spi: cadence-quadspi: setup ADDR Bits in cmd reads

Setup the Addr bit field while issuing register reads in STIG mode. This
is needed for example flashes like cypress define in their transaction
table that to read any register there is 1 cmd byte and a few more address
bytes trailing the cmd byte. Absence of addr bytes will obviously fail
to read correct data from flash register that maybe requested by flash
driver because the controller doesn't even specify which address of the
flash register the read is being requested from.

Signed-off-by: Dhruva Gole <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: DhruvaG2000

drivers/spi/spi-cadence-quadspi.c

@@ -532,6 +532,17 @@ static int cqspi_command_read(struct cqspi_flash_pdata *f_pdata,
 	/* 0 means 1 byte. */
 	reg |= (((n_rx - 1) & CQSPI_REG_CMDCTRL_RD_BYTES_MASK)
 		<< CQSPI_REG_CMDCTRL_RD_BYTES_LSB);
+
+	/* setup ADDR BIT field */
+	if (op->addr.nbytes) {
+		reg |= (0x1 << CQSPI_REG_CMDCTRL_ADDR_EN_LSB);
+		reg |= ((op->addr.nbytes - 1) &
+			CQSPI_REG_CMDCTRL_ADD_BYTES_MASK)
+			<< CQSPI_REG_CMDCTRL_ADD_BYTES_LSB;
+
+		writel(op->addr.val, reg_base + CQSPI_REG_CMDADDRESS);
+	}
+
 	status = cqspi_exec_flash_cmd(cqspi, reg);
 	if (status)
 		return status;