[PATCH v2 0/4] soc: samsung: exynos-chipid and asv improvements

[PATCH v2 0/4] soc: samsung: exynos-chipid and asv improvements

[Krzysztof Kozlowski]

Hi,

Changes since v1:
1. Drop patch "soc: samsung: exynos-chipid: initialize later - with
   arch_initcall" which is now superseded by convertin to a driver.
2. Include Marek's patch, just for the reference and rebase.
3. Add patch "soc: samsung: exynos-asv: handle reading revision register
   error".
4. Add patch "soc: samsung: exynos-chipid: convert to driver and merge
   exynos-asv".

Best regards,
Krzysztof

Krzysztof Kozlowski (3):
  soc: samsung: exynos-asv: handle reading revision register error
  soc: samsung: exynos-chipid: order list of SoCs by name
  soc: samsung: exynos-chipid: convert to driver and merge exynos-asv

Marek Szyprowski (1):
  soc: samsung: exynos-asv: don't defer early on not-supported SoCs

 arch/arm/mach-exynos/Kconfig        |  1 -
 drivers/soc/samsung/Kconfig         | 12 ++---
 drivers/soc/samsung/Makefile        |  3 +-
 drivers/soc/samsung/exynos-asv.c    | 57 ++++++++-------------
 drivers/soc/samsung/exynos-asv.h    |  2 +
 drivers/soc/samsung/exynos-chipid.c | 78 ++++++++++++++++++++---------
 6 files changed, 81 insertions(+), 72 deletions(-)

-- 
2.25.1


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[PATCH v2 1/4] soc: samsung: exynos-asv: don't defer early on not-supported SoCs

[Krzysztof Kozlowski]

From: Marek Szyprowski <m.szyprowski@samsung.com>

Check if the SoC is really supported before gathering the needed
resources. This fixes endless deferred probe on some SoCs other than
Exynos5422 (like Exynos5410).

Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
---
 drivers/soc/samsung/exynos-asv.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index 8abf4dfaa5c5..f653e3533f0f 100644
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -119,11 +119,6 @@ static int exynos_asv_probe(struct platform_device *pdev)
 	u32 product_id = 0;
 	int ret, i;
 
-	cpu_dev = get_cpu_device(0);
-	ret = dev_pm_opp_get_opp_count(cpu_dev);
-	if (ret < 0)
-		return -EPROBE_DEFER;
-
 	asv = devm_kzalloc(&pdev->dev, sizeof(*asv), GFP_KERNEL);
 	if (!asv)
 		return -ENOMEM;
@@ -144,6 +139,11 @@ static int exynos_asv_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	cpu_dev = get_cpu_device(0);
+	ret = dev_pm_opp_get_opp_count(cpu_dev);
+	if (ret < 0)
+		return -EPROBE_DEFER;
+
 	ret = of_property_read_u32(pdev->dev.of_node, "samsung,asv-bin",
 				   &asv->of_bin);
 	if (ret < 0)
-- 
2.25.1


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[PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision register error

[Krzysztof Kozlowski]

If regmap_read() fails, the product_id local variable will contain
random value from the stack.  Do not try to parse such value and fail
the ASV driver probe.

Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
---
 drivers/soc/samsung/exynos-asv.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index f653e3533f0f..5daeadc36382 100644
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -129,7 +129,13 @@ static int exynos_asv_probe(struct platform_device *pdev)
 		return PTR_ERR(asv->chipid_regmap);
 	}
 
-	regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID, &product_id);
+	ret = regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID,
+			  &product_id);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Cannot read revision from ChipID: %d\n",
+			ret);
+		return -ENODEV;
+	}
 
 	switch (product_id & EXYNOS_MASK) {
 	case 0xE5422000:
-- 
2.25.1


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[PATCH v2 3/4] soc: samsung: exynos-chipid: order list of SoCs by name

[Krzysztof Kozlowski]

Bring some order to the list of SoCs.  No functional change.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
---
 drivers/soc/samsung/exynos-chipid.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/samsung/exynos-chipid.c b/drivers/soc/samsung/exynos-chipid.c
index 8d4d05086906..b4cd0cc00f45 100644
--- a/drivers/soc/samsung/exynos-chipid.c
+++ b/drivers/soc/samsung/exynos-chipid.c
@@ -20,6 +20,7 @@ static const struct exynos_soc_id {
 	const char *name;
 	unsigned int id;
 } soc_ids[] = {
+	/* List ordered by SoC name */
 	{ "EXYNOS3250", 0xE3472000 },
 	{ "EXYNOS4210", 0x43200000 },	/* EVT0 revision */
 	{ "EXYNOS4210", 0x43210000 },
@@ -29,10 +30,10 @@ static const struct exynos_soc_id {
 	{ "EXYNOS5260", 0xE5260000 },
 	{ "EXYNOS5410", 0xE5410000 },
 	{ "EXYNOS5420", 0xE5420000 },
+	{ "EXYNOS5433", 0xE5433000 },
 	{ "EXYNOS5440", 0xE5440000 },
 	{ "EXYNOS5800", 0xE5422000 },
 	{ "EXYNOS7420", 0xE7420000 },
-	{ "EXYNOS5433", 0xE5433000 },
 };
 
 static const char * __init product_id_to_soc_id(unsigned int product_id)
-- 
2.25.1


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[PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and merge exynos-asv

[Krzysztof Kozlowski]

The Exynos Chip ID driver on Exynos SoCs has so far only informational
purpose - to expose the SoC device in sysfs.  No other drivers depend on
it so there is really no benefit of initializing it early.

The code would be the most flexible if converted to a regular driver.
However there is already another driver - Exynos ASV (Adaptive Supply
Voltage) - which binds to the device node of Chip ID.

The solution is to convert the Exynos Chip ID to a built in driver and
merge the Exynos ASV into it.

This has several benefits:
1. Although the Exynos ASV driver binds to a device node present in all
   Exynos DTS (generic compatible), it fails to probe except on the
   supported ones (only Exynos5422).  This means that the regular boot
   process has a planned/expected device probe failure.

