4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nikita Yushchenko <nikita.yo...@cogentembedded.com>
[ 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 <nikita.yo...@cogentembedded.com>
Signed-off-by: Jonathan Cameron <ji...@kernel.org>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
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(&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);
