brcm2708: update to latest patches from RPi Foundation

[openwrt/staging/dedeckeh.git] / target / linux / brcm2708 / patches-4.19 / 950-0700-regulator-gpio-Allow-nonexclusive-GPIO-access.patch

diff --git a/target/linux/brcm2708/patches-4.19/950-0700-regulator-gpio-Allow-nonexclusive-GPIO-access.patch b/target/linux/brcm2708/patches-4.19/950-0700-regulator-gpio-Allow-nonexclusive-GPIO-access.patch
new file mode 100644 (file)
index 0000000..e0ffaae
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0700-regulator-gpio-Allow-nonexclusive-GPIO-access.patch
@@ -0,0 +1,79 @@
+From f6d983b7bc9ae79d0eb4dea7bc30a1ad5ff428a7 Mon Sep 17 00:00:00 2001
+From: Linus Walleij <linus.walleij@linaro.org>
+Date: Fri, 12 Oct 2018 14:54:12 +0200
+Subject: [PATCH] regulator/gpio: Allow nonexclusive GPIO access
+
+commit b0ce7b29bfcd090ddba476f45a75ec0a797b048a upstream.
+
+[ This is a partial cherry-pick, omitting the regulator
+change which isn't required ]
+
+This allows nonexclusive (simultaneous) access to a single
+GPIO line for the fixed regulator enable line. This happens
+when several regulators use the same GPIO for enabling and
+disabling a regulator, and all need a handle on their GPIO
+descriptor.
+
+This solution with a special flag is not entirely elegant
+and should ideally be replaced by something more careful as
+this makes it possible for several consumers to
+enable/disable the same GPIO line to the left and right
+without any consistency. The current use inside the regulator
+core should however be fine as it takes special care to
+handle this.
+
+For the state of the GPIO backend, this is still the
+lesser evil compared to going back to global GPIO
+numbers.
+
+Cc: Marek Szyprowski <m.szyprowski@samsung.com>
+Cc: Jon Hunter <jonathanh@nvidia.com>
+Fixes: efdfeb079cc3 ("regulator: fixed: Convert to use GPIO descriptor only")
+Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
+Tested-by: Jon Hunter <jonathanh@nvidia.com>
+Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
+Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
+Signed-off-by: Mark Brown <broonie@kernel.org>
+---
+ drivers/gpio/gpiolib.c        | 19 +++++++++++++++++--
+ include/linux/gpio/consumer.h |  1 +
+ 2 files changed, 18 insertions(+), 2 deletions(-)
+
+--- a/drivers/gpio/gpiolib.c
++++ b/drivers/gpio/gpiolib.c
+@@ -3979,8 +3979,23 @@ struct gpio_desc *__must_check gpiod_get
+        * the device name as label
+        */
+       status = gpiod_request(desc, con_id ? con_id : devname);
+-      if (status < 0)
+-              return ERR_PTR(status);
++      if (status < 0) {
++              if (status == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE) {
++                      /*
++                       * This happens when there are several consumers for
++                       * the same GPIO line: we just return here without
++                       * further initialization. It is a bit if a hack.
++                       * This is necessary to support fixed regulators.
++                       *
++                       * FIXME: Make this more sane and safe.
++                       */
++                      dev_info(dev, "nonexclusive access to GPIO for %s\n",
++                               con_id ? con_id : devname);
++                      return desc;
++              } else {
++                      return ERR_PTR(status);
++              }
++      }
+ 
+       status = gpiod_configure_flags(desc, con_id, lookupflags, flags);
+       if (status < 0) {
+--- a/include/linux/gpio/consumer.h
++++ b/include/linux/gpio/consumer.h
+@@ -30,6 +30,7 @@ struct gpio_descs {
+ #define GPIOD_FLAGS_BIT_DIR_OUT               BIT(1)
+ #define GPIOD_FLAGS_BIT_DIR_VAL               BIT(2)
+ #define GPIOD_FLAGS_BIT_OPEN_DRAIN    BIT(3)
++#define GPIOD_FLAGS_BIT_NONEXCLUSIVE  BIT(4)
+ 
+ /**
+  * Optional flags that can be passed to one of gpiod_* to configure direction