soc: samsung: exynos-chipid: add google,gs101-otp support

GS101 is different (but also e850 and autov9 I assume) from the SoCs
that are currently handled by the exynos-chipid driver because the
chip ID info is part of the OTP registers. GS101 OTP has a clock, an
interrupt line, a register space (that contains product and chip ID,
TMU data, ASV, etc) and a 32Kbit memory space that can be
read/program/locked with specific commands. On GS101 the "ChipID block"
is just an abstraction, it's not a physical device. When the power-on
sequence progresses, the OTP chipid values are loaded to the OTP
registers.

Add the GS101 chip ID support. The support is intentionally added in the
exynos-chipid driver, and not in a dedicated Exynos OTP driver, because
we estimate that there will not be any OTP consumers in the kernel other
than the chip ID/SoC interface. The downstream GS101 drivers confirm
this supposition.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20251222-gs101-chipid-v4-4-aa8e20ce7bb3@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

Author: ambarus

drivers/soc/samsung/exynos-chipid.c

@@ -15,7 +15,8 @@
 #include <linux/array_size.h>
 #include <linux/device.h>
 #include <linux/device/devres.h>
-#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/ioport.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -28,9 +29,11 @@
 #include "exynos-asv.h"
 
 struct exynos_chipid_variant {
-	unsigned int rev_reg;		/* revision register offset */
+	unsigned int main_rev_reg;	/* main revision register offset */
+	unsigned int sub_rev_reg;	/* sub revision register offset */
 	unsigned int main_rev_shift;	/* main revision offset in rev_reg */
 	unsigned int sub_rev_shift;	/* sub revision offset in rev_reg */
+	bool efuse;
 };
 
 struct exynos_chipid_info {
@@ -69,6 +72,8 @@ static const struct exynos_soc_id {
 	{ "EXYNOS990", 0xE9830000 },
 	{ "EXYNOSAUTOV9", 0xAAA80000 },
 	{ "EXYNOSAUTOV920", 0x0A920000 },
+	/* Compatible with: google,gs101-otp */
+	{ "GS101", 0x9845000 },
 };
 
 static const char *exynos_product_id_to_name(unsigned int product_id)
@@ -93,19 +98,53 @@ static int exynos_chipid_get_chipid_info(struct device *dev,
 		return dev_err_probe(dev, ret, "failed to read Product ID\n");
 	soc_info->product_id = val & EXYNOS_MASK;
 
-	if (data->rev_reg != EXYNOS_CHIPID_REG_PRO_ID) {
-		ret = regmap_read(regmap, data->rev_reg, &val);
+	if (data->sub_rev_reg == EXYNOS_CHIPID_REG_PRO_ID) {
+		/* exynos4210 case */
+		main_rev = (val >> data->main_rev_shift) & EXYNOS_REV_PART_MASK;
+		sub_rev = (val >> data->sub_rev_shift) & EXYNOS_REV_PART_MASK;
+	} else {
+		unsigned int val2;
+
+		ret = regmap_read(regmap, data->sub_rev_reg, &val2);
 		if (ret < 0)
 			return dev_err_probe(dev, ret,
 					     "failed to read revision\n");
+
+		if (data->main_rev_reg == EXYNOS_CHIPID_REG_PRO_ID)
+			/* gs101 case */
+			main_rev = (val >> data->main_rev_shift) & EXYNOS_REV_PART_MASK;
+		else
+			/* exynos850 case */
+			main_rev = (val2 >> data->main_rev_shift) & EXYNOS_REV_PART_MASK;
+
+		sub_rev = (val2 >> data->sub_rev_shift) & EXYNOS_REV_PART_MASK;
 	}
-	main_rev = (val >> data->main_rev_shift) & EXYNOS_REV_PART_MASK;
-	sub_rev = (val >> data->sub_rev_shift) & EXYNOS_REV_PART_MASK;
+
 	soc_info->revision = (main_rev << EXYNOS_REV_PART_SHIFT) | sub_rev;
 
 	return 0;
 }
 
+static struct regmap *exynos_chipid_get_efuse_regmap(struct platform_device *pdev)
+{
+	struct resource *res;
+	void __iomem *base;
+
+	base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(base))
+		return ERR_CAST(base);
+
+	const struct regmap_config reg_config = {
+		.reg_bits = 32,
+		.reg_stride = 4,
+		.val_bits = 32,
+		.use_relaxed_mmio = true,
+		.max_register = (resource_size(res) - reg_config.reg_stride),
+	};
+
+	return devm_regmap_init_mmio_clk(&pdev->dev, "pclk", base, &reg_config);
+}
+
 static void exynos_chipid_unregister_soc(void *data)
 {
 	soc_device_unregister(data);
@@ -127,7 +166,11 @@ static int exynos_chipid_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, -EINVAL,
 				     "failed to get match data\n");
 
-	regmap = device_node_to_regmap(dev->of_node);
+	if (drv_data->efuse)
+		regmap = exynos_chipid_get_efuse_regmap(pdev);
+	else
+		regmap = device_node_to_regmap(dev->of_node);
+
 	if (IS_ERR(regmap))
 		return dev_err_probe(dev, PTR_ERR(regmap),
 				     "failed to get regmap\n");
@@ -177,19 +220,28 @@ static int exynos_chipid_probe(struct platform_device *pdev)
 }
 
 static const struct exynos_chipid_variant exynos4210_chipid_drv_data = {
-	.rev_reg	= 0x0,
 	.main_rev_shift	= 4,
 	.sub_rev_shift	= 0,
 };
 
 static const struct exynos_chipid_variant exynos850_chipid_drv_data = {
-	.rev_reg	= 0x10,
+	.main_rev_reg	= 0x10,
+	.sub_rev_reg	= 0x10,
 	.main_rev_shift	= 20,
 	.sub_rev_shift	= 16,
 };
 
+static const struct exynos_chipid_variant gs101_chipid_drv_data = {
+	.sub_rev_reg	= 0x10,
+	.sub_rev_shift	= 16,
+	.efuse = true,
+};
+
 static const struct of_device_id exynos_chipid_of_device_ids[] = {
 	{
+		.compatible	= "google,gs101-otp",
+		.data		= &gs101_chipid_drv_data,
+	}, {
 		.compatible	= "samsung,exynos4210-chipid",
 		.data		= &exynos4210_chipid_drv_data,
 	}, {