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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Jonathan Cameron <jic23@kernel.org>,
	Daniel Lezcano <daniel.lezcano@kernel.org>,
	linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: "David Lechner" <dlechner@baylibre.com>,
	"Nuno Sá" <nuno.sa@analog.com>,
	"Andy Shevchenko" <andy@kernel.org>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	Sashiko <sashiko-bot@kernel.org>
Subject: [PATCH v1 1/1] iio: adc: nxp-sar-adc: Fix the delay calculation in nxp_sar_adc_wait_for()
Date: Tue, 19 May 2026 23:56:06 +0200	[thread overview]
Message-ID: <20260519215607.78241-1-andriy.shevchenko@linux.intel.com> (raw)

The original code was using ndelay() twice. In one case the delay
is calculated as 1/3 of ADC clock and in the other as 80 ADC clocks.
But according to the comments in all cases it should be a multiplier
of the ADC clock, and not a fraction of it. Inadvertently
nxp_sar_adc_wait_for() takes the wrong case and spread it over
the code make it wrong in all places. Fix this by modifying a helper
to correctly use the multiplier.

Fixes: 7e5c0f97c66a ("iio: adc: nxp-sar-adc: Avoid division by zero")
Fixes: 4434072a893e ("iio: adc: Add the NXP SAR ADC support for the s32g2/3 platforms")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260416090122.758990-1-andriy.shevchenko%40linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iio/adc/nxp-sar-adc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/nxp-sar-adc.c b/drivers/iio/adc/nxp-sar-adc.c
index 01f3da56e987..68d237ef30c2 100644
--- a/drivers/iio/adc/nxp-sar-adc.c
+++ b/drivers/iio/adc/nxp-sar-adc.c
@@ -198,13 +198,13 @@ static void nxp_sar_adc_irq_cfg(struct nxp_sar_adc *info, bool enable)
 		writel(0, NXP_SAR_ADC_IMR(info->regs));
 }
 
-static void nxp_sar_adc_wait_for(struct nxp_sar_adc *info, unsigned int cycles)
+static void nxp_sar_adc_wait_for(struct nxp_sar_adc *info, u64 cycles)
 {
 	u64 rate;
 
 	rate = clk_get_rate(info->clk);
 	if (rate)
-		ndelay(div64_u64(NSEC_PER_SEC, rate * cycles));
+		ndelay(div64_u64(NSEC_PER_SEC * cycles, rate));
 }
 
 static bool nxp_sar_adc_set_enabled(struct nxp_sar_adc *info, bool enable)
-- 
2.50.1


             reply	other threads:[~2026-05-19 21:56 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-19 21:56 Andy Shevchenko [this message]
2026-05-20 11:42 ` [PATCH v1 1/1] iio: adc: nxp-sar-adc: Fix the delay calculation in nxp_sar_adc_wait_for() Stepan Ionichev
2026-05-22 17:35 ` Jonathan Cameron
2026-05-26 12:48   ` Daniel Lezcano
2026-07-03 19:06     ` Jonathan Cameron
2026-07-03 20:42       ` Daniel Lezcano
2026-07-03 22:55         ` Jonathan Cameron

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