Source code for ska_low_sps_tpm_api.base.spi

import xml.etree.ElementTree as eTree

from ska_low_sps_tpm_api import LibraryError, SPIDeviceInfo




class SPI:
    """A class which handles information on SPI devices"""



    def __init__(self, xml_string):
        """
        class constructor.

        :param xml_string: XML string containing SPI device information
        """

        # SPI device list
        self.spi_map = {}

        # SPI selection
        self.spi_address = None
        self.spi_address_mask = None
        self.write_data = None
        self.write_data_mask = None
        self.read_data = None
        self.read_data_mask = None
        self.chip_select = None
        self.chip_select_mask = None
        self.sclk = None
        self.sclk_mask = None
        self.cmd_address = None
        self.cmd_start_mask = None
        self.cmd_rnw_mask = None

        # Process xml string
        self._process_xml_string(xml_string)




    def clear(self):
        """Clear SPI map"""
        self.spi_map = {}


    def _process_xml_string(self, xml_string):
        """
        Process xml string containing SPI device information.

        :param xml_string: XML string containing SPI device information
        """

        # Parse string and get root
        tree = eTree.fromstring(xml_string)

        self.clear()

        # Iterate through all child node to get SPI devices
        for device_node in tree:
            # Get device information
            try:
                device_id = device_node.attrib["id"]
                device = SPIDeviceInfo(
                    name=device_id,
                    spi_en=int(device_node.attrib["spi_en"]),
                    spi_sclk=int(device_node.attrib["spi_sclk"]),
                )

                self.spi_map[device_id] = device
            except:
                raise LibraryError("Missing information in SPI file")



    def has_device(self, device):
        """
        Check if spi map contains specified device.

        :param device: Device to check
        """
        return device in list(self.spi_map.keys())


    def __getitem__(self, key):
        """Override __getitem__, return SPI device information for specified register"""
        # If no spi map exists, return None
        if len(self.spi_map) == 0:
            raise LibraryError("Cannot get device from uninitialised SPI map")

        if key not in list(self.spi_map.keys()):
            raise LibraryError("Specified SPI device {}, does not exist in SPI map")

        # Register found, return information
        return self.spi_map[key]

    def __len__(self):
        return len(self.spi_map)