[PATCH] reset: gpio: Add self-deasserting reset callback

[Shenwei Wang <shenwei.wang@nxp.com>]

During the driver probe phase, many drivers leverage convenience
wrapper APIs such as device_reset and device_reset_optional provided
by the reset core driver. However, both of these APIs depend on the
presence of a .reset callback within the reset controller's operations
structure.

Introducing the self-deasserting reset callback enhances flexibility for
users and enables a more simple reset process during device initialization.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 drivers/reset/reset-gpio.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/reset/reset-gpio.c b/drivers/reset/reset-gpio.c
index 2290b25b6703..614f9e261a13 100644
--- a/drivers/reset/reset-gpio.c
+++ b/drivers/reset/reset-gpio.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
+#include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
@@ -37,6 +38,17 @@ static int reset_gpio_deassert(struct reset_controller_dev *rc,
 	return 0;
 }
 
+static int reset_gpio_reset(struct reset_controller_dev *rc, unsigned long id)
+{
+	struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
+
+	gpiod_set_value_cansleep(priv->reset, 1);
+	usleep_range(10, 20);
+	gpiod_set_value_cansleep(priv->reset, 0);
+
+	return 0;
+}
+
 static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id)
 {
 	struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
@@ -47,6 +59,7 @@ static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id)
 static const struct reset_control_ops reset_gpio_ops = {
 	.assert = reset_gpio_assert,
 	.deassert = reset_gpio_deassert,
+	.reset = reset_gpio_reset,
 	.status = reset_gpio_status,
 };
 
-- 
2.43.0