   Merging the ASV into Chip ID will remove this probe failure because
   the final driver will always bind, just with disabled ASV features.

2. Allows to use dev_info() as the SoC bus is present (since
   core_initcall).

3. Could speed things up because of execution of Chip ID code in a SMP
   environment (after bringing up secondary CPUs, unlike early_initcall),
   This reduces the amount of work to be done early, when the kernel has
   to bring up critical devices.

5. Makes the Chip ID code defer-probe friendly,

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
---
 arch/arm/mach-exynos/Kconfig        |  1 -
 drivers/soc/samsung/Kconfig         | 12 ++---
 drivers/soc/samsung/Makefile        |  3 +-
 drivers/soc/samsung/exynos-asv.c    | 45 +++++------------
 drivers/soc/samsung/exynos-asv.h    |  2 +
 drivers/soc/samsung/exynos-chipid.c | 75 ++++++++++++++++++++---------
 6 files changed, 70 insertions(+), 68 deletions(-)

diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 56d272967fc0..5a48abac6af4 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -13,7 +13,6 @@ menuconfig ARCH_EXYNOS
 	select ARM_GIC
 	select EXYNOS_IRQ_COMBINER
 	select COMMON_CLK_SAMSUNG
-	select EXYNOS_ASV
 	select EXYNOS_CHIPID
 	select EXYNOS_THERMAL
 	select EXYNOS_PMU
diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
index fc7f48a92288..5745d7e5908e 100644
--- a/drivers/soc/samsung/Kconfig
+++ b/drivers/soc/samsung/Kconfig
@@ -7,21 +7,19 @@ menuconfig SOC_SAMSUNG
 
 if SOC_SAMSUNG
 
-config EXYNOS_ASV
-	bool "Exynos Adaptive Supply Voltage support" if COMPILE_TEST
-	depends on (ARCH_EXYNOS && EXYNOS_CHIPID) || COMPILE_TEST
-	select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
-
 # There is no need to enable these drivers for ARMv8
 config EXYNOS_ASV_ARM
 	bool "Exynos ASV ARMv7-specific driver extensions" if COMPILE_TEST
-	depends on EXYNOS_ASV
+	depends on EXYNOS_CHIPID
 
 config EXYNOS_CHIPID
-	bool "Exynos Chipid controller driver" if COMPILE_TEST
+	bool "Exynos ChipID controller and ASV driver" if COMPILE_TEST
 	depends on ARCH_EXYNOS || COMPILE_TEST
+	select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
 	select MFD_SYSCON
 	select SOC_BUS
+	help
+	  Support for Samsung Exynos SoC ChipID and Adaptive Supply Voltage.
 
 config EXYNOS_PMU
 	bool "Exynos PMU controller driver" if COMPILE_TEST
diff --git a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile
index 59e8e9453f27..0c523a8de4eb 100644
--- a/drivers/soc/samsung/Makefile
+++ b/drivers/soc/samsung/Makefile
@@ -1,9 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 
-obj-$(CONFIG_EXYNOS_ASV)	+= exynos-asv.o
 obj-$(CONFIG_EXYNOS_ASV_ARM)	+= exynos5422-asv.o
 
-obj-$(CONFIG_EXYNOS_CHIPID)	+= exynos-chipid.o
+obj-$(CONFIG_EXYNOS_CHIPID)	+= exynos-chipid.o exynos-asv.o
 obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o
 
 obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS)	+= exynos3250-pmu.o exynos4-pmu.o \
diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index 5daeadc36382..d60af8acc391 100644
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -2,7 +2,9 @@
 /*
  * Copyright (c) 2019 Samsung Electronics Co., Ltd.
  *	      http://www.samsung.com/
+ * Copyright (c) 2020 Krzysztof Kozlowski <krzk@kernel.org>
  * Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
+ * Author: Krzysztof Kozlowski <krzk@kernel.org>
  *
  * Samsung Exynos SoC Adaptive Supply Voltage support
  */
@@ -10,12 +12,7 @@
 #include <linux/cpu.h>
 #include <linux/device.h>
 #include <linux/errno.h>
-#include <linux/init.h>
-#include <linux/mfd/syscon.h>
-#include <linux/module.h>
 #include <linux/of.h>
-#include <linux/of_device.h>
-#include <linux/platform_device.h>
 #include <linux/pm_opp.h>
 #include <linux/regmap.h>
 #include <linux/soc/samsung/exynos-chipid.h>
@@ -111,7 +108,7 @@ static int exynos_asv_update_opps(struct exynos_asv *asv)
 	return	0;
 }
 
-static int exynos_asv_probe(struct platform_device *pdev)
+int exynos_asv_init(struct device *dev, struct regmap *regmap)
 {
 	int (*probe_func)(struct exynos_asv *asv);
 	struct exynos_asv *asv;
@@ -119,21 +116,16 @@ static int exynos_asv_probe(struct platform_device *pdev)
 	u32 product_id = 0;
 	int ret, i;
 
-	asv = devm_kzalloc(&pdev->dev, sizeof(*asv), GFP_KERNEL);
+	asv = devm_kzalloc(dev, sizeof(*asv), GFP_KERNEL);
 	if (!asv)
 		return -ENOMEM;
 
-	asv->chipid_regmap = device_node_to_regmap(pdev->dev.of_node);
-	if (IS_ERR(asv->chipid_regmap)) {
-		dev_err(&pdev->dev, "Could not find syscon regmap\n");
-		return PTR_ERR(asv->chipid_regmap);
-	}
-
+	asv->chipid_regmap = regmap;
+	asv->dev = dev;
 	ret = regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID,
 			  &product_id);
 	if (ret < 0) {
-		dev_err(&pdev->dev, "Cannot read revision from ChipID: %d\n",
-			ret);
+		dev_err(dev, "Cannot read revision from ChipID: %d\n", ret);
 		return -ENODEV;
 	}
 
