spi_slave_hd_read_buffer() function
Read the shared registers
Arguments
host_id
Host to read the shared registers
addr
Address of register to read, 0 to ``SOC_SPI_MAXIMUM_BUFFER_SIZE-1``
out_data
Output buffer to store the read data
len
Length to read, not larger than ``SOC_SPI_MAXIMUM_BUFFER_SIZE-addr``