[PATCH 4/4] i3c: dw: Preserve DAT entry bits when restoring addresses

adrianhoyin.ng at altera.com adrianhoyin.ng at altera.com
Tue Nov 4 00:51:11 PST 2025


From: Adrian Ng Ho Yin <adrianhoyin.ng at altera.com>

Update dw_i3c_master_restore_addrs() to preserve existing bits in each
Device Address Table (DAT) entry when restoring addresses. This prevents
overwriting configuration bits during PM runtime resumes.

Signed-off-by: Adrian Ng Ho Yin <adrianhoyin.ng at altera.com>
---
 drivers/i3c/master/dw-i3c-master.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 12ee4c4afedf..0a9f10677360 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -1688,11 +1688,13 @@ static void dw_i3c_master_restore_addrs(struct dw_i3c_master *master)
 		if (master->free_pos & BIT(pos))
 			continue;
 
+		reg_val = readl(master->regs + DEV_ADDR_TABLE_LOC(master->datstartaddr, pos));
+
 		if (master->devs[pos].is_i2c_addr)
-			reg_val = DEV_ADDR_TABLE_LEGACY_I2C_DEV |
+			reg_val |= DEV_ADDR_TABLE_LEGACY_I2C_DEV |
 			       DEV_ADDR_TABLE_STATIC_ADDR(master->devs[pos].addr);
 		else
-			reg_val = DEV_ADDR_TABLE_DYNAMIC_ADDR(master->devs[pos].addr);
+			reg_val |= DEV_ADDR_TABLE_DYNAMIC_ADDR(master->devs[pos].addr);
 
 		writel(reg_val, master->regs + DEV_ADDR_TABLE_LOC(master->datstartaddr, pos));
 	}
-- 
2.49.GIT




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