tpm: Introduce TPM_CHIP_FLAG_VIRTUAL

Introduce TPM_CHIP_FLAG_VIRTUAL to be used when the chip device has no
parent device.

Prevent sysfs entries requiring a parent device from being created.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

2 files changed, 6 insertions, 2 deletions

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 57d9794dac94..1965dc780688 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -181,6 +181,9 @@ struct tpm_chip *tpm_chip_alloc(struct device *dev,
         if (rc)
                 goto out;
 
+        if (!dev)
+                chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
+
         cdev_init(&chip->cdev, &tpm_fops);
         chip->cdev.owner = THIS_MODULE;
         chip->cdev.kobj.parent = &chip->dev.kobj;
@@ -298,7 +301,7 @@ static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
 {
         struct attribute **i;
 
-        if (chip->flags & TPM_CHIP_FLAG_TPM2)
+        if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
                 return;
 
         sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
@@ -316,7 +319,7 @@ static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
         struct attribute **i;
         int rc;
 
-        if (chip->flags & TPM_CHIP_FLAG_TPM2)
+        if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
                 return 0;
 
         rc = __compat_only_sysfs_link_entry_to_kobj(
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 508e8e00c9c1..ff4e53cde70e 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -138,6 +138,7 @@ enum tpm_chip_flags {
         TPM_CHIP_FLAG_REGISTERED        = BIT(0),
         TPM_CHIP_FLAG_TPM2              = BIT(1),
         TPM_CHIP_FLAG_IRQ               = BIT(2),
+        TPM_CHIP_FLAG_VIRTUAL           = BIT(3),
 };
 
 struct tpm_chip {