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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
        Thierry Reding <treding@nvidia.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: [PATCH 4.19 17/34] gpio: tegra186: Fix chip_data type confusion
Date:   Mon, 28 Feb 2022 18:24:23 +0100
Message-Id: <20220228172209.845156606@linuxfoundation.org>
In-Reply-To: <20220228172207.090703467@linuxfoundation.org>
References: <20220228172207.090703467@linuxfoundation.org>
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From: Marc Zyngier <maz@kernel.org>

commit d1e972ace42390de739cde87d96043dcbe502286 upstream.

The tegra186 GPIO driver makes the assumption that the pointer
returned by irq_data_get_irq_chip_data() is a pointer to a
tegra_gpio structure. Unfortunately, it is actually a pointer
to the inner gpio_chip structure, as mandated by the gpiolib
infrastructure. Nice try.

The saving grace is that the gpio_chip is the first member of
tegra_gpio, so the bug has gone undetected since... forever.

Fix it by performing a container_of() on the pointer. This results
in no additional code, and makes it possible to understand how
the whole thing works.

Fixes: 5b2b135a87fc ("gpio: Add Tegra186 support")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20220211093904.1112679-1-maz@kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpio/gpio-tegra186.c |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

--- a/drivers/gpio/gpio-tegra186.c
+++ b/drivers/gpio/gpio-tegra186.c
@@ -237,9 +237,12 @@ static int tegra186_gpio_of_xlate(struct
 	return offset + pin;
 }
 
+#define to_tegra_gpio(x) container_of((x), struct tegra_gpio, gpio)
+
 static void tegra186_irq_ack(struct irq_data *data)
 {
-	struct tegra_gpio *gpio = irq_data_get_irq_chip_data(data);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct tegra_gpio *gpio = to_tegra_gpio(gc);
 	void __iomem *base;
 
 	base = tegra186_gpio_get_base(gpio, data->hwirq);
@@ -251,7 +254,8 @@ static void tegra186_irq_ack(struct irq_
 
 static void tegra186_irq_mask(struct irq_data *data)
 {
-	struct tegra_gpio *gpio = irq_data_get_irq_chip_data(data);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct tegra_gpio *gpio = to_tegra_gpio(gc);
 	void __iomem *base;
 	u32 value;
 
@@ -266,7 +270,8 @@ static void tegra186_irq_mask(struct irq
 
 static void tegra186_irq_unmask(struct irq_data *data)
 {
-	struct tegra_gpio *gpio = irq_data_get_irq_chip_data(data);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct tegra_gpio *gpio = to_tegra_gpio(gc);
 	void __iomem *base;
 	u32 value;
 
@@ -281,7 +286,8 @@ static void tegra186_irq_unmask(struct i
 
 static int tegra186_irq_set_type(struct irq_data *data, unsigned int flow)
 {
-	struct tegra_gpio *gpio = irq_data_get_irq_chip_data(data);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct tegra_gpio *gpio = to_tegra_gpio(gc);
 	void __iomem *base;
 	u32 value;