spi: cadence-quadspi: Disable the DAC for Intel LGM SoC

On Intel Lightning Mountain(LGM) SoCs QSPI controller do not use
Direct Access Controller(DAC).

This patch adds a quirk to disable the Direct Access Controller
for data transfer instead it uses indirect data transfe

DAC bit resets to 1 so there is no need to explicitly set it.

Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
Link: https://lore.kernel.org/r/20201124041840.31066-3-vadivel.muruganx.ramuthevar@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-cadence-quadspi.c

@@ -1384,10 +1384,12 @@ static void cqspi_controller_init(struct cqspi_st *cqspi)
 	writel(cqspi->fifo_depth * cqspi->fifo_width / 8,
 	       cqspi->iobase + CQSPI_REG_INDIRECTWRWATERMARK);
 
-	/* Enable Direct Access Controller */
-	reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
-	reg |= CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
-	writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
+	/* Disable direct access controller */
+	if (!cqspi->use_direct_mode) {
+		reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
+		reg &= ~CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
+		writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
+	}
 
 	cqspi_controller_enable(cqspi, 1);
 }
@@ -1675,6 +1677,10 @@ static const struct cqspi_driver_platdata am654_ospi = {
 	.quirks = CQSPI_NEEDS_WR_DELAY,
 };
 
+static const struct cqspi_driver_platdata intel_lgm_qspi = {
+	.quirks = CQSPI_DISABLE_DAC_MODE,
+};
+
 static const struct of_device_id cqspi_dt_ids[] = {
 	{
 		.compatible = "cdns,qspi-nor",
@@ -1690,6 +1696,7 @@ static const struct of_device_id cqspi_dt_ids[] = {
 	},
 	{
 		.compatible = "intel,lgm-qspi",
+		.data = &intel_lgm_qspi,
 	},
 	{ /* end of table */ }
 };