char: tpm: cr50: Set TPM_FIRMWARE_POWER_MANAGED based on device property

Set TPM_FIRMWARE_POWER_MANAGED flag based on 'firmware-power-managed'
ACPI DSD property. For the CR50 TPM, this flag defaults to true when
the property is unset.

When this flag is set to false, the CR50 TPM driver will always send
a shutdown command whenever the system suspends.
Signed-off-by: Rob Barnes <robbarnes@google.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

drivers/char/tpm/tpm_tis_i2c_cr50.c

@@ -628,6 +628,19 @@ static bool tpm_cr50_i2c_req_canceled(struct tpm_chip *chip, u8 status)
 	return status == TPM_STS_COMMAND_READY;
 }
 
+static bool tpm_cr50_i2c_is_firmware_power_managed(struct device *dev)
+{
+	u8 val;
+	int ret;
+
+	/* This flag should default true when the device property is not present */
+	ret = device_property_read_u8(dev, "firmware-power-managed", &val);
+	if (ret)
+		return true;
+
+	return val;
+}
+
 static const struct tpm_class_ops cr50_i2c = {
 	.flags = TPM_OPS_AUTO_STARTUP,
 	.status = &tpm_cr50_i2c_tis_status,
@@ -686,7 +699,8 @@ static int tpm_cr50_i2c_probe(struct i2c_client *client)
 
 	/* cr50 is a TPM 2.0 chip */
 	chip->flags |= TPM_CHIP_FLAG_TPM2;
-	chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
+	if (tpm_cr50_i2c_is_firmware_power_managed(dev))
+		chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
 
 	/* Default timeouts */
 	chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);

drivers/char/tpm/tpm_tis_spi_cr50.c

@@ -185,6 +185,19 @@ static int cr50_spi_flow_control(struct tpm_tis_spi_phy *phy,
 	return 0;
 }
 
+static bool tpm_cr50_spi_is_firmware_power_managed(struct device *dev)
+{
+	u8 val;
+	int ret;
+
+	/* This flag should default true when the device property is not present */
+	ret = device_property_read_u8(dev, "firmware-power-managed", &val);
+	if (ret)
+		return true;
+
+	return val;
+}
+
 static int tpm_tis_spi_cr50_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
 				     u8 *in, const u8 *out)
 {
@@ -309,7 +322,8 @@ int cr50_spi_probe(struct spi_device *spi)
 	cr50_print_fw_version(&phy->priv);
 
 	chip = dev_get_drvdata(&spi->dev);
-	chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
+	if (tpm_cr50_spi_is_firmware_power_managed(&spi->dev))
+		chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
 
 	return 0;
 }