misc: keba: Add basic KEBA CP500 system FPGA support

The KEBA CP500 system FPGA is a PCIe device, which consists of multiple
IP cores. Every IP core has its own auxiliary driver. The cp500 driver
registers an auxiliary device for each device and the corresponding
drivers are loaded by the Linux driver infrastructure.

Currently 3 variants of this device exists. Every variant has its own
PCI device ID, which is used to determine the list of available IP
cores. In this first version only the auxiliary device for the I2C
controller is registered.

Besides the auxiliary device registration some other basic functions of
the FPGA are implemented; e.g, FPGA version sysfs file, keep FPGA
configuration on reset sysfs file, error message for errors on the
internal AXI bus of the FPGA.

Signed-off-by: Gerhard Engleder <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Gerhard Engleder

Documentation/ABI/stable/sysfs-driver-misc-cp500

@@ -0,0 +1,25 @@
+What:		/sys/devices/pciXXXX:XX/0000:XX:XX.X/0000:XX:XX.X/version
+Date:		June 2024
+KernelVersion:	6.11
+Contact:	Gerhard Engleder <[email protected]>
+Description:	Version of the FPGA configuration bitstream as printable string.
+		This file is read only.
+Users:		KEBA
+
+What:		/sys/devices/pciXXXX:XX/0000:XX:XX.X/0000:XX:XX.X/keep_cfg
+Date:		June 2024
+KernelVersion:	6.11
+Contact:	Gerhard Engleder <[email protected]>
+Description:	Flag which signals if FPGA shall keep or reload configuration
+		bitstream on reset. Normal FPGA behavior and default is to keep
+		configuration bitstream and to only reset the configured logic.
+
+		Reloading configuration on reset enables an update of the
+		configuration bitstream with a simple reboot. Otherwise it is
+		necessary to power cycle the device to reload the new
+		configuration bitstream.
+
+		This file is read/write. The values are as follows:
+		1 = keep configuration bitstream on reset, default
+		0 = reload configuration bitstream on reset
+Users:		KEBA

drivers/misc/Kconfig

@@ -602,4 +602,5 @@ source "drivers/misc/cardreader/Kconfig"
 source "drivers/misc/uacce/Kconfig"
 source "drivers/misc/pvpanic/Kconfig"
 source "drivers/misc/mchp_pci1xxxx/Kconfig"
+source "drivers/misc/keba/Kconfig"
 endmenu

drivers/misc/Makefile

@@ -69,3 +69,4 @@ obj-$(CONFIG_TMR_INJECT)	+= xilinx_tmr_inject.o
 obj-$(CONFIG_TPS6594_ESM)	+= tps6594-esm.o
 obj-$(CONFIG_TPS6594_PFSM)	+= tps6594-pfsm.o
 obj-$(CONFIG_NSM)		+= nsm.o
+obj-y				+= keba/

drivers/misc/keba/Kconfig

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+config KEBA_CP500
+	tristate "KEBA CP500 system FPGA support"
+	depends on PCI
+	help
+	  This driver supports the KEBA CP500 system FPGA, which is used in
+	  KEBA CP500 devices. It registers all sub devices present on the CP500
+	  system FPGA as separate devices. A driver is needed for each sub
+	  device.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called cp500.

drivers/misc/keba/Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_KEBA_CP500)	+= cp500.o