spi: docs: convert to ReST and add it to the kABI bookset

While there's one file there with briefily describes the uAPI,
the documentation was written just like most subsystems: focused
on kernel developers. So, add it together with driver-api books.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 0 insertions, 79 deletions

diff --git a/Documentation/spi/spi-lm70llp b/Documentation/spi/spi-lm70llp
deleted file mode 100644
index 463f6d01fa15..000000000000
--- a/Documentation/spi/spi-lm70llp
+++ /dev/null
@@ -1,79 +0,0 @@
-spi_lm70llp :  LM70-LLP parport-to-SPI adapter
-==============================================
-
-Supported board/chip:
-  * National Semiconductor LM70 LLP evaluation board
-    Datasheet: http://www.national.com/pf/LM/LM70.html
-
-Author:
-        Kaiwan N Billimoria <kaiwan@designergraphix.com>
-
-Description
------------
-This driver provides glue code connecting a National Semiconductor LM70 LLP
-temperature sensor evaluation board to the kernel's SPI core subsystem.
-
-This is a SPI master controller driver. It can be used in conjunction with
-(layered under) the LM70 logical driver (a "SPI protocol driver").
-In effect, this driver turns the parallel port interface on the eval board
-into a SPI bus with a single device, which will be driven by the generic
-LM70 driver (drivers/hwmon/lm70.c).
-
-
-Hardware Interfacing
---------------------
-The schematic for this particular board (the LM70EVAL-LLP) is
-available (on page 4) here:
-
-  http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf
-
-The hardware interfacing on the LM70 LLP eval board is as follows:
-
-   Parallel                 LM70 LLP
-     Port      Direction   JP2 Header
-   ----------- --------- ----------------
-      D0     2      -         -
-      D1     3     -->      V+   5
-      D2     4     -->      V+   5
-      D3     5     -->      V+   5
-      D4     6     -->      V+   5
-      D5     7     -->      nCS  8
-      D6     8     -->      SCLK 3
-      D7     9     -->      SI/O 5
-     GND    25      -       GND  7
-    Select  13     <--      SI/O 1
-   ----------- --------- ----------------
-
-Note that since the LM70 uses a "3-wire" variant of SPI, the SI/SO pin
-is connected to both pin D7 (as Master Out) and Select (as Master In)
-using an arrangement that lets either the parport or the LM70 pull the
-pin low.  This can't be shared with true SPI devices, but other 3-wire
-devices might share the same SI/SO pin.
-
-The bitbanger routine in this driver (lm70_txrx) is called back from
-the bound "hwmon/lm70" protocol driver through its sysfs hook, using a
-spi_write_then_read() call.  It performs Mode 0 (SPI/Microwire) bitbanging.
-The lm70 driver then inteprets the resulting digital temperature value
-and exports it through sysfs.
-
-A "gotcha": National Semiconductor's LM70 LLP eval board circuit schematic
-shows that the SI/O line from the LM70 chip is connected to the base of a
-transistor Q1 (and also a pullup, and a zener diode to D7); while the
-collector is tied to VCC.
-
-Interpreting this circuit, when the LM70 SI/O line is High (or tristate
-and not grounded by the host via D7), the transistor conducts and switches
-the collector to zero, which is reflected on pin 13 of the DB25 parport
-connector.  When SI/O is Low (driven by the LM70 or the host) on the other
-hand, the transistor is cut off and the voltage tied to it's collector is
-reflected on pin 13 as a High level.
-
-So: the getmiso inline routine in this driver takes this fact into account,
-inverting the value read at pin 13.
-
-
-Thanks to
----------
-o David Brownell for mentoring the SPI-side driver development.
-o Dr.Craig Hollabaugh for the (early) "manual" bitbanging driver version.
-o Nadir Billimoria for help interpreting the circuit schematic.