[PATCH] power: supply: use ktime_divns() to avoid 64-bit division

[PATCH] power: supply: use ktime_divns() to avoid 64-bit division

[Michal Kubecek]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1639 bytes --]

The build of intel_dc_ti_battery module on i386 (32-bit) fails with

ERROR: modpost: "__udivdi3" [drivers/power/supply/intel_dc_ti_battery.ko]

This is caused by 64-bit division of ktime values by NSEC_PER_USEC. Use
ktime_divns() helper which handles the division correctly on 32-bit
architectures.

Fixes: 8c5795fe5527 ("power: supply: Add new Intel Dollar Cove TI battery driver")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
---
 drivers/power/supply/intel_dc_ti_battery.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/intel_dc_ti_battery.c b/drivers/power/supply/intel_dc_ti_battery.c
index 56b0c92e9d28..c26209ef9577 100644
--- a/drivers/power/supply/intel_dc_ti_battery.c
+++ b/drivers/power/supply/intel_dc_ti_battery.c
@@ -141,7 +141,7 @@ static int dc_ti_battery_get_voltage_and_current_now(struct power_supply *psy, i
 	if (ret)
 		goto out_err;
 
-	cnt_start_usec = ktime_get_ns() / NSEC_PER_USEC;
+	cnt_start_usec = ktime_divns(ktime_get_ns(), NSEC_PER_USEC);
 
 	/* Read Vbat, convert IIO mV to power-supply ųV */
 	ret = iio_read_channel_processed_scale(chip->vbat_channel, volt, 1000);
@@ -149,7 +149,7 @@ static int dc_ti_battery_get_voltage_and_current_now(struct power_supply *psy, i
 		goto out_err;
 
 	/* Sleep at least 3 sample-times + slack to get 3+ CC samples */
-	now_usec = ktime_get_ns() / NSEC_PER_USEC;
+	now_usec = ktime_divns(ktime_get_ns(), NSEC_PER_USEC);
 	sleep_usec = 3 * SMPL_INTVL_US + SLEEP_SLACK_US - (now_usec - cnt_start_usec);
 	if (sleep_usec > 0 && sleep_usec < 1000000)
 		usleep_range(sleep_usec, sleep_usec + SLEEP_SLACK_US);
-- 
2.51.0

Re: [PATCH] power: supply: use ktime_divns() to avoid 64-bit division

[Hans de Goede]

Hi Michal,

On 15-Oct-25 9:56 AM, Michal Kubecek wrote:
> The build of intel_dc_ti_battery module on i386 (32-bit) fails with
> 
> ERROR: modpost: "__udivdi3" [drivers/power/supply/intel_dc_ti_battery.ko]
> 
> This is caused by 64-bit division of ktime values by NSEC_PER_USEC. Use
> ktime_divns() helper which handles the division correctly on 32-bit
> architectures.
> 
> Fixes: 8c5795fe5527 ("power: supply: Add new Intel Dollar Cove TI battery driver")
> Signed-off-by: Michal Kubecek <mkubecek@suse.cz>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hansg@kernel.org>

Regards,

Hans



> ---
>  drivers/power/supply/intel_dc_ti_battery.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/power/supply/intel_dc_ti_battery.c b/drivers/power/supply/intel_dc_ti_battery.c
> index 56b0c92e9d28..c26209ef9577 100644
> --- a/drivers/power/supply/intel_dc_ti_battery.c
> +++ b/drivers/power/supply/intel_dc_ti_battery.c
> @@ -141,7 +141,7 @@ static int dc_ti_battery_get_voltage_and_current_now(struct power_supply *psy, i
>  	if (ret)
>  		goto out_err;
>  
> -	cnt_start_usec = ktime_get_ns() / NSEC_PER_USEC;
> +	cnt_start_usec = ktime_divns(ktime_get_ns(), NSEC_PER_USEC);
>  
>  	/* Read Vbat, convert IIO mV to power-supply ųV */
>  	ret = iio_read_channel_processed_scale(chip->vbat_channel, volt, 1000);
> @@ -149,7 +149,7 @@ static int dc_ti_battery_get_voltage_and_current_now(struct power_supply *psy, i
>  		goto out_err;
>  
>  	/* Sleep at least 3 sample-times + slack to get 3+ CC samples */
> -	now_usec = ktime_get_ns() / NSEC_PER_USEC;
> +	now_usec = ktime_divns(ktime_get_ns(), NSEC_PER_USEC);
>  	sleep_usec = 3 * SMPL_INTVL_US + SLEEP_SLACK_US - (now_usec - cnt_start_usec);
>  	if (sleep_usec > 0 && sleep_usec < 1000000)
>  		usleep_range(sleep_usec, sleep_usec + SLEEP_SLACK_US);

Re: [PATCH] power: supply: use ktime_divns() to avoid 64-bit division

[Dhruva Gole]

On Oct 15, 2025 at 09:56:31 +0200, Michal Kubecek wrote:
> The build of intel_dc_ti_battery module on i386 (32-bit) fails with
> 
> ERROR: modpost: "__udivdi3" [drivers/power/supply/intel_dc_ti_battery.ko]
> 
> This is caused by 64-bit division of ktime values by NSEC_PER_USEC. Use
> ktime_divns() helper which handles the division correctly on 32-bit
> architectures.
> 
> Fixes: 8c5795fe5527 ("power: supply: Add new Intel Dollar Cove TI battery driver")
> Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
> ---

Good catch!
Reviewed-by: Dhruva Gole <d-gole@ti.com>

-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated

Re: [PATCH] power: supply: use ktime_divns() to avoid 64-bit division

[Sebastian Reichel]

On Wed, 15 Oct 2025 09:56:31 +0200, Michal Kubecek wrote:
> The build of intel_dc_ti_battery module on i386 (32-bit) fails with
> 
> ERROR: modpost: "__udivdi3" [drivers/power/supply/intel_dc_ti_battery.ko]
> 
> This is caused by 64-bit division of ktime values by NSEC_PER_USEC. Use
> ktime_divns() helper which handles the division correctly on 32-bit
> architectures.
> 
> [...]

Applied, thanks!

[1/1] power: supply: use ktime_divns() to avoid 64-bit division
      commit: 3fd1695f5da0538ef72e1268baa00528b589347a

Best regards,
-- 
Sebastian Reichel <sebastian.reichel@collabora.com>