aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/brcm2708/patches-4.19/950-0802-regulator-gpio-Allow-nonexclusive-GPIO-access.patch
diff options
context:
space:
mode:
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0802-regulator-gpio-Allow-nonexclusive-GPIO-access.patch')
-rw-r--r--target/linux/brcm2708/patches-4.19/950-0802-regulator-gpio-Allow-nonexclusive-GPIO-access.patch79
1 files changed, 79 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0802-regulator-gpio-Allow-nonexclusive-GPIO-access.patch b/target/linux/brcm2708/patches-4.19/950-0802-regulator-gpio-Allow-nonexclusive-GPIO-access.patch
new file mode 100644
index 0000000000..c7d3c99613
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0802-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 802/806] 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
+@@ -3942,8 +3942,23 @@ 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