arm64: dts: hikey: name the GPIO lines

This names the GPIO lines on the HiKey board in accordance with
the 96Board Specification for especially the Low Speed External
Connector: "GPIO-A" thru "GPIO-L".

This will make these line names reflect through to userspace
so that they can easily be identified and used with the new
character device ABI.

Some care has been taken to name all lines, not just those used
by the external connectors, also lines that are muxed into some
other function than GPIO: these are named "[FOO]" so that users
can see with lsgpio what all lines are used for.

Cc: devicetree@vger.kernel.org
Cc: John Stultz <john.stultz@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: David Mandala <david.mandala@linaro.org>
Cc: Haojian Zhuang <haojian.zhuang@linaro.org>
Cc: Wei Xu <xuwei5@hisilicon.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>

arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts

@@ -66,6 +66,149 @@ uart3: uart@f7113000 {
 			status = "ok";
 		};
 
+		/*
+		 * Legend: proper name = the GPIO line is used as GPIO
+		 *         NC = not connected (not routed from the SoC)
+		 *         "[PER]" = pin is muxed for peripheral (not GPIO)
+		 *         "" = no idea, schematic doesn't say, could be
+		 *              unrouted (not connected to any external pin)
+		 *         LSEC = Low Speed External Connector
+		 *         HSEC = High Speed External Connector
+		 *
+		 * Pin assignments taken from LeMaker and CircuitCo Schematics
+		 * Rev A1.
+		 *
+		 * For the lines routed to the external connectors the
+		 * lines are named after the 96Boards CE Specification 1.0,
+		 * Appendix "Expansion Connector Signal Description".
+		 *
+		 * When the 96Board naming of a line and the schematic name of
+		 * the same line are in conflict, the 96Board specification
+		 * takes precedence, which means that the external UART on the
+		 * LSEC is named UART0 while the schematic and SoC names this
+		 * UART2. This is only for the informational lines i.e. "[FOO]",
+		 * the GPIO named lines "GPIO-A" thru "GPIO-L" are the only
+		 * ones actually used for GPIO.
+		 */
+		gpio0: gpio@f8011000 {
+			gpio-line-names = "PWR_HOLD", "DSI_SEL",
+			"USB_HUB_RESET_N", "USB_SEL", "HDMI_PD", "WL_REG_ON",
+			"PWRON_DET", "5V_HUB_EN";
+		};
+
+		gpio1: gpio@f8012000 {
+			gpio-line-names = "SD_DET", "HDMI_INT", "PMU_IRQ_N",
+			"WL_HOST_WAKE", "NC", "NC", "NC", "BT_REG_ON";
+		};
+
+		gpio2: gpio@f8013000 {
+			gpio-line-names =
+				"GPIO-A", /* LSEC Pin 23: GPIO2_0 */
+				"GPIO-B", /* LSEC Pin 24: GPIO2_1 */
+				"GPIO-C", /* LSEC Pin 25: GPIO2_2 */
+				"GPIO-D", /* LSEC Pin 26: GPIO2_3 */
+				"GPIO-E", /* LSEC Pin 27: GPIO2_4 */
+				"USB_ID_DET", "USB_VBUS_DET",
+				"GPIO-H"; /* LSEC Pin 30: GPIO2_7 */
+		};
+
+		gpio3: gpio@f8014000 {
