pinctrl: generic: add slew rate config parameter

Add PIN_CONFIG_SLEW_RATE parameter into pinconf-generic driver.

Signed-off-by: Haojian Zhuang <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/pinconf-generic.c

···
 	PCONFDUMP(PIN_CONFIG_INPUT_SCHMITT, "input schmitt trigger", NULL),
 	PCONFDUMP(PIN_CONFIG_INPUT_DEBOUNCE, "input debounce", "time units"),
 	PCONFDUMP(PIN_CONFIG_POWER_SOURCE, "pin power source", "selector"),
+	PCONFDUMP(PIN_CONFIG_SLEW_RATE, "slew rate", NULL),
 	PCONFDUMP(PIN_CONFIG_LOW_POWER_MODE, "pin low power", "mode"),
 	PCONFDUMP(PIN_CONFIG_OUTPUT, "pin output", "level"),
 };

include/linux/pinctrl/pinconf-generic.h

···
  * @PIN_CONFIG_POWER_SOURCE: if the pin can select between different power
  *	supplies, the argument to this parameter (on a custom format) tells
  *	the driver which alternative power source to use.
+ * @PIN_CONFIG_SLEW_RATE: if the pin can select slew rate, the argument to
+ * 	this parameter (on a custom format) tells the driver which alternative
+ * 	slew rate to use.
  * @PIN_CONFIG_LOW_POWER_MODE: this will configure the pin for low power
  *	operation, if several modes of operation are supported these can be
  *	passed in the argument on a custom form, else just use argument 1
···
 	PIN_CONFIG_INPUT_SCHMITT,
 	PIN_CONFIG_INPUT_DEBOUNCE,
 	PIN_CONFIG_POWER_SOURCE,
+	PIN_CONFIG_SLEW_RATE,
 	PIN_CONFIG_LOW_POWER_MODE,
 	PIN_CONFIG_OUTPUT,
 	PIN_CONFIG_END = 0x7FFF,