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[PATCH 4/4] iio: hi8435: cleanup reset gpio

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Reset GPIO is active low.

Currently driver uses gpiod_set_value(1) to clean reset, which depends
on device tree to contain GPIO_ACTIVE_HIGH - that does not match reality.

This fixes driver to use _raw version of gpiod_set_value() to enforce
active-low semantics despite of what's written in device tree. Allowing
device tree to override that only opens possibility for errors and does
not add any value.

Additionally, use _cansleep version to make things work with i2c-gpio
and other sleeping gpio drivers.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
---
 drivers/iio/adc/hi8435.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/hi8435.c b/drivers/iio/adc/hi8435.c
index d09cb6ff8044..ab59969b7c49 100644
--- a/drivers/iio/adc/hi8435.c
+++ b/drivers/iio/adc/hi8435.c
@@ -476,13 +476,15 @@ static int hi8435_probe(struct spi_device *spi)
 	priv->spi = spi;
 
 	reset_gpio = devm_gpiod_get(&spi->dev, NULL, GPIOD_OUT_LOW);
-	if (IS_ERR(reset_gpio)) {
-		/* chip s/w reset if h/w reset failed */
+	if (!IS_ERR(reset_gpio)) {
+		/* need >=100ns low pulse to reset chip */
+		gpiod_set_raw_value_cansleep(reset_gpio, 0);
+		udelay(1);
+		gpiod_set_raw_value_cansleep(reset_gpio, 1);
+	} else {
+		/* s/w reset chip if h/w reset is not available */
 		hi8435_writeb(priv, HI8435_CTRL_REG, HI8435_CTRL_SRST);
 		hi8435_writeb(priv, HI8435_CTRL_REG, 0);
-	} else {
-		udelay(5);
-		gpiod_set_value(reset_gpio, 1);
 	}
 
 	spi_set_drvdata(spi, idev);
-- 
2.11.0

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[PATCH 1/4] iio: hi8435: add raw access Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-05-19 16:50 +0200
  [PATCH 4/4] iio: hi8435: cleanup reset gpio Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-05-19 16:50 +0200
    Re: [PATCH 4/4] iio: hi8435: cleanup reset gpio Jonathan Cameron <jic23@kernel.org> - 2017-05-20 18:40 +0200
    Re: [PATCH 4/4] iio: hi8435: cleanup reset gpio Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-05-23 10:20 +0200
      Re: [PATCH 4/4] iio: hi8435: cleanup reset gpio Vladimir Barinov <vladimir.barinov@cogentembedded.com> - 2017-05-24 13:30 +0200
        Re: [PATCH 4/4] iio: hi8435: cleanup reset gpio Jonathan Cameron <jic23@kernel.org> - 2017-05-24 21:40 +0200
  [PATCH 2/4] iio: hi8435: avoid garbage event at first enable Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-05-19 16:50 +0200
    Re: [PATCH 2/4] iio: hi8435: avoid garbage event at first enable Jonathan Cameron <jic23@kernel.org> - 2017-05-20 18:40 +0200
    Re: [PATCH 2/4] iio: hi8435: avoid garbage event at first enable Vladimir Barinov <vladimir.barinov@cogentembedded.com> - 2017-05-22 20:30 +0200
      Re: [PATCH 2/4] iio: hi8435: avoid garbage event at first enable Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-05-23 09:30 +0200
  Re: [PATCH 1/4] iio: hi8435: add raw access Jonathan Cameron <jic23@kernel.org> - 2017-05-20 18:40 +0200
    Re: [PATCH 1/4] iio: hi8435: add raw access Vladimir Barinov <vladimir.barinov@cogentembedded.com> - 2017-05-22 19:30 +0200

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