openwrt-mirror/target/linux/brcm63xx/patches-4.14/143-gpio-fix-device-tree-gpio-hogs-on-dual-role-gpio-pin.patch

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
@@ -237,12 +237,15 @@ static struct gpio_desc *of_parse_own_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 gpio_desc *desc = NULL;
 	struct device_node *np;
@@ -250,7 +253,7 @@ static int of_gpiochip_scan_gpios(struct
 	enum gpio_lookup_flags lflags;
 	enum gpiod_flags dflags;
 	unsigned int i;
-	int ret;
+	int ret, hwgpio;
 
 	for_each_available_child_of_node(chip->of_node, np) {
 		if (!of_property_read_bool(np, "gpio-hog"))
@@ -262,6 +265,10 @@ static int of_gpiochip_scan_gpios(struct
 			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) {
 				of_node_put(np);
@@ -499,12 +506,13 @@ int of_gpiochip_add(struct gpio_chip *ch
 
 	of_node_get(chip->of_node);
 
-	status = of_gpiochip_scan_gpios(chip);
-	if (status) {
-		of_node_put(chip->of_node);
-		gpiochip_remove_pin_ranges(chip);
+	if (!chip->request) {
+		status = of_gpiochip_scan_gpios(chip, 0, chip->ngpio);
+		if (status) {
+			of_node_put(chip->of_node);
+			gpiochip_remove_pin_ranges(chip);
+		}
 	}
-
 	return status;
 }
 
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1938,7 +1938,8 @@ int gpiochip_add_pingroup_range(struct g
 
 	list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
-	return 0;
+	return of_gpiochip_scan_gpios(chip, gpio_offset,
+				      pin_range->range.npins);
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
 
@@ -1990,7 +1991,7 @@ int gpiochip_add_pin_range(struct gpio_c
 
 	list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
-	return 0;
+	return of_gpiochip_scan_gpios(chip, gpio_offset, npins);
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
 
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -99,6 +99,8 @@ struct gpio_desc *of_get_named_gpiod_fla
 		   const char *list_name, int index, enum of_gpio_flags *flags);
 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);
 #else
 static inline struct gpio_desc *of_find_gpio(struct device *dev,
 					     const char *con_id,
@@ -114,6 +116,12 @@ static inline struct gpio_desc *of_get_n
 }
 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;
+}
 #endif /* CONFIG_OF_GPIO */
 
 #ifdef CONFIG_ACPI