Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-24 13:11:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

iio: adc: max1027: Introduce an end of conversion helper

Browse Source 
For now this helper only waits for the maximum duration of a single
conversion.

In practice, a "temperature measurement" will take twice this
time because it will also carry another analog conversion but as here we
will only care about the temperature conversion which happens first, we
can still only wait for a single sample and get the right data.

This helper will soon be improved to properly handle the end of
conversion interrupt as well as a higher number of samples.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20210921115408.66711-13-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Miquel Raynal 2021-09-21 13:54:04 +02:00 committed by Jonathan Cameron
parent c757fc0708
commit a0e831653e
1 changed files with 16 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/iio/adc/max1027.c
View File

@ -60,6 +60,9 @@
#define MAX1027_NAVG_32 (0x03 << 2)
#define MAX1027_AVG_EN BIT(4)
/* Device can achieve 300ksps so we assume a 3.33us conversion delay */
#define MAX1027_CONVERSION_UDELAY 4
enum max1027_id {
max1027,
max1029,
@ -272,6 +275,15 @@ struct max1027_state {
u8 reg ____cacheline_aligned;
};
static int max1027_wait_eoc(struct iio_dev *indio_dev)
{
unsigned int conversion_time = MAX1027_CONVERSION_UDELAY;
usleep_range(conversion_time, conversion_time * 2);
return 0;
}
/* Scan from chan 0 to the highest requested channel. Include temperature on demand. */
static int max1027_configure_chans_and_start(struct iio_dev *indio_dev)
{
@ -331,9 +343,11 @@ static int max1027_read_single_value(struct iio_dev *indio_dev,
/*
* For an unknown reason, when we use the mode "10" (write
* conversion register), the interrupt doesn't occur every time.
* So we just wait 1 ms.
* So we just wait the maximum conversion time and deliver the value.
*/
mdelay(1);
ret = max1027_wait_eoc(indio_dev);
if (ret)
return ret;
/* Read result */
ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);