[RFC 3/7] pinctrl: introduce pinctrl_gpio_get_config()

[Dan Carpenter]

From: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>

This is a counterpart of pinctrl_gpio_set_config(), which will initially
be used to implement gpio_get interface in SCMI pinctrl based GPIO driver.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
 drivers/pinctrl/core.c           | 35 ++++++++++++++++++++++++++++++++
 include/linux/pinctrl/consumer.h |  9 ++++++++
 2 files changed, 44 insertions(+)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 4bdbf6bb26e2..4310f9e2118b 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -30,6 +30,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/pinctrl/devinfo.h>
 #include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinconf.h>
 #include <linux/pinctrl/pinctrl.h>
 
 #include "core.h"
@@ -937,6 +938,40 @@ int pinctrl_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 }
 EXPORT_SYMBOL_GPL(pinctrl_gpio_set_config);
 
+/**
+ * pinctrl_gpio_get_config() - Get the config for a given GPIO pin
+ * @gc: GPIO chip structure from the GPIO subsystem
+ * @offset: hardware offset of the GPIO relative to the controller
+  * @config: the configuration to query.  On success it holds the result
+ */
+int pinctrl_gpio_get_config(struct gpio_chip *gc, unsigned int offset, unsigned long *config)
+{
+	struct pinctrl_gpio_range *range;
+	const struct pinconf_ops *ops;
+	struct pinctrl_dev *pctldev;
+	int ret, pin;
+
+	ret = pinctrl_get_device_gpio_range(gc, offset, &pctldev, &range);
+	if (ret)
+		return ret;
+
+	ops = pctldev->desc->confops;
+	if (!ops || !ops->pin_config_get)
+		return -EINVAL;
+
+	mutex_lock(&pctldev->mutex);
+	pin = gpio_to_pin(range, gc, offset);
+	ret = ops->pin_config_get(pctldev, pin, config);
+	mutex_unlock(&pctldev->mutex);
+
+	if (ret)
+		return ret;
+
+	*config = pinconf_to_config_argument(*config);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pinctrl_gpio_get_config);
+
 static struct pinctrl_state *find_state(struct pinctrl *p,
 					const char *name)
 {
diff --git a/include/linux/pinctrl/consumer.h b/include/linux/pinctrl/consumer.h
index 73de70362b98..e5815b3382dc 100644
--- a/include/linux/pinctrl/consumer.h
+++ b/include/linux/pinctrl/consumer.h
@@ -35,6 +35,8 @@ int pinctrl_gpio_direction_output(struct gpio_chip *gc,
 				  unsigned int offset);
 int pinctrl_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 				unsigned long config);
+int pinctrl_gpio_get_config(struct gpio_chip *gc, unsigned int offset,
+			    unsigned long *config);
 
 struct pinctrl * __must_check pinctrl_get(struct device *dev);
 void pinctrl_put(struct pinctrl *p);
@@ -96,6 +98,13 @@ pinctrl_gpio_direction_output(struct gpio_chip *gc, unsigned int offset)
 	return 0;
 }
 
+static inline int
+pinctrl_gpio_get_config(struct gpio_chip *gc, unsigned int offset,
+			unsigned long *config)
+{
+	return 0;
+}
+
 static inline int
 pinctrl_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 			    unsigned long config)
-- 
2.47.2