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Commit 305964b7 authored by Lukas Wunner's avatar Lukas Wunner Committed by Daniel Vetter
Browse files

apple-gmux: Sphinxify docs 



Convert asciidoc-formatted docs to rst in accordance with Jonathan's and
Jani's effort to use sphinx for kernel-doc rendering in 4.8.

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Acked-by: default avatarDarren Hart <dvhart@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/4c1b29986fa77772156b1af0c965d3799e43a47b.1467628307.git.lukas@wunner.de
parent 3c31760e

drivers/platform/x86/apple-gmux.c

+29 −26
Original line number Diff line number Diff line
@@ -31,19 +31,21 @@ 
/**

 * DOC: Overview

 *

 * :1:  http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx

 * :2:  http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp

 *

 * gmux is a microcontroller built into the MacBook Pro to support dual GPUs:

 * A {1}[Lattice XP2] on pre-retinas, a {2}[Renesas R4F2113] on retinas.

 * A `Lattice XP2`_ on pre-retinas, a `Renesas R4F2113`_ on retinas.

 *

 * (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has

 * dual GPUs but no built-in display.)

 *

 * gmux is connected to the LPC bus of the southbridge. Its I/O ports are

 * accessed differently depending on the microcontroller: Driver functions

 * to access a pre-retina gmux are infixed `_pio_`, those for a retina gmux

 * are infixed `_index_`.

 * to access a pre-retina gmux are infixed ``_pio_``, those for a retina gmux

 * are infixed ``_index_``.

 *

 * .. _Lattice XP2:

 *     http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx

 * .. _Renesas R4F2113:

 *     http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp

 */



struct apple_gmux_data {
@@ -272,15 +274,15 @@ static bool gmux_is_indexed(struct apple_gmux_data *gmux_data) 
/**

 * DOC: Backlight control

 *

 * :3:  http://www.ti.com/lit/ds/symlink/lp8543.pdf

 * :4:  http://www.ti.com/lit/ds/symlink/lp8545.pdf

 *

 * On single GPU MacBooks, the PWM signal for the backlight is generated by

 * the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended

 * to conserve energy. Hence the PWM signal needs to be generated by a separate

 * backlight driver which is controlled by gmux. The earliest generation

 * MBP5 2008/09 uses a {3}[TI LP8543] backlight driver. All newer models

 * use a {4}[TI LP8545].

 * MBP5 2008/09 uses a `TI LP8543`_ backlight driver. All newer models

 * use a `TI LP8545`_.

 *

 * .. _TI LP8543: http://www.ti.com/lit/ds/symlink/lp8543.pdf

 * .. _TI LP8545: http://www.ti.com/lit/ds/symlink/lp8545.pdf

 */



static int gmux_get_brightness(struct backlight_device *bd)
@@ -312,28 +314,20 @@ static const struct backlight_ops gmux_bl_ops = { 
/**

 * DOC: Graphics mux

 *

 * :5:  http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf

 * :6:  http://www.nxp.com/documents/data_sheet/CBTL06141.pdf

 * :7:  http://www.ti.com/lit/ds/symlink/hd3ss212.pdf

 * :8:  https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf

 * :9:  http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf

 * :10: http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf

 * :11: http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf

 *

 * On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes

 * either of them to the panel. One of the tricks gmux has up its sleeve is

 * to lengthen the blanking interval of its output during a switch to

 * synchronize it with the GPU switched to. This allows for a flicker-free

 * switch that is imperceptible by the user ({5}[US 8,687,007 B2]).

 * switch that is imperceptible by the user (`US 8,687,007 B2`_).

 *

 * On retinas, muxing is no longer done by gmux itself, but by a separate

 * chip which is controlled by gmux. The chip is triple sourced, it is

 * either an {6}[NXP CBTL06142], {7}[TI HD3SS212] or {8}[Pericom PI3VDP12412].

 * either an `NXP CBTL06142`_, `TI HD3SS212`_ or `Pericom PI3VDP12412`_.

 * The panel is driven with eDP instead of LVDS since the pixel clock

 * required for retina resolution exceeds LVDS' limits.

 *

 * Pre-retinas are able to switch the panel's DDC pins separately.

 * This is handled by a {9}[TI SN74LV4066A] which is controlled by gmux.

 * This is handled by a `TI SN74LV4066A`_ which is controlled by gmux.

 * The inactive GPU can thus probe the panel's EDID without switching over

 * the entire panel. Retinas lack this functionality as the chips used for

 * eDP muxing are incapable of switching the AUX channel separately (see
@@ -344,15 +338,15 @@ static const struct backlight_ops gmux_bl_ops = { 
 *

 * The external DP port is only fully switchable on the first two unibody

 * MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an

 * {6}[NXP CBTL06141] which is controlled by gmux. It's the predecessor of the

 * `NXP CBTL06141`_ which is controlled by gmux. It's the predecessor of the

 * eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.

 *

 * The following MacBook Pro generations replaced the external DP port with a

 * combined DP/Thunderbolt port and lost the ability to switch it between GPUs,

 * connecting it either to the discrete GPU or the Thunderbolt controller.

 * Oddly enough, while the full port is no longer switchable, AUX and HPD

 * are still switchable by way of an {10}[NXP CBTL03062] (on pre-retinas

 * MBP8 2011 and MBP9 2012) or two {11}[TI TS3DS10224] (on retinas) under the

 * are still switchable by way of an `NXP CBTL03062`_ (on pre-retinas

 * MBP8 2011 and MBP9 2012) or two `TI TS3DS10224`_ (on retinas) under the

 * control of gmux. Since the integrated GPU is missing the main link,

 * external displays appear to it as phantoms which fail to link-train.

 *
@@ -365,10 +359,19 @@ static const struct backlight_ops gmux_bl_ops = { 
 * of this feature.

 *

 * gmux' initial switch state on bootup is user configurable via the EFI

 * variable `gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9` (5th byte,

 * variable ``gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9`` (5th byte,

 * 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to

 * switch the panel and the external DP connector and allocates a framebuffer

 * for the selected GPU.

 *

 * .. _US 8,687,007 B2: http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf

 * .. _NXP CBTL06141:   http://www.nxp.com/documents/data_sheet/CBTL06141.pdf

 * .. _NXP CBTL06142:   http://www.nxp.com/documents/data_sheet/CBTL06141.pdf

 * .. _TI HD3SS212:     http://www.ti.com/lit/ds/symlink/hd3ss212.pdf

 * .. _Pericom PI3VDP12412: https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf

 * .. _TI SN74LV4066A:  http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf

 * .. _NXP CBTL03062:   http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf

 * .. _TI TS3DS10224:   http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf

 */



static void gmux_read_switch_state(struct apple_gmux_data *gmux_data)