[PATCH v1 1/1] iio: adc: nxp-sar-adc: Fix the delay calculation in nxp_sar_adc_wait_for()

From: Andy Shevchenko

Date: Tue May 19 2026 - 17:56:17 EST


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@xxxxxxxxxx>
Closes: https://sashiko.dev/#/patchset/20260416090122.758990-1-andriy.shevchenko%40linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
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