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From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20=28The=20Capable=20Hub=29?= <u.kleine-koenig@baylibre.com>
To: Lee Jones <lee@kernel.org>
Cc: mfd@lists.linux.dev,
	linux-kernel@vger.kernel.org,
	Linus Walleij <linusw@kernel.org>
Subject: [PATCH v4 03/20] mfd: kempld: Simplify device abstraction
Date: Tue, 10 Nov 2026 22:54:28 +0100
Message-ID:  <f751652cc2cee4addd2168e66e6d89bde275f39c.1794347059.git.u.kleine-koenig@baylibre.com>
In-Reply-To: <cover.1794347059.git.u.kleine-koenig@baylibre.com>
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The devices that are created by the driver from DMI data and also ACPI
devices all use the same platform data. Other devices don't exist. (A
provider of such a device would need to know about struct
kempld_platform_data, but none of the other consumers of
<linux/mfd/kempld.h> creates devices.)

Simplify the driver by hardcoding this instead of using the ACPI
abstraction for multi-variant support without real variants.

Then apart from .gpio_base all members of `struct kempld_platform_data`
are only used in drivers/mfd/kempld-core.c, so they can be dropped.

Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
---
 drivers/mfd/kempld-core.c  | 64 ++++++++++----------------------------
 include/linux/mfd/kempld.h | 12 -------
 2 files changed, 16 insertions(+), 60 deletions(-)

diff --git a/drivers/mfd/kempld-core.c b/drivers/mfd/kempld-core.c
index 47062f876e5d..fbbff3eac500 100644
--- a/drivers/mfd/kempld-core.c
+++ b/drivers/mfd/kempld-core.c
@@ -118,25 +118,19 @@ static struct resource kempld_ioresource = {
 };
 
 static const struct kempld_platform_data kempld_platform_data_generic = {
-	.pld_clock		= KEMPLD_CLK,
-	.ioresource		= &kempld_ioresource,
-	.get_hardware_mutex	= kempld_get_hardware_mutex,
-	.release_hardware_mutex	= kempld_release_hardware_mutex,
-	.get_info		= kempld_get_info_generic,
-	.register_cells		= kempld_register_cells_generic,
 };
 
 static struct platform_device *kempld_pdev;
 
-static int kempld_create_platform_device(const struct kempld_platform_data *pdata)
+static int kempld_create_platform_device(void)
 {
 	const struct platform_device_info pdevinfo = {
 		.name = "kempld",
 		.id = PLATFORM_DEVID_NONE,
-		.res = pdata->ioresource,
+		.res = &kempld_ioresource,
 		.num_res = 1,
-		.data = pdata,
-		.size_data = sizeof(*pdata),
+		.data = &kempld_platform_data_generic,
+		.size_data = sizeof(kempld_platform_data_generic),
 	};
 
 	kempld_pdev = platform_device_register_full(&pdevinfo);
@@ -235,10 +229,8 @@ EXPORT_SYMBOL_GPL(kempld_write32);
  */
 void kempld_get_mutex(struct kempld_device_data *pld)
 {
-	const struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
-
 	mutex_lock(&pld->lock);
-	pdata->get_hardware_mutex(pld);
+	kempld_get_hardware_mutex(pld);
 }
 EXPORT_SYMBOL_GPL(kempld_get_mutex);
 
@@ -248,9 +240,7 @@ EXPORT_SYMBOL_GPL(kempld_get_mutex);
  */
 void kempld_release_mutex(struct kempld_device_data *pld)
 {
-	const struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
-
-	pdata->release_hardware_mutex(pld);
+	kempld_release_hardware_mutex(pld);
 	mutex_unlock(&pld->lock);
 }
 EXPORT_SYMBOL_GPL(kempld_release_mutex);
@@ -266,10 +256,9 @@ EXPORT_SYMBOL_GPL(kempld_release_mutex);
 static int kempld_get_info(struct kempld_device_data *pld)
 {
 	int ret;
-	const struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
 	char major, minor;
 
-	ret = pdata->get_info(pld);
+	ret = kempld_get_info_generic(pld);
 	if (ret)
 		return ret;
 
@@ -296,20 +285,6 @@ static int kempld_get_info(struct kempld_device_data *pld)
 	return 0;
 }
 
-/*
- * kempld_register_cells - register cell drivers
- *
- * This function registers cell drivers for the detected hardware by calling
- * the configured kempld_register_cells_XXXX function which is responsible
- * to detect and register the needed cell drivers.
- */
-static int kempld_register_cells(struct kempld_device_data *pld)
-{
-	const struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
-
-	return pdata->register_cells(pld);
-}
-
 static const char *kempld_get_type_string(struct kempld_device_data *pld)
 {
 	const char *version_type;
@@ -399,12 +374,12 @@ static int kempld_detect_device(struct kempld_device_data *pld)
 		 pld->info.version, kempld_get_type_string(pld),
 		 pld->info.spec_major, pld->info.spec_minor);
 
