[PATCH AUTOSEL 5.4 11/20] pinctrl: armada-37xx: propagate error from armada_37xx_gpio_get_direction()

[Sasha Levin <sashal@kernel.org>]

From: Gabor Juhos <j4g8y7@gmail.com>

[ Upstream commit 6481c0a83367b0672951ccc876fbae7ee37b594b ]

The regmap_read() function can fail, so propagate its error up to
the stack instead of silently ignoring that.

Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Link: https://lore.kernel.org/20250514-pinctrl-a37xx-fixes-v2-6-07e9ac1ab737@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

Based on my analysis, let me provide my assessment: **YES** This commit
should be backported to stable kernel trees. **Detailed Analysis:** 1.
**Bug Fix Nature**: This commit addresses a real bug where
`regmap_read()` errors are silently ignored in
`armada_37xx_gpio_get_direction()`. The function signature shows it
returns `int`, indicating it can fail and return error codes. 2. **Error
Propagation Pattern**: Looking at similar drivers (e.g.,
`/home/sasha/linux/drivers/pinctrl/meson/pinctrl-amlogic-a4.c`), the
standard pattern is: ```c ret = regmap_read(bank->reg_gpio, reg, &val);
if (ret) return ret; ``` This commit follows the exact same pattern,
which is the correct approach. 3. **Critical Function**: The
`armada_37xx_gpio_get_direction()` function is part of the GPIO
subsystem API that userspace and kernel code rely on. If `regmap_read()`
fails (due to hardware issues, power management states, etc.), the
function currently returns a potentially garbage direction value, which
could lead to: - Incorrect GPIO configuration - Silent hardware access
failures - Potential system instability 4. **Small and Contained
Change**: The fix is minimal: - Adds error checking for `regmap_read()`
- Propagates the error up the stack - No architectural changes - No new
features introduced 5. **Low Risk**: This change has minimal regression
risk because: - It only affects error paths that were previously ignored
- Normal operation (when regmap_read succeeds) is unchanged - It follows
established patterns in the same subsystem 6. **Similar Historical
Commits**: Looking at the provided examples, this aligns with commits
marked as "Backport Status: YES": - Similar Commit #2 fixed
direction_output callback behavior with error handling - The pattern of
adding proper error propagation is common in stable backports 7.
**Hardware Impact**: The Armada 37xx pinctrl driver is used in real
hardware (Marvell Armada 3700 SoCs), so fixing silent error conditions
improves reliability for users. 8. **Stable Criteria Compliance**: This
commit meets stable tree criteria: - Fixes a real bug (silent error
handling) - Small, contained change - No feature additions - Improves
system reliability The commit properly addresses a silent failure mode
in a hardware interface, making it a good candidate for stable
backporting to ensure system reliability across kernel versions.

 drivers/pinctrl/mvebu/pinctrl-armada-37xx.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c b/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
index 1ae1a944f35e0..45127d1237766 100644
--- a/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
+++ b/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
@@ -395,10 +395,13 @@ static int armada_37xx_gpio_get_direction(struct gpio_chip *chip,
 	struct armada_37xx_pinctrl *info = gpiochip_get_data(chip);
 	unsigned int reg = OUTPUT_EN;
 	unsigned int val, mask;
+	int ret;
 
 	armada_37xx_update_reg(&reg, &offset);
 	mask = BIT(offset);
-	regmap_read(info->regmap, reg, &val);
+	ret = regmap_read(info->regmap, reg, &val);
+	if (ret)
+		return ret;
 
 	return !(val & mask);
 }
-- 
2.39.5