[PATCH v2 0/4] platform/x86: panasonic-laptop: Bind to a platform device instead of an ACPI one

[PATCH v2 0/4] platform/x86: panasonic-laptop: Bind to a platform device instead of an ACPI one

[Rafael J. Wysocki]

Hi All,

This is an update of

https://lore.kernel.org/linux-acpi/3616223.QJadu78ljV@rafael.j.wysocki/

adding one patch and updating one patch to fix the driver removal
code ordering.

This series is part of a larger effort to switch over all drivers using
the struct acpi_driver interface to the more common struct platform_driver
interface and eliminate the former.  The background is explained in
Documentation/driver-api/acpi/acpi-drivers.rst and in the changelog of
the patch that introduced the above document:

https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/

The bottom line is that the kernel would be better off without struct
acpi_driver and so it is better to get rid of it.

This series carries out driver conversion of the platform x86 Panasonic
hotkey and LCD brightness control driver.

Patch [1/4] fixes the rollback path in acpi_pcc_hotkey_add() and rearranges
the driver removal code ordering to match it.

Patch [2/4] removes some redundant checks from the driver.

Patch [3/4] updates the driver to install an ACPI notify handler by itself
instead of using the .notify() callback from struct acpi_driver, which is
requisite for the driver conversion.

Patch [4/4] converts the driver to using struct platform_driver for device
binding.

Thanks!

[PATCH v2 1/4] platform/x86: panasonic-laptop: Fix rollback path in acpi_pcc_hotkey_add()

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

The rollback ordering in acpi_pcc_hotkey_add() is different from the
cleanup ordering in acpi_pcc_hotkey_remove().  Moreover, the latter
calls pcc_unregister_optd_notifier() unconditionally while the former
never calls it and the OPTD notifier is only registered if pcc->platform
is not NULL.

Address that by:
 * moving the pcc_register_optd_notifier() call after the device_create_file()
   return value check,
 * adding a new label to the acpi_pcc_hotkey_add() rollback code for
   pcc_register_optd_notifier() error handling,
 * moving the pcc_unregister_optd_notifier() call in acpi_pcc_hotkey_remove()
   before the removal of the cdpower sysfs attribute.

Also update pcc_register_optd_notifier() to return an error when
acpi_install_notify_handler() fails.

Fixes: d5a81d8e864b ("platform/x86: panasonic-laptop: Add support for optical driver power in Y and W series")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

v1 -> v2: New patch

---
 drivers/platform/x86/panasonic-laptop.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/x86/panasonic-laptop.c
index d923ddaa4849..debab5916782 100644
--- a/drivers/platform/x86/panasonic-laptop.c
+++ b/drivers/platform/x86/panasonic-laptop.c
@@ -897,15 +897,15 @@ static int pcc_register_optd_notifier(struct pcc_acpi *pcc, char *node)
 	acpi_handle handle;
 
 	status = acpi_get_handle(NULL, node, &handle);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
 
-	if (ACPI_SUCCESS(status)) {
-		status = acpi_install_notify_handler(handle,
-				ACPI_SYSTEM_NOTIFY,
-				pcc_optd_notify, pcc);
-		if (ACPI_FAILURE(status))
-			pr_err("Failed to register notify on %s\n", node);
-	} else
+	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
+					     pcc_optd_notify, pcc);
+	if (ACPI_FAILURE(status)) {
+		pr_err("Failed to register notify on %s\n", node);
 		return -ENODEV;
+	}
 
 	return 0;
 }
@@ -1093,9 +1093,12 @@ static int acpi_pcc_hotkey_add(struct acpi_device *device)
 		}
 		result = device_create_file(&pcc->platform->dev,
 			&dev_attr_cdpower);
-		pcc_register_optd_notifier(pcc, "\\_SB.PCI0.EHCI.ERHB.OPTD");
 		if (result)
 			goto out_platform;
+
+		result = pcc_register_optd_notifier(pcc, "\\_SB.PCI0.EHCI.ERHB.OPTD");
+		if (result)
+			goto out_cdpower;
 	} else {
 		pcc->platform = NULL;
 	}
@@ -1103,6 +1106,8 @@ static int acpi_pcc_hotkey_add(struct acpi_device *device)
 	i8042_install_filter(panasonic_i8042_filter, NULL);
 	return 0;
 