+			gpio-line-names = "GPIO3_0", "NC", "NC", "", "NC", "",
+			"WLAN_ACTIVE", "NC", "NC";
+		};
+
+		gpio4: gpio@f7020000 {
+			gpio-line-names = "USER_LED1", "USER_LED2", "USER_LED3",
+			"USER_LED4", "SD_SEL", "NC", "NC", "BT_ACTIVE";
+		};
+
+		gpio5: gpio@f7021000 {
+			gpio-line-names = "NC", "NC",
+			"[UART1_RxD]", /* LSEC Pin 11: UART3_RX */
+			"[UART1_TxD]", /* LSEC Pin 13: UART3_TX */
+			"[AUX_SSI1]", "NC",
+			"[PCM_CLK]", /* LSEC Pin 18: MODEM_PCM_XCLK */
+			"[PCM_FS]"; /* LSEC Pin 16: MODEM_PCM_XFS */
+		};
+
+		gpio6: gpio@f7022000 {
+			gpio-line-names =
+			"[SPI0_DIN]", /* Pin 10: SPI0_DI */
+			"[SPI0_DOUT]", /* Pin 14: SPI0_DO */
+			"[SPI0_CS]", /* Pin 12: SPI0_CS_N */
+			"[SPI0_SCLK]", /* Pin 8: SPI0_SCLK */
+			"NC", "NC", "NC",
+			"GPIO-G"; /* Pin 29: GPIO6_7_DSI_TE0 */
+		};
+
+		gpio7: gpio@f7023000 {
+			gpio-line-names = "NC", "NC", "NC", "NC",
+			"[PCM_DI]", /* Pin 22: MODEM_PCM_DI */
+			"[PCM_DO]", /* Pin 20: MODEM_PCM_DO */
+			"NC", "NC";
+		};
+
+		gpio8: gpio@f7024000 {
+			gpio-line-names = "NC", "[CEC_CLK_19_2MHZ]", "NC",
+			"", "", "", "", "", "";
+		};
+
+		gpio9: gpio@f7025000 {
+			gpio-line-names = "",
+			"GPIO-J", /* LSEC Pin 32: ISP_PWDN0_GPIO9_1 */
+			"GPIO-L", /* LSEC Pin 34: ISP_PWDN1_GPIO9_2 */
+			"NC", "NC", "NC", "NC", "[ISP_CCLK0]";
+		};
+
+		gpio10: gpio@f7026000 {
+			gpio-line-names = "BOOT_SEL",
+			"[ISP_CCLK1]",
+			"GPIO-I", /* LSEC Pin 31: ISP_RSTB0_GPIO10_2 */
+			"GPIO-K", /* LSEC Pin 33: ISP_RSTB1_GPIO10_3 */
+			"NC", "NC",
+			"[I2C2_SDA]", /* HSEC Pin 34: ISP0_SDA */
+			"[I2C2_SCL]"; /* HSEC Pin 32: ISP0_SCL */
+		};
+
+		gpio11: gpio@f7027000 {
+			gpio-line-names =
+			"[I2C3_SDA]", /* HSEC Pin 38: ISP1_SDA */
+			"[I2C3_SCL]", /* HSEC Pin 36: ISP1_SCL */
+			"", "NC", "NC", "NC", "", "";
+		};
+
+		gpio12: gpio@f7028000 {
+			gpio-line-names = "[BT_PCM_XFS]", "[BT_PCM_DI]",
+			"[BT_PCM_DO]",
+			"NC", "NC", "NC", "NC",
+			"GPIO-F"; /* LSEC Pin 28: BL_PWM_GPIO12_7 */
+		};
+
+		gpio13: gpio@f7029000 {
+			gpio-line-names = "[UART0_RX]", "[UART0_TX]",
+			"[BT_UART1_CTS]", "[BT_UART1_RTS]",
+			"[BT_UART1_RX]", "[BT_UART1_TX]",
+			"[UART0_CTS]", /* LSEC Pin 3: UART2_CTS_N */
+			"[UART0_RTS]"; /* LSEC Pin 9: UART2_RTS_N */
+		};
+
+		gpio14: gpio@f702a000 {
+			gpio-line-names =
+			"[UART0_RxD]", /* LSEC Pin 7: UART2_RX */
+			"[UART0_TxD]", /* LSEC Pin 5: UART2_TX */
+			"[I2C0_SCL]", /* LSEC Pin 15: I2C0_SCL */
+			"[I2C0_SDA]", /* LSEC Pin 17: I2C0_SDA */
+			"[I2C1_SCL]", /* LSEC Pin 19: I2C1_SCL */
+			"[I2C1_SDA]", /* LSEC Pin 21: I2C1_SDA */
+			"[I2C2_SCL]", "[I2C2_SDA]";
+		};
+
+		gpio15: gpio@f702b000 {
+			gpio-line-names = "", "", "", "", "", "", "NC", "";
+		};
+
+		/* GPIO blocks 16 thru 19 do not appear to be routed to pins */
+
 		dwmmc_2: dwmmc2@f723f000 {
 			ti,non-removable;
 			non-removable;