apm821xx: import gpio-export DT code from lantiq

This will come in handy for the Netgear WNDAP620's antennae mux.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

diff --git a/target/linux/apm821xx/patches-4.14/140-GPIO-add-named-gpio-exports.patch b/target/linux/apm821xx/patches-4.14/140-GPIO-add-named-gpio-exports.patch
new file mode 100644 (file)
index 0000000..95cdf8c
--- /dev/null
+++ b/target/linux/apm821xx/patches-4.14/140-GPIO-add-named-gpio-exports.patch
@@ -0,0 +1,169 @@
+From cc809a441d8f2924f785eb863dfa6aef47a25b0b Mon Sep 17 00:00:00 2001
+From: John Crispin <blogic@openwrt.org>
+Date: Tue, 12 Aug 2014 20:49:27 +0200
+Subject: [PATCH 30/36] GPIO: add named gpio exports
+
+Signed-off-by: John Crispin <blogic@openwrt.org>
+---
+ drivers/gpio/gpiolib-of.c     |   68 +++++++++++++++++++++++++++++++++++++++++
+ drivers/gpio/gpiolib.c        |   11 +++++--
+ include/asm-generic/gpio.h    |    5 +++
+ include/linux/gpio/consumer.h |    8 +++++
+ 4 files changed, 90 insertions(+), 2 deletions(-)
+
+--- a/drivers/gpio/gpiolib-of.c
++++ b/drivers/gpio/gpiolib-of.c
+@@ -23,6 +23,8 @@
+ #include <linux/pinctrl/pinctrl.h>
+ #include <linux/slab.h>
+ #include <linux/gpio/machine.h>
++#include <linux/init.h>
++#include <linux/platform_device.h>
+ 
+ #include "gpiolib.h"
+ 
+@@ -506,3 +508,72 @@ void of_gpiochip_remove(struct gpio_chip
+       gpiochip_remove_pin_ranges(chip);
+       of_node_put(chip->of_node);
+ }
++
++#ifdef CONFIG_GPIO_SYSFS
++
++static struct of_device_id gpio_export_ids[] = {
++      { .compatible = "gpio-export" },
++      { /* sentinel */ }
++};
++
++static int of_gpio_export_probe(struct platform_device *pdev)
++{
++      struct device_node *np = pdev->dev.of_node;
++      struct device_node *cnp;
++      u32 val;
++      int nb = 0;
++
++      for_each_child_of_node(np, cnp) {
++              const char *name = NULL;
++              int gpio;
++              bool dmc;
++              int max_gpio = 1;
++              int i;
++
++              of_property_read_string(cnp, "gpio-export,name", &name);
++
++              if (!name)
++                      max_gpio = of_gpio_count(cnp);
++
++              for (i = 0; i < max_gpio; i++) {
++                      unsigned flags = 0;
++                      enum of_gpio_flags of_flags;
++
++                      gpio = of_get_gpio_flags(cnp, i, &of_flags);
++                      if (!gpio_is_valid(gpio))
++                              return gpio;
++
++                      if (of_flags == OF_GPIO_ACTIVE_LOW)
++                              flags |= GPIOF_ACTIVE_LOW;
++
++                      if (!of_property_read_u32(cnp, "gpio-export,output", &val))
++                              flags |= val ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
++                      else
++                              flags |= GPIOF_IN;
++
++                      if (devm_gpio_request_one(&pdev->dev, gpio, flags, name ? name : of_node_full_name(np)))
++                              continue;
++
++                      dmc = of_property_read_bool(cnp, "gpio-export,direction_may_change");
++                      gpio_export_with_name(gpio, dmc, name);
++                      nb++;
++              }
++      }
++
++      dev_info(&pdev->dev, "%d gpio(s) exported\n", nb);
++
++      return 0;
++}
++
++static struct platform_driver gpio_export_driver = {
++      .driver         = {
++              .name           = "gpio-export",
++              .owner  = THIS_MODULE,
++              .of_match_table = of_match_ptr(gpio_export_ids),
++      },
++      .probe          = of_gpio_export_probe,
++};
++
++module_platform_driver(gpio_export_driver);
++
++#endif
+--- a/include/asm-generic/gpio.h
++++ b/include/asm-generic/gpio.h
+@@ -127,6 +127,12 @@ static inline int gpio_export(unsigned g
+       return gpiod_export(gpio_to_desc(gpio), direction_may_change);
+ }
+ 
++int __gpiod_export(struct gpio_desc *desc, bool direction_may_change, const char *name);
++static inline int gpio_export_with_name(unsigned gpio, bool direction_may_change, const char *name)
++{
++      return __gpiod_export(gpio_to_desc(gpio), direction_may_change, name);
++}
++
+ static inline int gpio_export_link(struct device *dev, const char *name,
+                                  unsigned gpio)
+ {
+--- a/include/linux/gpio/consumer.h
++++ b/include/linux/gpio/consumer.h
+@@ -451,6 +451,7 @@ struct gpio_desc *devm_fwnode_get_gpiod_
+ 
+ #if IS_ENABLED(CONFIG_GPIOLIB) && IS_ENABLED(CONFIG_GPIO_SYSFS)
+ 
++int _gpiod_export(struct gpio_desc *desc, bool direction_may_change, const char *name);
+ int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
+ int gpiod_export_link(struct device *dev, const char *name,
+                     struct gpio_desc *desc);
+@@ -458,6 +459,13 @@ void gpiod_unexport(struct gpio_desc *de
+ 
+ #else  /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */
+ 
++static inline int _gpiod_export(struct gpio_desc *desc,
++                             bool direction_may_change,
++                             const char *name)
++{
++      return -ENOSYS;
++}
++
+ static inline int gpiod_export(struct gpio_desc *desc,
+                              bool direction_may_change)
+ {
+--- a/drivers/gpio/gpiolib-sysfs.c
++++ b/drivers/gpio/gpiolib-sysfs.c
+@@ -553,7 +553,7 @@ static struct class gpio_class = {
+  *
+  * Returns zero on success, else an error.
+  */
+-int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
++int __gpiod_export(struct gpio_desc *desc, bool direction_may_change, const char *name)
+ {
+       struct gpio_chip        *chip;
+       struct gpio_device      *gdev;
+@@ -615,6 +615,8 @@ int gpiod_export(struct gpio_desc *desc,
+       offset = gpio_chip_hwgpio(desc);
+       if (chip->names && chip->names[offset])
+               ioname = chip->names[offset];
++      if (name)
++              ioname = name;
+ 
+       dev = device_create_with_groups(&gpio_class, &gdev->dev,
+                                       MKDEV(0, 0), data, gpio_groups,
+@@ -636,6 +638,12 @@ err_unlock:
+       gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+       return status;
+ }
++EXPORT_SYMBOL_GPL(__gpiod_export);
++
++int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
++{
++      return __gpiod_export(desc, direction_may_change, NULL);
++}
+ EXPORT_SYMBOL_GPL(gpiod_export);
+ 
+ static int match_export(struct device *dev, const void *desc)