[PATCH 5.9 070/152] bus: ti-sysc: Fix bogus resetdone warning on enable for cpsw

[Greg Kroah-Hartman]

From: Tony Lindgren <tony@xxxxxxxxxxx>

[ Upstream commit e7ae08d398e094e1305dee823435b1f996d39106 ]

Bail out early from sysc_wait_softreset() just like we do in sysc_reset()
if there's no sysstatus srst_shift to fix a bogus resetdone warning on
enable as suggested by Grygorii Strashko <grygorii.strashko@xxxxxx>.

We do not currently handle resets for modules that need writing to the
sysstatus register. If we at some point add that, we also need to add
SYSS_QUIRK_RESETDONE_INVERTED flag for cpsw as the sysstatus bit is low
when reset is done as described in the am335x TRM "Table 14-202
SOFT_RESET Register Field Descriptions"

Fixes: d46f9fbec719 ("bus: ti-sysc: Use optional clocks on for enable and wait for softreset bit")
Suggested-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Acked-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/bus/ti-sysc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
index 88a751c11677b..16132e6e91f8d 100644
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -227,6 +227,9 @@ static int sysc_wait_softreset(struct sysc *ddata)
 	u32 sysc_mask, syss_done, rstval;
 	int syss_offset, error = 0;
 
+	if (ddata->cap->regbits->srst_shift < 0)
+		return 0;
+
 	syss_offset = ddata->offsets[SYSC_SYSSTATUS];
 	sysc_mask = BIT(ddata->cap->regbits->srst_shift);
 
-- 
2.27.0