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rtc: mpfs: fix unchecked devm_clk_get() error pointer in probe()

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devm_clk_get(&pdev->dev, "rtcref")'s return value was passed straight
into clk_get_rate() without checking it for an error first, unlike the
"rtc" clock a few lines above which is correctly checked with
IS_ERR(). clk_get_rate() only guards against a NULL clk, not an error
pointer:

	if (!clk)
		return 0;
	...
	rate = clk_core_get_rate_recalc(clk->core);

so if devm_clk_get() ever returns an error pointer here (for example
ERR_PTR(-EPROBE_DEFER), which is the normal, expected outcome if the
clkcfg clock-provider this RTC depends on has not registered its
clocks yet by the time this driver probes), clk_get_rate() dereferences
that error pointer instead of returning 0, crashing instead of letting
probe defer.

Capture the clock in the existing 'clk' local and check it with
IS_ERR() before calling clk_get_rate(), matching the handling already
used for the "rtc" clock in this same function.

Signed-off-by: Manush Prajwal <manushprajwal555@gmail.com>
Fixes: 0b31d70359 ("rtc: Add driver for Microchip PolarFire SoC")
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/6a9d4b02.7d74b517.206c4c.75f8@mx.google.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Manush Prajwal 2026-09-06 16:44:09 +05:30 committed by Alexandre Belloni
parent fcf0b58e97
commit ac41b05d15
1 changed files with 5 additions and 1 deletions
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6
drivers/rtc/rtc-mpfs.c
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@ -256,8 +256,12 @@ static int mpfs_rtc_probe(struct platform_device *pdev)
return ret;
}
clk = devm_clk_get(&pdev->dev, "rtcref");
if (IS_ERR(clk))
return PTR_ERR(clk);
/* prescaler hardware adds 1 to reg value */
prescaler = clk_get_rate(devm_clk_get(&pdev->dev, "rtcref")) - 1;
prescaler = clk_get_rate(clk) - 1;
if (prescaler > MAX_PRESCALER_COUNT) {
dev_dbg(&pdev->dev, "invalid prescaler %lu\n", prescaler);
return -EINVAL;