Re: [PATCH] pwm: tegra: Fix 32 bit build
From: Jon Hunter
Date: Thu Nov 10 2022 - 08:19:04 EST
On 10/11/2022 11:45, Steven Price wrote:
The value of NSEC_PER_SEC << PWM_DUTY_WIDTH doesn't fix within a 32 bit
integer causing a build warning/error (and the value truncated):
drivers/pwm/pwm-tegra.c: In function ‘tegra_pwm_config’:
drivers/pwm/pwm-tegra.c:148:53: error: result of ‘1000000000 << 8’ requires 39 bits to represent, but ‘long int’ only has 32 bits [-Werror=shift-overflow=]
148 | required_clk_rate = DIV_ROUND_UP_ULL(NSEC_PER_SEC << PWM_DUTY_WIDTH,
| ^~
Explicitly cast to a u64 to ensure the correct result.
Fixes: cfcb68817fb3 ("pwm: tegra: Improve required rate calculation")
Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
drivers/pwm/pwm-tegra.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c
index 6fc4b69a3ba7..249dc0193297 100644
--- a/drivers/pwm/pwm-tegra.c
+++ b/drivers/pwm/pwm-tegra.c
@@ -145,7 +145,7 @@ static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
* source clock rate as required_clk_rate, PWM controller will
* be able to configure the requested period.
*/
- required_clk_rate = DIV_ROUND_UP_ULL(NSEC_PER_SEC << PWM_DUTY_WIDTH,
+ required_clk_rate = DIV_ROUND_UP_ULL((u64)NSEC_PER_SEC << PWM_DUTY_WIDTH,
period_ns);
if (required_clk_rate > clk_round_rate(pc->clk, required_clk_rate))
Thanks!
Reviewed-by: Jon Hunter <jonathanh@xxxxxxxxxx>
Jon
--
nvpublic