gpio: search gpio-line-names property in dm_gpio_lookup_name

In scripts as well as interactively, it's much nicer to be able to
refer to GPIOs via their names defined in the device tree property
"gpio-line-names", instead of the rather opaque names derived from the
bank name with a _xx suffix. E.g.

  gpio read factory_reset FACTORY_RESET
  if test $factory_reset = 1 ; then ...

versus

  gpio read factory_reset gpio@481ac000_16
  if test $factory_reset = 1 ; then ...

This is also consistent with the move on the linux/userspace side towards
using line names instead of legacy chip+offset or the even more legacy
global gpio numbering in sysfs.

As dev_read_stringlist_search() depends on both OF_CONTROL and
OF_LIBFDT (which matters for the SPL case), we need some .config
conditional. However, it only adds about ~50 bytes of code to U-Boot
proper, and dm_gpio_lookup_name() most often ends up being GC'ed for
SPL, thus adds no overhead there, so for now make it a hidden symbol
which is merely a convenient shorthand for
CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(OF_LIBFDT).

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
Reviewed-by: Heiko Schocher <hs@nabladev.com>

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index db077e472a8157537dad8162eb8aa56773c271dd..a47c127d98ca628ab66d750832ba55cee1044bd0 100644 (file)
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -97,6 +97,22 @@ config SPL_DM_GPIO_LOOKUP_LABEL
          different gpios on different hardware versions
          for the same functionality in board code.
 
+config DM_GPIO_LOOKUP_LINE_NAME
+       def_bool y
+       depends on OF_CONTROL && OF_LIBFDT
+       help
+         This option enables specifying a GPIO by referring to its
+         name as defined by the "gpio-line-names" property in the
+         gpio controller's devicetree node.
+
+config SPL_DM_GPIO_LOOKUP_LINE_NAME
+       def_bool y
+       depends on SPL_OF_CONTROL && SPL_OF_LIBFDT
+       help
+         This option enables specifying a GPIO by referring to its
+         name as defined by the "gpio-line-names" property in the
+         gpio controller's devicetree node.
+
 config ADI_GPIO
        bool "ADI GPIO driver"
        depends on DM_GPIO && ARCH_SC5XX

diff --git a/drivers/gpio/gpio-uclass.c b/drivers/gpio/gpio-uclass.c
index 3d9f8b32b8d2baeb10e3c950e794fdb4fa22fbd6..6f52fdf4ef4e88d8e4710b6738cc474b7d81d2ef 100644 (file)
--- a/drivers/gpio/gpio-uclass.c
+++ b/drivers/gpio/gpio-uclass.c
@@ -164,7 +164,7 @@ int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc)
        for (uclass_first_device(UCLASS_GPIO, &dev);
             dev;
             uclass_next_device(&dev)) {
-               int len;
+               int len, ret;
 
                uc_priv = dev_get_uclass_priv(dev);
                if (numeric != -1) {
@@ -188,6 +188,15 @@ int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc)
                 */
                if (!dm_gpio_lookup_label(name, uc_priv, &offset))
                        break;
+
+               /* Also search the "gpio-line-names" property in DT for a match. */
+               if (CONFIG_IS_ENABLED(DM_GPIO_LOOKUP_LINE_NAME)) {
+                       ret = dev_read_stringlist_search(dev, "gpio-line-names", name);
+                       if (ret >= 0) {
+                               offset = ret;
+                               break;
+                       }
+               }
        }
 
        if (!dev)