[PATCH AUTOSEL 5.15 18/33] pinctrl: armada-37xx: propagate error from armada_37xx_gpio_get()

[Sasha Levin <sashal@kernel.org>]

From: Gabor Juhos <j4g8y7@gmail.com>

[ Upstream commit 57273ff8bb16f3842c2597b5bbcd49e7fa12edf7 ]

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-v2-4-07e9ac1ab737@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

Based on my comprehensive analysis, here is my determination: **YES**
This commit should be backported to stable kernel trees. Here's my
detailed analysis: ## Analysis of the Code Change The commit fixes a
clear bug in the `armada_37xx_gpio_get()` function in
`drivers/pinctrl/mvebu/pinctrl-armada-37xx.c`. The specific changes are:
1. **Before**: `regmap_read(info->regmap, reg, &val);` - ignores return
value 2. **After**: `ret = regmap_read(info->regmap, reg, &val); if
(ret) return ret;` - properly handles errors ## Backport Suitability
Assessment ### ✅ **Meets Stable Tree Criteria:** 1. **Bug Fix**: This
clearly fixes a real bug where regmap read failures are silently
ignored, potentially returning garbage data to userspace. 2. **Small and
Contained**: The change is minimal (3 lines added) and extremely
focused, affecting only error handling in a single function. 3. **Low
Regression Risk**: The change only adds error checking where none
existed before. It cannot introduce new bugs - it can only prevent
incorrect behavior. 4. **No Architectural Changes**: This is purely
error handling improvement with no changes to the driver's architecture
or interfaces. 5. **Important Subsystem**: GPIO operations are
fundamental and used by many kernel subsystems and userspace
applications. ### ✅ **Follows Established Kernel Patterns:** My analysis
of other GPIO drivers shows this error handling pattern is **universal**
across the kernel: - `gpio-arizona.c`, `gpio-bd71828.c`, `gpio-
madera.c`, `gpio-max77620.c`, `pinctrl-axp209.c`, and many others -
**Every examined driver** checks `regmap_read` return values in GPIO get
functions - The armada-37xx driver was an outlier in ignoring these
errors ### ✅ **Real-World Impact:** This fix addresses scenarios where:
- **Hardware communication failures** (I2C/SPI bus errors, device power
issues) - **Device disconnect events** (hot-plug scenarios, power
management) - **Timing/electrical issues** causing intermittent regmap
failures Without this fix, `gpio_get()` would return potentially garbage
values (using uninitialized `val`) when hardware communication fails,
leading to incorrect GPIO state reporting to userspace. ### ✅
**Reference Similar Commits:** Looking at the provided examples, this
commit closely resembles: - **Similar Commit #3 (Status: YES)**: "Fix
irq_of_parse_and_map() return value" - fixes incorrect error handling -
**Similar Commit #1 (Status: YES)**: "Convert to use dev_err_probe()" -
improves error handling patterns Both are small, focused error handling
improvements that were deemed suitable for backporting. ## Conclusion
This is a textbook example of a stable tree candidate: it's a small,
safe bug fix that brings the driver in line with kernel-wide error
handling standards, addresses real hardware failure scenarios, and has
zero risk of regression while providing tangible benefits for system
reliability.

 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 85b37f1b8a4ec..ff293f962d170 100644
--- a/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
+++ b/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
@@ -437,11 +437,14 @@ static int armada_37xx_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	struct armada_37xx_pinctrl *info = gpiochip_get_data(chip);
 	unsigned int reg = INPUT_VAL;
 	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) != 0;
 }
-- 
2.39.5