[PATCH v3 2/3] arm64: dts: lx2160a: fix IIC1 pinmux submask rejected by pinctrl-single

IIC1_PMUX is a single bit field at RCWSR14 bit 10, so the mask for the
two iic1 pinmux nodes was narrowed from 0x7 to 0x1 to avoid writing the
two reserved bits next to it.

With pinctrl-single,bit-per-mux the driver does not take the supplied
mask as the bits to modify. It derives the field from the node's
pinctrl-single,function-mask, which is 0x7 here, and then requires the
supplied mask to match it exactly:

	bit_pos = __ffs(mask);			/* 10 */
	mask_pos = ((pcs->fmask) << bit_pos);	/* 0x7 << 10 = 0x1c00 */
	submask = mask & mask_pos;		/* 0x400 */
	...
	if (submask != mask_pos) {
		dev_warn(pcs->dev,
			 "Invalid submask 0x%x for %pOFn at 0x%x\n",
			 submask, np, offset);
		continue;
	}

A one bit mask gives submask 0x400 against mask_pos 0x1c00, so both
nodes are rejected and the pins are never muxed with this message:

  pinctrl-single 70010012c.pinmux: Invalid submask 0x400 for iic1-i2c-pins
  pinctrl-single 70010012c.pinmux: Invalid submask 0x400 for iic1-gpio-pins

The values are not changed:
  - 0x0 selects IIC1
  - 0x1 << 10 selects GPIO_1[3:2].

Fixes: 7a3cc49ad1fc ("arm64: dts: lx2160a: change i2c0 (iic1) pinmux mask to one bit")
Signed-off-by: Vincent Jardin <[email protected]>
---
 arch/arm64/boot/dts/freescale/fsl-lx216x.dtsi | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/freescale/fsl-lx216x.dtsi b/arch/arm64/boot/dts/freescale/fsl-lx216x.dtsi
index d4522a19405a9..d9d4500a40510 100644
--- a/arch/arm64/boot/dts/freescale/fsl-lx216x.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-lx216x.dtsi
@@ -1687,12 +1687,19 @@ i2c6_i2c7_pins: iic8-iic7-i2c-pins {
 			};
 
 			/* RCWSR14 */
+			/*
+			 * IIC1_PMUX is a single bit at RCWSR14[10], but bit-per-mux
+			 * uses the mask for the field to clear before applying the
+			 * value.
+			 * So bits 11 and 12, which are reserved, are written as 0
+			 * on every mux switch, it is harmless.
+			 */
 			i2c0_pins: iic1-i2c-pins {
-				pinctrl-single,bits = <0x8 0x0 (0x1 << 10)>;
+				pinctrl-single,bits = <0x8 0x0 (0x7 << 10)>;
 			};
 
 			gpio0_3_2_pins: iic1-gpio-pins {
-				pinctrl-single,bits = <0x8 (0x1 << 10) (0x1 << 10)>;
+				pinctrl-single,bits = <0x8 (0x1 << 10) (0x7 << 10)>;
 			};
 		};
 

-- 
2.43.0