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 <[e-mail]>
Cc: Jani Nikula <[e-mail]>
Signed-off-by: Lukas Wunner <[e-mail]>
Acked-by: Darren Hart <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: http://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/platform/x86/apple-gmux.c

···
 /**
  * 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 {
···
 /**
  * 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)
···
 /**
  * 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
···
  *
  * 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.
  *
···
  * 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)