We are racing the registering of .to_irq when probing the
i2c driver. This results in random failure of touchscreen
devices.
Following errors could be seen in dmesg logs when gc->to_irq is NULL
[2.101857] i2c_hid i2c-FTS3528:00: HID over i2c has not been provided an Int IRQ
[2.101953] i2c_hid: probe of i2c-FTS3528:00 failed with error -22
To avoid this situation, defer probing until to_irq is registered.
This issue has been reported many times in past and people have been
using workarounds like changing the pinctrl_amd to built-in instead
of loading it as a module or by adding a softdep for pinctrl_amd into
the config file.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209413
Reviewed-by: Linus Walleij <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Shreeya Patel <[email protected]>
---
Changes in v3
- Fix the error reported by kernel test robot.
Changes in v2
- Add a condition to check for irq chip to avoid bogus error.
---
drivers/gpio/gpiolib.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index abfbf546d159..4d7fb349e837 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3111,6 +3111,16 @@ int gpiod_to_irq(const struct gpio_desc *desc)
return retirq;
}
+#ifdef CONFIG_GPIOLIB_IRQCHIP
+ if (gc->irq.chip) {
+ /*
+ * avoid race condition with other code, which tries to lookup
+ * an IRQ before the irqchip has been properly registered,
+ * i.e. while gpiochip is still being brought up.
+ */
+ return -EPROBE_DEFER;
+ }
+#endif
return -ENXIO;
}
EXPORT_SYMBOL_GPL(gpiod_to_irq);
--
2.30.2