2017-09-05 12:15:06

by Dragos Bogdan

Subject: [PATCH 1/2] iio: ad_sigma_delta: Implement a dedicated reset function

Since most of the SD ADCs have the option of reseting the serial
interface by sending a number of SCLKs with CS = 0 and DIN = 1,
a dedicated function that can do this is usefull.

Signed-off-by: Dragos Bogdan <[email protected]>
---
drivers/iio/adc/ad_sigma_delta.c | 28 ++++++++++++++++++++++++++++
include/linux/iio/adc/ad_sigma_delta.h | 3 +++
2 files changed, 31 insertions(+)

diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index d10bd0c97233..22c4c17cd996 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -177,6 +177,34 @@ int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
}
EXPORT_SYMBOL_GPL(ad_sd_read_reg);

+/**
+ * ad_sd_reset() - Reset the serial interface
+ *
+ * @sigma_delta: The sigma delta device
+ * @reset_length: Number of SCLKs with DIN = 1
+ *
+ * Returns 0 on success, an error code otherwise.
+ **/
+int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
+ unsigned int reset_length)
+{
+ uint8_t *buf;
+ unsigned int size;
+ int ret;
+
+ size = DIV_ROUND_UP(reset_length, 8);
+ buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ memset(buf, 0xff, size);
+ ret = spi_write(sigma_delta->spi, buf, size);
+ kfree(buf);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ad_sd_reset);
+
static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
unsigned int mode, unsigned int channel)
{
diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h
index 5ba430cc9a87..1fc7abd28b0b 100644
--- a/include/linux/iio/adc/ad_sigma_delta.h
+++ b/include/linux/iio/adc/ad_sigma_delta.h
@@ -111,6 +111,9 @@ int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
unsigned int size, unsigned int *val);

+int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
+ unsigned int reset_length);
+
int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, int *val);
int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
--
2.11.0

2017-09-05 12:43:26

by Lars-Peter Clausen

Subject: Re: [PATCH 1/2] iio: ad_sigma_delta: Implement a dedicated reset function

On 09/05/2017 02:14 PM, Dragos Bogdan wrote:
> Since most of the SD ADCs have the option of reseting the serial
> interface by sending a number of SCLKs with CS = 0 and DIN = 1,
> a dedicated function that can do this is usefull.
>
> Signed-off-by: Dragos Bogdan <[email protected]>

Acked-by: Lars-Peter Clausen <[email protected]>

> ---
> drivers/iio/adc/ad_sigma_delta.c | 28 ++++++++++++++++++++++++++++
> include/linux/iio/adc/ad_sigma_delta.h | 3 +++
> 2 files changed, 31 insertions(+)
>
> diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
> index d10bd0c97233..22c4c17cd996 100644
> --- a/drivers/iio/adc/ad_sigma_delta.c
> +++ b/drivers/iio/adc/ad_sigma_delta.c
> @@ -177,6 +177,34 @@ int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
> }
> EXPORT_SYMBOL_GPL(ad_sd_read_reg);
>
> +/**
> + * ad_sd_reset() - Reset the serial interface
> + *
> + * @sigma_delta: The sigma delta device
> + * @reset_length: Number of SCLKs with DIN = 1
> + *
> + * Returns 0 on success, an error code otherwise.
> + **/
> +int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
> + unsigned int reset_length)
> +{
> + uint8_t *buf;
> + unsigned int size;
> + int ret;
> +
> + size = DIV_ROUND_UP(reset_length, 8);
> + buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + memset(buf, 0xff, size);
> + ret = spi_write(sigma_delta->spi, buf, size);
> + kfree(buf);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(ad_sd_reset);
> +
> static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
> unsigned int mode, unsigned int channel)
> {
> diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h
> index 5ba430cc9a87..1fc7abd28b0b 100644
> --- a/include/linux/iio/adc/ad_sigma_delta.h
> +++ b/include/linux/iio/adc/ad_sigma_delta.h
> @@ -111,6 +111,9 @@ int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
> int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
> unsigned int size, unsigned int *val);
>
> +int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
> + unsigned int reset_length);
> +
> int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
> const struct iio_chan_spec *chan, int *val);
> int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
>

2017-09-10 15:22:23

by Jonathan Cameron

Subject: Re: [PATCH 1/2] iio: ad_sigma_delta: Implement a dedicated reset function

On Tue, 5 Sep 2017 14:16:42 +0200
Lars-Peter Clausen <[email protected]> wrote:

> On 09/05/2017 02:14 PM, Dragos Bogdan wrote:
> > Since most of the SD ADCs have the option of reseting the serial
> > interface by sending a number of SCLKs with CS = 0 and DIN = 1,
> > a dedicated function that can do this is usefull.
> >
> > Signed-off-by: Dragos Bogdan <[email protected]>
>
> Acked-by: Lars-Peter Clausen <[email protected]>

Applied to the fixes-togreg branch of iio.git and marked
for stable. I added a note that this was a precursor for
the following patch to justify the stable cc.

Jonathan
>
> > ---
> > drivers/iio/adc/ad_sigma_delta.c | 28 ++++++++++++++++++++++++++++
> > include/linux/iio/adc/ad_sigma_delta.h | 3 +++
> > 2 files changed, 31 insertions(+)
> >
> > diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
> > index d10bd0c97233..22c4c17cd996 100644
> > --- a/drivers/iio/adc/ad_sigma_delta.c
> > +++ b/drivers/iio/adc/ad_sigma_delta.c
> > @@ -177,6 +177,34 @@ int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
> > }
> > EXPORT_SYMBOL_GPL(ad_sd_read_reg);
> >
> > +/**
> > + * ad_sd_reset() - Reset the serial interface
> > + *
> > + * @sigma_delta: The sigma delta device
> > + * @reset_length: Number of SCLKs with DIN = 1
> > + *
> > + * Returns 0 on success, an error code otherwise.
> > + **/
> > +int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
> > + unsigned int reset_length)
> > +{
> > + uint8_t *buf;
> > + unsigned int size;
> > + int ret;
> > +
> > + size = DIV_ROUND_UP(reset_length, 8);
> > + buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
> > + if (!buf)
> > + return -ENOMEM;
> > +
> > + memset(buf, 0xff, size);
> > + ret = spi_write(sigma_delta->spi, buf, size);
> > + kfree(buf);
> > +
> > + return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(ad_sd_reset);
> > +
> > static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
> > unsigned int mode, unsigned int channel)
> > {
> > diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h
> > index 5ba430cc9a87..1fc7abd28b0b 100644
> > --- a/include/linux/iio/adc/ad_sigma_delta.h
> > +++ b/include/linux/iio/adc/ad_sigma_delta.h
> > @@ -111,6 +111,9 @@ int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
> > int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
> > unsigned int size, unsigned int *val);
> >
> > +int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
> > + unsigned int reset_length);
> > +
> > int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
> > const struct iio_chan_spec *chan, int *val);
> > int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
> >
>