@@ -142,7 +134,9 @@ static int exynos_asv_probe(struct platform_device *pdev)
 		probe_func = exynos5422_asv_init;
 		break;
 	default:
-		return -ENODEV;
+		dev_dbg(dev, "No ASV support for this SoC\n");
+		devm_kfree(dev, asv);
+		return 0;
 	}
 
 	cpu_dev = get_cpu_device(0);
@@ -150,14 +144,11 @@ static int exynos_asv_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return -EPROBE_DEFER;
 
-	ret = of_property_read_u32(pdev->dev.of_node, "samsung,asv-bin",
+	ret = of_property_read_u32(dev->of_node, "samsung,asv-bin",
 				   &asv->of_bin);
 	if (ret < 0)
 		asv->of_bin = -EINVAL;
 
-	asv->dev = &pdev->dev;
-	dev_set_drvdata(&pdev->dev, asv);
-
 	for (i = 0; i < ARRAY_SIZE(asv->subsys); i++)
 		asv->subsys[i].asv = asv;
 
@@ -167,17 +158,3 @@ static int exynos_asv_probe(struct platform_device *pdev)
 
 	return exynos_asv_update_opps(asv);
 }
-
-static const struct of_device_id exynos_asv_of_device_ids[] = {
-	{ .compatible = "samsung,exynos4210-chipid" },
-	{}
-};
-
-static struct platform_driver exynos_asv_driver = {
-	.driver = {
-		.name = "exynos-asv",
-		.of_match_table = exynos_asv_of_device_ids,
-	},
-	.probe	= exynos_asv_probe,
-};
-module_platform_driver(exynos_asv_driver);
diff --git a/drivers/soc/samsung/exynos-asv.h b/drivers/soc/samsung/exynos-asv.h
index 3fd1f2acd999..dcbe154db31e 100644
--- a/drivers/soc/samsung/exynos-asv.h
+++ b/drivers/soc/samsung/exynos-asv.h
@@ -68,4 +68,6 @@ static inline u32 exynos_asv_opp_get_frequency(const struct exynos_asv_subsys *s
 	return __asv_get_table_entry(&subsys->table, level, 0);
 }
 
+int exynos_asv_init(struct device *dev, struct regmap *regmap);
+
 #endif /* __LINUX_SOC_EXYNOS_ASV_H */
diff --git a/drivers/soc/samsung/exynos-chipid.c b/drivers/soc/samsung/exynos-chipid.c
index b4cd0cc00f45..fa6a9b9f6d70 100644
--- a/drivers/soc/samsung/exynos-chipid.c
+++ b/drivers/soc/samsung/exynos-chipid.c
@@ -2,20 +2,28 @@
 /*
  * Copyright (c) 2019 Samsung Electronics Co., Ltd.
  *	      http://www.samsung.com/
+ * Copyright (c) 2020 Krzysztof Kozlowski <krzk@kernel.org>
  *
  * Exynos - CHIP ID support
  * Author: Pankaj Dubey <pankaj.dubey@samsung.com>
  * Author: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
+ * Author: Krzysztof Kozlowski <krzk@kernel.org>
+ *
+ * Samsung Exynos SoC Adaptive Supply Voltage and Chip ID support
  */
 
-#include <linux/io.h>
+#include <linux/device.h>
+#include <linux/errno.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of.h>
+#include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/soc/samsung/exynos-chipid.h>
 #include <linux/sys_soc.h>
 
+#include "exynos-asv.h"
+
 static const struct exynos_soc_id {
 	const char *name;
 	unsigned int id;
@@ -46,25 +54,17 @@ static const char * __init product_id_to_soc_id(unsigned int product_id)
 	return NULL;
 }
 
-static int __init exynos_chipid_early_init(void)
+static int exynos_chipid_probe(struct platform_device *pdev)
 {
 	struct soc_device_attribute *soc_dev_attr;
 	struct soc_device *soc_dev;
 	struct device_node *root;
-	struct device_node *syscon;
 	struct regmap *regmap;
 	u32 product_id;
 	u32 revision;
 	int ret;
 
-	syscon = of_find_compatible_node(NULL, NULL,
-					 "samsung,exynos4210-chipid");
-	if (!syscon)
-		return -ENODEV;
-
-	regmap = device_node_to_regmap(syscon);
-	of_node_put(syscon);
-
+	regmap = device_node_to_regmap(pdev->dev.of_node);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
 
@@ -74,7 +74,8 @@ static int __init exynos_chipid_early_init(void)
 
 	revision = product_id & EXYNOS_REV_MASK;
 
-	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	soc_dev_attr = devm_kzalloc(&pdev->dev, sizeof(*soc_dev_attr),
+				    GFP_KERNEL);
 	if (!soc_dev_attr)
 		return -ENOMEM;
 
@@ -84,31 +85,57 @@ static int __init exynos_chipid_early_init(void)
 	of_property_read_string(root, "model", &soc_dev_attr->machine);
 	of_node_put(root);
 
-	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%x", revision);
+	soc_dev_attr->revision = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+						"%x", revision);
 	soc_dev_attr->soc_id = product_id_to_soc_id(product_id);
 	if (!soc_dev_attr->soc_id) {
 		pr_err("Unknown SoC\n");
-		ret = -ENODEV;
-		goto err;
+		return -ENODEV;
 	}
 
 	/* please note that the actual registration will be deferred */
 	soc_dev = soc_device_register(soc_dev_attr);
-	if (IS_ERR(soc_dev)) {
-		ret = PTR_ERR(soc_dev);
+	if (IS_ERR(soc_dev))
+		return PTR_ERR(soc_dev);
+
+	ret = exynos_asv_init(&pdev->dev, regmap);
+	if (ret)
 		goto err;
-	}
 
