gpio: tegra186: Fix tegra186_gpio_is_accessible() check

The controller has several register bits describing access control
information for a given GPIO pin. When SCR_SEC_[R|W]EN is unset, it
means we have full read/write access to all the registers for given GPIO
pin. When SCR_SEC[R|W]EN is set, it means we need to further check the
accompanying SCR_SEC_G1[R|W] bit to determine read/write access to all
the registers for given GPIO pin.

This check was previously declaring that a GPIO pin was accessible
only if either of the following conditions were met:

  - SCR_SEC_REN + SCR_SEC_WEN both set

    or

  - SCR_SEC_REN + SCR_SEC_WEN both set and
    SCR_SEC_G1R + SCR_SEC_G1W both set

Update the check to properly handle cases where only one of
SCR_SEC_REN or SCR_SEC_WEN is set.

Fixes: b2b56a163230 ("gpio: tegra186: Check GPIO pin permission before access.")
Signed-off-by: Prathamesh Shete <pshete@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20240424095514.24397-1-pshete@nvidia.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c
index d87dd06db40d07a5dd6fc1c0fa83be06d8e291f5..9130c691a2dd324f3e9ef3c57ff7c4f31fccee6f 100644 (file)
--- a/drivers/gpio/gpio-tegra186.c
+++ b/drivers/gpio/gpio-tegra186.c
@@ -36,12 +36,6 @@
 #define  TEGRA186_GPIO_SCR_SEC_REN             BIT(27)
 #define  TEGRA186_GPIO_SCR_SEC_G1W             BIT(9)
 #define  TEGRA186_GPIO_SCR_SEC_G1R             BIT(1)
-#define  TEGRA186_GPIO_FULL_ACCESS             (TEGRA186_GPIO_SCR_SEC_WEN | \
-                                                TEGRA186_GPIO_SCR_SEC_REN | \
-                                                TEGRA186_GPIO_SCR_SEC_G1R | \
-                                                TEGRA186_GPIO_SCR_SEC_G1W)
-#define  TEGRA186_GPIO_SCR_SEC_ENABLE          (TEGRA186_GPIO_SCR_SEC_WEN | \
-                                                TEGRA186_GPIO_SCR_SEC_REN)
 
 /* control registers */
 #define TEGRA186_GPIO_ENABLE_CONFIG 0x00
@@ -177,10 +171,18 @@ static inline bool tegra186_gpio_is_accessible(struct tegra_gpio *gpio, unsigned
 
        value = __raw_readl(secure + TEGRA186_GPIO_SCR);
 
-       if ((value & TEGRA186_GPIO_SCR_SEC_ENABLE) == 0)
-               return true;
+       /*
+        * When SCR_SEC_[R|W]EN is unset, then we have full read/write access to all the
+        * registers for given GPIO pin.
+        * When SCR_SEC[R|W]EN is set, then there is need to further check the accompanying
+        * SCR_SEC_G1[R|W] bit to determine read/write access to all the registers for given
+        * GPIO pin.
+        */
 
-       if ((value & TEGRA186_GPIO_FULL_ACCESS) == TEGRA186_GPIO_FULL_ACCESS)
+       if (((value & TEGRA186_GPIO_SCR_SEC_REN) == 0 ||
+            ((value & TEGRA186_GPIO_SCR_SEC_REN) && (value & TEGRA186_GPIO_SCR_SEC_G1R))) &&
+            ((value & TEGRA186_GPIO_SCR_SEC_WEN) == 0 ||
+            ((value & TEGRA186_GPIO_SCR_SEC_WEN) && (value & TEGRA186_GPIO_SCR_SEC_G1W))))
                return true;
 
        return false;