* [PATCH] pwm: atmel: Fix duty cycle calculation in .get_state()
@ 2021-04-18 20:57 ` Uwe Kleine-König
0 siblings, 0 replies; 4+ messages in thread
From: Uwe Kleine-König @ 2021-04-18 20:57 UTC (permalink / raw)
To: Claudiu Beznea, Thierry Reding, Lee Jones
Cc: Nicolas Ferre, Alexandre Belloni, Ludovic Desroches,
linux-arm-kernel, linux-pwm
The CDTY register contains the number of inactive cycles. .apply() does
this correctly, however .get_state got this wrong.
Fixes: 651b510a74d4 ("pwm: atmel: Implement .get_state()")
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
---
drivers/pwm/pwm-atmel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index d49da708337f..c30a0dac4b2d 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -319,7 +319,7 @@ static void atmel_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
cdty = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
atmel_pwm->data->regs.duty);
- tmp = (u64)cdty * NSEC_PER_SEC;
+ tmp = (u64)(cdty - cprd) * NSEC_PER_SEC;
tmp <<= pres;
state->duty_cycle = DIV64_U64_ROUND_UP(tmp, rate);
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] pwm: atmel: Fix duty cycle calculation in .get_state()
@ 2021-04-18 20:57 ` Uwe Kleine-König
0 siblings, 0 replies; 4+ messages in thread
From: Uwe Kleine-König @ 2021-04-18 20:57 UTC (permalink / raw)
To: Claudiu Beznea, Thierry Reding, Lee Jones
Cc: linux-pwm, Alexandre Belloni, Ludovic Desroches, linux-arm-kernel
The CDTY register contains the number of inactive cycles. .apply() does
this correctly, however .get_state got this wrong.
Fixes: 651b510a74d4 ("pwm: atmel: Implement .get_state()")
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
---
drivers/pwm/pwm-atmel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index d49da708337f..c30a0dac4b2d 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -319,7 +319,7 @@ static void atmel_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
cdty = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
atmel_pwm->data->regs.duty);
- tmp = (u64)cdty * NSEC_PER_SEC;
+ tmp = (u64)(cdty - cprd) * NSEC_PER_SEC;
tmp <<= pres;
state->duty_cycle = DIV64_U64_ROUND_UP(tmp, rate);
--
2.30.2
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] pwm: atmel: Fix duty cycle calculation in .get_state()
2021-04-18 20:57 ` Uwe Kleine-König
@ 2021-04-19 19:29 ` Uwe Kleine-König
-1 siblings, 0 replies; 4+ messages in thread
From: Uwe Kleine-König @ 2021-04-19 19:29 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: Claudiu Beznea, Thierry Reding, Lee Jones, Nicolas Ferre,
Alexandre Belloni, Ludovic Desroches, linux-arm-kernel,
linux-pwm
[-- Attachment #1: Type: text/plain, Size: 474 bytes --]
Hello,
On Sun, Apr 18, 2021 at 10:57:47PM +0200, Uwe Kleine-König wrote:
> - tmp = (u64)cdty * NSEC_PER_SEC;
> + tmp = (u64)(cdty - cprd) * NSEC_PER_SEC;
This is wrong, it must be cprd - cdty. I will send a fixed patch
together with another patch that improves precision of _apply.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] pwm: atmel: Fix duty cycle calculation in .get_state()
@ 2021-04-19 19:29 ` Uwe Kleine-König
0 siblings, 0 replies; 4+ messages in thread
From: Uwe Kleine-König @ 2021-04-19 19:29 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: linux-pwm, Alexandre Belloni, Ludovic Desroches, Thierry Reding,
Lee Jones, Claudiu Beznea, linux-arm-kernel
[-- Attachment #1.1: Type: text/plain, Size: 474 bytes --]
Hello,
On Sun, Apr 18, 2021 at 10:57:47PM +0200, Uwe Kleine-König wrote:
> - tmp = (u64)cdty * NSEC_PER_SEC;
> + tmp = (u64)(cdty - cprd) * NSEC_PER_SEC;
This is wrong, it must be cprd - cdty. I will send a fixed patch
together with another patch that improves precision of _apply.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
[-- Attachment #2: Type: text/plain, Size: 176 bytes --]
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-04-19 19:31 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-04-18 20:57 [PATCH] pwm: atmel: Fix duty cycle calculation in .get_state() Uwe Kleine-König
2021-04-18 20:57 ` Uwe Kleine-König
2021-04-19 19:29 ` Uwe Kleine-König
2021-04-19 19:29 ` Uwe Kleine-König
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