2023-09-29 19:01:23

by David Lechner

Subject: [PATCH v3 16/27] staging: iio: resolver: ad2s1210: read excitation frequency from control register

From: David Lechner <[email protected]>

From: David Lechner <[email protected]>

This modifies the ad2s1210_show_fexcit() function to read the excitation
frequency from the control register. This way we don't have to keep
track of the value and don't risk returning a stale value.

Signed-off-by: David Lechner <[email protected]>
---

v3 changes: None

drivers/staging/iio/resolver/ad2s1210.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index 28ab877e1bc0..b15d71b17266 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -76,7 +76,6 @@ struct ad2s1210_state {
struct regmap *regmap;
/** The external oscillator frequency in Hz. */
unsigned long clkin_hz;
- unsigned int fexcit;
u8 resolution;
/** For reading raw sample value via SPI. */
__be16 sample __aligned(IIO_DMA_MINALIGN);
@@ -206,8 +205,6 @@ static int ad2s1210_reinit_excitation_frequency(struct ad2s1210_state *st,
if (ret < 0)
return ret;

- st->fexcit = fexcit;
-
/*
* Software reset reinitializes the excitation frequency output.
* It does not reset any of the configuration registers.
@@ -232,8 +229,22 @@ static ssize_t ad2s1210_show_fexcit(struct device *dev,
char *buf)
{
struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+ unsigned int value;
+ u16 fexcit;
+ int ret;

- return sprintf(buf, "%u\n", st->fexcit);
+ 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,

--
2.42.0

2023-09-30 15:08:31

by Jonathan Cameron

Subject: Re: [PATCH v3 16/27] staging: iio: resolver: ad2s1210: read excitation frequency from control register

On Fri, 29 Sep 2023 12:23:21 -0500
David Lechner <[email protected]> wrote:

> From: David Lechner <[email protected]>
>
> From: David Lechner <[email protected]>
>
> This modifies the ad2s1210_show_fexcit() function to read the excitation
> frequency from the control register. This way we don't have to keep
> track of the value and don't risk returning a stale value.
>
> Signed-off-by: David Lechner <[email protected]>
Applied.

A bit more fuzz with this one as context was different for the first hunk.

Jonathan

> ---
>
> v3 changes: None
>
> drivers/staging/iio/resolver/ad2s1210.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
> index 28ab877e1bc0..b15d71b17266 100644
> --- a/drivers/staging/iio/resolver/ad2s1210.c
> +++ b/drivers/staging/iio/resolver/ad2s1210.c
> @@ -76,7 +76,6 @@ struct ad2s1210_state {
> struct regmap *regmap;
> /** The external oscillator frequency in Hz. */
> unsigned long clkin_hz;
> - unsigned int fexcit;
> u8 resolution;
> /** For reading raw sample value via SPI. */
> __be16 sample __aligned(IIO_DMA_MINALIGN);
> @@ -206,8 +205,6 @@ static int ad2s1210_reinit_excitation_frequency(struct ad2s1210_state *st,
> if (ret < 0)
> return ret;
>
> - st->fexcit = fexcit;
> -
> /*
> * Software reset reinitializes the excitation frequency output.
> * It does not reset any of the configuration registers.
> @@ -232,8 +229,22 @@ static ssize_t ad2s1210_show_fexcit(struct device *dev,
> char *buf)
> {
> struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
> + unsigned int value;
> + u16 fexcit;
> + int ret;
>
> - return sprintf(buf, "%u\n", st->fexcit);
> + 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,
>