From: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
To: Jonathan Cameron <jic23@kernel.org>,
Hartmut Knaack <knaack.h@gmx.de>,
Lars-Peter Clausen <lars@metafoo.de>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
Matt Ranostay <mranostay@gmail.com>,
Gregor Boirie <gregor.boirie@parrot.com>,
Sanchayan Maity <maitysanchayan@gmail.com>
Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
Jeff White <Jeff.White@zii.aero>,
Chris Healy <Chris.Healy@zii.aero>,
Vladimir Barinov <vladimir.barinov@cogentembedded.com>,
Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Subject: [PATCH 2/4] iio: hi8435: avoid garbage event at first enable
Date: Fri, 19 May 2017 17:48:00 +0300 [thread overview]
Message-ID: <20170519144802.14427-2-nikita.yoush@cogentembedded.com> (raw)
In-Reply-To: <20170519144802.14427-1-nikita.yoush@cogentembedded.com>
Currently, driver generates events for channels if new reading differs
from previous one. This "previous value" is initialized to zero, which
results into event if value is constant-one.
Fix that by initializing "previous value" by reading at event enable
time.
This provides reliable sequence for userspace:
- enable event,
- AFTER THAT read current value,
- AFTER THAT each event will correspond to change.
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
---
drivers/iio/adc/hi8435.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/adc/hi8435.c b/drivers/iio/adc/hi8435.c
index cb8e6342eddf..45a92e3e8f2b 100644
--- a/drivers/iio/adc/hi8435.c
+++ b/drivers/iio/adc/hi8435.c
@@ -141,10 +141,21 @@ static int hi8435_write_event_config(struct iio_dev *idev,
enum iio_event_direction dir, int state)
{
struct hi8435_priv *priv = iio_priv(idev);
+ int ret;
+ u32 tmp;
+
+ if (state) {
+ ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp);
+ if (ret < 0)
+ return ret;
+ if (tmp & BIT(chan->channel))
+ priv->event_prev_val |= BIT(chan->channel);
+ else
+ priv->event_prev_val &= ~BIT(chan->channel);
- priv->event_scan_mask &= ~BIT(chan->channel);
- if (state)
priv->event_scan_mask |= BIT(chan->channel);
+ } else
+ priv->event_scan_mask &= ~BIT(chan->channel);
return 0;
}
--
2.11.0
next prev parent reply other threads:[~2017-05-19 14:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-19 14:47 [PATCH 1/4] iio: hi8435: add raw access Nikita Yushchenko
2017-05-19 14:48 ` Nikita Yushchenko [this message]
2017-05-20 16:34 ` [PATCH 2/4] iio: hi8435: avoid garbage event at first enable Jonathan Cameron
2017-05-22 18:20 ` Vladimir Barinov
2017-05-23 7:21 ` Nikita Yushchenko
2017-05-19 14:48 ` [PATCH 3/4] iio: hi8435: make in_voltage_sensing_mode_available visible Nikita Yushchenko
2017-05-20 16:35 ` Jonathan Cameron
2017-05-19 14:48 ` [PATCH 4/4] iio: hi8435: cleanup reset gpio Nikita Yushchenko
2017-05-20 16:37 ` Jonathan Cameron
[not found] ` <18fc343b-d7a4-c5b8-84e6-702af6e94e44@cogentembedded.com>
2017-05-23 8:18 ` Nikita Yushchenko
2017-05-24 11:27 ` Vladimir Barinov
2017-05-24 19:38 ` Jonathan Cameron
2017-05-25 6:27 ` Nikita Yushchenko
2017-05-28 15:42 ` Jonathan Cameron
2017-05-29 7:57 ` Nikita Yushchenko
2017-05-29 17:08 ` Linus Walleij
2017-05-20 16:33 ` [PATCH 1/4] iio: hi8435: add raw access Jonathan Cameron
2017-05-22 17:27 ` Vladimir Barinov
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