* [PATCH v4] pwm: atmel: Enable clk when pwm already enabled in bootloader
@ 2023-07-12 13:43 Guiting Shen
2023-07-12 13:55 ` Uwe Kleine-König
0 siblings, 1 reply; 3+ messages in thread
From: Guiting Shen @ 2023-07-12 13:43 UTC (permalink / raw)
To: thierry.reding, u.kleine-koenig
Cc: linux-pwm, alexandre.belloni, Guiting Shen, linux-kernel,
claudiu.beznea, linux-arm-kernel
The driver would never call clk_enable() if the PWM channel was already
enabled in bootloader which lead to dump the warning message "the PWM
clock already disabled" when turning off the PWM channel.
Add atmel_pwm_enable_clk_if_on() in probe function to enable clock if
the PWM channel was already enabled in bootloader.
Signed-off-by: Guiting Shen <aarongt.shen@gmail.com>
---
drivers/pwm/pwm-atmel.c | 40 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index cdbc23649032..28ea0f7267ca 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -36,7 +36,7 @@
#define PWM_SR 0x0C
#define PWM_ISR 0x1C
/* Bit field in SR */
-#define PWM_SR_ALL_CH_ON 0x0F
+#define PWM_SR_ALL_CH_MASK 0x0F
/* The following register is PWM channel related registers */
#define PWM_CH_REG_OFFSET 0x200
@@ -464,6 +464,37 @@ static const struct of_device_id atmel_pwm_dt_ids[] = {
};
MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
+static int atmel_pwm_enable_clk_if_on(struct atmel_pwm_chip *atmel_pwm)
+{
+ unsigned int i;
+ int err;
+ u32 sr;
+
+ sr = atmel_pwm_readl(atmel_pwm, PWM_SR);
+ if (!(sr & PWM_SR_ALL_CH_MASK))
+ return 0;
+
+ for (i = 0; i < atmel_pwm->chip.npwm; i++) {
+ if (!(sr & (1 << i)))
+ continue;
+
+ err = clk_enable(atmel_pwm->clk);
+ if (err) {
+ dev_err(atmel_pwm->chip.dev,
+ "failed to enable clock for pwm #%d: %pe\n",
+ i, ERR_PTR(err));
+
+ while (i--) {
+ if (sr & (1 << i))
+ clk_disable(atmel_pwm->clk);
+ }
+ return err;
+ }
+ }
+
+ return 0;
+}
+
static int atmel_pwm_probe(struct platform_device *pdev)
{
struct atmel_pwm_chip *atmel_pwm;
@@ -504,8 +535,15 @@ static int atmel_pwm_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, atmel_pwm);
+ ret = atmel_pwm_enable_clk_if_on(atmel_pwm);
+ if (ret < 0)
+ goto remove_pwmchip;
+
return ret;
+remove_pwmchip:
+ pwmchip_remove(&atmel_pwm->chip);
+
unprepare_clk:
clk_unprepare(atmel_pwm->clk);
return ret;
--
2.25.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v4] pwm: atmel: Enable clk when pwm already enabled in bootloader
2023-07-12 13:43 [PATCH v4] pwm: atmel: Enable clk when pwm already enabled in bootloader Guiting Shen
@ 2023-07-12 13:55 ` Uwe Kleine-König
2023-07-12 14:28 ` Guiting Shen
0 siblings, 1 reply; 3+ messages in thread
From: Uwe Kleine-König @ 2023-07-12 13:55 UTC (permalink / raw)
To: Guiting Shen
Cc: linux-pwm, alexandre.belloni, linux-kernel, thierry.reding,
claudiu.beznea, linux-arm-kernel
[-- Attachment #1.1: Type: text/plain, Size: 2709 bytes --]
On Wed, Jul 12, 2023 at 09:43:47PM +0800, Guiting Shen wrote:
> The driver would never call clk_enable() if the PWM channel was already
> enabled in bootloader which lead to dump the warning message "the PWM
> clock already disabled" when turning off the PWM channel.
>
> Add atmel_pwm_enable_clk_if_on() in probe function to enable clock if
> the PWM channel was already enabled in bootloader.
>
> Signed-off-by: Guiting Shen <aarongt.shen@gmail.com>
> ---
> drivers/pwm/pwm-atmel.c | 40 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
> index cdbc23649032..28ea0f7267ca 100644
> --- a/drivers/pwm/pwm-atmel.c
> +++ b/drivers/pwm/pwm-atmel.c
> @@ -36,7 +36,7 @@
> #define PWM_SR 0x0C
> #define PWM_ISR 0x1C
> /* Bit field in SR */
> -#define PWM_SR_ALL_CH_ON 0x0F
> +#define PWM_SR_ALL_CH_MASK 0x0F
>
> /* The following register is PWM channel related registers */
> #define PWM_CH_REG_OFFSET 0x200
> @@ -464,6 +464,37 @@ static const struct of_device_id atmel_pwm_dt_ids[] = {
> };
> MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
>
> +static int atmel_pwm_enable_clk_if_on(struct atmel_pwm_chip *atmel_pwm)
> +{
> + unsigned int i;
> + int err;
> + u32 sr;
> +
> + sr = atmel_pwm_readl(atmel_pwm, PWM_SR);
> + if (!(sr & PWM_SR_ALL_CH_MASK))
> + return 0;
> +
> + for (i = 0; i < atmel_pwm->chip.npwm; i++) {
> + if (!(sr & (1 << i)))
> + continue;
> +
> + err = clk_enable(atmel_pwm->clk);
> + if (err) {
> + dev_err(atmel_pwm->chip.dev,
> + "failed to enable clock for pwm #%d: %pe\n",
> + i, ERR_PTR(err));
> +
> + while (i--) {
> + if (sr & (1 << i))
> + clk_disable(atmel_pwm->clk);
> + }
> + return err;
> + }
> + }
> +
> + return 0;
> +}
> +
> static int atmel_pwm_probe(struct platform_device *pdev)
> {
> struct atmel_pwm_chip *atmel_pwm;
> @@ -504,8 +535,15 @@ static int atmel_pwm_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, atmel_pwm);
>
> + ret = atmel_pwm_enable_clk_if_on(atmel_pwm);
> + if (ret < 0)
> + goto remove_pwmchip;
> +
> return ret;
>
> +remove_pwmchip:
> + pwmchip_remove(&atmel_pwm->chip);
> +
I'd consider it more natural to do the atmel_pwm_enable_clk_if_on() call
before registering the pwmchip. But I guess it works like this, too.
