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| author | Russell King <linux@armlinux.org.uk> | 2020-05-21 09:57:22 +0100 |
|---|---|---|
| committer | Petr Štetiar <ynezz@true.cz> | 2020-05-21 12:55:31 +0200 |
| commit | 72a1d5c3acd5b0bec46612f94bb8a82fe4d56179 (patch) | |
| tree | e40c6f6d1a688ba1f29fcd3d3c6b5f70272efed7 | |
| parent | 017320ead3a21415ab876012d1a2844e783c071f (diff) | |
| download | upstream-72a1d5c3acd5b0bec46612f94bb8a82fe4d56179.tar.gz upstream-72a1d5c3acd5b0bec46612f94bb8a82fe4d56179.tar.bz2 upstream-72a1d5c3acd5b0bec46612f94bb8a82fe4d56179.zip | |
kernel: backport gpio emulated open drain output fix
Backport the GPIO emulated open drain output fix from v5.5, which is
required for the i2c-pxa backport.
Signed-off-by: Russell King <linux@armlinux.org.uk>
| -rw-r--r-- | target/linux/generic/backport-5.4/802-v5.5-gpiolib-fix-up-emulated-open-drain-outputs.patch | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.4/802-v5.5-gpiolib-fix-up-emulated-open-drain-outputs.patch b/target/linux/generic/backport-5.4/802-v5.5-gpiolib-fix-up-emulated-open-drain-outputs.patch new file mode 100644 index 0000000000..311d4ed448 --- /dev/null +++ b/target/linux/generic/backport-5.4/802-v5.5-gpiolib-fix-up-emulated-open-drain-outputs.patch @@ -0,0 +1,45 @@ +From: Russell King <rmk+kernel@armlinux.org.uk> +Bcc: linux@mail.armlinux.org.uk +Cc: Linus Walleij <linus.walleij@linaro.org>,Bartosz Golaszewski <bgolaszewski@baylibre.com>,linux-gpio@vger.kernel.org +Subject: [PATCH] gpiolib: fix up emulated open drain outputs +MIME-Version: 1.0 +Content-Disposition: inline +Content-Transfer-Encoding: 8bit +Content-Type: text/plain; charset="utf-8" + +gpiolib has a corner case with open drain outputs that are emulated. +When such outputs are outputting a logic 1, emulation will set the +hardware to input mode, which will cause gpiod_get_direction() to +report that it is in input mode. This is different from the behaviour +with a true open-drain output. + +Unify the semantics here. + +Suggested-by: Linus Walleij <linus.walleij@linaro.org> +Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> +--- + drivers/gpio/gpiolib.c | 8 ++++++++ + 1 file changed, 8 insertions(+) + +diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c +index 104ed299d5ea..99d19f80440e 100644 +--- a/drivers/gpio/gpiolib.c ++++ b/drivers/gpio/gpiolib.c +@@ -220,6 +220,14 @@ int gpiod_get_direction(struct gpio_desc *desc) + chip = gpiod_to_chip(desc); + offset = gpio_chip_hwgpio(desc); + ++ /* ++ * Open drain emulation using input mode may incorrectly report ++ * input here, fix that up. ++ */ ++ if (test_bit(FLAG_OPEN_DRAIN, &desc->flags) && ++ test_bit(FLAG_IS_OUT, &desc->flags)) ++ return 0; ++ + if (!chip->get_direction) + return -ENOTSUPP; + +-- +2.20.1 + |