pinctrl: sh-pfc: Add drive strength support

Add support for the drive-strengh pin configuration using the generic
pinconf DT bindings.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
diff --git a/drivers/pinctrl/sh-pfc/core.h b/drivers/pinctrl/sh-pfc/core.h
index 62f53b2..fc05d0c 100644
--- a/drivers/pinctrl/sh-pfc/core.h
+++ b/drivers/pinctrl/sh-pfc/core.h
@@ -62,6 +62,9 @@
 u32 sh_pfc_read_raw_reg(void __iomem *mapped_reg, unsigned int reg_width);
 void sh_pfc_write_raw_reg(void __iomem *mapped_reg, unsigned int reg_width,
 			  u32 data);
+u32 sh_pfc_read_reg(struct sh_pfc *pfc, u32 reg, unsigned int width);
+void sh_pfc_write_reg(struct sh_pfc *pfc, u32 reg, unsigned int width,
+		      u32 data);
 
 int sh_pfc_get_pin_index(struct sh_pfc *pfc, unsigned int pin);
 int sh_pfc_config_mux(struct sh_pfc *pfc, unsigned mark, int pinmux_type);