[PATCH v3 3/3] gnss: ubx: add support for the reset gpio

Wolfram Sang
2023-09-21T20:17:10Z

Tested with a Renesas KingFisher board. Because my GNSS device is hooked
up via UART and I2C simultaneously, I could verify functionality by
opening/closing the GNSS device using UART and see if the corresponding
I2C device was visible on the bus.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
drivers/gnss/ubx.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/gnss/ubx.c b/drivers/gnss/ubx.c
index 9b76b101ba5e..e7d151cbc8c3 100644
--- a/drivers/gnss/ubx.c
+++ b/drivers/gnss/ubx.c
@@ -7,6 +7,7 @@

#include <linux/errno.h>
#include <linux/gnss.h>
+#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -18,6 +19,7 @@

struct ubx_data {
struct regulator *vcc;
+ struct gpio_desc *reset_gpio;
};

static int ubx_set_active(struct gnss_serial *gserial)
@@ -29,6 +31,8 @@ static int ubx_set_active(struct gnss_serial *gserial)
if (ret)
return ret;

+ gpiod_set_value_cansleep(data->reset_gpio, 0);
+
return 0;
}

@@ -37,6 +41,8 @@ static int ubx_set_standby(struct gnss_serial *gserial)
struct ubx_data *data = gnss_serial_get_drvdata(gserial);
int ret;

+ gpiod_set_value_cansleep(data->reset_gpio, 1);
+
ret = regulator_disable(data->vcc);
if (ret)
return ret;
@@ -90,6 +96,13 @@ static int ubx_probe(struct serdev_device *serdev)
if (ret < 0 && ret != -ENODEV)
goto err_free_gserial;

+ /* Start with reset asserted */
+ data->reset_gpio = devm_gpiod_get_optional(&serdev->dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(data->reset_gpio)) {
+ ret = PTR_ERR(data->reset_gpio);
+ goto err_free_gserial;
+ }
+
ret = gnss_serial_register(gserial);
if (ret)
goto err_free_gserial;
--
2.35.1