tpm_tis does not consider -EPROBE_DEFER in tpm_tis_plat_probe().
Instead, without notification it falls back to polling mode if
platform_get_irq_optional() returns a negative value.

This could lead to different behavior depending on wether tpm_tis was
compiled builtin or as a module; in the latter case
platform_get_irq_optional() often if not always returns a valid IRQ
number on the first attempt.

Harmonize builtin and module behavior by returning -EPROBE_DEFER,
effectively putting the device on the deferred probe list for later
probe attempts.

Signed-off-by: Dirk Gouders <redacted>
---
 drivers/char/tpm/tpm_tis.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 4ed6e660273a..4cf863704aa1 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c

@@ -320,6 +320,9 @@ static int tpm_tis_plat_probe(struct platform_device *pdev)
 
 	tpm_info.irq = platform_get_irq_optional(pdev, 0);
 	if (tpm_info.irq <= 0) {
+                if (tpm_info.irq == -EPROBE_DEFER)
+                        /* Enter deferred probe list and try again, later. */
+                        return -EPROBE_DEFER;
 		if (pdev != force_pdev)
 			tpm_info.irq = -1;
 		else

-- 
2.26.2