* [PATCH v1] tpm_crb: Convert ACPI driver to a platform one
@ 2026-02-23 15:55 Rafael J. Wysocki
2026-03-03 21:47 ` Jarkko Sakkinen
0 siblings, 1 reply; 2+ messages in thread
From: Rafael J. Wysocki @ 2026-02-23 15:55 UTC (permalink / raw)
To: Jarkko Sakkinen
Cc: Peter Huewe, Jason Gunthorpe, linux-integrity, LKML, Linux ACPI
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 tpm_crb 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.
Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/ [1]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/char/tpm/tpm_crb.c | 35 ++++++++++++++++-------------------
1 file changed, 16 insertions(+), 19 deletions(-)
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 6c25305c256e..7d1377e8e616 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -15,6 +15,7 @@
#include <linux/highmem.h>
#include <linux/rculist.h>
#include <linux/module.h>
+#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#ifdef CONFIG_ARM64
#include <linux/arm-smccc.h>
@@ -602,13 +603,13 @@ static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
return io_res->end - start + 1;
}
-static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
+static int crb_map_io(struct device *dev, struct crb_priv *priv,
struct acpi_table_tpm2 *buf)
{
+ struct acpi_device *device = ACPI_COMPANION(dev);
struct list_head acpi_resource_list;
struct resource iores_array[TPM_CRB_MAX_RESOURCES + 1] = { {0} };
void __iomem *iobase_array[TPM_CRB_MAX_RESOURCES] = {NULL};
- struct device *dev = &device->dev;
struct resource *iores;
void __iomem **iobase_ptr;
int i;
@@ -782,12 +783,13 @@ static int crb_map_pluton(struct device *dev, struct crb_priv *priv,
return 0;
}
-static int crb_acpi_add(struct acpi_device *device)
+static int crb_acpi_probe(struct platform_device *pdev)
{
+ struct device *dev = &pdev->dev;
+ struct acpi_device *device = ACPI_COMPANION(dev);
struct acpi_table_tpm2 *buf;
struct crb_priv *priv;
struct tpm_chip *chip;
- struct device *dev = &device->dev;
struct tpm2_crb_smc *crb_smc;
struct tpm2_crb_ffa *crb_ffa;
struct tpm2_crb_pluton *crb_pluton;
@@ -867,7 +869,7 @@ static int crb_acpi_add(struct acpi_device *device)
priv->sm = sm;
priv->hid = acpi_device_hid(device);
- rc = crb_map_io(device, priv, buf);
+ rc = crb_map_io(dev, priv, buf);
if (rc)
goto out;
@@ -901,12 +903,9 @@ static int crb_acpi_add(struct acpi_device *device)
return rc;
}
-static void crb_acpi_remove(struct acpi_device *device)
+static void crb_acpi_remove(struct platform_device *pdev)
{
- struct device *dev = &device->dev;
- struct tpm_chip *chip = dev_get_drvdata(dev);
-
- tpm_chip_unregister(chip);
+ tpm_chip_unregister(platform_get_drvdata(pdev));
}
static const struct dev_pm_ops crb_pm = {
@@ -919,19 +918,17 @@ static const struct acpi_device_id crb_device_ids[] = {
};
MODULE_DEVICE_TABLE(acpi, crb_device_ids);
-static struct acpi_driver crb_acpi_driver = {
- .name = "tpm_crb",
- .ids = crb_device_ids,
- .ops = {
- .add = crb_acpi_add,
- .remove = crb_acpi_remove,
- },
- .drv = {
+static struct platform_driver crb_acpi_driver = {
+ .probe = crb_acpi_probe,
+ .remove = crb_acpi_remove,
+ .driver = {
+ .name = "tpm_crb_acpi",
+ .acpi_match_table = crb_device_ids,
.pm = &crb_pm,
},
};
-module_acpi_driver(crb_acpi_driver);
+module_platform_driver(crb_acpi_driver);
MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
MODULE_DESCRIPTION("TPM2 Driver");
MODULE_VERSION("0.1");
--
2.51.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v1] tpm_crb: Convert ACPI driver to a platform one
2026-02-23 15:55 [PATCH v1] tpm_crb: Convert ACPI driver to a platform one Rafael J. Wysocki
@ 2026-03-03 21:47 ` Jarkko Sakkinen
0 siblings, 0 replies; 2+ messages in thread
From: Jarkko Sakkinen @ 2026-03-03 21:47 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Peter Huewe, Jason Gunthorpe, linux-integrity, LKML, Linux ACPI
On Mon, Feb 23, 2026 at 04:55:21PM +0100, Rafael J. Wysocki wrote:
> 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 tpm_crb 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.
