kvmd spi driver

1 files changed, 154 insertions, 0 deletions

diff --git a/kvmd/plugins/hid/spi.py b/kvmd/plugins/hid/spi.py
new file mode 100644
index 00000000..77d2f34c
--- /dev/null
+++ b/kvmd/plugins/hid/spi.py
@@ -0,0 +1,154 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2018  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import os
+import contextlib
+import time
+
+from typing import List
+from typing import Dict
+from typing import Generator
+from typing import Any
+
+import spidev
+
+from ...yamlconf import Option
+
+from ...validators.basic import valid_int_f0
+from ...validators.basic import valid_int_f1
+from ...validators.basic import valid_float_f0
+from ...validators.basic import valid_float_f01
+
+from ._mcu import BasePhyConnection
+from ._mcu import BasePhy
+from ._mcu import BaseMcuHid
+
+
+# =====
+class SpiPhyError(Exception):
+    pass
+
+
+class _SpiPhyConnection(BasePhyConnection):
+    def __init__(
+        self,
+        spi: spidev.SpiDev,
+        read_timeout: float,
+        read_delay: float,
+    ) -> None:
+
+        self.__spi = spi
+        self.__read_timeout = read_timeout
+        self.__read_delay = read_delay
+
+    def send(self, request: bytes, receive: int) -> bytes:
+        assert 0 < receive <= len(request)
+
+        dummy = b"\x00" * len(request)
+        deadline_ts = time.time() + self.__read_timeout
+        while time.time() < deadline_ts:
+            garbage = bytes(self.__spi.xfer(dummy))
+            if garbage == dummy:
+                break
+        else:
+            raise SpiPhyError("Timeout reached while reading a garbage")
+
+        self.__spi.xfer(request)
+
+        response: List[int] = []
+        dummy = b"\x00" * receive
+        deadline_ts = time.time() + self.__read_timeout
+        found = False
+        while time.time() < deadline_ts:
+            if not found:
+                time.sleep(self.__read_delay)
+            for byte in self.__spi.xfer(dummy):
+                if not found:
+                    if byte == 0:
+                        continue
+                    found = True
+                response.append(byte)
+                if len(response) >= receive:
+                    break
+            if len(response) >= receive:
+                break
+        else:
+            raise SpiPhyError("Timeout reached while responce waiting")
+
+        assert len(response) == receive
+        return bytes(response)
+
+
+class _SpiPhy(BasePhy):
+    def __init__(
+        self,
+        bus: int,
+        chip: int,
+        max_freq: int,
+        read_timeout: float,
+        read_delay: float,
+    ) -> None:
+
+        self.__bus = bus
+        self.__chip = chip
+        self.__max_freq = max_freq
+        self.__read_timeout = read_timeout
+        self.__read_delay = read_delay
+
+    def has_device(self) -> bool:
+        return os.path.exists(f"/dev/spidev{self.__bus}.{self.__chip}")
+
+    @contextlib.contextmanager
+    def connected(self) -> Generator[_SpiPhyConnection, None, None]:  # type: ignore
+        with contextlib.closing(spidev.SpiDev(self.__bus, self.__chip)) as spi:
+            spi.mode = 0
+            spi.max_speed_hz = self.__max_freq
+            yield _SpiPhyConnection(spi, self.__read_timeout, self.__read_delay)
+
+
+# =====
+class Plugin(BaseMcuHid):
+    def __init__(
+        self,
+        bus: int,
+        chip: int,
+        max_freq: int,
+        read_timeout: float,
+        read_delay: float,
+        **kwargs: Any,
+    ) -> None:
+
+        super().__init__(
+            phy=_SpiPhy(bus, chip, max_freq, read_timeout, read_delay),
+            **kwargs,
+        )
+
+    @classmethod
+    def get_plugin_options(cls) -> Dict:
+        return {
+            "bus":          Option(0,       type=valid_int_f0),
+            "chip":         Option(0,       type=valid_int_f0),
+            "max_freq":     Option(1000000, type=valid_int_f1),
+            "read_timeout": Option(2.0,     type=valid_float_f01),
+            "read_delay":   Option(0.001,   type=valid_float_f0),
+            **BaseMcuHid.get_plugin_options(),
+        }