linux-kernel - [PATCH 3/5] tpm: tpm_tis: get optionally defined reset gpio

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Date:   Thu,  7 Apr 2022 13:18:47 +0200
From:   Lino Sanfilippo <LinoSanfilippo@....de>
To:     peterhuewe@....de, jarkko@...nel.org, jgg@...pe.ca,
        =robh+dt@...nel.org
Cc:     devicetree@...r.kernel.org, linux-integrity@...r.kernel.org,
        linux-kernel@...r.kernel.org, stefanb@...ux.ibm.com,
        p.rosenberger@...bus.com, lukas@...ner.de,
        Lino Sanfilippo <LinoSanfilippo@....de>
Subject: [PATCH 3/5] tpm: tpm_tis: get optionally defined reset gpio

Get the optionally specified reset gpio. This property can be set with the
con-id "reset-gpios".

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@....de>
---
 drivers/char/tpm/tpm_tis_core.c | 20 ++++++++++++++++++++
 drivers/char/tpm/tpm_tis_core.h |  1 +
 2 files changed, 21 insertions(+)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 11e5e045f3a7..89bfee3cfb18 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -24,6 +24,7 @@
 #include <linux/wait.h>
 #include <linux/acpi.h>
 #include <linux/freezer.h>
+#include <linux/gpio/consumer.h>
 #include "tpm.h"
 #include "tpm_tis_core.h"
 
@@ -919,6 +920,21 @@ static const struct tpm_class_ops tpm_tis = {
 	.clk_enable = tpm_tis_clkrun_enable,
 };
 
+/*
+ * Retrieve the reset GPIO if it is defined.
+ */
+static int tpm_tis_get_reset_gpio(struct device *dev, struct tpm_tis_data *data)
+{
+	data->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(data->reset_gpio))
+		return PTR_ERR(data->reset_gpio);
+
+	if (data->reset_gpio)
+		gpiod_set_consumer_name(data->reset_gpio, "TPM reset");
+
+	return 0;
+}
+
 int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 		      const struct tpm_tis_phy_ops *phy_ops,
 		      acpi_handle acpi_dev_handle)
@@ -952,6 +968,10 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 
 	dev_set_drvdata(&chip->dev, priv);
 
+	rc = tpm_tis_get_reset_gpio(dev, priv);
+	if (rc)
+		return rc;
+
 	if (priv->phy_ops->unset_reset)
 		priv->phy_ops->unset_reset(priv);
 
diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index f1a67445a5c5..502816d91353 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -94,6 +94,7 @@ struct tpm_tis_data {
 	int irq;
 	bool irq_tested;
 	unsigned long flags;
+	struct gpio_desc *reset_gpio;
 	void __iomem *ilb_base_addr;
 	u16 clkrun_enabled;
 	wait_queue_head_t int_queue;
-- 
2.35.1