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

Jonathan Cameron
2023-09-30T15:12:13Z

On Fri, 29 Sep 2023 12:23:22 -0500
David Lechner <dlechner@baylibre.com> wrote:

> 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>
And this is the point where things got non trivial given I skipped
the hysterisis patch.

This looks good to me though, so will pick it up once questions on that
earlier patch are resolved.

Thanks,

Jonathan

> ---
>
> 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,
>