On Fri, 21 Mar 2025 21:28:51 +0100
Angelo Dureghello <adureghello@xxxxxxxxxxxx> 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);
> +}
> +
> 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);
Probably better to use a const string and then you can use strlen() to get
the length from that. I don't much like counting characters!
> + 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)) {
As above, I'd like to see some strlen() on const strings for this.
FWIW strncmp doesn't care about NULL terminators as such so just ensure you only
compare the characters.
> + ret = ad3552r_hs_set_data_source(st,
> + IIO_BACKEND_INTERNAL_RAMP_16BIT);
> + if (ret)
> + return ret;
> + } else {
> + return -EINVAL;
> + }
> +
> + return count;
> +}
...
Thanks,
Jonathan
