device *fetch_trigger;
struct pwm_waveform conv_wf;
struct pwm_waveform fetch_wf;
struct gpio_descs *pga_gpios;
struct spi_device *spi;
struct regmap *regmap;
Expand Down Expand Up @@ -258,10 +261,10 @@ static int ad4630_reg_access(struct iio_dev *indio_dev, unsigned int reg,

static void ad4630_get_sampling_freq(const struct ad4630_state *st, int *freq)
{
struct pwm_state conversion_state;
struct pwm_waveform conversion_wf;

pwm_get_state(st->conv_trigger, &conversion_state);
*freq = DIV_ROUND_CLOSEST_ULL(NANO, conversion_state.period);
pwm_get_waveform_might_sleep(st->conv_trigger, &conversion_wf);
*freq = DIV_ROUND_CLOSEST_ULL(NANO, conversion_wf.period_length_ns);
}

static int ad4630_get_chan_gain(struct iio_dev *indio_dev, int ch, int *val)
Expand Down Expand Up @@ -370,26 +373,24 @@ static int ad4630_read_avail(struct iio_dev *indio_dev,
}
}

static int __ad4630_set_sampling_freq(const struct ad4630_state *st, unsigned int freq)
static int __ad4630_set_sampling_freq(struct ad4630_state *st, unsigned int freq)
{
struct pwm_state conv_state = {
.duty_cycle = 10,
.enabled = true,
}, fetch_state = {
.duty_cycle = 10,
.enabled = true,
struct pwm_waveform conv_wf = {
.duty_length_ns = 10,
}, fetch_wf = {
.duty_length_ns = 10,
};
int ret;

conv_state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
ret = pwm_apply_state(st->conv_trigger, &conv_state);
conv_wf.period_length_ns = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
ret = pwm_set_waveform_might_sleep(st->conv_trigger, &conv_wf, false);
if (ret)
return ret;

if (!st->fetch_trigger)
return 0;

fetch_state.period = conv_state.period;
fetch_wf.period_length_ns = conv_wf.period_length_ns;

if (st->out_data == AD4630_30_AVERAGED_DIFF) {
u32 avg;
Expand All @@ -398,23 +399,33 @@ static int __ad4630_set_sampling_freq(const struct ad4630_state *st, unsigned in
if (ret)
return ret;

fetch_state.period <<= FIELD_GET(AD4630_AVG_AVG_VAL, avg);
fetch_wf.period_length_ns <<= FIELD_GET(AD4630_AVG_AVG_VAL, avg);
}

/*
* The hardware does the capture on zone 2 (when spi trigger PWM
* is used). This means that the spi trigger signal should happen at
* tsync + tquiet_con_delay being tsync the conversion signal period
* and tquiet_con_delay 9.8ns. Hence set the PWM phase accordingly.
*
* The PWM waveform API only supports nanosecond resolution right now,
* so round this setting to the closest available value.
*/
fetch_state.phase = AD4630_TQUIET_CNV_DELAY_PS;
fetch_wf.duty_offset_ns = AD4630_TQUIET_CNV_DELAY_NS;

return pwm_apply_state(st->fetch_trigger, &fetch_state);
ret = pwm_set_waveform_might_sleep(st->fetch_trigger, &fetch_wf, false);
if (ret)
return ret;

st->conv_wf = conv_wf;
st->fetch_wf = fetch_wf;

return 0;
}

static int ad4630_set_sampling_freq(struct iio_dev *indio_dev, unsigned int freq)
{
const struct ad4630_state *st = iio_priv(indio_dev);
struct ad4630_state *st = iio_priv(indio_dev);
int ret;

if (!freq || freq > st->max_rate)
Expand Down Expand Up @@ -592,17 +603,17 @@ static int ad4630_write_raw(struct iio_dev *indio_dev,

static int ad4630_update_sample_fetch_trigger(const struct ad4630_state *st, u32 avg)
{
struct pwm_state fetch_state, conv_state;
struct pwm_waveform fetch_wf = { }, conv_wf = { };

if (!st->fetch_trigger)
return 0;

pwm_get_state(st->conv_trigger, &conv_state);
pwm_get_state(st->fetch_trigger, &fetch_state);
fetch_state.period = conv_state.period * 1 << avg;
fetch_state.phase = AD4630_TQUIET_CNV_DELAY_PS;
pwm_get_waveform_might_sleep(st->conv_trigger, &conv_wf);
pwm_get_waveform_might_sleep(st->fetch_trigger, &fetch_wf);
fetch_wf.period_length_ns = conv_wf.period_length_ns * 1 << avg;
fetch_wf.duty_offset_ns = AD4630_TQUIET_CNV_DELAY_NS;

return pwm_apply_state(st->fetch_trigger, &fetch_state);
return pwm_set_waveform_might_sleep(st->fetch_trigger, &fetch_wf, false);
}

static int ad4630_set_avg_frame_len(struct iio_dev *dev,
Expand Down Expand Up @@ -648,21 +659,21 @@ static int ad4630_get_avg_frame_len(struct iio_dev *dev,

static int ad4630_sampling_enable(const struct ad4630_state *st, bool enable)
{
struct pwm_state conv_state, fetch_state;
struct pwm_waveform conv_wf = { }, fetch_wf = { };
int ret;

pwm_get_state(st->conv_trigger, &conv_state);
conv_state.enabled = enable;
pwm_get_waveform_might_sleep(st->conv_trigger, &conv_wf);

ret = pwm_apply_state(st->conv_trigger, &conv_state);
ret = pwm_set_waveform_might_sleep(st->conv_trigger, &conv_wf, false);
if (ret)
return ret;

if (!st->fetch_trigger)
return 0;

pwm_get_state(st->fetch_trigger, &fetch_state);
fetch_state.enabled = enable;
return pwm_apply_state(st->fetch_trigger, &fetch_state);
pwm_get_waveform_might_sleep(st->fetch_trigger, &fetch_wf);

return pwm_set_waveform_might_sleep(st->fetch_trigger, &fetch_wf, false);
}

static int ad4630_spi_transfer_update(struct ad4630_state *st)
Expand Down Expand Up @@ -731,6 +742,14 @@ static int ad4630_buffer_preenable(struct iio_dev *indio_dev)
spi_engine_ex_offload_enable(st->spi, true);
ad4630_sampling_enable(st, true);

ret = pwm_set_waveform_might_sleep(st->conv_trigger, &st->conv_wf, false);
if (ret)
return ret;

ret = pwm_set_waveform_might_sleep(st->fetch_trigger, &st->fetch_wf, false);
if (ret)
return ret;

return 0;
out_error:
pm_runtime_mark_last_busy(&st->spi->dev);
Expand Down

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