Commit 6c7bc1d2 authored by Leonard Göhrs's avatar Leonard Göhrs Committed by Jonathan Cameron
Browse files

iio: adc: ti-lmp92064: add buffering support 



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: default avatarLeonard Göhrs <l.goehrs@pengutronix.de>
Reviewed-by: default avatarNuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230707063635.1496437-1-l.goehrs@pengutronix.de


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 1f2a4d50

drivers/iio/adc/ti-lmp92064.c

+53 −0
Original line number Diff line number Diff line
@@ -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);

}