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staging: iio: resolver: ad2s1210: implement fault events
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When reading the position and velocity on the AD2S1210, there is also a
3rd byte following the two data bytes that contains the fault flag bits.
This patch adds support for reading this byte and generating events when
faults occur.

The faults are mapped to various channels and event type in order to
have a unique event for each fault.

Signed-off-by: David Lechner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Cameron <[email protected]>
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@dlech
dlech committed Oct 31, 2023
1 parent fd62cd0 commit eaeab25
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Showing 2 changed files with 212 additions and 14 deletions.
15 changes: 15 additions & 0 deletions Documentation/ABI/testing/sysfs-bus-iio
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Original file line number Diff line number Diff line change
Expand Up @@ -2207,3 +2207,18 @@ Contact: [email protected]
Description:
An example format is 16-bytes, 2-digits-per-byte, HEX-string
representing the sensor unique ID number.

What: /sys/bus/iio/devices/iio:deviceX/events/in_altvoltageY_mag_either_label
What: /sys/bus/iio/devices/iio:deviceX/events/in_altvoltageY_mag_rising_label
What: /sys/bus/iio/devices/iio:deviceX/events/in_altvoltageY_thresh_falling_label
What: /sys/bus/iio/devices/iio:deviceX/events/in_altvoltageY_thresh_rising_label
What: /sys/bus/iio/devices/iio:deviceX/events/in_anglvelY_mag_rising_label
What: /sys/bus/iio/devices/iio:deviceX/events/in_anglY_thresh_rising_label
What: /sys/bus/iio/devices/iio:deviceX/events/in_phaseY_mag_rising_label
KernelVersion: 6.7
Contact: [email protected]
Description:
Optional symbolic label to a device channel event.
If a label is defined for this event add that to the event
specific attributes. This is useful for userspace to be able to
better identify an individual event.
211 changes: 197 additions & 14 deletions drivers/staging/iio/resolver/ad2s1210.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
#include <linux/types.h>

#include <linux/iio/buffer.h>
#include <linux/iio/events.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
Expand All @@ -35,6 +36,16 @@
#define AD2S1210_SET_ENRES GENMASK(3, 2)
#define AD2S1210_SET_RES GENMASK(1, 0)

/* fault register flags */
#define AD2S1210_FAULT_CLIP BIT(7)
#define AD2S1210_FAULT_LOS BIT(6)
#define AD2S1210_FAULT_DOS_OVR BIT(5)
#define AD2S1210_FAULT_DOS_MIS BIT(4)
#define AD2S1210_FAULT_LOT BIT(3)
#define AD2S1210_FAULT_VELOCITY BIT(2)
#define AD2S1210_FAULT_PHASE BIT(1)
#define AD2S1210_FAULT_CONFIG_PARITY BIT(0)

#define AD2S1210_REG_POSITION_MSB 0x80
#define AD2S1210_REG_POSITION_LSB 0x81
#define AD2S1210_REG_VELOCITY_MSB 0x82
Expand Down Expand Up @@ -71,6 +82,8 @@
/* max voltage for threshold registers is 0x7F * 38 mV */
#define THRESHOLD_RANGE_STR "[0 38 4826]"

#define FAULT_ONESHOT(bit, new, old) (new & bit && !(old & bit))

enum ad2s1210_mode {
MOD_POS = 0b00,
MOD_VEL = 0b01,
Expand Down Expand Up @@ -100,8 +113,13 @@ struct ad2s1210_state {
int hysteresis_available[2];
/** The selected resolution */
enum ad2s1210_resolution resolution;
/** Copy of fault register from the previous read. */
u8 prev_fault_flags;
/** For reading raw sample value via SPI. */
__be16 sample __aligned(IIO_DMA_MINALIGN);
struct {
__be16 raw;
u8 fault;
} sample __aligned(IIO_DMA_MINALIGN);
/** Scan buffer */
struct {
__be16 chan[2];
Expand Down Expand Up @@ -160,7 +178,15 @@ static int ad2s1210_regmap_reg_write(void *context, unsigned int reg,
if (ret < 0)
return ret;

return spi_sync_transfer(st->sdev, xfers, ARRAY_SIZE(xfers));
ret = spi_sync_transfer(st->sdev, xfers, ARRAY_SIZE(xfers));
if (ret < 0)
return ret;

/* soft reset also clears the fault register */
if (reg == AD2S1210_REG_SOFT_RESET)
st->prev_fault_flags = 0;

return 0;
}

/*
Expand Down Expand Up @@ -203,6 +229,10 @@ static int ad2s1210_regmap_reg_read(void *context, unsigned int reg,
if (ret < 0)
return ret;

/* reading the fault register also clears it */
if (reg == AD2S1210_REG_FAULT)
st->prev_fault_flags = 0;