-	return kempld_register_cells(pld);
+	return kempld_register_cells_generic(pld);
 }
 
 static int kempld_probe(struct platform_device *pdev)
 {
-	const struct kempld_platform_data *pdata;
+	const struct kempld_platform_data *pdata = &kempld_platform_data_generic;
 	struct device *dev = &pdev->dev;
 	struct kempld_device_data *pld;
 	struct resource *ioport;
@@ -415,16 +390,10 @@ static int kempld_probe(struct platform_device *pdev)
 		 * No kempld_pdev device has been registered in kempld_init,
 		 * so we seem to be probing an ACPI platform device.
 		 */
-		pdata = device_get_match_data(dev);
-		if (!pdata)
-			return -ENODEV;
-
 		ret = platform_device_add_data(pdev, pdata, sizeof(*pdata));
 		if (ret)
 			return ret;
-	} else if (kempld_pdev == pdev) {
-		pdata = dev_get_platdata(dev);
-	} else {
+	} else if (kempld_pdev != pdev) {
 		/*
 		 * The platform device we are probing is not the one we
 		 * registered in kempld_init using the DMI table, so this one
@@ -451,7 +420,7 @@ static int kempld_probe(struct platform_device *pdev)
 
 	pld->io_index = pld->io_base;
 	pld->io_data = pld->io_base + 1;
-	pld->pld_clock = pdata->pld_clock;
+	pld->pld_clock = KEMPLD_CLK;
 	pld->dev = dev;
 
 	mutex_init(&pld->lock);
@@ -463,15 +432,14 @@ static int kempld_probe(struct platform_device *pdev)
 static void kempld_remove(struct platform_device *pdev)
 {
 	struct kempld_device_data *pld = platform_get_drvdata(pdev);
-	const struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
 
 	mfd_remove_devices(&pdev->dev);
-	pdata->release_hardware_mutex(pld);
+	kempld_release_hardware_mutex(pld);
 }
 
 static const struct acpi_device_id kempld_acpi_table[] = {
-	{ "KEM0000", (kernel_ulong_t)&kempld_platform_data_generic },
-	{ "KEM0001", (kernel_ulong_t)&kempld_platform_data_generic },
+	{ "KEM0000" },
+	{ "KEM0001" },
 	{}
 };
 MODULE_DEVICE_TABLE(acpi, kempld_acpi_table);
@@ -787,13 +755,13 @@ static int __init kempld_init(void)
 	if (force_device_id[0]) {
 		for (id = kempld_dmi_table; id->matches[0].slot != DMI_NONE; id++)
 			if (strstr(id->ident, force_device_id))
-				if (!kempld_create_platform_device(&kempld_platform_data_generic))
+				if (!kempld_create_platform_device())
 					break;
 		if (id->matches[0].slot == DMI_NONE)
 			return -ENODEV;
 	} else {
 		for (id = dmi_first_match(kempld_dmi_table); id; id = dmi_first_match(id+1))
-			if (kempld_create_platform_device(&kempld_platform_data_generic))
+			if (kempld_create_platform_device())
 				break;
 	}
 	return platform_driver_register(&kempld_driver);
diff --git a/include/linux/mfd/kempld.h b/include/linux/mfd/kempld.h
index 5d75071eaaea..d7a823ba1a7a 100644
--- a/include/linux/mfd/kempld.h
+++ b/include/linux/mfd/kempld.h
@@ -97,22 +97,10 @@ struct kempld_device_data {
 
 /**
  * struct kempld_platform_data - PLD hardware configuration structure
- * @pld_clock:			PLD clock frequency
  * @gpio_base:			GPIO base pin number
- * @ioresource:			IO addresses of the PLD
- * @get_hardware_mutex:		PLD specific get_mutex callback
- * @release_hardware_mutex:	PLD specific release_mutex callback
- * @get_info:			PLD specific get_info callback
- * @register_cells:		PLD specific register_cells callback
  */
 struct kempld_platform_data {
-	u32				pld_clock;
 	int				gpio_base;
-	struct resource			*ioresource;
-	void (*get_hardware_mutex)	(struct kempld_device_data *);
-	void (*release_hardware_mutex)	(struct kempld_device_data *);
-	int (*get_info)			(struct kempld_device_data *);
-	int (*register_cells)		(struct kempld_device_data *);
 };
 
 extern void kempld_get_mutex(struct kempld_device_data *pld);
-- 
2.56.0.rc1