>
> Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/ [1]
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/char/tpm/tpm_crb.c | 35 ++++++++++++++++-------------------
> 1 file changed, 16 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 6c25305c256e..7d1377e8e616 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -15,6 +15,7 @@
> #include <linux/highmem.h>
> #include <linux/rculist.h>
> #include <linux/module.h>
> +#include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> #ifdef CONFIG_ARM64
> #include <linux/arm-smccc.h>
> @@ -602,13 +603,13 @@ static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
> return io_res->end - start + 1;
> }
>
> -static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
> +static int crb_map_io(struct device *dev, struct crb_priv *priv,
> struct acpi_table_tpm2 *buf)
> {
> + struct acpi_device *device = ACPI_COMPANION(dev);
> struct list_head acpi_resource_list;
> struct resource iores_array[TPM_CRB_MAX_RESOURCES + 1] = { {0} };
> void __iomem *iobase_array[TPM_CRB_MAX_RESOURCES] = {NULL};
> - struct device *dev = &device->dev;
> struct resource *iores;
> void __iomem **iobase_ptr;
> int i;
> @@ -782,12 +783,13 @@ static int crb_map_pluton(struct device *dev, struct crb_priv *priv,
> return 0;
> }
>
> -static int crb_acpi_add(struct acpi_device *device)
> +static int crb_acpi_probe(struct platform_device *pdev)
> {
> + struct device *dev = &pdev->dev;
> + struct acpi_device *device = ACPI_COMPANION(dev);
> struct acpi_table_tpm2 *buf;
> struct crb_priv *priv;
> struct tpm_chip *chip;
> - struct device *dev = &device->dev;
> struct tpm2_crb_smc *crb_smc;
> struct tpm2_crb_ffa *crb_ffa;
> struct tpm2_crb_pluton *crb_pluton;
> @@ -867,7 +869,7 @@ static int crb_acpi_add(struct acpi_device *device)
> priv->sm = sm;
> priv->hid = acpi_device_hid(device);
>
> - rc = crb_map_io(device, priv, buf);
> + rc = crb_map_io(dev, priv, buf);
> if (rc)
> goto out;
>
> @@ -901,12 +903,9 @@ static int crb_acpi_add(struct acpi_device *device)
> return rc;
> }
>
> -static void crb_acpi_remove(struct acpi_device *device)
> +static void crb_acpi_remove(struct platform_device *pdev)
> {
> - struct device *dev = &device->dev;
> - struct tpm_chip *chip = dev_get_drvdata(dev);
> -
> - tpm_chip_unregister(chip);
> + tpm_chip_unregister(platform_get_drvdata(pdev));
> }
>
> static const struct dev_pm_ops crb_pm = {
> @@ -919,19 +918,17 @@ static const struct acpi_device_id crb_device_ids[] = {
> };
> MODULE_DEVICE_TABLE(acpi, crb_device_ids);
>
> -static struct acpi_driver crb_acpi_driver = {
> - .name = "tpm_crb",
> - .ids = crb_device_ids,
> - .ops = {
> - .add = crb_acpi_add,
> - .remove = crb_acpi_remove,
> - },
> - .drv = {
> +static struct platform_driver crb_acpi_driver = {
> + .probe = crb_acpi_probe,
> + .remove = crb_acpi_remove,
> + .driver = {
> + .name = "tpm_crb_acpi",
> + .acpi_match_table = crb_device_ids,
> .pm = &crb_pm,
> },
> };
>
> -module_acpi_driver(crb_acpi_driver);
> +module_platform_driver(crb_acpi_driver);
> MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
> MODULE_DESCRIPTION("TPM2 Driver");
> MODULE_VERSION("0.1");
> --
> 2.51.0
>
>
>
>
Yep, historical relic, thank you.
Applied.
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
BR, Jarkko
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-03-03 21:47 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-02-23 15:55 [PATCH v1] tpm_crb: Convert ACPI driver to a platform one Rafael J. Wysocki
2026-03-03 21:47 ` Jarkko Sakkinen
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox