linux-kernel - [PATCH misc v2] misc: cardreader: fix overwritten return value in RTS5260 driver

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Message-Id: <20250729013510.34358-1-27392025k@gmail.com>
Date: Mon, 28 Jul 2025 18:35:10 -0700
From: Tian <27392025k@...il.com>
To: gregkh@...uxfoundation.org
Cc: arnd@...db.de,
	linux-kernel@...r.kernel.org,
	Tian Liu <27392025k@...il.com>
Subject: [PATCH misc v2] misc: cardreader: fix overwritten return value in RTS5260 driver

From: Tian Liu <27392025k@...il.com>

In both rts5260.c and rtsx_pcr.c, a return value is assigned and then
overwritten by a subsequent call, which causes the original result to be
lost. This may result in silently ignoring errors from the first write.

This patch uses `err |=` to preserve earlier failure status.

This is an untested cleanup inspired by commit c55c7a85e02a ("um: ubd: Preserve earlier error value in ubd_user") which fixed similar error-handling logic. While this change has not been functionally tested on hardware, it is a mechanical fix and aligns with expected error-handling style.

Fixes: bede03a579b3 ("misc: rtsx: Enable OCP for rts522a rts524a rts525a rts5260")
Fixes: c0e5f4e73a71 ("misc: rtsx: Add support for RTS5261")

Signed-off-by: Tian Liu <27392025k@...il.com>

Changes in v2:
- Use full name in Signed-off-by and From
- Add Fixes: tag
- Clarify that patch is untested, but reasoned from upstream style
- Cc: appropriate public mailing list

---
 drivers/misc/cardreader/rts5260.c  | 2 +-
 drivers/misc/cardreader/rtsx_pcr.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/cardreader/rts5260.c b/drivers/misc/cardreader/rts5260.c
index d2d3a6ccb8f7..ed8adaab54a8 100644
--- a/drivers/misc/cardreader/rts5260.c
+++ b/drivers/misc/cardreader/rts5260.c
@@ -269,7 +269,7 @@ static int rts5260_card_power_off(struct rtsx_pcr *pcr, int card)
 	rts5260_card_before_power_off(pcr);
 	err = rtsx_pci_write_register(pcr, LDO_VCC_CFG1,
 			 LDO_POW_SDVDD1_MASK, LDO_POW_SDVDD1_OFF);
-	err = rtsx_pci_write_register(pcr, LDO_CONFIG2,
+	err |= rtsx_pci_write_register(pcr, LDO_CONFIG2,
 			 DV331812_POWERON, DV331812_POWEROFF);
 	if (pcr->option.ocp_en)
 		rtsx_pci_disable_ocp(pcr);
diff --git a/drivers/misc/cardreader/rtsx_pcr.c b/drivers/misc/cardreader/rtsx_pcr.c
index a7b066c48740..9fb22f2cedbd 100644
--- a/drivers/misc/cardreader/rtsx_pcr.c
+++ b/drivers/misc/cardreader/rtsx_pcr.c
@@ -1196,7 +1196,7 @@ static int rtsx_pci_init_hw(struct rtsx_pcr *pcr)
 		/* Gating real mcu clock */
 		err = rtsx_pci_write_register(pcr, RTS5261_FW_CFG1,
 			RTS5261_MCU_CLOCK_GATING, 0);
-		err = rtsx_pci_write_register(pcr, RTS5261_REG_FPDCTL,
+		err |= rtsx_pci_write_register(pcr, RTS5261_REG_FPDCTL,
 			SSC_POWER_DOWN, 0);
 	} else {
 		err = rtsx_pci_write_register(pcr, FPDCTL, SSC_POWER_DOWN, 0);
-- 
2.39.5 (Apple Git-154)