From e058fa1969019c2f6705c53c4130e364a877d4e6 Mon Sep 17 00:00:00 2001
From: Jonas Gorski <jonas.gorski@gmail.com>
Date: Sun, 26 Nov 2017 12:07:31 +0100
Subject: [PATCH] gpio: fix device tree gpio hogs on dual role gpio/pincontrol
 controllers

For dual role gpio and pincontrol controller, the device registration
path is often:

  pinctrl_register(...);
  gpiochip_add_data(...);
  gpiochip_add_pin_range(...);

If the device tree node has any gpio-hogs, the code will try to apply them
in the gpiochip_add_data step, but fail as they cannot be requested, as the
ranges are missing. But we also cannot first add the pinranges, as the
appropriate data structures are only initialized in gpiochip_add_data.

To fix this, defer gpio-hogs to the time pin ranges get added instead of
directly at chip request time, if the gpio-chip has a request method.

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
---

 drivers/gpio/gpiolib-of.c | 20 +++++++++++++++-----
 drivers/gpio/gpiolib.c    |  5 +++--
 drivers/gpio/gpiolib.h    |  8 ++++++++
 3 files changed, 26 insertions(+), 7 deletions(-)

--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -646,23 +646,30 @@ static struct gpio_desc *of_parse_own_gp
  * of_gpiochip_add_hog - Add all hogs in a hog device node
  * @chip:	gpio chip to act on
  * @hog:	device node describing the hogs
+ * @start:	first gpio to check
+ * @num:	number of gpios to check
  *
  * Returns error if it fails otherwise 0 on success.
  */
-static int of_gpiochip_add_hog(struct gpio_chip *chip, struct device_node *hog)
+static int of_gpiochip_add_hog(struct gpio_chip *chip, struct device_node *hog,
+			       unsigned int start, unsigned int num)
 {
 	enum gpiod_flags dflags;
 	struct gpio_desc *desc;
 	unsigned long lflags;
 	const char *name;
 	unsigned int i;
-	int ret;
+	int ret, hwgpio;
 
 	for (i = 0;; i++) {
 		desc = of_parse_own_gpio(hog, chip, i, &name, &lflags, &dflags);
 		if (IS_ERR(desc))
 			break;
 
+		hwgpio = gpio_chip_hwgpio(desc);
+		if (hwgpio < start || hwgpio >= (start + num))
+			continue;
+
 		ret = gpiod_hog(desc, name, lflags, dflags);
 		if (ret < 0)
 			return ret;
@@ -678,12 +685,15 @@ static int of_gpiochip_add_hog(struct gp
 /**
  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
  * @chip:	gpio chip to act on
+ * @start:	first gpio to check
+ * @num:	number of gpios to check
  *
- * This is only used by of_gpiochip_add to request/set GPIO initial
- * configuration.
+ * This is used by of_gpiochip_add, gpiochip_add_pingroup_range and
+ * gpiochip_add_pin_range to request/set GPIO initial configuration.
  * It returns error if it fails otherwise 0 on success.
  */
-static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
+int of_gpiochip_scan_gpios(struct gpio_chip *chip, unsigned int start,
+			   unsigned int num)
 {
 	struct device_node *np;
 	int ret;
@@ -692,7 +702,7 @@ static int of_gpiochip_scan_gpios(struct
 		if (!of_property_read_bool(np, "gpio-hog"))
 			continue;
 
-		ret = of_gpiochip_add_hog(chip, np);
+		ret = of_gpiochip_add_hog(chip, np, start, num);
 		if (ret < 0) {
 			of_node_put(np);
 			return ret;
@@ -758,7 +768,7 @@ static int of_gpio_notify(struct notifie
 		if (chip == NULL)
 			return NOTIFY_OK;	/* not for us */
 
-		ret = of_gpiochip_add_hog(chip, rd->dn);
+		ret = of_gpiochip_add_hog(chip, rd->dn, 0, chip->ngpio);
 		if (ret < 0) {
 			pr_err("%s: failed to add hogs for %pOF\n", __func__,
 			       rd->dn);
@@ -1037,9 +1047,11 @@ int of_gpiochip_add(struct gpio_chip *ch
 
 	of_node_get(chip->of_node);
 
-	ret = of_gpiochip_scan_gpios(chip);
-	if (ret)
-		of_node_put(chip->of_node);
+	if (!chip->request) {
+		ret = of_gpiochip_scan_gpios(chip, 0, chip->ngpio);
+		if (ret)
+			of_node_put(chip->of_node);
+	}
 
 	return ret;
 }
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1802,7 +1802,8 @@ int gpiochip_add_pingroup_range(struct g
 
 	list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
-	return 0;
+	return of_gpiochip_scan_gpios(gc, gpio_offset,
+				      pin_range->range.npins);
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
 
@@ -1859,7 +1860,7 @@ int gpiochip_add_pin_range(struct gpio_c
 
 	list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
-	return 0;
+	return of_gpiochip_scan_gpios(gc, gpio_offset, npins);
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
 
--- a/drivers/gpio/gpiolib-of.h
+++ b/drivers/gpio/gpiolib-of.h
@@ -13,6 +13,8 @@ struct gpio_desc *of_find_gpio(struct de
 			       unsigned long *lookupflags);
 int of_gpiochip_add(struct gpio_chip *gc);
 void of_gpiochip_remove(struct gpio_chip *gc);
+int of_gpiochip_scan_gpios(struct gpio_chip *chip, unsigned int start,
+			   unsigned int num);
 int of_gpio_get_count(struct device *dev, const char *con_id);
 bool of_gpio_need_valid_mask(const struct gpio_chip *gc);
 void of_gpio_dev_init(struct gpio_chip *gc, struct gpio_device *gdev);
@@ -26,6 +28,12 @@ static inline struct gpio_desc *of_find_
 }
 static inline int of_gpiochip_add(struct gpio_chip *gc) { return 0; }
 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
+static inline int of_gpiochip_scan_gpios(struct gpio_chip *chip,
+					 unsigned int start,
+					 unsigned int num)
+{
+	return 0;
+}
 static inline int of_gpio_get_count(struct device *dev, const char *con_id)
 {
 	return 0;
