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iio: adc: ti-lmp92064: add buffering support

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Enable buffered reading of samples from the LMP92064 ADC.
The main benefit of this change is being able to read out current and
voltage measurements in a single transfer, allowing instantaneous power
measurements.

Reads into the buffer can be triggered by any software triggers, e.g.
the iio-trig-hrtimer:

    $ mkdir /sys/kernel/config/iio/triggers/hrtimer/my-trigger
    $ cat /sys/bus/iio/devices/iio\:device3/name
    lmp92064
    $ iio_readdev -t my-trigger -b 16 iio:device3 | hexdump
    WARNING: High-speed mode not enabled
    0000000 0000 0176 0101 0001 5507 abd5 7645 1768
    0000010 0000 016d 0101 0001 ee1e ac6b 7645 1768
    ...

Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230707063635.1496437-1-l.goehrs@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Leonard Göhrs 2023-07-07 08:36:35 +02:00 committed by Jonathan Cameron
parent 1f2a4d506f
commit 6c7bc1d27b
1 changed files with 53 additions and 0 deletions
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53
drivers/iio/adc/ti-lmp92064.c
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@ -16,7 +16,10 @@
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/driver.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#define TI_LMP92064_REG_CONFIG_A 0x0000
#define TI_LMP92064_REG_CONFIG_B 0x0001
@ -91,6 +94,12 @@ static const struct iio_chan_spec lmp92064_adc_channels[] = {
.address = TI_LMP92064_CHAN_INC,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
.scan_index = TI_LMP92064_CHAN_INC,
.scan_type = {
.sign = 'u',
.realbits = 12,
.storagebits = 16,
},
.datasheet_name = "INC",
},
{
@ -98,8 +107,20 @@ static const struct iio_chan_spec lmp92064_adc_channels[] = {
.address = TI_LMP92064_CHAN_INV,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
.scan_index = TI_LMP92064_CHAN_INV,
.scan_type = {
.sign = 'u',
.realbits = 12,
.storagebits = 16,
},
.datasheet_name = "INV",
},
IIO_CHAN_SOFT_TIMESTAMP(2),
};
static const unsigned long lmp92064_scan_masks[] = {
BIT(TI_LMP92064_CHAN_INC) | BIT(TI_LMP92064_CHAN_INV),
0
};
static int lmp92064_read_meas(struct lmp92064_adc_priv *priv, u16 *res)
@ -171,6 +192,32 @@ static int lmp92064_read_raw(struct iio_dev *indio_dev,
}
}
static irqreturn_t lmp92064_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct lmp92064_adc_priv *priv = iio_priv(indio_dev);
struct {
u16 values[2];
int64_t timestamp __aligned(8);
} data;
int ret;
memset(&data, 0, sizeof(data));
ret = lmp92064_read_meas(priv, data.values);
if (ret)
goto err;
iio_push_to_buffers_with_timestamp(indio_dev, &data,
iio_get_time_ns(indio_dev));
err:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int lmp92064_reset(struct lmp92064_adc_priv *priv,
struct gpio_desc *gpio_reset)
{
@ -301,6 +348,12 @@ static int lmp92064_adc_probe(struct spi_device *spi)
indio_dev->channels = lmp92064_adc_channels;
indio_dev->num_channels = ARRAY_SIZE(lmp92064_adc_channels);
indio_dev->info = &lmp92064_adc_info;
indio_dev->available_scan_masks = lmp92064_scan_masks;
ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
lmp92064_trigger_handler, NULL);
if (ret)
return dev_err_probe(dev, ret, "Failed to setup buffered read\n");
return devm_iio_device_register(dev, indio_dev);
}