(Well unless it's possible that there are set bits in PWM_SR and the
clock is off.)
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] 3+ messages in thread
* Re: [PATCH v4] pwm: atmel: Enable clk when pwm already enabled in bootloader
2023-07-12 13:55 ` Uwe Kleine-König
@ 2023-07-12 14:28 ` Guiting Shen
0 siblings, 0 replies; 3+ messages in thread
From: Guiting Shen @ 2023-07-12 14:28 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: linux-pwm, alexandre.belloni, linux-kernel, thierry.reding,
claudiu.beznea, linux-arm-kernel
On Wed,Jul 12,2023 at 21:55:53PM GMT+8, Uwe Kleine-König wrote:
> On Wed, Jul 12, 2023 at 09:43:47PM +0800, Guiting Shen wrote:
>> The driver would never call clk_enable() if the PWM channel was already
>> enabled in bootloader which lead to dump the warning message "the PWM
>> clock already disabled" when turning off the PWM channel.
>>
>> Add atmel_pwm_enable_clk_if_on() in probe function to enable clock if
>> the PWM channel was already enabled in bootloader.
>>
>> Signed-off-by: Guiting Shen <aarongt.shen@gmail.com>
>> ---
>> drivers/pwm/pwm-atmel.c | 40 +++++++++++++++++++++++++++++++++++++++-
>> 1 file changed, 39 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
>> index cdbc23649032..28ea0f7267ca 100644
>> --- a/drivers/pwm/pwm-atmel.c
>> +++ b/drivers/pwm/pwm-atmel.c
>> @@ -36,7 +36,7 @@
>> #define PWM_SR 0x0C
>> #define PWM_ISR 0x1C
>> /* Bit field in SR */
>> -#define PWM_SR_ALL_CH_ON 0x0F
>> +#define PWM_SR_ALL_CH_MASK 0x0F
>>
>> /* The following register is PWM channel related registers */
>> #define PWM_CH_REG_OFFSET 0x200
>> @@ -464,6 +464,37 @@ static const struct of_device_id atmel_pwm_dt_ids[] = {
>> };
>> MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
>>
>> +static int atmel_pwm_enable_clk_if_on(struct atmel_pwm_chip *atmel_pwm)
>> +{
>> + unsigned int i;
>> + int err;
>> + u32 sr;
>> +
>> + sr = atmel_pwm_readl(atmel_pwm, PWM_SR);
>> + if (!(sr & PWM_SR_ALL_CH_MASK))
>> + return 0;
>> +
>> + for (i = 0; i < atmel_pwm->chip.npwm; i++) {
>> + if (!(sr & (1 << i)))
>> + continue;
>> +
>> + err = clk_enable(atmel_pwm->clk);
>> + if (err) {
>> + dev_err(atmel_pwm->chip.dev,
>> + "failed to enable clock for pwm #%d: %pe\n",
>> + i, ERR_PTR(err));
>> +
>> + while (i--) {
>> + if (sr & (1 << i))
>> + clk_disable(atmel_pwm->clk);
>> + }
>> + return err;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static int atmel_pwm_probe(struct platform_device *pdev)
>> {
>> struct atmel_pwm_chip *atmel_pwm;
>> @@ -504,8 +535,15 @@ static int atmel_pwm_probe(struct platform_device *pdev)
>>
>> platform_set_drvdata(pdev, atmel_pwm);
>>
>> + ret = atmel_pwm_enable_clk_if_on(atmel_pwm);
>> + if (ret < 0)
>> + goto remove_pwmchip;
>> +
>> return ret;
>>
>> +remove_pwmchip:
>> + pwmchip_remove(&atmel_pwm->chip);
>> +
>
> I'd consider it more natural to do the atmel_pwm_enable_clk_if_on() call
> before registering the pwmchip. But I guess it works like this, too.
> (Well unless it's possible that there are set bits in PWM_SR and the
> clock is off.)
It need to invoke something like atmel_pwm_disable_clk_if_on() after
failing to register the pwmchip when call the
atmel_pwm_enable_clk_if_on() first which I feel inconvenient.
And it's impossible to enable PWM channels before enabling the clock.
The bits set in PWM_SR means that the PWM channel and the clock turn on.
--
Best regards,
Guiting Shen
_______________________________________________
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] 3+ messages in thread
end of thread, other threads:[~2023-07-12 14:28 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-07-12 13:43 [PATCH v4] pwm: atmel: Enable clk when pwm already enabled in bootloader Guiting Shen
2023-07-12 13:55 ` Uwe Kleine-König
2023-07-12 14:28 ` Guiting Shen
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).