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

Miquel Raynal
2018-05-15T09:57:22Z

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@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