-	/* it is too early to use dev_info() here (soc_dev is NULL) */
-	pr_info("soc soc0: Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x] Detected\n",
-		soc_dev_attr->soc_id, product_id, revision);
+	platform_set_drvdata(pdev, soc_dev);
+
+	dev_info(soc_device_to_device(soc_dev),
+		 "Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x] Detected\n",
+		 soc_dev_attr->soc_id, product_id, revision);
 
 	return 0;
 
 err:
-	kfree(soc_dev_attr->revision);
-	kfree(soc_dev_attr);
+	soc_device_unregister(soc_dev);
+
 	return ret;
 }
 
-early_initcall(exynos_chipid_early_init);
+static int exynos_chipid_remove(struct platform_device *pdev)
+{
+	struct soc_device *soc_dev = platform_get_drvdata(pdev);
+
+	soc_device_unregister(soc_dev);
+
+	return 0;
+}
+
+static const struct of_device_id exynos_chipid_of_device_ids[] = {
+	{ .compatible = "samsung,exynos4210-chipid" },
+	{}
+};
+
+static struct platform_driver exynos_chipid_driver = {
+	.driver = {
+		.name = "exynos-chipid",
+		.of_match_table = exynos_chipid_of_device_ids,
+	},
+	.probe	= exynos_chipid_probe,
+	.remove	= exynos_chipid_remove,
+};
+builtin_platform_driver(exynos_chipid_driver);
-- 
2.25.1


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RE: [PATCH v2 1/4] soc: samsung: exynos-asv: don't defer early on not-supported SoCs

[Pankaj Dubey]

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@kernel.org>
> Sent: Tuesday, December 8, 2020 12:35 AM
> To: Krzysztof Kozlowski <krzk@kernel.org>; linux-arm-
> kernel@lists.infradead.org; linux-samsung-soc@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Cc: Sylwester Nawrocki <snawrocki@kernel.org>; Marek Szyprowski
> <m.szyprowski@samsung.com>; Bartlomiej Zolnierkiewicz
> <b.zolnierkie@samsung.com>; Arnd Bergmann <arnd@arndb.de>; Chanwoo
> Choi <cw00.choi@samsung.com>; Alim Akhtar <alim.akhtar@samsung.com>;
> Pankaj Dubey <pankaj.dubey@samsung.com>; stable@vger.kernel.org
> Subject: [PATCH v2 1/4] soc: samsung: exynos-asv: don't defer early on
not-
> supported SoCs
> 
> From: Marek Szyprowski <m.szyprowski@samsung.com>
> 
> Check if the SoC is really supported before gathering the needed
resources.
> This fixes endless deferred probe on some SoCs other than
> Exynos5422 (like Exynos5410).
> 
> Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage
> driver")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  drivers/soc/samsung/exynos-asv.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/soc/samsung/exynos-asv.c
> b/drivers/soc/samsung/exynos-asv.c
> index 8abf4dfaa5c5..f653e3533f0f 100644
> --- a/drivers/soc/samsung/exynos-asv.c
> +++ b/drivers/soc/samsung/exynos-asv.c
> @@ -119,11 +119,6 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
>  	u32 product_id = 0;
>  	int ret, i;
> 
> -	cpu_dev = get_cpu_device(0);
> -	ret = dev_pm_opp_get_opp_count(cpu_dev);
> -	if (ret < 0)
> -		return -EPROBE_DEFER;
> -
>  	asv = devm_kzalloc(&pdev->dev, sizeof(*asv), GFP_KERNEL);
>  	if (!asv)
>  		return -ENOMEM;
> @@ -144,6 +139,11 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
>  		return -ENODEV;
>  	}
> 
> +	cpu_dev = get_cpu_device(0);
> +	ret = dev_pm_opp_get_opp_count(cpu_dev);
> +	if (ret < 0)
> +		return -EPROBE_DEFER;
> +
>  	ret = of_property_read_u32(pdev->dev.of_node, "samsung,asv-
> bin",
>  				   &asv->of_bin);
>  	if (ret < 0)
> --
> 2.25.1

Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>


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RE: [PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision register error

[Pankaj Dubey]

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@kernel.org>
> Sent: Tuesday, December 8, 2020 12:35 AM
> To: Krzysztof Kozlowski <krzk@kernel.org>; linux-arm-
> kernel@lists.infradead.org; linux-samsung-soc@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Cc: Sylwester Nawrocki <snawrocki@kernel.org>; Marek Szyprowski
> <m.szyprowski@samsung.com>; Bartlomiej Zolnierkiewicz
> <b.zolnierkie@samsung.com>; Arnd Bergmann <arnd@arndb.de>; Chanwoo
> Choi <cw00.choi@samsung.com>; Alim Akhtar <alim.akhtar@samsung.com>;
> Pankaj Dubey <pankaj.dubey@samsung.com>; stable@vger.kernel.org
> Subject: [PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision
> register error
> 
> If regmap_read() fails, the product_id local variable will contain random
value
> from the stack.  Do not try to parse such value and fail the ASV driver
probe.
> 
> Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage
> driver")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  drivers/soc/samsung/exynos-asv.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/soc/samsung/exynos-asv.c
> b/drivers/soc/samsung/exynos-asv.c
> index f653e3533f0f..5daeadc36382 100644
> --- a/drivers/soc/samsung/exynos-asv.c
> +++ b/drivers/soc/samsung/exynos-asv.c
> @@ -129,7 +129,13 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
>  		return PTR_ERR(asv->chipid_regmap);
>  	}
> 
> -	regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID,
> &product_id);
> +	ret = regmap_read(asv->chipid_regmap,
> EXYNOS_CHIPID_REG_PRO_ID,
> +			  &product_id);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Cannot read revision from
> ChipID: %d\n",
> +			ret);
> +		return -ENODEV;
> +	}
> 
>  	switch (product_id & EXYNOS_MASK) {
>  	case 0xE5422000:
> --
> 2.25.1

Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>


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RE: [PATCH v2 3/4] soc: samsung: exynos-chipid: order list of SoCs by name

[Pankaj Dubey]

