[PATCH v3, 2/4] mtd: spi-nor: Add Octal SPI support to Cadence QSPI driver.

[Artur Jedrysek]

Recent versions of Cadence QSPI controller support Octal SPI transfers
as well. This patch updates existing driver to support such feature.

It is not possible to determine whether or not octal mode is supported
just by looking at revision register alone. To solve that, an additional
compatible in Device Tree is added to indicate such capability.
Both (revision and compatible) are used to determine, which mode to
pass to spi_nor_scan() call.

Signed-off-by: Artur Jedrysek <jartur@xxxxxxxxxxx>
---
Changelog:
v2: Use new compatible in DT, instead of boolean property, to indicate
Octal SPI support.
Extracted Kconfig update to seperate patch.
---
v3: Fixed handling revision register.
---
 drivers/mtd/spi-nor/cadence-quadspi.c | 56 ++++++++++++++++++++++++++++++-----
 1 file changed, 48 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 9f8102d..a1561d0 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -76,6 +76,7 @@ struct cqspi_st {
 	u32			fifo_depth;
 	u32			fifo_width;
 	u32			trigger_address;
+	u32			caps;
 	struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
 };
 
@@ -87,6 +88,9 @@ struct cqspi_st {
 #define CQSPI_INST_TYPE_SINGLE			0
 #define CQSPI_INST_TYPE_DUAL			1
 #define CQSPI_INST_TYPE_QUAD			2
+#define CQSPI_INST_TYPE_OCTAL			3
+
+#define CQSPI_FLAG_SUPPORTS_OCTAL		BIT(0)
 
 #define CQSPI_DUMMY_CLKS_PER_BYTE		8
 #define CQSPI_DUMMY_BYTES_MAX			4
@@ -204,6 +208,14 @@ struct cqspi_st {
 #define CQSPI_REG_CMDWRITEDATALOWER		0xA8
 #define CQSPI_REG_CMDWRITEDATAUPPER		0xAC
 
+#define CQSPI_REG_MODULEID			0xFC
+#define CQSPI_REG_MODULEID_CONF_ID_MASK		0x3
+#define CQSPI_REG_MODULEID_CONF_ID_LSB		0
+#define CQSPI_REG_MODULEID_CONF_ID_OCTAL_PHY	0x0
+#define CQSPI_REG_MODULEID_CONF_ID_OCTAL	0x1
+#define CQSPI_REG_MODULEID_CONF_ID_QUAD_PHY	0x2
+#define CQSPI_REG_MODULEID_CONF_ID_QUAD		0x3
+
 /* Interrupt status bits */
 #define CQSPI_REG_IRQ_MODE_ERR			BIT(0)
 #define CQSPI_REG_IRQ_UNDERFLOW			BIT(1)
@@ -866,6 +878,9 @@ static int cqspi_set_protocol(struct spi_nor *nor, const int read)
 		case SPI_NOR_QUAD:
 			f_pdata->data_width = CQSPI_INST_TYPE_QUAD;
 			break;
+		case SPI_NOR_OCTAL:
+			f_pdata->data_width = CQSPI_INST_TYPE_OCTAL;
+			break;
 		default:
 			return -EINVAL;
 		}
@@ -977,6 +992,17 @@ static int cqspi_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
 	return ret;
 }
 
+static struct of_device_id const cqspi_dt_ids[] = {
+	{ .compatible = "cdns,qspi-nor", .data = (void *)0 },
+	{
+		.compatible = "cdns,ospi-nor",
+		.data = (void *)CQSPI_FLAG_SUPPORTS_OCTAL
+	},
+	{ /* end of table */ }
+};
+
+MODULE_DEVICE_TABLE(of, cqspi_dt_ids);
+
 static int cqspi_of_get_flash_pdata(struct platform_device *pdev,
 				    struct cqspi_flash_pdata *f_pdata,
 				    struct device_node *np)
@@ -1018,6 +1044,12 @@ static int cqspi_of_get_pdata(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct cqspi_st *cqspi = platform_get_drvdata(pdev);
+	const struct of_device_id *match;
+
+	match = of_match_node(cqspi_dt_ids, np);
+	if (match && match->data)
+		cqspi->caps |= (unsigned long)match->data &
+				CQSPI_FLAG_SUPPORTS_OCTAL;
 
 	cqspi->is_decoded_cs = of_property_read_bool(np, "cdns,is-decoded-cs");
 
@@ -1074,9 +1106,23 @@ static int cqspi_setup_flash(struct cqspi_st *cqspi, struct device_node *np)
 	struct cqspi_flash_pdata *f_pdata;
 	struct spi_nor *nor;
 	struct mtd_info *mtd;
+	enum read_mode mode = SPI_NOR_QUAD;
 	unsigned int cs;
+	unsigned int rev_reg;
 	int i, ret;
 
+	if (cqspi->caps & CQSPI_FLAG_SUPPORTS_OCTAL) {
+		/* Determine, whether or not octal transfer MAY be supported */
+		rev_reg = readl(cqspi->iobase + CQSPI_REG_MODULEID);
+		dev_info(dev, "CQSPI Module id %x\n", rev_reg);
+
+		switch (rev_reg & CQSPI_REG_MODULEID_CONF_ID_MASK) {
+		case CQSPI_REG_MODULEID_CONF_ID_OCTAL_PHY:
+		case CQSPI_REG_MODULEID_CONF_ID_OCTAL:
+			mode = SPI_NOR_OCTAL;
+		}
+	}
+
 	/* Get flash device data */
 	for_each_available_child_of_node(dev->of_node, np) {
 		ret = of_property_read_u32(np, "reg", &cs);
@@ -1123,7 +1169,7 @@ static int cqspi_setup_flash(struct cqspi_st *cqspi, struct device_node *np)
 			goto err;
 		}
 
-		ret = spi_nor_scan(nor, NULL, SPI_NOR_QUAD);
+		ret = spi_nor_scan(nor, NULL, mode);
 		if (ret)
 			goto err;
 
@@ -1160,6 +1206,7 @@ static int cqspi_probe(struct platform_device *pdev)
 	mutex_init(&cqspi->bus_mutex);
 	cqspi->pdev = pdev;
 	platform_set_drvdata(pdev, cqspi);
+	cqspi->caps = 0;
 
 	/* Obtain configuration from OF. */
 	ret = cqspi_of_get_pdata(pdev);
@@ -1277,13 +1324,6 @@ static const struct dev_pm_ops cqspi__dev_pm_ops = {
 #define CQSPI_DEV_PM_OPS	NULL
 #endif
 
-static struct of_device_id const cqspi_dt_ids[] = {
-	{.compatible = "cdns,qspi-nor",},
-	{ /* end of table */ }
-};
-
-MODULE_DEVICE_TABLE(of, cqspi_dt_ids);
-
 static struct platform_driver cqspi_platform_driver = {
 	.probe = cqspi_probe,
 	.remove = cqspi_remove,
-- 
2.2.2