+out_cdpower:
+	device_remove_file(&pcc->platform->dev, &dev_attr_cdpower);
 out_platform:
 	platform_device_unregister(pcc->platform);
 out_sysfs:
@@ -1129,10 +1134,10 @@ static void acpi_pcc_hotkey_remove(struct acpi_device *device)
 	i8042_remove_filter(panasonic_i8042_filter);
 
 	if (pcc->platform) {
+		pcc_unregister_optd_notifier(pcc, "\\_SB.PCI0.EHCI.ERHB.OPTD");
 		device_remove_file(&pcc->platform->dev, &dev_attr_cdpower);
 		platform_device_unregister(pcc->platform);
 	}
-	pcc_unregister_optd_notifier(pcc, "\\_SB.PCI0.EHCI.ERHB.OPTD");
 
 	sysfs_remove_group(&device->dev.kobj, &pcc_attr_group);
 
-- 
2.51.0

[PATCH v2 2/4] platform/x86: panasonic-laptop: Remove redundant checks from 3 functions

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

The device pointer cannot be NULL in acpi_pcc_hotkey_add() and
acpi_pcc_hotkey_remove() because these functions are ACPI driver
callbacks and NULL is never passed to any of them as an argument.

Likewise, acpi_pcc_hotkey_resume() is a resume callback of a
device driver and NULL is never passed to it as an argument, so
the dev pointer in it cannot be NULL.

Moreover, since acpi_pcc_hotkey_remove() and acpi_pcc_hotkey_resume()
can only run after acpi_pcc_hotkey_add() has completed successfully,
the acpi_driver_data() of the device object used by them cannot be
NULL when they run.

Drop all of the redundant NULL checks of the pointers mentioned above.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

v1 -> v2: No changes

---
 drivers/platform/x86/panasonic-laptop.c | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/x86/panasonic-laptop.c
index debab5916782..8825142ea9de 100644
--- a/drivers/platform/x86/panasonic-laptop.c
+++ b/drivers/platform/x86/panasonic-laptop.c
@@ -968,14 +968,7 @@ static int acpi_pcc_init_input(struct pcc_acpi *pcc)
 #ifdef CONFIG_PM_SLEEP
 static int acpi_pcc_hotkey_resume(struct device *dev)
 {
-	struct pcc_acpi *pcc;
-
-	if (!dev)
-		return -EINVAL;
-
-	pcc = acpi_driver_data(to_acpi_device(dev));
-	if (!pcc)
-		return -EINVAL;
+	struct pcc_acpi *pcc = acpi_driver_data(to_acpi_device(dev));
 
 	if (pcc->num_sifr > SINF_MUTE)
 		acpi_pcc_write_sset(pcc, SINF_MUTE, pcc->mute);
@@ -997,9 +990,6 @@ static int acpi_pcc_hotkey_add(struct acpi_device *device)
 	struct pcc_acpi *pcc;
 	int num_sifr, result;
 
-	if (!device)
-		return -EINVAL;
-
 	num_sifr = acpi_pcc_get_sqty(device);
 
 	/*
@@ -1128,9 +1118,6 @@ static void acpi_pcc_hotkey_remove(struct acpi_device *device)
 {
 	struct pcc_acpi *pcc = acpi_driver_data(device);
 
-	if (!device || !pcc)
-		return;
-
 	i8042_remove_filter(panasonic_i8042_filter);
 
 	if (pcc->platform) {
-- 
2.51.0

[PATCH v2 3/4] platform/x86: panasonic-laptop: Register ACPI notify handler directly

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

To facilitate subsequent conversion of the driver to a platform one,
make it install an ACPI notify handler directly instead of using
a .notify() callback in struct acpi_driver.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

v1 -> v2: Adjust remove code ordering to match probe rollback code
   ordering (Ilpo)