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@kernel.org>
> Sent: Tuesday, December 8, 2020 12:35 AM
> To: Krzysztof Kozlowski <krzk@kernel.org>; linux-arm-
> kernel@lists.infradead.org; linux-samsung-soc@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Cc: Sylwester Nawrocki <snawrocki@kernel.org>; Marek Szyprowski
> <m.szyprowski@samsung.com>; Bartlomiej Zolnierkiewicz
> <b.zolnierkie@samsung.com>; Arnd Bergmann <arnd@arndb.de>; Chanwoo
> Choi <cw00.choi@samsung.com>; Alim Akhtar <alim.akhtar@samsung.com>;
> Pankaj Dubey <pankaj.dubey@samsung.com>
> Subject: [PATCH v2 3/4] soc: samsung: exynos-chipid: order list of SoCs by
> name
> 
> Bring some order to the list of SoCs.  No functional change.
> 
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  drivers/soc/samsung/exynos-chipid.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/soc/samsung/exynos-chipid.c
> b/drivers/soc/samsung/exynos-chipid.c
> index 8d4d05086906..b4cd0cc00f45 100644
> --- a/drivers/soc/samsung/exynos-chipid.c
> +++ b/drivers/soc/samsung/exynos-chipid.c
> @@ -20,6 +20,7 @@ static const struct exynos_soc_id {
>  	const char *name;
>  	unsigned int id;
>  } soc_ids[] = {
> +	/* List ordered by SoC name */
>  	{ "EXYNOS3250", 0xE3472000 },
>  	{ "EXYNOS4210", 0x43200000 },	/* EVT0 revision */
>  	{ "EXYNOS4210", 0x43210000 },
> @@ -29,10 +30,10 @@ static const struct exynos_soc_id {
>  	{ "EXYNOS5260", 0xE5260000 },
>  	{ "EXYNOS5410", 0xE5410000 },
>  	{ "EXYNOS5420", 0xE5420000 },
> +	{ "EXYNOS5433", 0xE5433000 },
>  	{ "EXYNOS5440", 0xE5440000 },
>  	{ "EXYNOS5800", 0xE5422000 },
>  	{ "EXYNOS7420", 0xE7420000 },
> -	{ "EXYNOS5433", 0xE5433000 },
>  };
> 
>  static const char * __init product_id_to_soc_id(unsigned int product_id)
> --
> 2.25.1

Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>


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RE: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and merge exynos-asv

[Pankaj Dubey]

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@kernel.org>
> Sent: Tuesday, December 8, 2020 12:35 AM
> To: Krzysztof Kozlowski <krzk@kernel.org>; linux-arm-
> kernel@lists.infradead.org; linux-samsung-soc@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Cc: Sylwester Nawrocki <snawrocki@kernel.org>; Marek Szyprowski
> <m.szyprowski@samsung.com>; Bartlomiej Zolnierkiewicz
> <b.zolnierkie@samsung.com>; Arnd Bergmann <arnd@arndb.de>; Chanwoo
> Choi <cw00.choi@samsung.com>; Alim Akhtar <alim.akhtar@samsung.com>;
> Pankaj Dubey <pankaj.dubey@samsung.com>
> Subject: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and
> merge exynos-asv
> 
> The Exynos Chip ID driver on Exynos SoCs has so far only informational
> purpose - to expose the SoC device in sysfs.  No other drivers depend on
it
> so there is really no benefit of initializing it early.
> 

One of the intention behind initializing Exynos Chip ID driver in early
stage was to simplify code in arch/arm/mach-exynos specifically calls such
as soc_is_exynosXXXX. 
But there were lot of resistance from community to add any such calls (or
exported function) from mach-exynos files to the driver file. Whereas some
other SoC code is using the same, e.g. tegra_get_chip_id being called from
mach-tegra files to drivers/soc/tegra/. Unfortunately we could not accept
similar solution for Exynos SoC and hence could not get rid of
soc_is_exynosxXXX and similar macros from various file in mach-exynos and
eventually converting those files into a full-fledged driver files. 

Any opinion how can we achieve this if we convert Exynos Chip ID driver to a
regular driver?

