iio: ltc2983: add support for optional reset gpio

Check if an optional reset gpio is present and if so, make sure to reset
the device.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20210825084149.11587-1-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index 3b4a0e60e6059481b7e3ea3c4ea79908a48ed6d8..22e6a26ce6b17d7f2dbaa55874e2e3dd920c318f 100644 (file)
--- a/drivers/iio/temperature/ltc2983.c
+++ b/drivers/iio/temperature/ltc2983.c
@@ -1470,6 +1470,7 @@ static int ltc2983_probe(struct spi_device *spi)
 {
        struct ltc2983_data *st;
        struct iio_dev *indio_dev;
+       struct gpio_desc *gpio;
        const char *name = spi_get_device_id(spi)->name;
        int ret;
 
@@ -1494,6 +1495,16 @@ static int ltc2983_probe(struct spi_device *spi)
        if (ret)
                return ret;
 
+       gpio = devm_gpiod_get_optional(&st->spi->dev, "reset", GPIOD_OUT_HIGH);
+       if (IS_ERR(gpio))
+               return PTR_ERR(gpio);
+
+       if (gpio) {
+               /* bring the device out of reset */
+               usleep_range(1000, 1200);
+               gpiod_set_value_cansleep(gpio, 0);
+       }
+
        ret = ltc2983_setup(st, true);
        if (ret)
                return ret;