[PATCH 4.4 056/190] iio: hi8435: cleanup reset gpio

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Nikita Yushchenko 


[ Upstream commit 61305664a542f874283f74bf0b27ddb31f5045d7 ]

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 
Signed-off-by: Jonathan Cameron 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/iio/adc/hi8435.c |   12 +++-
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/drivers/iio/adc/hi8435.c
+++ b/drivers/iio/adc/hi8435.c
@@ -453,13 +453,15 @@ static int hi8435_probe(struct spi_devic
priv->spi = spi;
 
reset_gpio = devm_gpiod_get(>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);

[PATCH 4.4 056/190] iio: hi8435: cleanup reset gpio

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Nikita Yushchenko 


[ Upstream commit 61305664a542f874283f74bf0b27ddb31f5045d7 ]

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 
Signed-off-by: Jonathan Cameron 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/iio/adc/hi8435.c |   12 +++-
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/drivers/iio/adc/hi8435.c
+++ b/drivers/iio/adc/hi8435.c
@@ -453,13 +453,15 @@ static int hi8435_probe(struct spi_devic
priv->spi = spi;
 
reset_gpio = devm_gpiod_get(>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);