Thanks,
Pankaj Dubey

> The code would be the most flexible if converted to a regular driver.
> However there is already another driver - Exynos ASV (Adaptive Supply
> Voltage) - which binds to the device node of Chip ID.
> 
> The solution is to convert the Exynos Chip ID to a built in driver and
merge
> the Exynos ASV into it.
> 
> This has several benefits:
> 1. Although the Exynos ASV driver binds to a device node present in all
>    Exynos DTS (generic compatible), it fails to probe except on the
>    supported ones (only Exynos5422).  This means that the regular boot
>    process has a planned/expected device probe failure.
> 
>    Merging the ASV into Chip ID will remove this probe failure because
>    the final driver will always bind, just with disabled ASV features.
> 
> 2. Allows to use dev_info() as the SoC bus is present (since
>    core_initcall).
> 
> 3. Could speed things up because of execution of Chip ID code in a SMP
>    environment (after bringing up secondary CPUs, unlike early_initcall),
>    This reduces the amount of work to be done early, when the kernel has
>    to bring up critical devices.
> 
> 5. Makes the Chip ID code defer-probe friendly,
> 
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  arch/arm/mach-exynos/Kconfig        |  1 -
>  drivers/soc/samsung/Kconfig         | 12 ++---
>  drivers/soc/samsung/Makefile        |  3 +-
>  drivers/soc/samsung/exynos-asv.c    | 45 +++++------------
>  drivers/soc/samsung/exynos-asv.h    |  2 +
>  drivers/soc/samsung/exynos-chipid.c | 75 ++++++++++++++++++++---------
>  6 files changed, 70 insertions(+), 68 deletions(-)
> 
> diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-
> exynos/Kconfig index 56d272967fc0..5a48abac6af4 100644
> --- a/arch/arm/mach-exynos/Kconfig
> +++ b/arch/arm/mach-exynos/Kconfig
> @@ -13,7 +13,6 @@ menuconfig ARCH_EXYNOS
>  	select ARM_GIC
>  	select EXYNOS_IRQ_COMBINER
>  	select COMMON_CLK_SAMSUNG
> -	select EXYNOS_ASV
>  	select EXYNOS_CHIPID
>  	select EXYNOS_THERMAL
>  	select EXYNOS_PMU
> diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
> index fc7f48a92288..5745d7e5908e 100644
> --- a/drivers/soc/samsung/Kconfig
> +++ b/drivers/soc/samsung/Kconfig
> @@ -7,21 +7,19 @@ menuconfig SOC_SAMSUNG
> 
>  if SOC_SAMSUNG
> 
> -config EXYNOS_ASV
> -	bool "Exynos Adaptive Supply Voltage support" if COMPILE_TEST
> -	depends on (ARCH_EXYNOS && EXYNOS_CHIPID) || COMPILE_TEST
> -	select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
> -
>  # There is no need to enable these drivers for ARMv8  config
> EXYNOS_ASV_ARM
>  	bool "Exynos ASV ARMv7-specific driver extensions" if
> COMPILE_TEST
> -	depends on EXYNOS_ASV
> +	depends on EXYNOS_CHIPID
> 
>  config EXYNOS_CHIPID
> -	bool "Exynos Chipid controller driver" if COMPILE_TEST
> +	bool "Exynos ChipID controller and ASV driver" if COMPILE_TEST
>  	depends on ARCH_EXYNOS || COMPILE_TEST
> +	select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
>  	select MFD_SYSCON
>  	select SOC_BUS
> +	help
> +	  Support for Samsung Exynos SoC ChipID and Adaptive Supply
> Voltage.
> 
>  config EXYNOS_PMU
>  	bool "Exynos PMU controller driver" if COMPILE_TEST diff --git
> a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile index
> 59e8e9453f27..0c523a8de4eb 100644
> --- a/drivers/soc/samsung/Makefile
> +++ b/drivers/soc/samsung/Makefile
> @@ -1,9 +1,8 @@
>  # SPDX-License-Identifier: GPL-2.0
> 
> -obj-$(CONFIG_EXYNOS_ASV)	+= exynos-asv.o
>  obj-$(CONFIG_EXYNOS_ASV_ARM)	+= exynos5422-asv.o
> 
> -obj-$(CONFIG_EXYNOS_CHIPID)	+= exynos-chipid.o
> +obj-$(CONFIG_EXYNOS_CHIPID)	+= exynos-chipid.o exynos-asv.o
>  obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o
> 
>  obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS)	+= exynos3250-
> pmu.o exynos4-pmu.o \
> diff --git a/drivers/soc/samsung/exynos-asv.c
> b/drivers/soc/samsung/exynos-asv.c
> index 5daeadc36382..d60af8acc391 100644
> --- a/drivers/soc/samsung/exynos-asv.c
> +++ b/drivers/soc/samsung/exynos-asv.c
> @@ -2,7 +2,9 @@
>  /*
>   * Copyright (c) 2019 Samsung Electronics Co., Ltd.
>   *	      http://www.samsung.com/
> + * Copyright (c) 2020 Krzysztof Kozlowski <krzk@kernel.org>
>   * Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
> + * Author: Krzysztof Kozlowski <krzk@kernel.org>
>   *
>   * Samsung Exynos SoC Adaptive Supply Voltage support
>   */
> @@ -10,12 +12,7 @@
>  #include <linux/cpu.h>
>  #include <linux/device.h>
>  #include <linux/errno.h>
> -#include <linux/init.h>
> -#include <linux/mfd/syscon.h>
> -#include <linux/module.h>
>  #include <linux/of.h>
> -#include <linux/of_device.h>
> -#include <linux/platform_device.h>
>  #include <linux/pm_opp.h>
>  #include <linux/regmap.h>
>  #include <linux/soc/samsung/exynos-chipid.h>
> @@ -111,7 +108,7 @@ static int exynos_asv_update_opps(struct
> exynos_asv *asv)
>  	return	0;
>  }
> 
> -static int exynos_asv_probe(struct platform_device *pdev)
> +int exynos_asv_init(struct device *dev, struct regmap *regmap)
>  {
>  	int (*probe_func)(struct exynos_asv *asv);
>  	struct exynos_asv *asv;
> @@ -119,21 +116,16 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
>  	u32 product_id = 0;
>  	int ret, i;
> 
> -	asv = devm_kzalloc(&pdev->dev, sizeof(*asv), GFP_KERNEL);
> +	asv = devm_kzalloc(dev, sizeof(*asv), GFP_KERNEL);
>  	if (!asv)
>  		return -ENOMEM;
> 
> -	asv->chipid_regmap = device_node_to_regmap(pdev-
> >dev.of_node);
> -	if (IS_ERR(asv->chipid_regmap)) {
> -		dev_err(&pdev->dev, "Could not find syscon regmap\n");
> -		return PTR_ERR(asv->chipid_regmap);
> -	}
> -
> +	asv->chipid_regmap = regmap;
> +	asv->dev = dev;
>  	ret = regmap_read(asv->chipid_regmap,
> EXYNOS_CHIPID_REG_PRO_ID,
>  			  &product_id);
>  	if (ret < 0) {
> -		dev_err(&pdev->dev, "Cannot read revision from
> ChipID: %d\n",
> -			ret);
> +		dev_err(dev, "Cannot read revision from ChipID: %d\n", ret);
>  		return -ENODEV;
>  	}
> 
> @@ -142,7 +134,9 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
>  		probe_func = exynos5422_asv_init;
