driver: add PPI support in tpm driver

The Physical Presence Interface enables the OS and the BIOS to cooperate and
provides a simple and straightforward platform user experience for
administering the TPM without sacrificing security.

V2: separate the patch out in a separate source file,
    add #ifdef CONFIG_ACPI so it compiles out on ppc,
    use standard error instead of ACPI error as return code of show/store fns.
V3: move #ifdef CONFIG_ACPI from .c file to .h file.
V4: move tpm_ppi code from tpm module to tpm_bios module.
V5: modify sys_add_ppi() so that ppi_attr_grp doesn't need to be exported

Signed-off-by: Xiaoyan Zhang <xiaoyan.zhang@intel.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 0a75638e3e56..39526c053158 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -1476,6 +1476,11 @@ struct tpm_chip *tpm_register_hardware(struct device *dev,
                 goto put_device;
         }
 
+        if (sys_add_ppi(&dev->kobj)) {
+                misc_deregister(&chip->vendor.miscdev);
+                goto put_device;
+        }
+
         chip->bios_dir = tpm_bios_log_setup(devname);
 
         /* Make chip available */