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SubjectRe: [PATCH 1/4] iio: adc: ad7476: Generate CONVST signal internally
On Wed, 11 Mar 2020 10:43:25 +0200
Beniamin Bia <beniamin.bia@analog.com> wrote:

> From: Dragos Bogdan <dragos.bogdan@analog.com>
>
> Compared to the other supported parts, AD7091R are dependent of
> a CONVST signal that initiates the conversion. At this moment, only
> sampling in buffered mode is supported for AD7091R and the only
> option until now was to generate this signal externally using an
> IIO trigger. This patch adds the option of generating it internally,
> more compatible triggers being available in this case.
>
> Also, it is an intermiate step of adding support more devices.
>
> Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
> Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Seems sensible. Applied to the togreg branch of iio.git and pushed
out as testing for the autobuilders to play with it.

Thanks,

Jonathan

> ---
> drivers/iio/adc/ad7476.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/iio/adc/ad7476.c b/drivers/iio/adc/ad7476.c
> index 76747488044b..32e857dfec9c 100644
> --- a/drivers/iio/adc/ad7476.c
> +++ b/drivers/iio/adc/ad7476.c
> @@ -12,9 +12,11 @@
> #include <linux/sysfs.h>
> #include <linux/spi/spi.h>
> #include <linux/regulator/consumer.h>
> +#include <linux/gpio/consumer.h>
> #include <linux/err.h>
> #include <linux/module.h>
> #include <linux/bitops.h>
> +#include <linux/delay.h>
>
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> @@ -34,6 +36,7 @@ struct ad7476_state {
> struct spi_device *spi;
> const struct ad7476_chip_info *chip_info;
> struct regulator *reg;
> + struct gpio_desc *convst_gpio;
> struct spi_transfer xfer;
> struct spi_message msg;
> /*
> @@ -64,6 +67,17 @@ enum ad7476_supported_device_ids {
> ID_ADS7868,
> };
>
> +static void ad7091_convst(struct ad7476_state *st)
> +{
> + if (!st->convst_gpio)
> + return;
> +
> + gpiod_set_value(st->convst_gpio, 0);
> + udelay(1); /* CONVST pulse width: 10 ns min */
> + gpiod_set_value(st->convst_gpio, 1);
> + udelay(1); /* Conversion time: 650 ns max */
> +}
> +
> static irqreturn_t ad7476_trigger_handler(int irq, void *p)
> {
> struct iio_poll_func *pf = p;
> @@ -71,6 +85,8 @@ static irqreturn_t ad7476_trigger_handler(int irq, void *p)
> struct ad7476_state *st = iio_priv(indio_dev);
> int b_sent;
>
> + ad7091_convst(st);
> +
> b_sent = spi_sync(st->spi, &st->msg);
> if (b_sent < 0)
> goto done;
> @@ -254,6 +270,12 @@ static int ad7476_probe(struct spi_device *spi)
> if (ret)
> return ret;
>
> + st->convst_gpio = devm_gpiod_get_optional(&spi->dev,
> + "adi,conversion-start",
> + GPIOD_OUT_LOW);
> + if (IS_ERR(st->convst_gpio))
> + return PTR_ERR(st->convst_gpio);
> +
> spi_set_drvdata(spi, indio_dev);
>
> st->spi = spi;

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