Hi, On 30/12/19 1:11 pm, Ramuthevar,Vadivel MuruganX wrote: [...] > +static u32 cqspi_cmd2addr(const unsigned char *addr_buf, u32 addr_width) > +{ > + unsigned int addr = 0; > + int i; > + > + /* Invalid address return zero. */ > + if (addr_width > 4) > + return 0; > + > + for (i = 0; i < addr_width; i++) { > + addr = addr << 8; > + addr |= addr_buf[i]; > + } > + > + return addr; > +} > + [...] > +static int cqspi_apb_read_setup(struct struct_cqspi *cqspi, > + const struct spi_mem_op *op, > + const u8 *addrbuf) > +{ > + void __iomem *reg_base = cqspi->iobase; > + size_t addrlen = op->addr.nbytes; > + size_t dummy_bytes = op->dummy.nbytes; > + unsigned int addr_value, dummy_clk, reg; > + > + if (addrlen) { > + addr_value = cqspi_cmd2addr(&addrbuf[0], addrlen); > + writel(addr_value, reg_base + CQSPI_REG_INDIRECTRDSTARTADDR); > + } > + Why do you need to swap the address bytes to SPI bus order? You are writing to a controller register that accepts 24 bit or 32 bit address. > + reg = op->cmd.opcode << CQSPI_REG_RD_INSTR_OPCODE_LSB; > + reg |= (op->data.buswidth & CQSPI_REG_RD_INSTR_TYPE_DATA_MASK) << > + CQSPI_REG_RD_INSTR_TYPE_DATA_LSB; > + This is wrong... op->data.buswidth's range is 1 to 8 whereas CQSPI_REG_RD_INSTR_TYPE range is 0 to 3. I wonder whether you tested dual/quad mode with this driver? I am still unable to get this series to work on my platform. Will continue to debug... -- Regards Vignesh