/*
* If the D7 bit is set on any read/write register, it indicates a
* parity error. The fault register is read-only and the D7 bit means
Expand Down Expand Up @@ -286,14 +316,101 @@ static ssize_t ad2s1210_clear_fault(struct device *dev,
return ret < 0 ? ret : len;
}

static int ad2s1210_single_conversion(struct ad2s1210_state *st,
static void ad2s1210_push_events(struct iio_dev *indio_dev,
u8 flags, s64 timestamp)
{
struct ad2s1210_state *st = iio_priv(indio_dev);

/* Sine/cosine inputs clipped */
if (FAULT_ONESHOT(AD2S1210_FAULT_CLIP, flags, st->prev_fault_flags)) {
/*
* The chip does not differentiate between fault on sine vs.
* cosine channel so we just send an event on both channels.
*/
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_ALTVOLTAGE, 1,
IIO_EV_TYPE_MAG,
IIO_EV_DIR_EITHER),
timestamp);
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_ALTVOLTAGE, 2,
IIO_EV_TYPE_MAG,
IIO_EV_DIR_EITHER),
timestamp);
}

/* Sine/cosine inputs below LOS threshold */
if (FAULT_ONESHOT(AD2S1210_FAULT_LOS, flags, st->prev_fault_flags))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_ALTVOLTAGE, 0,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_FALLING),
timestamp);

/* Sine/cosine inputs exceed DOS overrange threshold */
if (FAULT_ONESHOT(AD2S1210_FAULT_DOS_OVR, flags, st->prev_fault_flags))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_ALTVOLTAGE, 0,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_RISING),
timestamp);

/* Sine/cosine inputs exceed DOS mismatch threshold */
if (FAULT_ONESHOT(AD2S1210_FAULT_DOS_MIS, flags, st->prev_fault_flags))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_ALTVOLTAGE, 0,
IIO_EV_TYPE_MAG,
IIO_EV_DIR_RISING),
timestamp);

/* Tracking error exceeds LOT threshold */
if (FAULT_ONESHOT(AD2S1210_FAULT_LOT, flags, st->prev_fault_flags))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_ANGL, 1,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_RISING),
timestamp);

/* Velocity exceeds maximum tracking rate */
if (FAULT_ONESHOT(AD2S1210_FAULT_VELOCITY, flags, st->prev_fault_flags))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_ANGL_VEL, 0,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_RISING),
timestamp);

/* Phase error exceeds phase lock range */
if (FAULT_ONESHOT(AD2S1210_FAULT_PHASE, flags, st->prev_fault_flags))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_PHASE, 0,
IIO_EV_TYPE_MAG,
IIO_EV_DIR_RISING),
timestamp);

/* Configuration parity error */
if (FAULT_ONESHOT(AD2S1210_FAULT_CONFIG_PARITY, flags,
st->prev_fault_flags))
/*
* Userspace should also get notified of this via error return
* when trying to write to any attribute that writes a register.
*/
dev_err_ratelimited(&indio_dev->dev,
"Configuration parity error\n");

st->prev_fault_flags = flags;
}

static int ad2s1210_single_conversion(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val)
{
struct ad2s1210_state *st = iio_priv(indio_dev);
s64 timestamp;
int ret;

mutex_lock(&st->lock);
gpiod_set_value(st->sample_gpio, 1);
timestamp = iio_get_time_ns(indio_dev);
/* delay (6 * tck + 20) nano seconds */
udelay(1);

Expand All @@ -310,24 +427,26 @@ static int ad2s1210_single_conversion(struct ad2s1210_state *st,
}
if (ret < 0)
goto error_ret;
ret = spi_read(st->sdev, &st->sample, 2);
ret = spi_read(st->sdev, &st->sample, 3);
if (ret < 0)
goto error_ret;

switch (chan->type) {
case IIO_ANGL:
*val = be16_to_cpu(st->sample);
*val = be16_to_cpu(st->sample.raw);
ret = IIO_VAL_INT;
break;
case IIO_ANGL_VEL:
*val = (s16)be16_to_cpu(st->sample);
*val = (s16)be16_to_cpu(st->sample.raw);
ret = IIO_VAL_INT;
break;
default:
ret = -EINVAL;
break;
}

ad2s1210_push_events(indio_dev, st->sample.fault, timestamp);

error_ret:
gpiod_set_value(st->sample_gpio, 0);
/* delay (2 * tck + 20) nano seconds */
Expand Down Expand Up @@ -611,7 +730,7 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,

switch (mask) {
case IIO_CHAN_INFO_RAW:
return ad2s1210_single_conversion(st, chan, val);
return ad2s1210_single_conversion(indio_dev, chan, val);
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_ANGL:
Expand Down Expand Up @@ -725,6 +844,14 @@ static const struct iio_event_spec ad2s1210_position_event_spec[] = {
},
};

static const struct iio_event_spec ad2s1210_velocity_event_spec[] = {
{
/* Velocity exceeds maximum tracking rate fault. */
.type = IIO_EV_TYPE_MAG,
.dir = IIO_EV_DIR_RISING,
},
};

static const struct iio_event_spec ad2s1210_phase_event_spec[] = {
{
/* Phase error fault. */
Expand Down Expand Up @@ -758,6 +885,14 @@ static const struct iio_event_spec ad2s1210_monitor_signal_event_spec[] = {
},
};

