char/tpm: Add new driver for Infineon I2C TIS TPM

This patch adds a driver to support Infineon's SLB 9635 TT 1.2 Soft I2C TPMs
which follow the TGC TIS 1.2 TPM specification[1] and Infineon's I2C Protocol
Stack Specification 0.20.
The I2C Protocol Stack Specification is a simple adaption of the LPC TIS
Protocol to the I2C Bus.
The I2C TPMs can be used when LPC Bus is not available (i.e. non x86
architectures like ARM).

The driver is based on the tpm_tis.c driver by Leendert van Dorn and Kyleen
Hall and has quite similar functionality.

Tested on Nvidia ARM Tegra2 Development Platform and Beagleboard (ARM OMAP)
Tested with the Trousers[2] TSS API Testsuite v 0.3 [3]
Compile-tested on x86 (32/64-bit)

Updates since version 2.1.4:
- included "Lock the I2C adapter for a sequence of requests", by Bryan Freed
- use __i2c_transfer instead of own implementation of unlocked i2c_transfer
- use struct dev_pm_ops for power management via SIMPLE_DEV_PM_OPS

Updates since version 2.1.3:
- use proper probing mechanism
* either add the tpm using I2C_BOARD_INFO to your board file or probe it
* during runtime e.g on BeagleBoard using :
* "echo tpm_i2c_infineon 0x20 > /sys/bus/i2c/devices/i2c-2/new_device"
- fix possible endless loop if hardware misbehaves
- improved return codes
- consistent spelling i2c/tpm -> I2C/TPM
- remove hardcoded sleep values and msleep usage
- removed debug statements
- added check for I2C functionality
- renaming to tpm_i2c_infineon

Updates since version 2.1.2:
- added sysfs entries for duration and timeouts
- updated to new tpm_do_selftest

Updates since version 2.1.0:
- improved error handling
- implemented workarounds needed by the tpm
- fixed typos

References:
[1]
http://www.trustedcomputinggroup.org/resources/pc_client_work_group_pc_client_
specific_tpm_interface_specification_tis_version_12/
[2] http://trousers.sourceforge.net/
[3]
http://sourceforge.net/projects/trousers/files/TSS%20API%20test%20suite/0.3/Reviewed-by: Andi Shyti <andi.shyti@gmail.com>
Acked-by: Marcel Selhorst <tpmdd@selhorst.net>
Signed-off-by: Peter Huewe <peter.huewe@infineon.com>
Signed-off-by: Bryan Freed <bfreed@chromium.org>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

drivers/char/tpm/Kconfig

@@ -33,6 +33,17 @@ config TCG_TIS
 	  from within Linux.  To compile this driver as a module, choose
 	  M here; the module will be called tpm_tis.
 
+config TCG_TIS_I2C_INFINEON
+	tristate "TPM Interface Specification 1.2 Interface (I2C - Infineon)"
+	depends on I2C
+	---help---
+	  If you have a TPM security chip that is compliant with the
+	  TCG TIS 1.2 TPM specification and Infineon's I2C Protocol Stack
+	  Specification 0.20 say Yes and it will be accessible from within
+	  Linux.
+	  To compile this driver as a module, choose M here; the module
+	  will be called tpm_tis_i2c_infineon.
+
 config TCG_NSC
 	tristate "National Semiconductor TPM Interface"
 	depends on X86

drivers/char/tpm/Makefile

@@ -6,6 +6,7 @@ ifdef CONFIG_ACPI
 	obj-$(CONFIG_TCG_TPM) += tpm_bios.o
 endif
 obj-$(CONFIG_TCG_TIS) += tpm_tis.o
+obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
 obj-$(CONFIG_TCG_NSC) += tpm_nsc.o
 obj-$(CONFIG_TCG_ATMEL) += tpm_atmel.o
 obj-$(CONFIG_TCG_INFINEON) += tpm_infineon.o