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... 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 7a983f00dc9de..92679fbc1ee2c 100644 --- a/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c +++ b/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c @@ -400,10 +400,13 @@ 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(®, &offset); mask = BIT(offset); - regmap_read(info->regmap, reg, &val); + ret = regmap_read(info->regmap, reg, &val); + if (ret) + return ret;
if (val & mask) return GPIO_LINE_DIRECTION_OUT;