diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0698-regulator-gpio-Allow-nonexclusive-GPIO-access.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0698-regulator-gpio-Allow-nonexclusive-GPIO-access.patch | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0698-regulator-gpio-Allow-nonexclusive-GPIO-access.patch b/target/linux/brcm2708/patches-4.19/950-0698-regulator-gpio-Allow-nonexclusive-GPIO-access.patch new file mode 100644 index 0000000000..a940736c3e --- /dev/null +++ b/target/linux/brcm2708/patches-4.19/950-0698-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 +@@ -3988,8 +3988,23 @@ 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 |