[PATCH 3/3] soc: ti: Add TDA54 SCM configuration syscon support

[Moteen Shah <m-shah@ti.com>]

Add the TDA54 SCM configuration driver providing access to the SCM register
space through regmap/syscon.

The driver handles proxy-based register access and SCM unlock/claim
handling, and registers TDA54 SoC information using the common K3 SoC
info helper exported by k3-socinfo, for which the TDA54 part number is
added to the SoC ID table.

Default the option to m on ARCH_K3, so that the driver gets built for TDA54
boards without requiring a defconfig change.

Signed-off-by: Moteen Shah <m-shah@ti.com>
Signed-off-by: Aniket Limaye <a-limaye@ti.com>
---
 drivers/soc/ti/Kconfig             |  16 +++
 drivers/soc/ti/Makefile            |   1 +
 drivers/soc/ti/k3-socinfo.c        |   2 +
 drivers/soc/ti/tda54-mcu-sysconf.c | 216 +++++++++++++++++++++++++++++
 4 files changed, 235 insertions(+)
 create mode 100644 drivers/soc/ti/tda54-mcu-sysconf.c

diff --git a/drivers/soc/ti/Kconfig b/drivers/soc/ti/Kconfig
index 163aadd589d3a..ea5da6722da29 100644
--- a/drivers/soc/ti/Kconfig
+++ b/drivers/soc/ti/Kconfig
@@ -82,6 +82,22 @@ config TI_PRUSS
 	  processors on various TI SoCs. It's safe to say N here if you're
 	  not interested in the PRU or if you are unsure.
 
+config TI_TDA54_MCU_SYSCONF
+	tristate "TI TDA54 SCM configuration controller"
+	depends on ARCH_K3 || COMPILE_TEST
+	depends on OF
+	default m if ARCH_K3
+	select MFD_SYSCON
+	select TI_K3_SOCINFO
+	help
+	  Support the SCM configuration controller found on TI TDA54.
+	  The controller provides a syscon regmap and is also the
+	  hardware access path used to obtain and register K3 SoC
+	  identification information.
+
+	  This driver can be built as a module, in which case the module
+	  will be called tda54-mcu-sysconf.
+
 endif # SOC_TI
 
 config TI_SCI_INTA_MSI_DOMAIN
diff --git a/drivers/soc/ti/Makefile b/drivers/soc/ti/Makefile
index cb800a745e66d..33f4ddca32ed6 100644
--- a/drivers/soc/ti/Makefile
+++ b/drivers/soc/ti/Makefile
@@ -11,4 +11,5 @@ obj-$(CONFIG_TI_SCI_INTA_MSI_DOMAIN)	+= ti_sci_inta_msi.o
 obj-$(CONFIG_TI_K3_RINGACC)		+= k3-ringacc.o
 obj-$(CONFIG_TI_K3_SOCINFO)		+= k3-socinfo.o
 obj-$(CONFIG_TI_PRUSS)			+= pruss.o
+obj-$(CONFIG_TI_TDA54_MCU_SYSCONF)	+= tda54-mcu-sysconf.o
 obj-$(CONFIG_POWER_AVS_OMAP)		+= smartreflex.o
diff --git a/drivers/soc/ti/k3-socinfo.c b/drivers/soc/ti/k3-socinfo.c
index 5fae03004e350..9869dd6358d1f 100644
--- a/drivers/soc/ti/k3-socinfo.c
+++ b/drivers/soc/ti/k3-socinfo.c
@@ -50,6 +50,7 @@
 #define JTAG_ID_PARTNO_AM62PX		0xBB9D
 #define JTAG_ID_PARTNO_J722S		0xBBA0
 #define JTAG_ID_PARTNO_AM62LX		0xBBA7
+#define JTAG_ID_PARTNO_TDA54		0xBBC1
 
 static const struct k3_soc_id {
 	unsigned int id;
@@ -66,6 +67,7 @@ static const struct k3_soc_id {
 	{ JTAG_ID_PARTNO_AM62PX, "AM62PX" },
 	{ JTAG_ID_PARTNO_J722S, "J722S" },
 	{ JTAG_ID_PARTNO_AM62LX, "AM62LX" },
+	{ JTAG_ID_PARTNO_TDA54, "TDA54" },
 };
 
