[U-Boot] [PATCH v4 26/32] tpm: add the possibility to reset the chip with a gpio

[Miquel Raynal]

On some designs, the reset line could not be connected to the SoC reset
line, in this case, request the GPIO and ensure the chip gets reset.

Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
---
 drivers/tpm/tpm2_tis_spi.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/tpm/tpm2_tis_spi.c b/drivers/tpm/tpm2_tis_spi.c
index 6a4d5284c9..1c7f8f3673 100644
--- a/drivers/tpm/tpm2_tis_spi.c
+++ b/drivers/tpm/tpm2_tis_spi.c
@@ -24,6 +24,9 @@
 #include <linux/compiler.h>
 #include <linux/types.h>
 #include <linux/unaligned/be_byteshift.h>
+#ifdef CONFIG_DM_GPIO
+#include <asm-generic/gpio.h>
+#endif
 
 #include "tpm_tis.h"
 #include "tpm_internal.h"
@@ -574,6 +577,20 @@ static int tpm_tis_spi_probe(struct udevice *dev)
 	struct tpm_chip_priv *priv = dev_get_uclass_priv(dev);
 	struct tpm_chip *chip = dev_get_priv(dev);
 	int ret;
+#ifdef CONFIG_DM_GPIO
+	struct gpio_desc reset_gpio;
+
+	ret = gpio_request_by_name(dev, "gpio-reset", 0,
+				   &reset_gpio, GPIOD_IS_OUT);
+	if (ret) {
+		log(LOGC_NONE, LOGL_NOTICE, "%s: missing reset GPIO\n",
+		    __func__);
+	} else {
+		dm_gpio_set_value(&reset_gpio, 0);
+		mdelay(1);
+		dm_gpio_set_value(&reset_gpio, 1);
+	}
+#endif
 
 	/* Ensure a minimum amount of time elapsed since reset of the TPM */
 	mdelay(drv_data->time_before_first_cmd_ms);
-- 
2.14.1