The hardware strap register(SCU70) only accepts write ‘1’,
to clear it to ‘0’, must set bits(write  ‘1’) to SCU7C

Signed-off-by: Yong Li <[email protected]>
---
 drivers/pinctrl/aspeed/pinctrl-aspeed.c | 9 +++++++--
 drivers/pinctrl/aspeed/pinctrl-aspeed.h | 1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/pinctrl/aspeed/pinctrl-aspeed.c 
b/drivers/pinctrl/aspeed/pinctrl-aspeed.c
index a86a4d6..4305052 100644
--- a/drivers/pinctrl/aspeed/pinctrl-aspeed.c
+++ b/drivers/pinctrl/aspeed/pinctrl-aspeed.c
@@ -213,8 +213,13 @@ static int aspeed_sig_expr_set(const struct 
aspeed_sig_expr *expr,
                if (desc->ip == ASPEED_IP_SCU && desc->reg == HW_STRAP2)
                        continue;
 
-               ret = regmap_update_bits(maps[desc->ip], desc->reg,
-                                        desc->mask, val);
+               if (desc->ip == ASPEED_IP_SCU && desc->reg == HW_STRAP1 &&
+                       val == 0)
+                       ret = regmap_update_bits(maps[desc->ip], HW_REVISION_ID,
+                               desc->mask, desc->mask);
+               else
+                       ret = regmap_update_bits(maps[desc->ip], desc->reg,
+                               desc->mask, val);
 
                if (ret)
                        return ret;
diff --git a/drivers/pinctrl/aspeed/pinctrl-aspeed.h 
b/drivers/pinctrl/aspeed/pinctrl-aspeed.h
index fa125db..d4d7f03 100644
--- a/drivers/pinctrl/aspeed/pinctrl-aspeed.h
+++ b/drivers/pinctrl/aspeed/pinctrl-aspeed.h
@@ -251,6 +251,7 @@
 #define SCU3C           0x3C /* System Reset Control/Status Register */
 #define SCU48           0x48 /* MAC Interface Clock Delay Setting */
 #define HW_STRAP1       0x70 /* AST2400 strapping is 33 bits, is split */
+#define HW_REVISION_ID  0x7C /* Silicon revision ID register */
 #define SCU80           0x80 /* Multi-function Pin Control #1 */
 #define SCU84           0x84 /* Multi-function Pin Control #2 */
 #define SCU88           0x88 /* Multi-function Pin Control #3 */
-- 
2.7.4

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