MFC r331868, r332046, r332194-r332196, r332198, r332219, r332231, r332233, r332240, r332258-r332259, r332261, r332292

r331868:
Add opt_platform.h for several modules that have #ifdef FDT in the source.

Submitted by:	Andre Albsmeier <Andre.Albsmeier@siemens.com>

r332046:
Add a missing MODULE_DEPEND().

r332194:
Add support for writing/changing spi device ivars.  The SPI mode (polarity
and phase) and the maximum bus speed can be changed.  The chip select
number cannot be changed, because the device instances which are children
of spibus are inherently associated with the chip select number they were
instantiated for.

r332195:
A couple minor improvements to spibus.c...

 - Change the description string to "SPI bus" (was "spibus bus").

 - This is the default driver for a SPI bus, not a generic implementation,
   so return the probe value that indicates such.

 - Use device_delete_children() at detach time, instead of a local loop
   to enumerate the children and detach each one individually.

r332196:
Return BUS_PROBE_DEFAULT, not zero, because this is not the one driver
implementation that must be used, it's just the base system default driver.

Also add a comment noting that we're being more liberal about the bus
frequency property than the dts binding documents require.

r332198:
Arrange the list of generated sources as 1-per-line alphbetical, and add
the files required when building for FDT-based systems.

r332219:
Remove the existing identify() hack to force-add a spigen device on
FDT-based systems, and instead add proper FDT probe code.  Because this
driver is freebsd-specific and just provides generic userland access to run
spibus transactions, there is no bindings document to mandate a compatible
string, so just arbitrarily use "freebsd,spigen".

r332231:
Generate a spibus_set_[ivarname]() convenience function for each ivar,
now that they can be set.

r332233:
Add an ioctl to get/set the SPI transfer mode.  Also, make the bus clock
frequency ioctl actually set the corresponding ivar instead of just storing
the value locally in the softc (and then not using it for anything).  Also,
return the correct error code if the ioctl cmd is not recognized.

r332240:
Add the ioctl definitions for spigen get/set spi mode.  Should have been
part of r332233.

r332258:
Don't check for impossible NULL return from malloc(..., M_WAITOK).

r332259:
Cast the data pointer to the correct type for the data being accessed (as
opposed to one that accidentally worked on the one arch I test-compiled for
on my first try).

Reported by:	np@, O. Hartmann <ohartmann@walstatt.org>
Pointy hat:	ian@

r332261:
Add a manpage for spigen(4).

r332292:
Allow hinted attachment on FDT-based systems.  Instead of returning ENXIO
when the FDT data doesn't enable the device instance, return
BUS_PROBE_NOWILDCARD, the same as for non-FDT systems.

