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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.

Needed for the patch:  iio: ad7793: Fix the serial interface reset
Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Dragos Bogdan 2017-09-05 15:14:45 +03:00 committed by Jonathan Cameron
parent 4b1f0c31f9
commit 7fc10de8d4
2 changed files with 31 additions and 0 deletions
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28
drivers/iio/adc/ad_sigma_delta.c
View File

@ -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)
{

3
include/linux/iio/adc/ad_sigma_delta.h
View File

@ -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,