i2c: gpio: add fault injector

Add fault injection capabilities to the i2c-gpio driver. When connected
to another I2C bus, it can create unusual states which the other I2C bus
master driver needs to handle. Only for debugging!

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 009345d..a9805c7 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -603,6 +603,14 @@
 	  This is a very simple bitbanging I2C driver utilizing the
 	  arch-neutral GPIO API to control the SCL and SDA lines.
 
+config I2C_GPIO_FAULT_INJECTOR
+	bool "GPIO-based fault injector"
+	depends on I2C_GPIO
+	help
+	  This adds some functionality to the i2c-gpio driver which can inject
+	  faults to an I2C bus, so another bus master can be stress-tested.
+	  This is for debugging. If unsure, say 'no'.
+
 config I2C_HIGHLANDER
 	tristate "Highlander FPGA SMBus interface"
 	depends on SH_HIGHLANDER