[v2] pwm: rockchip: State of pwm clock should synchronize with pwm enabled state

Message ID 1488363362-26624-1-git-send-email-david.wu@rock-chips.com
State Superseded
Headers show

Commit Message

David Wu March 1, 2017, 10:16 a.m.
From: "david.wu" <david.wu@rock-chips.com>

If the pwm was not enabled at uboot loader, pwm could not work for clock
always disabled at pwm driver. The pwm clock is enabled at beginning of
pwm_apply(), but disabled at end of pwm_apply().

If the pwm was enabled at uboot loader, pwm clock is always enabled unless
closed by ATF. The pwm-backlight might turn off the power at early suspend,
should disable pwm clock for saving power consume.

It is important to provide opportunity to enable/disable clock at pwm driver,
the pwm consumer should ensure correct order to call pwm enable/disable, and
pwm driver ensure state of pwm clock synchronized with pwm enabled state.

Fixes: 2bf1c98aa5a4 ("pwm: rockchip: Add support for atomic update")
Cc: stable@vger.kernel.org
Signed-off-by: David Wu <david.wu@rock-chips.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
 drivers/pwm/pwm-rockchip.c | 40 +++++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

Comments

Boris Brezillon March 1, 2017, 10:19 a.m. | #1
On Wed,  1 Mar 2017 18:16:02 +0800
David Wu <david.wu@rock-chips.com> wrote:

> From: "david.wu" <david.wu@rock-chips.com>
> 
> If the pwm was not enabled at uboot loader, pwm could not work for clock
> always disabled at pwm driver. The pwm clock is enabled at beginning of
> pwm_apply(), but disabled at end of pwm_apply().
> 
> If the pwm was enabled at uboot loader, pwm clock is always enabled unless
> closed by ATF. The pwm-backlight might turn off the power at early suspend,
> should disable pwm clock for saving power consume.
> 
> It is important to provide opportunity to enable/disable clock at pwm driver,
> the pwm consumer should ensure correct order to call pwm enable/disable, and
> pwm driver ensure state of pwm clock synchronized with pwm enabled state.
> 
> Fixes: 2bf1c98aa5a4 ("pwm: rockchip: Add support for atomic update")
> Cc: stable@vger.kernel.org
> Signed-off-by: David Wu <david.wu@rock-chips.com>
> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
>  drivers/pwm/pwm-rockchip.c | 40 +++++++++++++++++++++++++++++++++-------
>  1 file changed, 33 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
> index ef89df1..dbee3c3 100644
> --- a/drivers/pwm/pwm-rockchip.c
> +++ b/drivers/pwm/pwm-rockchip.c
> @@ -191,6 +191,28 @@ static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	return 0;
>  }
>  
> +static int rk_pwm_enable(struct pwm_chip *chip,
> +			 struct pwm_device *pwm,
> +			 bool enable,
> +			 enum pwm_polarity polarity)

You didn't change the function name:

s/rk_pwm_enable/rockchip_pwm_enable/

> +{
> +	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
> +	int ret;
> +
> +	if (enable) {
> +		ret = clk_enable(pc->clk);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	pc->data->set_enable(chip, pwm, enable, polarity);
> +
> +	if (!enable)
> +		clk_disable(pc->clk);
> +
> +	return 0;
> +}
> +
>  static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  			      struct pwm_state *state)
>  {
> @@ -207,22 +229,26 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  		return ret;
>  
>  	if (state->polarity != curstate.polarity && enabled) {
> -		pc->data->set_enable(chip, pwm, false, state->polarity);
> +		ret = rk_pwm_enable(chip, pwm, false, state->polarity);
> +		if (ret)
> +			goto out;
>  		enabled = false;
>  	}
>  
>  	ret = rockchip_pwm_config(chip, pwm, state->duty_cycle, state->period);
>  	if (ret) {
>  		if (enabled != curstate.enabled)
> -			pc->data->set_enable(chip, pwm, !enabled,
> -					     state->polarity);
> -
> +			rk_pwm_enable(chip, pwm, !enabled,
> +				      state->polarity);
>  		goto out;
>  	}
>  
> -	if (state->enabled != enabled)
> -		pc->data->set_enable(chip, pwm, state->enabled,
> -				     state->polarity);
> +	if (state->enabled != enabled) {
> +		ret = rk_pwm_enable(chip, pwm, state->enabled,
> +				    state->polarity);
> +		if (ret)
> +			goto out;
> +	}
>  
>  	/*
>  	 * Update the state with the real hardware, which can differ a bit

--
To unsubscribe from this list: send the line "unsubscribe linux-pwm" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
David Wu March 1, 2017, 11 a.m. | #2
Hi Boris,