 static const char * const j721e_rev_string_map[] = {
diff --git a/drivers/soc/ti/tda54-mcu-sysconf.c b/drivers/soc/ti/tda54-mcu-sysconf.c
new file mode 100644
index 0000000000000..8598080f6c48e
--- /dev/null
+++ b/drivers/soc/ti/tda54-mcu-sysconf.c
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * TDA54 SCM Configuration syscon driver
+ *
+ * Copyright (C) 2026 Texas Instruments Incorporated - https://www.ti.com/
+ */
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/soc/ti/k3-socinfo.h>
+#include <linux/types.h>
+
+/* Size of a single proxy window into the scm_conf register space */
+#define TDA54_SCM_CONF_PROXY_STRIDE		0x4000
+
+#define TDA54_JTAG_ID_REG_OFFSET		0x14
+
+#define TDA54_SCM_CONF_LOCK_KICK0_UNLOCK_VAL	0x68EF3490
+#define TDA54_SCM_CONF_LOCK_KICK1_UNLOCK_VAL	0xD172BC5A
+
+/*
+ * Claim registers start at 0x3100. Claim register i holds the claim bit
+ * for each of the 32 registers in the (i * TDA54_SCM_CONF_CLAIM_BLOCK_SIZE)
+ * .. (i * TDA54_SCM_CONF_CLAIM_BLOCK_SIZE + 0x7c) block, one bit per
+ * register, i.e. bit b of claim register i corresponds to the register at
+ * offset i * TDA54_SCM_CONF_CLAIM_BLOCK_SIZE + b * 4.
+ */
+#define TDA54_SCM_CONF_CLAIM_REG_STRIDE		0x4
+#define TDA54_SCM_CONF_CLAIM_REGS_PER_WORD	32
+#define TDA54_SCM_CONF_CLAIM_BLOCK_SIZE		\
+	(TDA54_SCM_CONF_CLAIM_REGS_PER_WORD * 0x4)
+
+/* Per-SoC register offset data (platform data) */
+struct tda54_scm_conf_data {
+	u32 lock_offset;
+	u32 claim_offset;
+	u32 claim_status_offset;
+};
+
+static const struct tda54_scm_conf_data tda54_scm_conf_data = {
+	.lock_offset		= 0x3008,
+	.claim_offset		= 0x3100,
+	.claim_status_offset	= 0x3300,
+};
+
+struct tda54_scm_conf {
+	void __iomem *base;
+	u32 proxy;
+	const struct tda54_scm_conf_data *pdata;
+};
+
+/*
+ * Make @reg writable through this proxy.
+ *
+ * Proxy 0 is the default access proxy for all unclaimed registers. Its claim
+ * bits are tied low, so it cannot claim anything and needs no claim to write;
+ * it can write @reg unless another proxy has claimed it, which is reported by
+ * the claim status.
+ *
+ * Any other proxy has to claim @reg first. Registers claimed by a proxy can no
+ * longer be written through any other proxy's address, until that proxy
+ * releases the claim. The claim status is set once any proxy owns @reg, so
+ * read the claim register back to check that the claim is held by this proxy.
+ */
+static int tda54_scm_conf_claim(struct tda54_scm_conf *scm, unsigned int reg)
+{
+	unsigned int block = reg / TDA54_SCM_CONF_CLAIM_BLOCK_SIZE;
+	unsigned int bit = (reg % TDA54_SCM_CONF_CLAIM_BLOCK_SIZE) /
+			   TDA54_SCM_CONF_CLAIM_REG_STRIDE;
+	unsigned int claim_reg = scm->pdata->claim_offset +
+				 block * TDA54_SCM_CONF_CLAIM_REG_STRIDE;
+	unsigned int status_reg = scm->pdata->claim_status_offset +
+				  block * TDA54_SCM_CONF_CLAIM_REG_STRIDE;
+	u32 val;
+
+	if (!scm->proxy) {
+		if (readl(scm->base + status_reg) & BIT(bit))
+			return -EBUSY;
+
+		return 0;
+	}
+
+	val = readl(scm->base + claim_reg);
+	val |= BIT(bit);
+	writel(val, scm->base + claim_reg);
+
+	if (!(readl(scm->base + claim_reg) & BIT(bit)))
+		return -EBUSY;
+
+	return 0;
+}
+
