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staging: iio: resolver: ad2s1210: read excitation frequency from control register

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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 <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20230929-ad2s1210-mainline-v3-16-fa4364281745@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
David Lechner 2023-09-29 12:23:21 -05:00 committed by Jonathan Cameron
parent de69623c7c
commit 500d7640f6
1 changed files with 15 additions and 4 deletions
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19
drivers/staging/iio/resolver/ad2s1210.c
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@ -76,7 +76,6 @@ struct ad2s1210_state {
struct regmap *regmap;
/** The external oscillator frequency in Hz. */
unsigned long clkin_hz;
unsigned int fexcit;
bool hysteresis;
u8 resolution;
/** For reading raw sample value via SPI. */
@ -207,8 +206,6 @@ 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.
@ -233,8 +230,22 @@ 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,