tpm_tis: Allow tpm_tis to be bound using DT

This provides an open firwmare driver binding for tpm_tis. OF
is useful on arches where ACPI/PNP is not used.

The tcg,tpm-tis-mmio register map interface is specified by the TCG.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

3 files changed, 37 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/security/tpm/tpm_tis_mmio.txt b/Documentation/devicetree/bindings/security/tpm/tpm_tis_mmio.txt
new file mode 100644
index 000000000000..41d740545189
--- /dev/null
+++ b/Documentation/devicetree/bindings/security/tpm/tpm_tis_mmio.txt
@@ -0,0 +1,25 @@
+Trusted Computing Group MMIO Trusted Platform Module
+
+The TCG defines multi vendor standard for accessing a TPM chip, this
+is the standard protocol defined to access the TPM via MMIO. Typically
+this interface will be implemented over Intel's LPC bus.
+
+Refer to the 'TCG PC Client Specific TPM Interface Specification (TIS)' TCG
+publication for the specification.
+
+Required properties:
+
+- compatible: should contain a string below for the chip, followed by
+              "tcg,tpm-tis-mmio". Valid chip strings are:
+	          * "atmel,at97sc3204"
+- reg: The location of the MMIO registers, should be at least 0x5000 bytes
+- interrupt-parent/interrupts: An optional interrupt indicating command completion.
+
+Example:
+
+	tpm_tis@90000 {
+				compatible = "atmel,at97sc3204", "tcg,tpm-tis-mmio";
+				reg = <0x90000 0x5000>;
+				interrupt-parent = <&EIC0>;
+				interrupts = <1 2>;
+	};
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index 9faa0b1e7766..277186d3b668 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -32,7 +32,7 @@ config TCG_TIS_CORE
 
 config TCG_TIS
 	tristate "TPM Interface Specification 1.2 Interface / TPM 2.0 FIFO Interface"
-	depends on X86
+	depends on X86 || OF
 	select TCG_TIS_CORE
 	---help---
 	  If you have a TPM security chip that is compliant with the
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index eaf5730d79eb..0127af130cb1 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -28,6 +28,8 @@
 #include <linux/wait.h>
 #include <linux/acpi.h>
 #include <linux/freezer.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include "tpm.h"
 #include "tpm_tis_core.h"
 
@@ -354,12 +356,21 @@ static int tpm_tis_plat_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id tis_of_platform_match[] = {
+	{.compatible = "tcg,tpm-tis-mmio"},
+	{},
+};
+MODULE_DEVICE_TABLE(of, tis_of_platform_match);
+#endif
+
 static struct platform_driver tis_drv = {
 	.probe = tpm_tis_plat_probe,
 	.remove = tpm_tis_plat_remove,
 	.driver = {
 		.name		= "tpm_tis",
 		.pm		= &tpm_tis_pm,
+		.of_match_table = of_match_ptr(tis_of_platform_match),
 	},
 };