devicetree: bindings: add Device Tree bindings for Armada 39x pin-muxing controller

This commit adds the Device Tree binding documentation to describe the
pin-muxing controller of the Marvell Armada 39x processors. Two
variants are supported for the moment: the 88F6920 (Armada 390) and
88F6928 (Armada 398).
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/marvell,armada-39x-pinctrl.txt

+* Marvell Armada 39x SoC pinctrl driver for mpp
+
+Please refer to marvell,mvebu-pinctrl.txt in this directory for common binding
+part and usage.
+
+Required properties:
+- compatible: "marvell,88f6920-pinctrl", "marvell,88f6928-pinctrl"
+  depending on the specific variant of the SoC being used.
+- reg: register specifier of MPP registers
+
+Available mpp pins/groups and functions:
+Note: brackets (x) are not part of the mpp name for marvell,function and given
+only for more detailed description in this document.
+
+name    pins    functions
+================================================================================
+mpp0	0	gpio, ua0(rxd)
+mpp1	1	gpio, ua0(txd)
+mpp2	2	gpio, i2c0(sck)
+mpp3	3	gpio, i2c0(sda)
+mpp4	4	gpio, ua1(txd), ua0(rts), smi(mdc)
+mpp5	5	gpio, ua1(rxd), ua0(cts), smi(mdio)
+mpp6	6	gpio, dev(cs3), xsmi(mdio)
+mpp7	7	gpio, dev(ad9), xsmi(mdc)
+mpp8	8	gpio, dev(ad10), ptp(trig)
+mpp9	9	gpio, dev(ad11), ptp(clk)
+mpp10	10	gpio, dev(ad12), ptp(event)
+mpp11	11	gpio, dev(ad13), led(clk)
+mpp12	12	gpio, pcie0(rstout), dev(ad14), led(stb)
+mpp13	13	gpio, dev(ad15), led(data)
+mpp14	14	gpio, m(vtt), dev(wen1), ua1(txd)
+mpp15	15	gpio, pcie0(rstout), spi0(mosi), i2c1(sck)
+mpp16	16	gpio, m(decc), spi0(miso), i2c1(sda)
+mpp17	17	gpio, ua1(rxd), spi0(sck), smi(mdio)
+mpp18	18	gpio, ua1(txd), spi0(cs0), i2c2(sck)
+mpp19	19	gpio, sata1(present) [1], ua0(cts), ua1(rxd), i2c2(sda)
+mpp20	20	gpio, sata0(present) [1], ua0(rts), ua1(txd), smi(mdc)
+mpp21	21	gpio, spi0(cs1), sata0(present) [1], sd(cmd), dev(bootcs), ge(rxd0)
+mpp22	22	gpio, spi0(mosi), dev(ad0)
+mpp23	23	gpio, spi0(sck), dev(ad2)
+mpp24	24	gpio, spi0(miso), ua0(cts), ua1(rxd), sd(d4), dev(readyn)
+mpp25	25	gpio, spi0(cs0), ua0(rts), ua1(txd), sd(d5), dev(cs0)
+mpp26	26	gpio, spi0(cs2), i2c1(sck), sd(d6), dev(cs1)
+mpp27	27	gpio, spi0(cs3), i2c1(sda), sd(d7), dev(cs2), ge(txclkout)
+mpp28	28	gpio, sd(clk), dev(ad5), ge(txd0)
+mpp29	29	gpio, dev(ale0), ge(txd1)
+mpp30	30	gpio, dev(oen), ge(txd2)
+mpp31	31	gpio, dev(ale1), ge(txd3)
+mpp32	32	gpio, dev(wen0), ge(txctl)
+mpp33	33	gpio, m(decc), dev(ad3)
+mpp34	34	gpio, dev(ad1)
+mpp35	35	gpio, ref(clk), dev(a1)
+mpp36	36	gpio, dev(a0)
+mpp37	37	gpio, sd(d3), dev(ad8), ge(rxclk)
+mpp38	38	gpio, ref(clk), sd(d0), dev(ad4), ge(rxd1)
+mpp39	39	gpio, i2c1(sck), ua0(cts), sd(d1), dev(a2), ge(rxd2)
+mpp40	40	gpio, i2c1(sda), ua0(rts), sd(d2), dev(ad6), ge(rxd3)
+mpp41	41	gpio, ua1(rxd), ua0(cts), spi1(cs3), dev(burstn), nd(rbn0), ge(rxctl)
+mpp42	42	gpio, ua1(txd), ua0(rts), dev(ad7)
+mpp43	43	gpio, pcie0(clkreq), m(vtt), m(decc), spi1(cs2), dev(clkout), nd(rbn1)
+mpp44	44	gpio, sata0(present) [1], sata1(present) [1], led(clk)
+mpp45	45	gpio, ref(clk), pcie0(rstout), ua1(rxd)
+mpp46	46	gpio, ref(clk), pcie0(rstout), ua1(txd), led(stb)
+mpp47	47	gpio, sata0(present) [1], sata1(present) [1], led(data)
+mpp48	48	gpio, sata0(present) [1], m(vtt), tdm(pclk) [1], audio(mclk) [1], sd(d4), pcie0(clkreq), ua1(txd)
+mpp49	49	gpio, tdm(fsync) [1], audio(lrclk) [1], sd(d5), ua2(rxd)
+mpp50	50	gpio, pcie0(rstout), tdm(drx) [1], audio(extclk) [1], sd(cmd), ua2(rxd)
+mpp51	51	gpio, tdm(dtx) [1], audio(sdo) [1], m(decc), ua2(txd)
+mpp52	52	gpio, pcie0(rstout), tdm(intn) [1], audio(sdi) [1], sd(d6), i2c3(sck)
+mpp53	53	gpio, sata1(present) [1], sata0(present) [1], tdm(rstn) [1], audio(bclk) [1], sd(d7), i2c3(sda)
+mpp54	54	gpio, sata0(present) [1], sata1(present) [1], pcie0(rstout), sd(d3), ua3(txd)
+mpp55	55	gpio, ua1(cts), spi1(cs1), sd(d0), ua1(rxd), ua3(rxd)
+mpp56	56	gpio, ua1(rts), m(decc), spi1(mosi), ua1(txd)
+mpp57	57	gpio, spi1(sck), sd(clk), ua1(txd)
+mpp58	58	gpio, i2c1(sck), pcie2(clkreq), spi1(miso), sd(d1), ua1(rxd)
+mpp59	59	gpio, pcie0(rstout), i2c1(sda), spi1(cs0), sd(d2)
+
+[1]: only available on 88F6928