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>

diff --git a/drivers/soc/samsung/exynos-chipid.c b/drivers/soc/samsung/exynos-chipid.c
index 5c8660374269c87ec38ebca242918bd7b1d362e5..6ef9751e2509c94bd9625072d0b81ddb93048d4a 100644 (file)
--- a/drivers/soc/samsung/exynos-chipid.c
+++ b/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,
        }, {