On Fri, 2025-03-21 at 21:28 +0100, Angelo Dureghello wrote:
> From: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
>
> The ad3552r can be feeded from the HDL controller by an internally
> generated 16bit ramp, useful for debug pourposes. Add debugfs a file
> to enable or disable it.
>
> Signed-off-by: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
> ---
> drivers/iio/dac/ad3552r-hs.c | 106 ++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 100 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/dac/ad3552r-hs.c b/drivers/iio/dac/ad3552r-hs.c
> index
> 37397e188f225a8099745ec03f7c604da76960b1..41fe78d982a68980db059b095fc27b37ea1a461b
> 100644
> --- a/drivers/iio/dac/ad3552r-hs.c
> +++ b/drivers/iio/dac/ad3552r-hs.c
> @@ -7,6 +7,7 @@
> */
>
> #include <linux/bitfield.h>
> +#include <linux/debugfs.h>
> #include <linux/delay.h>
> #include <linux/gpio/consumer.h>
> #include <linux/iio/backend.h>
> @@ -65,6 +66,18 @@ static int ad3552r_hs_reg_read(struct ad3552r_hs_state *st, u32
> reg, u32 *val,
> return st->data->bus_reg_read(st->back, reg, val, xfer_size);
> }
>
> +static int ad3552r_hs_set_data_source(struct ad3552r_hs_state *st,
> + enum iio_backend_data_source type)
> +{
> + int ret;
> +
> + ret = iio_backend_data_source_set(st->back, 0, type);
> + if (ret)
> + return ret;
> +
> + return iio_backend_data_source_set(st->back, 1, type);
>
I know it's a debug thing but we could use some locking in the above...
> +}
> +
> static int ad3552r_hs_update_reg_bits(struct ad3552r_hs_state *st, u32 reg,
> u32 mask, u32 val, size_t xfer_size)
> {
> @@ -483,6 +496,66 @@ static int ad3552r_hs_reg_access(struct iio_dev *indio_dev,
> unsigned int reg,
> return st->data->bus_reg_write(st->back, reg, writeval, 1);
> }
>
> +static ssize_t ad3552r_hs_show_data_source(struct file *f, char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct ad3552r_hs_state *st = file_inode(f)->i_private;
> + enum iio_backend_data_source type;
> + int ret;
> +
> + ret = iio_backend_data_source_get(st->back, 0, &type);
> + if (ret)
> + return ret;
> +
> + switch (type) {
> + case IIO_BACKEND_INTERNAL_RAMP_16BIT:
> + return simple_read_from_buffer(userbuf, count, ppos,
> + "backend-ramp-generator", 22);
> + case IIO_BACKEND_EXTERNAL:
> + return simple_read_from_buffer(userbuf, count, ppos,
> + "iio-buffer", 10);
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static ssize_t ad3552r_hs_write_data_source(struct file *f,
> + const char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct ad3552r_hs_state *st = file_inode(f)->i_private;
> + char buf[64];
> + int ret;
> +
> + ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, userbuf,
> + count);
> + if (ret < 0)
> + return ret;
> +
> + buf[count] = 0;
> +
> + if (count == 10 && !strncmp(buf, "iio-buffer", 10)) {
> + ret = ad3552r_hs_set_data_source(st, IIO_BACKEND_EXTERNAL);
> + if (ret)
> + return ret;
> + } else if (count == 22 && !strncmp(buf, "backend-ramp-generator", 22)) {
> + ret = ad3552r_hs_set_data_source(st,
> + IIO_BACKEND_INTERNAL_RAMP_16BIT);
> + if (ret)
> + return ret;
> + } else {
> + return -EINVAL;
> + }
Are we expected to add more data types in the future? If not, this could be simply an
enable/disable ramp generator thing... It would be much simpler.
Anyways, you could define a static array and use match_string()?
Lastly, for insterfaces like this, it's always helpful to have an _available kind of
attribute.
- Nuno Sá
>
> static const struct of_device_id ad3552r_hs_of_id[] = {
>
