From: Sonny Rao <sonny...@chromium.org>
The suspend/resume behavior of the TPM can be controlled
by setting "powered-while-suspended" in the DTS.
Signed-off-by: Sonny Rao <sonny...@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
---
Documentation/devicetree/bindings/tpm/tpm.txt | 25 +++++++++++++++++++++++++
drivers/char/tpm/tpm_i2c_infineon.c | 25 ++++++++++++++++++++++++-
2 files changed, 49 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/tpm/tpm.txt
diff --git a/Documentation/devicetree/bindings/tpm/tpm.txt
b/Documentation/devicetree/bindings/tpm/tpm.txt
new file mode 100644
index 0000000..af4de0d
--- /dev/null
+++ b/Documentation/devicetree/bindings/tpm/tpm.txt
@@ -0,0 +1,25 @@
+TPM (Trusted Platform Module)
+
+A TPM on the I2C bus is a child of the node for the bus.
+
+Required properties:
+- compatible: should be "infineon,<chip>"
+- reg: the I2C address
+
+Optional properties:
+- powered-while-suspended: present when the TPM is left powered on between
+ suspend and resume (makes the suspend/resume callbacks do nothing).
+
+Example:
+ i2c@12C90000 {
+ samsung,i2c-sda-delay = <100>;
+ samsung,i2c-max-bus-freq = <66000>;
+ gpios = <&gpa1 2 3 3 0>,
+ <&gpa1 3 3 3 0>;
+
+ tpm {
+ compatible = "infineon,slb9635tt";
+ reg = <0x20>;
+ powered-while-suspended;
+ };
+ };
diff --git a/drivers/char/tpm/tpm_i2c_infineon.c
b/drivers/char/tpm/tpm_i2c_infineon.c
index 62ee44e..19d9522 100644
--- a/drivers/char/tpm/tpm_i2c_infineon.c
+++ b/drivers/char/tpm/tpm_i2c_infineon.c
@@ -70,6 +70,7 @@ struct tpm_inf_dev {
u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
struct tpm_chip *chip;
enum i2c_chip_type chip_type;
+ bool powered_while_suspended;
};
static struct tpm_inf_dev tpm_dev;
@@ -599,6 +600,11 @@ static int tpm_tis_i2c_init(struct device *dev)
goto out_err;
}
+ if (dev->of_node &&
+ of_get_property(dev->of_node, "powered-while-suspended", NULL)) {
+ tpm_dev.powered_while_suspended = true;
+ }
+
/* read four bytes from DID_VID register */
if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
dev_err(dev, "could not read vendor id\n");
@@ -662,7 +668,24 @@ static const struct of_device_id tpm_tis_i2c_of_match[] = {
MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
#endif
-static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
+static int __maybe_unused tpm_tis_i2c_suspend(struct device *dev)
+{
+ if (tpm_dev.powered_while_suspended)
+ return 0;
+
+ return tpm_pm_suspend(dev);
+}
+
+static int __maybe_unused tpm_tis_i2c_resume(struct device *dev)
+{
+ if (tpm_dev.powered_while_suspended)
+ return 0;
+
+ return tpm_pm_resume(dev);
+}
+
+static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_tis_i2c_suspend,
+ tpm_tis_i2c_resume);
static int tpm_tis_i2c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
--
2.9.3