在 2017/3/1 18:19, Boris Brezillon 写道:
> On Wed,  1 Mar 2017 18:16:02 +0800
> David Wu <david.wu@rock-chips.com> wrote:
>
>> From: "david.wu" <david.wu@rock-chips.com>
>>
>> If the pwm was not enabled at uboot loader, pwm could not work for clock
>> always disabled at pwm driver. The pwm clock is enabled at beginning of
>> pwm_apply(), but disabled at end of pwm_apply().
>>
>> If the pwm was enabled at uboot loader, pwm clock is always enabled unless
>> closed by ATF. The pwm-backlight might turn off the power at early suspend,
>> should disable pwm clock for saving power consume.
>>
>> It is important to provide opportunity to enable/disable clock at pwm driver,
>> the pwm consumer should ensure correct order to call pwm enable/disable, and
>> pwm driver ensure state of pwm clock synchronized with pwm enabled state.
>>
>> Fixes: 2bf1c98aa5a4 ("pwm: rockchip: Add support for atomic update")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: David Wu <david.wu@rock-chips.com>
>> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
>> ---
>>  drivers/pwm/pwm-rockchip.c | 40 +++++++++++++++++++++++++++++++++-------
>>  1 file changed, 33 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
>> index ef89df1..dbee3c3 100644
>> --- a/drivers/pwm/pwm-rockchip.c
>> +++ b/drivers/pwm/pwm-rockchip.c
>> @@ -191,6 +191,28 @@ static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>>  	return 0;
>>  }
>>
>> +static int rk_pwm_enable(struct pwm_chip *chip,
>> +			 struct pwm_device *pwm,
>> +			 bool enable,
>> +			 enum pwm_polarity polarity)
>
> You didn't change the function name:
>
> s/rk_pwm_enable/rockchip_pwm_enable/

Sorry, it is a pity not to fix in in v2.

>
>> +{
>> +	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
>> +	int ret;
>> +
>> +	if (enable) {
>> +		ret = clk_enable(pc->clk);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>> +	pc->data->set_enable(chip, pwm, enable, polarity);
>> +
>> +	if (!enable)
>> +		clk_disable(pc->clk);
>> +
>> +	return 0;
>> +}
>> +
>>  static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>>  			      struct pwm_state *state)
>>  {
>> @@ -207,22 +229,26 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>>  		return ret;
>>
>>  	if (state->polarity != curstate.polarity && enabled) {
>> -		pc->data->set_enable(chip, pwm, false, state->polarity);
>> +		ret = rk_pwm_enable(chip, pwm, false, state->polarity);
>> +		if (ret)
>> +			goto out;
>>  		enabled = false;
>>  	}
>>
>>  	ret = rockchip_pwm_config(chip, pwm, state->duty_cycle, state->period);
>>  	if (ret) {
>>  		if (enabled != curstate.enabled)
>> -			pc->data->set_enable(chip, pwm, !enabled,
>> -					     state->polarity);
>> -
>> +			rk_pwm_enable(chip, pwm, !enabled,
>> +				      state->polarity);
>>  		goto out;
>>  	}
>>
>> -	if (state->enabled != enabled)
>> -		pc->data->set_enable(chip, pwm, state->enabled,
>> -				     state->polarity);
>> +	if (state->enabled != enabled) {
>> +		ret = rk_pwm_enable(chip, pwm, state->enabled,
>> +				    state->polarity);
>> +		if (ret)
>> +			goto out;
>> +	}
>>
>>  	/*
>>  	 * Update the state with the real hardware, which can differ a bit
>
>
>
>

--
To unsubscribe from this list: send the line "unsubscribe linux-pwm" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index ef89df1..dbee3c3 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c
@@ -191,6 +191,28 @@  static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
+static int rk_pwm_enable(struct pwm_chip *chip,
+			 struct pwm_device *pwm,
+			 bool enable,
+			 enum pwm_polarity polarity)
+{
+	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+	int ret;
+
+	if (enable) {
+		ret = clk_enable(pc->clk);
+		if (ret)
+			return ret;
+	}
+
+	pc->data->set_enable(chip, pwm, enable, polarity);
+
+	if (!enable)
+		clk_disable(pc->clk);
+
+	return 0;
+}
+
 static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			      struct pwm_state *state)
 {
@@ -207,22 +229,26 @@  static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		return ret;
 
 	if (state->polarity != curstate.polarity && enabled) {
-		pc->data->set_enable(chip, pwm, false, state->polarity);
+		ret = rk_pwm_enable(chip, pwm, false, state->polarity);
+		if (ret)
+			goto out;
 		enabled = false;
 	}
 
 	ret = rockchip_pwm_config(chip, pwm, state->duty_cycle, state->period);
 	if (ret) {
 		if (enabled != curstate.enabled)
-			pc->data->set_enable(chip, pwm, !enabled,
-					     state->polarity);
-
+			rk_pwm_enable(chip, pwm, !enabled,
+				      state->polarity);
 		goto out;
 	}
 
-	if (state->enabled != enabled)
-		pc->data->set_enable(chip, pwm, state->enabled,
-				     state->polarity);
+	if (state->enabled != enabled) {
+		ret = rk_pwm_enable(chip, pwm, state->enabled,
+				    state->polarity);
+		if (ret)
+			goto out;
+	}
 
 	/*
 	 * Update the state with the real hardware, which can differ a bit