>  		break;
>  	default:
> -		return -ENODEV;
> +		dev_dbg(dev, "No ASV support for this SoC\n");
> +		devm_kfree(dev, asv);
> +		return 0;
>  	}
> 
>  	cpu_dev = get_cpu_device(0);
> @@ -150,14 +144,11 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
>  	if (ret < 0)
>  		return -EPROBE_DEFER;
> 
> -	ret = of_property_read_u32(pdev->dev.of_node, "samsung,asv-
> bin",
> +	ret = of_property_read_u32(dev->of_node, "samsung,asv-bin",
>  				   &asv->of_bin);
>  	if (ret < 0)
>  		asv->of_bin = -EINVAL;
> 
> -	asv->dev = &pdev->dev;
> -	dev_set_drvdata(&pdev->dev, asv);
> -
>  	for (i = 0; i < ARRAY_SIZE(asv->subsys); i++)
>  		asv->subsys[i].asv = asv;
> 
> @@ -167,17 +158,3 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
> 
>  	return exynos_asv_update_opps(asv);
>  }
> -
> -static const struct of_device_id exynos_asv_of_device_ids[] = {
> -	{ .compatible = "samsung,exynos4210-chipid" },
> -	{}
> -};
> -
> -static struct platform_driver exynos_asv_driver = {
> -	.driver = {
> -		.name = "exynos-asv",
> -		.of_match_table = exynos_asv_of_device_ids,
> -	},
> -	.probe	= exynos_asv_probe,
> -};
> -module_platform_driver(exynos_asv_driver);
> diff --git a/drivers/soc/samsung/exynos-asv.h
> b/drivers/soc/samsung/exynos-asv.h
> index 3fd1f2acd999..dcbe154db31e 100644
> --- a/drivers/soc/samsung/exynos-asv.h
> +++ b/drivers/soc/samsung/exynos-asv.h
> @@ -68,4 +68,6 @@ static inline u32 exynos_asv_opp_get_frequency(const
> struct exynos_asv_subsys *s
>  	return __asv_get_table_entry(&subsys->table, level, 0);  }
> 
> +int exynos_asv_init(struct device *dev, struct regmap *regmap);
> +
>  #endif /* __LINUX_SOC_EXYNOS_ASV_H */
> diff --git a/drivers/soc/samsung/exynos-chipid.c
> b/drivers/soc/samsung/exynos-chipid.c
> index b4cd0cc00f45..fa6a9b9f6d70 100644
> --- a/drivers/soc/samsung/exynos-chipid.c
> +++ b/drivers/soc/samsung/exynos-chipid.c
> @@ -2,20 +2,28 @@
>  /*
>   * Copyright (c) 2019 Samsung Electronics Co., Ltd.
>   *	      http://www.samsung.com/
> + * Copyright (c) 2020 Krzysztof Kozlowski <krzk@kernel.org>
>   *
>   * Exynos - CHIP ID support
>   * Author: Pankaj Dubey <pankaj.dubey@samsung.com>
>   * Author: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> + * Author: Krzysztof Kozlowski <krzk@kernel.org>
> + *
> + * Samsung Exynos SoC Adaptive Supply Voltage and Chip ID support
>   */
> 
> -#include <linux/io.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
>  #include <linux/mfd/syscon.h>
>  #include <linux/of.h>
> +#include <linux/platform_device.h>
>  #include <linux/regmap.h>
>  #include <linux/slab.h>
>  #include <linux/soc/samsung/exynos-chipid.h>
>  #include <linux/sys_soc.h>
> 
> +#include "exynos-asv.h"
> +
>  static const struct exynos_soc_id {
>  	const char *name;
>  	unsigned int id;
> @@ -46,25 +54,17 @@ static const char * __init
> product_id_to_soc_id(unsigned int product_id)
>  	return NULL;
>  }
> 
> -static int __init exynos_chipid_early_init(void)
> +static int exynos_chipid_probe(struct platform_device *pdev)
>  {
>  	struct soc_device_attribute *soc_dev_attr;
>  	struct soc_device *soc_dev;
>  	struct device_node *root;
> -	struct device_node *syscon;
>  	struct regmap *regmap;
>  	u32 product_id;
>  	u32 revision;
>  	int ret;
> 
> -	syscon = of_find_compatible_node(NULL, NULL,
> -					 "samsung,exynos4210-chipid");
> -	if (!syscon)
> -		return -ENODEV;
> -
> -	regmap = device_node_to_regmap(syscon);
> -	of_node_put(syscon);
> -
> +	regmap = device_node_to_regmap(pdev->dev.of_node);
>  	if (IS_ERR(regmap))
>  		return PTR_ERR(regmap);
> 
> @@ -74,7 +74,8 @@ static int __init exynos_chipid_early_init(void)
> 
>  	revision = product_id & EXYNOS_REV_MASK;
> 
> -	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
> +	soc_dev_attr = devm_kzalloc(&pdev->dev, sizeof(*soc_dev_attr),
> +				    GFP_KERNEL);
>  	if (!soc_dev_attr)
>  		return -ENOMEM;
> 
> @@ -84,31 +85,57 @@ static int __init exynos_chipid_early_init(void)
>  	of_property_read_string(root, "model", &soc_dev_attr->machine);
>  	of_node_put(root);
> 
> -	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%x", revision);
> +	soc_dev_attr->revision = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> +						"%x", revision);
>  	soc_dev_attr->soc_id = product_id_to_soc_id(product_id);
>  	if (!soc_dev_attr->soc_id) {
>  		pr_err("Unknown SoC\n");
> -		ret = -ENODEV;
> -		goto err;
> +		return -ENODEV;
>  	}
> 
>  	/* please note that the actual registration will be deferred */
>  	soc_dev = soc_device_register(soc_dev_attr);
> -	if (IS_ERR(soc_dev)) {
> -		ret = PTR_ERR(soc_dev);
> +	if (IS_ERR(soc_dev))
> +		return PTR_ERR(soc_dev);
> +
> +	ret = exynos_asv_init(&pdev->dev, regmap);
> +	if (ret)
>  		goto err;
> -	}
> 
> -	/* it is too early to use dev_info() here (soc_dev is NULL) */
> -	pr_info("soc soc0: Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x]
> Detected\n",
> -		soc_dev_attr->soc_id, product_id, revision);
> +	platform_set_drvdata(pdev, soc_dev);
> +
> +	dev_info(soc_device_to_device(soc_dev),
> +		 "Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x] Detected\n",
> +		 soc_dev_attr->soc_id, product_id, revision);
> 
>  	return 0;
> 
>  err:
> -	kfree(soc_dev_attr->revision);
> -	kfree(soc_dev_attr);
> +	soc_device_unregister(soc_dev);
> +
>  	return ret;
>  }
> 
> -early_initcall(exynos_chipid_early_init);
> +static int exynos_chipid_remove(struct platform_device *pdev) {
> +	struct soc_device *soc_dev = platform_get_drvdata(pdev);
> +
> +	soc_device_unregister(soc_dev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id exynos_chipid_of_device_ids[] = {
> +	{ .compatible = "samsung,exynos4210-chipid" },
> +	{}
> +};
> +
> +static struct platform_driver exynos_chipid_driver = {
> +	.driver = {
> +		.name = "exynos-chipid",
> +		.of_match_table = exynos_chipid_of_device_ids,
> +	},
> +	.probe	= exynos_chipid_probe,
> +	.remove	= exynos_chipid_remove,
> +};
> +builtin_platform_driver(exynos_chipid_driver);
> --
> 2.25.1



