From ccd6a39589195d3d770a912b0aa6f65a83ba25fc Mon Sep 17 00:00:00 2001 From: Conor Dooley Date: Wed, 13 May 2026 18:55:55 +0100 Subject: [PATCH] rtc: mpfs: fix counter upload completion condition The condition that needs to be checked for upload completion is the UPLOAD bit in the completion register going low. The original iterations of this driver used a do-while and this was converted to a read_poll_timeout() during upstreaming without the condition being inverted as it should have been. I suspect that this went unnoticed until now because a) the first read was done when the bit was still set, immediately completing the read_poll_timeout() and b) because the RTC doesn't hold time when power is removed from the SoC reducing its utility (I for one keep it disabled). If my first suspicion was true when the driver was upstreamed, it's not true any longer though, hence the detection of the problem. Fixes: 0b31d703598dc ("rtc: Add driver for Microchip PolarFire SoC") CC: stable@vger.kernel.org Signed-off-by: Conor Dooley Signed-off-by: Linux RISC-V bot --- drivers/rtc/rtc-mpfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/rtc/rtc-mpfs.c b/drivers/rtc/rtc-mpfs.c index 6aa3eae575d2ad..ece6de4a6adbd1 100644 --- a/drivers/rtc/rtc-mpfs.c +++ b/drivers/rtc/rtc-mpfs.c @@ -112,7 +112,7 @@ static int mpfs_rtc_settime(struct device *dev, struct rtc_time *tm) ctrl |= CONTROL_UPLOAD_BIT; writel(ctrl, rtcdev->base + CONTROL_REG); - ret = read_poll_timeout(readl, prog, prog & CONTROL_UPLOAD_BIT, 0, UPLOAD_TIMEOUT_US, + ret = read_poll_timeout(readl, prog, !(prog & CONTROL_UPLOAD_BIT), 0, UPLOAD_TIMEOUT_US, false, rtcdev->base + CONTROL_REG); if (ret) { dev_err(dev, "timed out uploading time to rtc");