1 files changed, 206 insertions, 0 deletions

diff --git a/share/man/man4/spigen.4 b/share/man/man4/spigen.4
new file mode 100644
index 0000000..f432fb7
--- /dev/null
+++ b/share/man/man4/spigen.4
@@ -0,0 +1,206 @@
+.\"
+.\" Copyright (c) 2018 Ian Lepore <ian@freebsd.org>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\"
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd April 7, 2018
+.Dt SPIGEN 4
+.Os
+.Sh NAME
+.Nm spigen
+.Nd SPI generic I/O device driver
+.Sh SYNOPSIS
+To compile this driver into the kernel,
+place the following lines in your
+kernel configuration file:
+.Bd -ragged -offset indent
+.Cd "device spi"
+.Cd "device spibus"
+.Cd "device spigen"
+.Ed
+.Pp
+Alternatively, to load the driver as a
+module at boot time, place the following line in
+.Xr loader.conf 5 :
+.Bd -literal -offset indent
+spigen_load="YES"
+.Ed
+.Sh DESCRIPTION
+The
+.Nm
+driver provides direct access to a slave device on the SPI bus.
+Each instance of a
+.Nm
+device is associated with a single chip-select
+line on the bus, and all I/O performed through that instance is done
+with that chip-select line asserted.
+.Pp
+SPI data transfers are inherently bi-directional; there are not separate
+read and write operations. 
+When commands and data are sent to a device, data also comes back from
+the device, although in some cases the data may not be useful (or even
+documented or predictable for some devices).
+Likewise on a read operation, whatever data is in the buffer at the start
+of the operation is sent to (and typically ignored by) the device, with each
+outgoing byte then replaced in the buffer by the corresponding incoming byte.
+Thus, all buffers passed to the transfer functions are both input and
+output buffers.
+.Pp
+The
+.Nm
+driver provides access to the SPI slave device with the following
+.Xr ioctl 2
+calls, defined in
+.In sys/spigenio.h :
+.Bl -tag -width indent
+.It Dv SPIGENIOC_TRANSFER Pq Vt "struct spigen_transfer"
+Transfer a command and optional associated data to/from the device,
+using the buffers described by the st_command and st_data fields in the
+.Vt spigen_transfer .
+Set
+.Vt st_data.iov_len
+to zero if there is no data associated with the command.
+.Bd -literal
+struct spigen_transfer {
+	struct iovec st_command;
+	struct iovec st_data;
+};
+.Ed
+.It Dv SPIGENIOC_TRANSFER_MMAPPED Pq Vt "spigen_transfer_mmapped"
+Transfer a command and optional associated data to/from the device.
+The buffers for the transfer are a previously-mmap'd region.
+The length of the command and data within that region are described by the
+.Vt stm_command_length
+and
+.Vt stm_data_length
+fields of
+.Vt spigen_transfer_mmapped .
+If
+.Vt stm_data_length
+is non-zero, the data appears in the memory region immediately
+following the command (that is, at offset
+.Vt stm_command_length
+from the start of the mapped region).
+.Bd -literal
+struct spigen_transfer_mmapped {
+	size_t stm_command_length;
+	size_t stm_data_length;
+};
+.Ed
+.It Dv SPIGENIOC_GET_CLOCK_SPEED Pq Vt uint32_t
+Get the maximum clock speed (bus frequency in Hertz) to be used
+when communicating with this slave device.
+.It Dv SPIGENIOC_SET_CLOCK_SPEED Pq Vt uint32_t
+Set the maximum clock speed (bus frequency in Hertz) to be used
+when communicating with this slave device.
+The setting remains in effect for subsequent transfers; it
+is not necessary to reset this before each transfer.
+The actual bus frequency may be lower due to hardware limitiations
+of the SPI bus controller device.
+.It Dv SPIGENIOC_GET_SPI_MODE Pq Vt uint32_t
+Get the SPI mode (clock polarity and phase) to be used
+when communicating with this device.
+.It Dv SPIGENIOC_SET_SPI_MODE Pq Vt uint32_t
+Set the SPI mode (clock polarity and phase) to be used
+when communicating with this device.
+The setting remains in effect for subsequent transfers; it
+is not necessary to reset this before each transfer.
+.El
+.Sh HINTS CONFIGURATION
+On a 
+.Xr device.hints 5
+based system, such as
+.Li MIPS ,
+these values are configurable for
+.Nm :
+.Bl -tag -width indent
+.It Va hint.spigen.%d.at
+The spibus the
+.Nm
+instance is attached to.
+.It Va hint.spigen.%d.clock
+The maximum bus frequency to use when communicating with this device.
+Actual bus speed may be lower, depending on the capabilities of the SPI
+bus controller hardware.
+.It Va hint.spigen.%d.cs
+The chip-select number to assert when performing I/O for this device.
+Set the high bit (1 << 31) to invert the logic level of the chip select line.
+.It Va hint.spigen.%d.mode
+The SPI mode (0-3) to use when communicating with this device.
+.El
+.Sh FDT CONFIGURATION
+On an
+.Xr fdt 4
+based system, the spigen device is defined as a slave device subnode
+of the SPI bus controller node.
+All properties documented in the
+.Va spibus.txt
+bindings document can be used with the
+.Nm
+device.
+The most commonly-used ones are documented below.
+.Pp
+The following properties are required in the
+.Nm
+device subnode:
+.Bl -tag -width indent
+.It Va compatible
+Must be the string "freebsd,spigen".
+.It Va reg
+Chip select address of device.
+.It Va spi-max-frequency
+The maximum bus frequency to use when communicating with this slave device.
+Actual bus speed may be lower, depending on the capabilities of the SPI
+bus controller hardware.
+.El
+.Pp
+The following properties are optional for the
+.Nm
+device subnode:
+.Bl -tag -width indent
+.It Va spi-cpha
+Empty property indicating the slave device requires shifted clock
+phase (CPHA) mode.
+.It Va spi-cpol
+Empty property indicating the slave device requires inverse clock
+polarity (CPOL) mode.
+.It Va spi-cs-high
+Empty property indicating the slave device requires chip select active high.
+.El
+.Sh FILES
+.Bl -tag -width -compact
+.It Pa /dev/spigen*
+.El
+.Sh SEE ALSO
+.Xr fdt 4 ,
+.Xr device.hints 5
+.Sh HISTORY
+The
+.Nm
+driver
+appeared in
+.Fx 11.0 .
+FDT support appeared in
+.Fx 11.2 .