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 <[email protected]>
---
drivers/pwm/pwm-atmel.c | 50 +++++++++++++++++++++++++++++++++++++++--
1 file changed, 48 insertions(+), 2 deletions(-)
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index cdbc23649032..4dd6e1319343 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 +464,45 @@ 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, bool on)
+{
+ unsigned int i, cnt = 0;
+ int ret = 0;
+ u32 sr;
+
+ sr = atmel_pwm_readl(atmel_pwm, PWM_SR) & PWM_SR_ALL_CH_MASK;
+ if (!sr)
+ return 0;
+
+ for (i = 0; i < atmel_pwm->chip.npwm; i++) {
+ if (sr & (1 << i))
+ cnt++;
+ }
+
+ if (!on)
+ goto disable_clk;
+
+ for (i = 0; i < cnt; i++) {
+ ret = clk_enable(atmel_pwm->clk);
+ if (ret) {
+ dev_err(atmel_pwm->chip.dev,
+ "failed to enable clock for pwm #%d: %pe\n",
+ i, ERR_PTR(ret));
+
+ cnt = i;
+ goto disable_clk;
+ }
+ }
+
+ return 0;
+
+disable_clk:
+ while (cnt--)
+ clk_disable(atmel_pwm->clk);
+
+ return ret;
+}
+
static int atmel_pwm_probe(struct platform_device *pdev)
{
struct atmel_pwm_chip *atmel_pwm;
@@ -496,16 +535,23 @@ static int atmel_pwm_probe(struct platform_device *pdev)
atmel_pwm->chip.ops = &atmel_pwm_ops;
atmel_pwm->chip.npwm = 4;
+ ret = atmel_pwm_enable_clk_if_on(atmel_pwm, true);
+ if (ret < 0)
+ goto unprepare_clk;
+
ret = pwmchip_add(&atmel_pwm->chip);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add PWM chip %d\n", ret);
- goto unprepare_clk;
+ goto disable_clk;
}
platform_set_drvdata(pdev, atmel_pwm);
return ret;
+disable_clk:
+ atmel_pwm_enable_clk_if_on(atmel_pwm, false);
+
unprepare_clk:
clk_unprepare(atmel_pwm->clk);
return ret;
--
2.25.1
On Sat, Jul 15, 2023 at 10:36:53AM +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 <[email protected]>
> ---
> drivers/pwm/pwm-atmel.c | 50 +++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 48 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
> index cdbc23649032..4dd6e1319343 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 +464,45 @@ 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, bool on)
> +{
> + unsigned int i, cnt = 0;
> + int ret = 0;
> + u32 sr;
> +
> + sr = atmel_pwm_readl(atmel_pwm, PWM_SR) & PWM_SR_ALL_CH_MASK;
> + if (!sr)
> + return 0;
> +
> + for (i = 0; i < atmel_pwm->chip.npwm; i++) {
> + if (sr & (1 << i))
> + cnt++;
> + }
If it's just about counting the set bits, there is the function
bitmap_weight().
> + if (!on)
> + goto disable_clk;
> +
> + for (i = 0; i < cnt; i++) {
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + dev_err(atmel_pwm->chip.dev,
> + "failed to enable clock for pwm #%d: %pe\n",
> + i, ERR_PTR(ret));
The output is bogus here. If SR is say 0xc, and the second enable
fails, it's about pwm #3, but then i is 1.
> + cnt = i;
> + goto disable_clk;
> + }
> + }
> +
> + return 0;
> +
> +disable_clk:
> + while (cnt--)
> + clk_disable(atmel_pwm->clk);
> +
> + return ret;
> +}
> +
> static int atmel_pwm_probe(struct platform_device *pdev)
> {
> struct atmel_pwm_chip *atmel_pwm;
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | https://www.pengutronix.de/ |
On Sat,Jul 15,2023 at 20:12:53PM GMT+8, Uwe Kleine-König wrote:
> On Sat, Jul 15, 2023 at 10:36:53AM +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 <[email protected]>
>> ---
>> drivers/pwm/pwm-atmel.c | 50 +++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 48 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
>> index cdbc23649032..4dd6e1319343 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 +464,45 @@ 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, bool on)
>> +{
>> + unsigned int i, cnt = 0;
>> + int ret = 0;
>> + u32 sr;
>> +
>> + sr = atmel_pwm_readl(atmel_pwm, PWM_SR) & PWM_SR_ALL_CH_MASK;
>> + if (!sr)
>> + return 0;
>> +
>> + for (i = 0; i < atmel_pwm->chip.npwm; i++) {
>> + if (sr & (1 << i))
>> + cnt++;
>> + }
>
> If it's just about counting the set bits, there is the function
> bitmap_weight().
Got it, Thank you.
>> + if (!on)
>> + goto disable_clk;
>> +
>> + for (i = 0; i < cnt; i++) {
>> + ret = clk_enable(atmel_pwm->clk);
>> + if (ret) {
>> + dev_err(atmel_pwm->chip.dev,
>> + "failed to enable clock for pwm #%d: %pe\n",
>> + i, ERR_PTR(ret));
>
> The output is bogus here. If SR is say 0xc, and the second enable
> fails, it's about pwm #3, but then i is 1.
I would just output the error clock message like this to fix it:
dev_err(atmel_pwm->chip.dev,
"failed to enable clock for pwm %pe\n", ERR_PTR(ret));
>> + cnt = i;
>> + goto disable_clk;
>> + }
>> + }
>> +
>> + return 0;
>> +
>> +disable_clk:
>> + while (cnt--)
>> + clk_disable(atmel_pwm->clk);
>> +
>> + return ret;
>> +}
>> +
>> static int atmel_pwm_probe(struct platform_device *pdev)
>> {
>> struct atmel_pwm_chip *atmel_pwm;
>
> Best regards
> Uwe
>
--
Best regards,
Guiting Shen