[PATCH] mmc: rtsx_usb_sdmmc: Fix clang -Wimplicit-fallthrough in sd_set_power_mode()

[Nathan Chancellor <nathan@kernel.org>]

Clang warns (or errors with CONFIG_WERROR=y):

  drivers/mmc/host/rtsx_usb_sdmmc.c:1042:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
   1042 |         case MMC_POWER_UNDEFINED:
        |         ^
  drivers/mmc/host/rtsx_usb_sdmmc.c:1042:2: note: insert 'break;' to avoid fall-through
   1042 |         case MMC_POWER_UNDEFINED:
        |         ^
        |         break;

Clang is a little more pedantic than GCC, which does not warn when
falling through to a case that is just break or return. Clang's version
is more in line with the kernel's own stance in deprecated.rst, which
states that all switch/case blocks must end in either break,
fallthrough, continue, goto, or return. Add the missing break to silence
the warning.

Fixes: 2c3809bd6f65 ("mmc: rtsx_usb_sdmmc: Add 74 clocks in poweron flow")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/mmc/host/rtsx_usb_sdmmc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mmc/host/rtsx_usb_sdmmc.c b/drivers/mmc/host/rtsx_usb_sdmmc.c
index 591d37206654..c5f6b9df066b 100644
--- a/drivers/mmc/host/rtsx_usb_sdmmc.c
+++ b/drivers/mmc/host/rtsx_usb_sdmmc.c
@@ -1039,6 +1039,8 @@ static void sd_set_power_mode(struct rtsx_usb_sdmmc *host,
 	case MMC_POWER_ON:
 		/* stop to send the clock signals */
 		rtsx_usb_write_register(ucr, SD_BUS_STAT, SD_CLK_TOGGLE_EN, 0x00);
+		break;
+
 	case MMC_POWER_UNDEFINED:
 		break;
 

---
base-commit: f5c755ef810009b85350884c483705bd04365370
change-id: 20250620-mmc-rtsx-usb-sdmmc-fix-clang-implicit-fallthrough-732a574554b0

Best regards,
--  
Nathan Chancellor <nathan@kernel.org>