1.\" $OpenBSD: amdisplay.4,v 1.4 2019/05/29 19:37:06 fcambus Exp $ 2.\" 3.\" Copyright (c) 2017 Ian Sutton <ians@openbsd.org> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: May 29 2019 $ 18.Dt AMDISPLAY 4 armv7 19.Os 20.Sh NAME 21.Nm amdisplay , 22.Nm nxphdmi 23.Nd Texas Instruments AM335x LCD display driver 24.Sh SYNOPSIS 25.Nm "amdisplay* at simplebus0" 26.Nm "nxphdmi* at iic*" 27.Nm "wsdisplay* at amdisplay*" 28.Sh DESCRIPTION 29The 30.Nm 31driver supports the LCD controller integrated in Texas Instruments' line of 32AM335x SoCs. 33The LCDC reads a framebuffer from memory via DMA and scans it out 34at the proper frequency to suit a display (along with the necessary 35hsync/vsync/etc. signals) to a PHY transmitter. 36The BeagleBone Black uses NXP/Freescale's TDA19988 HDMI transmitter, 37which is additionally supported by the 38.Nm nxphdmi 39driver. 40.Sh SEE ALSO 41.Xr intro 4 , 42.Xr wsdisplay 4 , 43.Xr wsfb 4 44.Sh HISTORY 45The 46.Nm 47driver first appeared in 48.Ox 6.2 . 49.Sh AUTHORS 50.An -nosplit 51The 52.Nm 53driver was written by 54.An Ian Sutton Aq Mt ians@openbsd.org . 55The 56.Nm nxphdmi 57driver was written by 58.An Oleksandr Tymoshenko Aq Mt gonzo@freebsd.org 59and later ported to 60.Ox . 61.Sh CAVEATS 62On the BeagleBone Black, the LCDC and onboard eMMC NAND chip share the same set 63of pads such that only one can be wired and used at a time. 64To boot from or use the onboard storage, disable 65.Nm 66via 67.Xr config 8 68in the kernel. 69.Pp 70A display must be attached at boot time, otherwise 71.Nm 72will fail to configure. 73.Pp 74Hotplugging is not supported. 75.Pp 76Only 16-bit color depth is supported due to a silicon bug. 77