---
 drivers/platform/x86/panasonic-laptop.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/x86/panasonic-laptop.c
index 8825142ea9de..6d776bb1c5d1 100644
--- a/drivers/platform/x86/panasonic-laptop.c
+++ b/drivers/platform/x86/panasonic-laptop.c
@@ -185,7 +185,7 @@ enum SINF_BITS { SINF_NUM_BATTERIES = 0,
 
 static int acpi_pcc_hotkey_add(struct acpi_device *device);
 static void acpi_pcc_hotkey_remove(struct acpi_device *device);
-static void acpi_pcc_hotkey_notify(struct acpi_device *device, u32 event);
+static void acpi_pcc_hotkey_notify(acpi_handle handle, u32 event, void *data);
 
 static const struct acpi_device_id pcc_device_ids[] = {
 	{ "MAT0012", 0},
@@ -208,7 +208,6 @@ static struct acpi_driver acpi_pcc_driver = {
 	.ops =		{
 				.add =		acpi_pcc_hotkey_add,
 				.remove =	acpi_pcc_hotkey_remove,
-				.notify =	acpi_pcc_hotkey_notify,
 			},
 	.drv.pm =	&acpi_pcc_hotkey_pm,
 };
@@ -869,9 +868,9 @@ static void acpi_pcc_generate_keyinput(struct pcc_acpi *pcc)
 		pr_err("Unknown hotkey event: 0x%04llx\n", result);
 }
 
-static void acpi_pcc_hotkey_notify(struct acpi_device *device, u32 event)
+static void acpi_pcc_hotkey_notify(acpi_handle handle, u32 event, void *data)
 {
-	struct pcc_acpi *pcc = acpi_driver_data(device);
+	struct pcc_acpi *pcc = data;
 
 	switch (event) {
 	case HKEY_NOTIFY:
@@ -1073,13 +1072,18 @@ static int acpi_pcc_hotkey_add(struct acpi_device *device)
 	if (result)
 		goto out_backlight;
 
+	result = acpi_dev_install_notify_handler(device, ACPI_DEVICE_NOTIFY,
+						 acpi_pcc_hotkey_notify, pcc);
+	if (result)
+		goto out_sysfs;
+
 	/* optical drive initialization */
 	if (ACPI_SUCCESS(check_optd_present())) {
 		pcc->platform = platform_device_register_simple("panasonic",
 			PLATFORM_DEVID_NONE, NULL, 0);
 		if (IS_ERR(pcc->platform)) {
 			result = PTR_ERR(pcc->platform);
-			goto out_sysfs;
+			goto out_notify_handler;
 		}
 		result = device_create_file(&pcc->platform->dev,
 			&dev_attr_cdpower);
@@ -1100,6 +1104,9 @@ static int acpi_pcc_hotkey_add(struct acpi_device *device)
 	device_remove_file(&pcc->platform->dev, &dev_attr_cdpower);
 out_platform:
 	platform_device_unregister(pcc->platform);
+out_notify_handler:
+	acpi_dev_remove_notify_handler(device, ACPI_DEVICE_NOTIFY,
+				       acpi_pcc_hotkey_notify);
 out_sysfs:
 	sysfs_remove_group(&device->dev.kobj, &pcc_attr_group);
 out_backlight:
@@ -1126,6 +1133,9 @@ static void acpi_pcc_hotkey_remove(struct acpi_device *device)
 		platform_device_unregister(pcc->platform);
 	}
 
+	acpi_dev_remove_notify_handler(device, ACPI_DEVICE_NOTIFY,
+				       acpi_pcc_hotkey_notify);
+
 	sysfs_remove_group(&device->dev.kobj, &pcc_attr_group);
 
 	backlight_device_unregister(pcc->backlight);
-- 
2.51.0

[PATCH v2 4/4] platform/x86: panasonic-laptop: Convert ACPI driver to a platform one

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

In all cases in which a struct acpi_driver is used for binding a driver
to an ACPI device object, a corresponding platform device is created by
the ACPI core and that device is regarded as a proper representation of
underlying hardware.  Accordingly, a struct platform_driver should be
used by driver code to bind to that device.  There are multiple reasons
why drivers should not bind directly to ACPI device objects [1].

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the Panasonic laptop ACPI driver to a platform
one.

While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.

To maintain backwards compatibility with possibly existing user space,
the sysfs attributes created by the driver under the ACPI device object
used by it are not relocated.  Accordingly, the driver will continue to
use the driver_data pointer in struct acpi_device which needs to be
cleared on driver removal.

Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/ [1]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

v1 -> v2: No changes

---
 drivers/platform/x86/panasonic-laptop.c | 33 ++++++++++++++-----------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/x86/panasonic-laptop.c
index 6d776bb1c5d1..e745cea340c0 100644
--- a/drivers/platform/x86/panasonic-laptop.c
+++ b/drivers/platform/x86/panasonic-laptop.c
@@ -183,8 +183,8 @@ enum SINF_BITS { SINF_NUM_BATTERIES = 0,
 	};
 /* R1 handles SINF_AC_CUR_BRIGHT as SINF_CUR_BRIGHT, doesn't know AC state */
 
-static int acpi_pcc_hotkey_add(struct acpi_device *device);
-static void acpi_pcc_hotkey_remove(struct acpi_device *device);
+static int acpi_pcc_hotkey_probe(struct platform_device *pdev);
+static void acpi_pcc_hotkey_remove(struct platform_device *pdev);
 static void acpi_pcc_hotkey_notify(acpi_handle handle, u32 event, void *data);
 
 static const struct acpi_device_id pcc_device_ids[] = {
@@ -201,15 +201,14 @@ static int acpi_pcc_hotkey_resume(struct device *dev);
 #endif
 static SIMPLE_DEV_PM_OPS(acpi_pcc_hotkey_pm, NULL, acpi_pcc_hotkey_resume);
 
-static struct acpi_driver acpi_pcc_driver = {
-	.name =		ACPI_PCC_DRIVER_NAME,
-	.class =	ACPI_PCC_CLASS,
-	.ids =		pcc_device_ids,
-	.ops =		{
-				.add =		acpi_pcc_hotkey_add,
-				.remove =	acpi_pcc_hotkey_remove,
-			},
-	.drv.pm =	&acpi_pcc_hotkey_pm,
+static struct platform_driver acpi_pcc_driver = {
+	.probe = acpi_pcc_hotkey_probe,
+	.remove = acpi_pcc_hotkey_remove,
+	.driver = {
+		.name = ACPI_PCC_DRIVER_NAME,
+		.acpi_match_table = pcc_device_ids,
+		.pm = &acpi_pcc_hotkey_pm,
+	},
 };
 
 static const struct key_entry panasonic_keymap[] = {
@@ -967,7 +966,7 @@ static int acpi_pcc_init_input(struct pcc_acpi *pcc)
 #ifdef CONFIG_PM_SLEEP
 static int acpi_pcc_hotkey_resume(struct device *dev)
 {
-	struct pcc_acpi *pcc = acpi_driver_data(to_acpi_device(dev));
+	struct pcc_acpi *pcc = acpi_driver_data(ACPI_COMPANION(dev));
 
 	if (pcc->num_sifr > SINF_MUTE)
 		acpi_pcc_write_sset(pcc, SINF_MUTE, pcc->mute);
@@ -983,8 +982,9 @@ static int acpi_pcc_hotkey_resume(struct device *dev)
 }
 #endif
 
-static int acpi_pcc_hotkey_add(struct acpi_device *device)
+static int acpi_pcc_hotkey_probe(struct platform_device *pdev)
 {
+	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 	struct backlight_properties props;
 	struct pcc_acpi *pcc;
 	int num_sifr, result;
@@ -1121,8 +1121,9 @@ static int acpi_pcc_hotkey_add(struct acpi_device *device)
 	return result;
 }
 
-static void acpi_pcc_hotkey_remove(struct acpi_device *device)
+static void acpi_pcc_hotkey_remove(struct platform_device *pdev)
 {
+	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 	struct pcc_acpi *pcc = acpi_driver_data(device);
 
 	i8042_remove_filter(panasonic_i8042_filter);
@@ -1142,8 +1143,10 @@ static void acpi_pcc_hotkey_remove(struct acpi_device *device)
 
 	input_unregister_device(pcc->input_dev);
 
+	device->driver_data = NULL;
+
 	kfree(pcc->sinf);
 	kfree(pcc);
 }
 
-module_acpi_driver(acpi_pcc_driver);
+module_platform_driver(acpi_pcc_driver);
-- 
2.51.0