[PATCH v3 17/27] staging: iio: resolver: ad2s1210: convert fexcit to channel attribute

David Lechner
2023-09-29T17:26:03Z

From: David Lechner <david@lechnology.com>

From: David Lechner <dlechner@baylibre.com>

The ad2s1210 driver has a device-specific attribute `fexcit` for setting
the frequency of the excitation output. This converts it to a channel in
order to use standard IIO ABI.

The excitation frequency is an analog output that generates a sine wave.
Only the frequency is configurable. According to the datasheet, the
specified range of the excitation frequency is from 2 kHz to 20 kHz and
can be set in increments of 250 Hz.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---

v3 changes:
* This is a new patch in v3 instead of "iio: resolver: ad2s1210: rename fexcit
attribute"

drivers/staging/iio/resolver/ad2s1210.c | 122 ++++++++++++++++++--------------
1 file changed, 70 insertions(+), 52 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index b15d71b17266..6accb9e3db46 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -224,54 +224,6 @@ static int ad2s1210_set_resolution_gpios(struct ad2s1210_state *st,
bitmap);
}

-static ssize_t ad2s1210_show_fexcit(struct device *dev,
- struct device_attribute *attr,
- char *buf)
-{
- struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
- unsigned int value;
- u16 fexcit;
- int ret;
-
- mutex_lock(&st->lock);
- ret = regmap_read(st->regmap, AD2S1210_REG_EXCIT_FREQ, &value);
- if (ret < 0)
- goto error_ret;
-
- fexcit = value * st->clkin_hz / (1 << 15);
-
- ret = sprintf(buf, "%u\n", fexcit);
-
-error_ret:
- mutex_unlock(&st->lock);
- return ret;
-}
-
-static ssize_t ad2s1210_store_fexcit(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t len)
-{
- struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
- u16 fexcit;
- int ret;
-
- ret = kstrtou16(buf, 10, &fexcit);
- if (ret < 0 || fexcit < AD2S1210_MIN_EXCIT || fexcit > AD2S1210_MAX_EXCIT)
- return -EINVAL;
-
- mutex_lock(&st->lock);
- ret = ad2s1210_reinit_excitation_frequency(st, fexcit);
- if (ret < 0)
- goto error_ret;
-
- ret = len;
-
-error_ret:
- mutex_unlock(&st->lock);
-
- return ret;
-}
-
static ssize_t ad2s1210_show_resolution(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -474,6 +426,38 @@ static int ad2s1210_set_hysteresis(struct ad2s1210_state *st, int val)
return ret;
}

+static int ad2s1210_get_excitation_frequency(struct ad2s1210_state *st, int *val)
+{
+ unsigned int reg_val;
+ int ret;
+
+ mutex_lock(&st->lock);
+ ret = regmap_read(st->regmap, AD2S1210_REG_EXCIT_FREQ, &reg_val);
+ if (ret < 0)
+ goto error_ret;
+
+ *val = reg_val * st->clkin_hz / (1 << 15);
+ ret = IIO_VAL_INT;
+
+error_ret:
+ mutex_unlock(&st->lock);
+ return ret;
+}
+
+static int ad2s1210_set_excitation_frequency(struct ad2s1210_state *st, int val)
+{
+ int ret;
+
+ if (val < AD2S1210_MIN_EXCIT || val > AD2S1210_MAX_EXCIT)
+ return -EINVAL;
+
+ mutex_lock(&st->lock);
+ ret = ad2s1210_reinit_excitation_frequency(st, val);
+ 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) */
@@ -506,6 +490,13 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
default:
return -EINVAL;
}
+ case IIO_CHAN_INFO_FREQUENCY:
+ switch (chan->type) {
+ case IIO_ALTVOLTAGE:
+ return ad2s1210_get_excitation_frequency(st, val);
+ default:
+ return -EINVAL;
+ }
case IIO_CHAN_INFO_HYSTERESIS:
switch (chan->type) {
case IIO_ANGL:
@@ -523,9 +514,23 @@ static int ad2s1210_read_avail(struct iio_dev *indio_dev,
const int **vals, int *type,
int *length, long mask)
{
+ static const int excitation_frequency_available[] = {
+ AD2S1210_MIN_EXCIT,
+ 250, /* step */
+ AD2S1210_MAX_EXCIT,
+ };
static const int hysteresis_available[] = { 0, 1 };

switch (mask) {
+ case IIO_CHAN_INFO_FREQUENCY:
+ switch (chan->type) {
+ case IIO_ALTVOLTAGE:
+ *type = IIO_VAL_INT;
+ *vals = excitation_frequency_available;
+ return IIO_AVAIL_RANGE;
+ default:
+ return -EINVAL;
+ }
case IIO_CHAN_INFO_HYSTERESIS:
switch (chan->type) {
case IIO_ANGL:
@@ -548,6 +553,13 @@ static int ad2s1210_write_raw(struct iio_dev *indio_dev,
struct ad2s1210_state *st = iio_priv(indio_dev);

switch (mask) {
+ case IIO_CHAN_INFO_FREQUENCY:
+ switch (chan->type) {
+ case IIO_ALTVOLTAGE:
+ return ad2s1210_set_excitation_frequency(st, val);
+ default:
+ return -EINVAL;
+ }
case IIO_CHAN_INFO_HYSTERESIS:
switch (chan->type) {
case IIO_ANGL:
@@ -560,8 +572,6 @@ static int ad2s1210_write_raw(struct iio_dev *indio_dev,
}
}

-static IIO_DEVICE_ATTR(fexcit, 0644,
- ad2s1210_show_fexcit, ad2s1210_store_fexcit, 0);
static IIO_DEVICE_ATTR(bits, 0644,
ad2s1210_show_resolution, ad2s1210_store_resolution, 0);
static IIO_DEVICE_ATTR(fault, 0644,
@@ -605,11 +615,19 @@ static const struct iio_chan_spec ad2s1210_channels[] = {
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
- }
+ }, {
+ /* excitation frequency output */
+ .type = IIO_ALTVOLTAGE,
+ .indexed = 1,
+ .channel = 0,
+ .output = 1,
+ .scan_index = -1,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_FREQUENCY),
+ .info_mask_separate_available = BIT(IIO_CHAN_INFO_FREQUENCY),
+ },
};

static struct attribute *ad2s1210_attributes[] = {
- &iio_dev_attr_fexcit.dev_attr.attr,
&iio_dev_attr_bits.dev_attr.attr,
&iio_dev_attr_fault.dev_attr.attr,
&iio_dev_attr_los_thrd.dev_attr.attr,

--
2.42.0