static const struct iio_event_spec ad2s1210_sin_cos_event_spec[] = {
{
/* Sine/cosine clipping fault. */
.type = IIO_EV_TYPE_MAG,
.dir = IIO_EV_DIR_EITHER,
},
};

static const struct iio_chan_spec ad2s1210_channels[] = {
{
.type = IIO_ANGL,
Expand Down Expand Up @@ -788,6 +923,8 @@ static const struct iio_chan_spec ad2s1210_channels[] = {
},
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.event_spec = ad2s1210_velocity_event_spec,
.num_event_specs = ARRAY_SIZE(ad2s1210_velocity_event_spec),
},
IIO_CHAN_SOFT_TIMESTAMP(2),
{
Expand Down Expand Up @@ -824,6 +961,22 @@ static const struct iio_chan_spec ad2s1210_channels[] = {
.scan_index = -1,
.event_spec = ad2s1210_monitor_signal_event_spec,
.num_event_specs = ARRAY_SIZE(ad2s1210_monitor_signal_event_spec),
}, {
/* sine input */
.type = IIO_ALTVOLTAGE,
.indexed = 1,
.channel = 1,
.scan_index = -1,
.event_spec = ad2s1210_sin_cos_event_spec,
.num_event_specs = ARRAY_SIZE(ad2s1210_sin_cos_event_spec),
}, {
/* cosine input */
.type = IIO_ALTVOLTAGE,
.indexed = 1,
.channel = 2,
.scan_index = -1,
.event_spec = ad2s1210_sin_cos_event_spec,
.num_event_specs = ARRAY_SIZE(ad2s1210_sin_cos_event_spec),
},
};

Expand Down Expand Up @@ -943,7 +1096,7 @@ static const struct attribute_group ad2s1210_event_attribute_group = {

static int ad2s1210_initial(struct ad2s1210_state *st)
{
unsigned char data;
unsigned int data;
int ret;

mutex_lock(&st->lock);
Expand Down Expand Up @@ -1043,6 +1196,36 @@ static int ad2s1210_write_event_value(struct iio_dev *indio_dev,
}
}

static int ad2s1210_read_event_label(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
enum iio_event_type type,
enum iio_event_direction dir,
char *label)
{
if (chan->type == IIO_ANGL)
return sprintf(label, "LOT\n");
if (chan->type == IIO_ANGL_VEL)
return sprintf(label, "max tracking rate\n");
if (chan->type == IIO_PHASE)
return sprintf(label, "phase lock\n");
if (chan->type == IIO_ALTVOLTAGE) {
if (chan->channel == 0) {
if (type == IIO_EV_TYPE_THRESH &&
dir == IIO_EV_DIR_FALLING)
return sprintf(label, "LOS\n");
if (type == IIO_EV_TYPE_THRESH &&
dir == IIO_EV_DIR_RISING)
return sprintf(label, "DOS overrange\n");
if (type == IIO_EV_TYPE_MAG)
return sprintf(label, "DOS mismatch\n");
}
if (chan->channel == 1 || chan->channel == 2)
return sprintf(label, "clipped\n");
}

return -EINVAL;
}

static int ad2s1210_debugfs_reg_access(struct iio_dev *indio_dev,
unsigned int reg, unsigned int writeval,
unsigned int *readval)
Expand Down Expand Up @@ -1080,27 +1263,26 @@ static irqreturn_t ad2s1210_trigger_handler(int irq, void *p)
if (ret < 0)
goto error_ret;

/* REVIST: we can read 3 bytes here and also get fault flags */
ret = spi_read(st->sdev, st->rx, 2);
ret = spi_read(st->sdev, &st->sample, 3);
if (ret < 0)
goto error_ret;

memcpy(&st->scan.chan[chan++], st->rx, 2);
memcpy(&st->scan.chan[chan++], &st->sample.raw, 2);
}

if (test_bit(1, indio_dev->active_scan_mask)) {
ret = ad2s1210_set_mode(st, MOD_VEL);
if (ret < 0)
goto error_ret;

/* REVIST: we can read 3 bytes here and also get fault flags */
ret = spi_read(st->sdev, st->rx, 2);
ret = spi_read(st->sdev, &st->sample, 3);
if (ret < 0)
goto error_ret;

memcpy(&st->scan.chan[chan++], st->rx, 2);
memcpy(&st->scan.chan[chan++], &st->sample.raw, 2);
}

ad2s1210_push_events(indio_dev, st->sample.fault, pf->timestamp);
iio_push_to_buffers_with_timestamp(indio_dev, &st->scan, pf->timestamp);

error_ret:
Expand All @@ -1119,6 +1301,7 @@ static const struct iio_info ad2s1210_info = {
.attrs = &ad2s1210_attribute_group,
.read_event_value = ad2s1210_read_event_value,
.write_event_value = ad2s1210_write_event_value,
.read_event_label = ad2s1210_read_event_label,
.debugfs_reg_access = &ad2s1210_debugfs_reg_access,
};

Expand Down

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