[PATCH v3 2/2] soc: ti: k3-socinfo: Add support for AM62P variants via NVMEM

[Judith Mendez <jm@ti.com>]

Add support for detecting AM62P silicon revisions.

On AM62P, silicon revision is discovered with GP_SW1 register instead
of JTAGID register. Use the NVMEM framework to read GP_SW1 from the
gpsw-efuse nvmem provider to determine SoC revision.

Signed-off-by: Judith Mendez <jm@ti.com>
Reviewed-by: Andrew Davis <afd@ti.com>
---
Changes since v2:
- Switch k3_chipinfo_variant_to_sr() parameter from pdev to dev for
  consistency
---
 drivers/soc/ti/k3-socinfo.c | 41 ++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/drivers/soc/ti/k3-socinfo.c b/drivers/soc/ti/k3-socinfo.c
index 42275cb5ba1c8..3a35fc456e544 100644
--- a/drivers/soc/ti/k3-socinfo.c
+++ b/drivers/soc/ti/k3-socinfo.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/mfd/syscon.h>
+#include <linux/nvmem-consumer.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/regmap.h>
@@ -25,6 +26,8 @@
 #define CTRLMMR_WKUP_JTAGID_VARIANT_SHIFT	(28)
 #define CTRLMMR_WKUP_JTAGID_VARIANT_MASK	GENMASK(31, 28)
 
+#define GP_SW1_ADR_MASK			GENMASK(3, 0)
+
 #define CTRLMMR_WKUP_JTAGID_PARTNO_SHIFT	(12)
 #define CTRLMMR_WKUP_JTAGID_PARTNO_MASK		GENMASK(27, 12)
 
@@ -70,6 +73,23 @@ static const char * const am62lx_rev_string_map[] = {
 	"1.0", "1.1",
 };
 
+static const char * const am62p_gpsw_rev_string_map[] = {
+	"1.0", "1.1", "1.2",
+};
+
+static int
+k3_chipinfo_get_gpsw_variant(struct device *dev)
+{
+	u32 gpsw_val = 0;
+	int ret;
+
+	ret = nvmem_cell_read_u32(dev, "gpsw1", &gpsw_val);
+	if (ret)
+		return ret;
+
+	return gpsw_val & GP_SW1_ADR_MASK;
+}
+
 static int
 k3_chipinfo_partno_to_names(unsigned int partno,
 			    struct soc_device_attribute *soc_dev_attr)
@@ -86,9 +106,11 @@ k3_chipinfo_partno_to_names(unsigned int partno,
 }
 
 static int
-k3_chipinfo_variant_to_sr(unsigned int partno, unsigned int variant,
-			  struct soc_device_attribute *soc_dev_attr)
+k3_chipinfo_variant_to_sr(struct device *dev, unsigned int partno,
+			  unsigned int variant, struct soc_device_attribute *soc_dev_attr)
 {
+	int gpsw_variant = 0;
+
 	switch (partno) {
 	case JTAG_ID_PARTNO_J721E:
 		if (variant >= ARRAY_SIZE(j721e_rev_string_map))
@@ -102,6 +124,19 @@ k3_chipinfo_variant_to_sr(unsigned int partno, unsigned int variant,
 		soc_dev_attr->revision = kasprintf(GFP_KERNEL, "SR%s",
 						   am62lx_rev_string_map[variant]);
 		break;
+	case JTAG_ID_PARTNO_AM62PX:
+		/* Check GP_SW1 for silicon revision */
+		gpsw_variant = k3_chipinfo_get_gpsw_variant(dev);
+		if (gpsw_variant == -EPROBE_DEFER)
+			return gpsw_variant;
+		if (gpsw_variant < 0 || gpsw_variant >= ARRAY_SIZE(am62p_gpsw_rev_string_map)) {
+			dev_warn(dev, "Failed to get silicon variant (%d), set SR1.0\n",
+				 gpsw_variant);
+			gpsw_variant = 0;
+		}
+		soc_dev_attr->revision = kasprintf(GFP_KERNEL, "SR%s",
+						   am62p_gpsw_rev_string_map[gpsw_variant]);
+		break;
 	default:
 		variant++;
 		soc_dev_attr->revision = kasprintf(GFP_KERNEL, "SR%x.0",
@@ -173,7 +208,7 @@ static int k3_chipinfo_probe(struct platform_device *pdev)
 		goto err;
 	}
 
-	ret = k3_chipinfo_variant_to_sr(partno_id, variant, soc_dev_attr);
+	ret = k3_chipinfo_variant_to_sr(dev, partno_id, variant, soc_dev_attr);
 	if (ret) {
 		dev_err(dev, "Unknown SoC SR[0x%08X]: %d\n", jtag_id, ret);
 		goto err;
-- 
2.52.0