tpm2: tis_spi: add the possibility to reset the chip with a gpio

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>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/tpm/tpm2_tis_spi.c b/drivers/tpm/tpm2_tis_spi.c
index 518a08b48defb7af1a0572dfc82d4881b225237a..c5d17a679d2d2965ea17d508886239568f67c3c4 100644 (file)
--- a/drivers/tpm/tpm2_tis_spi.c
+++ b/drivers/tpm/tpm2_tis_spi.c
@@ -23,6 +23,7 @@
 #include <linux/compiler.h>
 #include <linux/types.h>
 #include <linux/unaligned/be_byteshift.h>
+#include <asm-generic/gpio.h>
 
 #include "tpm_tis.h"
 #include "tpm_internal.h"
@@ -574,6 +575,21 @@ static int tpm_tis_spi_probe(struct udevice *dev)
        struct tpm_chip *chip = dev_get_priv(dev);
        int ret;
 
+       if (IS_ENABLED(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);
+               }
+       }
+
        /* Ensure a minimum amount of time elapsed since reset of the TPM */
        mdelay(drv_data->time_before_first_cmd_ms);