soc: samsung: exynos-pmu: update to use of_syscon_register_regmap()

For SoCs like gs101 that need a special regmap, register this with
of_syscon_register_regmap api, so it can be returned by
syscon_regmap_lookup_by_phandle() and friends.

For SoCs that don't require a custom regmap, revert back to syscon
creating the mmio regmap rather than duplicating the logic here.

exynos_get_pmu_regmap_by_phandle() api is also updated to retrieve
the regmap via syscon. The exynos_get_pmu_regmap_by_phandle() api
is kept around until fw_devlink support for syscon property is added
for the pinctrl-samsung driver that also runs at postcore_initcall
level.

All other exynos client drivers can revert back to
syscon_regmap_lookup_by_phandle().
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Tested-by: Will McVicker <willmcvicker@google.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240621115544.1655458-3-peter.griffin@linaro.orgSigned-off-by: Lee Jones <lee@kernel.org>

drivers/soc/samsung/exynos-pmu.c

@@ -204,16 +204,6 @@ static const struct regmap_config regmap_smccfg = {
 	.reg_update_bits = tensor_sec_update_bits,
 };
 
-static const struct regmap_config regmap_mmiocfg = {
-	.name = "pmu_regs",
-	.reg_bits = 32,
-	.reg_stride = 4,
-	.val_bits = 32,
-	.fast_io = true,
-	.use_single_read = true,
-	.use_single_write = true,
-};
-
 static const struct exynos_pmu_data gs101_pmu_data = {
 	.pmu_secure = true
 };
@@ -290,7 +280,6 @@ EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap);
 struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np,
 						const char *propname)
 {
-	struct exynos_pmu_context *ctx;
 	struct device_node *pmu_np;
 	struct device *dev;
 
@@ -316,9 +305,7 @@ struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np,
 	if (!dev)
 		return ERR_PTR(-EPROBE_DEFER);
 
-	ctx = dev_get_drvdata(dev);
-
-	return ctx->pmureg;
+	return syscon_node_to_regmap(pmu_np);
 }
 EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap_by_phandle);
 
@@ -355,19 +342,22 @@ static int exynos_pmu_probe(struct platform_device *pdev)
 		regmap = devm_regmap_init(dev, NULL,
 					  (void *)(uintptr_t)res->start,
 					  &pmu_regmcfg);
-	} else {
-		/* All other SoCs use a MMIO regmap */
-		pmu_regmcfg = regmap_mmiocfg;
-		pmu_regmcfg.max_register = resource_size(res) -
-					   pmu_regmcfg.reg_stride;
-		regmap = devm_regmap_init_mmio(dev, pmu_base_addr,
-					       &pmu_regmcfg);
-	}
 
 		if (IS_ERR(regmap))
 			return dev_err_probe(&pdev->dev, PTR_ERR(regmap),
 					     "regmap init failed\n");
 
+		ret = of_syscon_register_regmap(dev->of_node, regmap);
+		if (ret)
+			return ret;
+	} else {
+		/* let syscon create mmio regmap */
+		regmap = syscon_node_to_regmap(dev->of_node);
+		if (IS_ERR(regmap))
+			return dev_err_probe(&pdev->dev, PTR_ERR(regmap),
+					     "syscon_node_to_regmap failed\n");
+	}
+
 	pmu_context->pmureg = regmap;
 	pmu_context->dev = dev;