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From:   Marek Szyprowski <m.szyprowski@samsung.com>
To:     linux-samsung-soc@vger.kernel.org
Cc:     Marek Szyprowski <m.szyprowski@samsung.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Saravana Kannan <saravanak@google.com>,
        linux-kernel@vger.kernel.org,
        "Rafael J . Wysocki" <rafael@kernel.org>
Subject: [PATCH] soc: samsung: pm_domains: Convert to regular platform
 driver
Date:   Wed, 13 Jan 2021 12:03:20 +0100
Message-Id: <20210113110320.13149-1-m.szyprowski@samsung.com>
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 201P
References: <CGME20210113110330eucas1p1e7efa719b5db55ccf3774450a8c1e452@eucas1p1.samsung.com>
Precedence: bulk

When Exynos power domain driver was introduced, the only way to ensure
that power domains will be instantiated before the devices which belongs
to them was to initialize them early enough, before the devices are
instantiated in the system. This in turn required not to use any platform
device infrastructure at all, as there have been no way to ensure proper
probe order between devices.

This has been finally changed and patch e590474768f1 ("driver core: Set
fw_devlink=on by default") ensures that each device will be probbed only
when its resource providers are ready. This allows to convert Exynos
power domain driver to regular platform driver.

This is also required by the mentioned commit to enable probing any
device which belongs to the Exynos power domains, as otherwise the core
won't notice that the power domains are in fact available.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
Some more comments are in the following thread:
https://lore.kernel.org/lkml/2556a69b-5da5-bf80-e051-df2d02fbc40f@samsung.com/
---
 drivers/soc/samsung/pm_domains.c | 97 ++++++++++++++++----------------
 1 file changed, 48 insertions(+), 49 deletions(-)

diff --git a/drivers/soc/samsung/pm_domains.c b/drivers/soc/samsung/pm_domains.c
index ab8582971bfc..5ec0c13f0aaf 100644
--- a/drivers/soc/samsung/pm_domains.c
+++ b/drivers/soc/samsung/pm_domains.c
@@ -16,7 +16,7 @@
 #include <linux/delay.h>
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
-#include <linux/sched.h>
+#include <linux/pm_runtime.h>
 
 struct exynos_pm_domain_config {
 	/* Value for LOCAL_PWR_CFG and STATUS fields for each domain */
@@ -73,15 +73,15 @@ static int exynos_pd_power_off(struct generic_pm_domain *domain)
 	return exynos_pd_power(domain, false);
 }
 
-static const struct exynos_pm_domain_config exynos4210_cfg __initconst = {
+static const struct exynos_pm_domain_config exynos4210_cfg = {
 	.local_pwr_cfg		= 0x7,
 };
 
-static const struct exynos_pm_domain_config exynos5433_cfg __initconst = {
+static const struct exynos_pm_domain_config exynos5433_cfg = {
 	.local_pwr_cfg		= 0xf,
 };
 
-static const struct of_device_id exynos_pm_domain_of_match[] __initconst = {
+static const struct of_device_id exynos_pm_domain_of_match[] = {
 	{
 		.compatible = "samsung,exynos4210-pd",
 		.data = &exynos4210_cfg,
@@ -92,7 +92,7 @@ static const struct of_device_id exynos_pm_domain_of_match[] __initconst = {
 	{ },
 };
 
-static __init const char *exynos_get_domain_name(struct device_node *node)
+static const char *exynos_get_domain_name(struct device_node *node)
 {
 	const char *name;
 
@@ -101,60 +101,44 @@ static __init const char *exynos_get_domain_name(struct device_node *node)
 	return kstrdup_const(name, GFP_KERNEL);
 }
 
-static __init int exynos4_pm_init_power_domain(void)
+static int exynos_pd_probe(struct platform_device *pdev)
 {
-	struct device_node *np;
-	const struct of_device_id *match;
-
-	for_each_matching_node_and_match(np, exynos_pm_domain_of_match, &match) {
-		const struct exynos_pm_domain_config *pm_domain_cfg;
-		struct exynos_pm_domain *pd;
-		int on;
+	const struct exynos_pm_domain_config *pm_domain_cfg;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct of_phandle_args child, parent;
+	struct exynos_pm_domain *pd;
+	int on, ret;
 
-		pm_domain_cfg = match->data;
+	pm_domain_cfg = of_device_get_match_data(dev);
+	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return -ENOMEM;
 
-		pd = kzalloc(sizeof(*pd), GFP_KERNEL);
-		if (!pd) {
-			of_node_put(np);
-			return -ENOMEM;
-		}
-		pd->pd.name = exynos_get_domain_name(np);
-		if (!pd->pd.name) {
-			kfree(pd);
-			of_node_put(np);
-			return -ENOMEM;
-		}
+	pd->pd.name = exynos_get_domain_name(np);
+	if (!pd->pd.name)
+		return -ENOMEM;
 
-		pd->base = of_iomap(np, 0);
-		if (!pd->base) {
-			pr_warn("%s: failed to map memory\n", __func__);
-			kfree_const(pd->pd.name);
-			kfree(pd);
-			continue;
-		}
-
-		pd->pd.power_off = exynos_pd_power_off;
-		pd->pd.power_on = exynos_pd_power_on;
-		pd->local_pwr_cfg = pm_domain_cfg->local_pwr_cfg;
+	pd->base = of_iomap(np, 0);
+	if (!pd->base) {
+		kfree_const(pd->pd.name);
+		return -ENODEV;
+	}
 
-		on = readl_relaxed(pd->base + 0x4) & pd->local_pwr_cfg;
+	pd->pd.power_off = exynos_pd_power_off;
+	pd->pd.power_on = exynos_pd_power_on;
+	pd->local_pwr_cfg = pm_domain_cfg->local_pwr_cfg;
 
-		pm_genpd_init(&pd->pd, NULL, !on);
-		of_genpd_add_provider_simple(np, &pd->pd);
-	}
+	on = readl_relaxed(pd->base + 0x4) & pd->local_pwr_cfg;
 
-	/* Assign the child power domains to their parents */
-	for_each_matching_node(np, exynos_pm_domain_of_match) {
-		struct of_phandle_args child, parent;
+	pm_genpd_init(&pd->pd, NULL, !on);
+	ret = of_genpd_add_provider_simple(np, &pd->pd);
 
+	if (ret == 0 && of_parse_phandle_with_args(np, "power-domains",
+				      "#power-domain-cells", 0, &parent) == 0) {
 		child.np = np;
 		child.args_count = 0;
 
-		if (of_parse_phandle_with_args(np, "power-domains",
-					       "#power-domain-cells", 0,
-					       &parent) != 0)
-			continue;
-
 		if (of_genpd_add_subdomain(&parent, &child))
 			pr_warn("%pOF failed to add subdomain: %pOF\n",
 				parent.np, child.np);
@@ -163,6 +147,21 @@ static __init int exynos4_pm_init_power_domain(void)
 				parent.np, child.np);
 	}
 
-	return 0;
+	pm_runtime_enable(dev);
+	return ret;
+}
+
+static struct platform_driver exynos_pd_driver = {
+	.probe	= exynos_pd_probe,
+	.driver	= {
+		.name		= "exynos-pd",
+		.of_match_table	= exynos_pm_domain_of_match,
+		.suppress_bind_attrs = true,
+	}
+};
+
+static __init int exynos4_pm_init_power_domain(void)
+{
+	return platform_driver_register(&exynos_pd_driver);
 }
 core_initcall(exynos4_pm_init_power_domain);
-- 
2.17.1