diff options
| author | Uwe Kleine-König <u.kleine-koenig@baylibre.com> | 2024-12-06 18:28:36 +0100 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2024-12-11 19:20:48 +0000 |
| commit | a87ef09b1fdf75fdc2d6b386ff23a35589173055 (patch) | |
| tree | 618bd0ed3b1c934cb3ad8505f6eb29c5f9fe4162 /include/linux | |
| parent | fa6068fb7828b5778cf7d5905c4d8c05e6f231ac (diff) | |
iio: adc: ad_sigma_delta: Add support for reading irq status using a GPIO
Some of the ADCs by Analog signal their irq condition on the MISO line.
So typically that line is connected to an SPI controller and a GPIO. The
GPIO is used as input and the respective interrupt is enabled when the
last SPI transfer is completed.
Depending on the GPIO controller the toggling MISO line might make the
interrupt pending even while it's masked. In that case the irq handler
is called immediately after irq_enable() and so before the device
actually pulls that line low which results in non-sense values being
reported to the upper layers.
The only way to find out if the line was actually pulled low is to read
the GPIO. (There is a flag in AD7124's status register that also signals
if an interrupt was asserted, but reading that register toggles the MISO
line and so might trigger another spurious interrupt.)
Add the possibility to specify an interrupt GPIO in the machine
description in addition to the plain interrupt. This GPIO is used then
to check if the irq line is actually active in the irq handler.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/5be9a4cc4dc600ec384c88db01dd661a21506b9c.1733504533.git.u.kleine-koenig@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/iio/adc/ad_sigma_delta.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h index 1851f8fed3a4..895b7ebf4be5 100644 --- a/include/linux/iio/adc/ad_sigma_delta.h +++ b/include/linux/iio/adc/ad_sigma_delta.h @@ -29,6 +29,7 @@ struct ad_sd_calib_data { struct ad_sigma_delta; struct device; +struct gpio_desc; struct iio_dev; /** @@ -96,6 +97,7 @@ struct ad_sigma_delta { unsigned int active_slots; unsigned int current_slot; unsigned int num_slots; + struct gpio_desc *rdy_gpiod; int irq_line; bool status_appended; /* map slots to channels in order to know what to expect from devices */ |