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Re: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and merge exynos-asv

['Krzysztof Kozlowski']

On Tue, Dec 08, 2020 at 12:31:23PM +0530, Pankaj Dubey wrote:
> 
> 
> > -----Original Message-----
> > From: Krzysztof Kozlowski <krzk@kernel.org>
> > Sent: Tuesday, December 8, 2020 12:35 AM
> > To: Krzysztof Kozlowski <krzk@kernel.org>; linux-arm-
> > kernel@lists.infradead.org; linux-samsung-soc@vger.kernel.org; linux-
> > kernel@vger.kernel.org
> > Cc: Sylwester Nawrocki <snawrocki@kernel.org>; Marek Szyprowski
> > <m.szyprowski@samsung.com>; Bartlomiej Zolnierkiewicz
> > <b.zolnierkie@samsung.com>; Arnd Bergmann <arnd@arndb.de>; Chanwoo
> > Choi <cw00.choi@samsung.com>; Alim Akhtar <alim.akhtar@samsung.com>;
> > Pankaj Dubey <pankaj.dubey@samsung.com>
> > Subject: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and
> > merge exynos-asv
> > 
> > The Exynos Chip ID driver on Exynos SoCs has so far only informational
> > purpose - to expose the SoC device in sysfs.  No other drivers depend on
> it
> > so there is really no benefit of initializing it early.
> > 
> 
> One of the intention behind initializing Exynos Chip ID driver in early
> stage was to simplify code in arch/arm/mach-exynos specifically calls such
> as soc_is_exynosXXXX. 
> But there were lot of resistance from community to add any such calls (or
> exported function) from mach-exynos files to the driver file. Whereas some
> other SoC code is using the same, e.g. tegra_get_chip_id being called from
> mach-tegra files to drivers/soc/tegra/. Unfortunately we could not accept
> similar solution for Exynos SoC and hence could not get rid of
> soc_is_exynosxXXX and similar macros from various file in mach-exynos and
> eventually converting those files into a full-fledged driver files. 
> 
> Any opinion how can we achieve this if we convert Exynos Chip ID driver to a
> regular driver?

a. Some parts of mach code can be moved to drivers and then use OF calls.

b. The ones which cannot be moved, could use soc_device_match() assuming
   they are called after the soc-bus is operational - so after
   core_initcalls.

c. The ones which are called early or without cache coherency
   (soc_device_match() uses krefs()), cannot be converted.

This chip ID conversion indeed kills case (b) above... which I am not
sure is worth bothering. Which parts of code could be moved like this?
Not mentioning that none of this work have happened since few years...

Best regards,
Krzysztof

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Re: [PATCH v2 1/4] soc: samsung: exynos-asv: don't defer early on not-supported SoCs

[Krzysztof Kozlowski]

On Mon, Dec 07, 2020 at 08:05:14PM +0100, Krzysztof Kozlowski wrote:
> From: Marek Szyprowski <m.szyprowski@samsung.com>
> 
> Check if the SoC is really supported before gathering the needed
> resources. This fixes endless deferred probe on some SoCs other than
> Exynos5422 (like Exynos5410).
> 
> Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  drivers/soc/samsung/exynos-asv.c | 10 +++++-----

Thanks, applied.

Best regards,
Krzysztof


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Re: (subset) [PATCH v2 0/4] soc: samsung: exynos-chipid and asv improvements

[Krzysztof Kozlowski]

On Mon, 7 Dec 2020 20:05:13 +0100, Krzysztof Kozlowski wrote:
> Changes since v1:
> 1. Drop patch "soc: samsung: exynos-chipid: initialize later - with
>    arch_initcall" which is now superseded by convertin to a driver.
> 2. Include Marek's patch, just for the reference and rebase.
> 3. Add patch "soc: samsung: exynos-asv: handle reading revision register
>    error".
> 4. Add patch "soc: samsung: exynos-chipid: convert to driver and merge
>    exynos-asv".
> 
> [...]

Applied, thanks!

[4/4] soc: samsung: exynos-chipid: convert to driver and merge exynos-asv
      commit: 352bfbb3e0230c96b2bce00d2ac3f0de303cc7b6

Best regards,
-- 
Krzysztof Kozlowski <krzk@kernel.org>

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Re: [PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision register error

[Krzysztof Kozlowski]

On Mon, Dec 07, 2020 at 08:05:15PM +0100, Krzysztof Kozlowski wrote:
> If regmap_read() fails, the product_id local variable will contain
> random value from the stack.  Do not try to parse such value and fail
> the ASV driver probe.
> 
> Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  drivers/soc/samsung/exynos-asv.c | 8 +++++++-

Applied.

Best regards,
Krzysztof


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