+static int tda54_scm_conf_reg_read(void *context, unsigned int reg,
+				   unsigned int *val)
+{
+	struct tda54_scm_conf *scm = context;
+
+	*val = readl(scm->base + reg);
+
+	return 0;
+}
+
+static int tda54_scm_conf_reg_write(void *context, unsigned int reg,
+				    unsigned int val)
+{
+	struct tda54_scm_conf *scm = context;
+	int ret;
+
+	ret = tda54_scm_conf_claim(scm, reg);
+	if (ret)
+		return ret;
+
+	writel(val, scm->base + reg);
+
+	return 0;
+}
+
+static const struct regmap_config tda54_scm_conf_regmap_cfg = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.reg_read = tda54_scm_conf_reg_read,
+	.reg_write = tda54_scm_conf_reg_write,
+};
+
+static int tda54_scm_conf_register_socinfo(struct device *dev,
+					   struct regmap *regmap)
+{
+	u32 jtag_id;
+	int ret;
+
+	ret = regmap_read(regmap, TDA54_JTAG_ID_REG_OFFSET, &jtag_id);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to read JTAG ID\n");
+
+	return k3_socinfo_register(dev, jtag_id);
+}
+
+static int tda54_scm_conf_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct tda54_scm_conf *scm;
+	struct regmap *regmap;
+	void __iomem *base;
+	int ret;
+
+	scm = devm_kzalloc(dev, sizeof(*scm), GFP_KERNEL);
+	if (!scm)
+		return -ENOMEM;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	if (of_property_read_u32(dev->of_node, "ti,proxy-id", &scm->proxy))
+		return dev_err_probe(dev, -ENODATA, "missing ti,proxy-id property\n");
+
+	if (scm->proxy >= 8)
+		return dev_err_probe(dev, -EINVAL,
+				     "ti,proxy-id must be between 0 and 7\n");
+
+	scm->base = base + scm->proxy * TDA54_SCM_CONF_PROXY_STRIDE;
+
+	/* Get register offsets from driver data (matched by compatible) */
+	scm->pdata = of_device_get_match_data(dev);
+
+	regmap = devm_regmap_init(dev, NULL, scm, &tda54_scm_conf_regmap_cfg);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	writel(TDA54_SCM_CONF_LOCK_KICK0_UNLOCK_VAL, scm->base + scm->pdata->lock_offset);
+	writel(TDA54_SCM_CONF_LOCK_KICK1_UNLOCK_VAL, scm->base + scm->pdata->lock_offset + 4);
+
+	/*
+	 * There is no way to unregister a syscon regmap, so publish it only
+	 * once nothing else in probe can fail.
+	 */
+	ret = of_syscon_register_regmap(dev->of_node, regmap);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to register syscon regmap\n");
+
+	/*
+	 * SoC identification is informational, so a failure here must not fail
+	 * the probe. It is registered last and released through devres.
+	 */
+	ret = tda54_scm_conf_register_socinfo(dev, regmap);
+	if (ret)
+		dev_warn(dev, "SoC info not registered: %d\n", ret);
+
+	return 0;
+}
+
+static const struct of_device_id tda54_scm_conf_of_match[] = {
+	{ .compatible = "ti,tda54-mcu-scm-conf", .data = &tda54_scm_conf_data },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, tda54_scm_conf_of_match);
+
+static struct platform_driver tda54_scm_conf_driver = {
+	.probe = tda54_scm_conf_probe,
+	.driver = {
+		.name = "k3-tda54-scm-conf",
+		.of_match_table = tda54_scm_conf_of_match,
+		.suppress_bind_attrs = true,
+	},
+};
+
+module_platform_driver(tda54_scm_conf_driver);
+
+MODULE_AUTHOR("Moteen Shah <m-shah@ti.com>");
+MODULE_DESCRIPTION("TDA54 SCM Configuration syscon driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1