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From:   Drew Fustini <drew@beagleboard.org>
To:     Tony Lindgren <tony@atomide.com>, Rob Herring <robh+dt@kernel.org>,
        bcousson@baylibre.com, Linus Walleij <linus.walleij@linaro.org>,
        Haojian Zhuang <haojian.zhuang@linaro.org>,
        Jason Kridner <jkridner@beagleboard.org>,
        Robert Nelson <robertcnelson@gmail.com>,
        linux-omap@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Drew Fustini <drew@beagleboard.org>
Subject: [PATCH v3] ARM: dts: am335x-pocketbeagle: set default mux for gpio pins
Date:   Fri, 10 Jul 2020 00:22:44 +0200
Message-Id: <20200709222244.776817-1-drew@beagleboard.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

These pins on the PocketBeagle P1 and P2 headers are connected to AM3358
balls with gpio lines, and these pins are not used for any other
peripherals by default. These GPIO lines are unclaimed and could be used
by userspace program through the gpiod ABI.

This patch adds a "default" state in the am33xx_pinmux node and sets the
mux for those pins to gpio (mode 7) and input enable.

The "pinctrl-single,bias-pullup" and "pinctrl-single,bias-pulldown"
pinconf properties are also set for each pin per the ball reset state in
section 4.2 of the datasheet [0].

This is the AM335x pin conf register format in Table 9-60 [1]:

bit	attribute      value
  6	slew           { 0: fast, 1: slow }
  5     rx_active      { 0: rx disable, 1: rx enabled }
  4     pu_typesel     { 0: pulldown select, 1: pullup select }
  3     puden          { 0: pud enable, 1: disabled }
  2     mode           3 bits to selec mode 0 to 7
  1     mode
  0     mode

The values for the bias pinconf properties are derived as follows:

pinctrl-single,bias-pullup   = <[input] [enabled] [disable] [mask]>;
pinctrl-single,bias-pullup   = <     8        16        8      24 >;

          2^5    2^4    2^3    2^2    2^1    2^0  |
         0x20   0x10   0x08   0x04   0x02   0x01  |
           32     16      8      4      2      1  |
-------------------------------------------------------
input       x      0      1     x      x      x   |   8
enabled     x      1      0     x      x      x   |  16
disabled    x      0      1     x      x      x   |   8
mask        x      1      1     x      x      x   |  24

pinctrl-single,bias-pulldown = <[input] [enabled] [disable] [mask]>;
pinctrl-single,bias-pulldown = <     8         0        8      24 >;

          2^5    2^4    2^3    2^2    2^1    2^0  |
         0x20   0x10   0x08   0x04   0x02   0x01  |
           32     16      8      4      2      1  |
-------------------------------------------------------
input       x      0      1     x      x      x   |   8
enabled     x      0      0     x      x      x   |   0
disabled    x      0      1     x      x      x   |   8
mask        x      1      1     x      x      x   |  24

[0] http://www.ti.com/lit/ds/symlink/am3358.pdf
[1] https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf

Signed-off-by: Drew Fustini <drew@beagleboard.org>
---
v3 changes:
- add pinconf bias properties as it is necessary for pcs_pinconf_set()
  to find the requested bias parameter in the PIN_MAP_TYPE_CONFIGS_GROUP
  pinctrl map.

v2 changes:
- change default mux from output to input.  Input is safer as it does
  not drive the line.  If the user wants output, they will need to edit
  this device tree.

 arch/arm/boot/dts/am335x-pocketbeagle.dts | 124 ++++++++++++++++++++++
 1 file changed, 124 insertions(+)

diff --git a/arch/arm/boot/dts/am335x-pocketbeagle.dts b/arch/arm/boot/dts/am335x-pocketbeagle.dts
index e08b5f73ccb5..4e7ba9872d2a 100644
--- a/arch/arm/boot/dts/am335x-pocketbeagle.dts
+++ b/arch/arm/boot/dts/am335x-pocketbeagle.dts
@@ -204,6 +204,130 @@ &gpio3 {
 };
 
 &am33xx_pinmux {
+
+	pinctrl-names = "default";
+	pinctrl-0 =   <	&P2_03_gpio &P1_34_gpio &P2_19_gpio &P2_24_gpio
+			&P2_33_gpio &P2_22_gpio &P2_18_gpio &P2_10_gpio
+			&P2_06_gpio &P2_04_gpio &P2_02_gpio &P2_08_gpio
+			&P2_17_gpio >;
+
+	/* P2_03 (ZCZ ball T10) gpio0_23 0x824 */
+	P2_03_gpio: pinmux_P2_03_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD9, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P1_34 (ZCZ ball T11) gpio0_26 0x828 */
+	P1_34_gpio: pinmux_P1_34_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD10, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+		/* P2_19 (ZCZ ball U12) gpio0_27 0x82c */
+	P2_19_gpio: pinmux_P2_19_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD11, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_24 (ZCZ ball T12) gpio1_12 0x830 */
+	P2_24_gpio: pinmux_P2_24_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD12, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_33 (ZCZ ball R12) gpio1_13 0x834 */
+	P2_33_gpio: pinmux_P2_33_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD13, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_22 (ZCZ ball V13) gpio1_14 0x838 */
+	P2_22_gpio: pinmux_P2_22_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD14, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_18 (ZCZ ball U13) gpio1_15 0x83c */
+	P2_18_gpio: pinmux_P2_18_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD15, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_10 (ZCZ ball R14) gpio1_20 0x850 */
+	P2_10_gpio: pinmux_P2_10_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_A4, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_06 (ZCZ ball U16) gpio1_25 0x864 */
+	P2_06_gpio: pinmux_P2_06_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_A9, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_04 (ZCZ ball T16) gpio1_26 0x868 */
+	P2_04_gpio: pinmux_P2_04_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_A10, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_02 (ZCZ ball V17) gpio1_27 0x86c */
+	P2_02_gpio: pinmux_P2_02_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_A11, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_08 (ZCZ ball U18) gpio1_28 0x878 */
+	P2_08_gpio: pinmux_P2_08_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_BEN1, PIN_INPUT_PULLDOWN, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
+	/* P2_17 (ZCZ ball V12) gpio2_1 0x88c */
+	P2_17_gpio: pinmux_P2_17_gpio {
+		pinctrl-single,pins = <
+			AM33XX_PADCONF(AM335X_PIN_GPMC_CLK, PIN_INPUT_PULLUP, MUX_MODE7)
+		>;
+		pinctrl-single,bias-pullup   = <  8 16  8 24>;
+		pinctrl-single,bias-pulldown = <  8  0  8 24>;
+	};
+
 	i2c2_pins: pinmux-i2c2-pins {
 		pinctrl-single,pins = <
 			AM33XX_PADCONF(AM335X_PIN_UART1_RTSN, PIN_INPUT_PULLUP, MUX_MODE3)	/* (D17) uart1_rtsn.I2C2_SCL */
-- 
2.25.1