[2/3] pwm: pwm-omap-dmtimer: Fix frequency when using prescaler

Message ID 20180117214737.GC11952@lenoch
State New
Headers show
Series
  • omap: dmtimer: Fix and cleanup moved driver
Related show

Commit Message

Ladislav Michl Jan. 17, 2018, 9:47 p.m.
Prescaler setting is currently not taken into account.
Fix that by introducing freq member variable and initialize
it at device probe time. This also avoids frequency
recomputing at each pwm configure time.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
---
 drivers/pwm/pwm-omap-dmtimer.c |   92 +++++++++++++++++++++++----------------
 1 file changed, 53 insertions(+), 39 deletions(-)

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Comments

Claudiu Beznea Jan. 22, 2018, 9:17 a.m. | #1
On 17.01.2018 23:47, Ladislav Michl wrote:
> Prescaler setting is currently not taken into account.
> Fix that by introducing freq member variable and initialize
> it at device probe time. This also avoids frequency
> recomputing at each pwm configure time.
> 
> Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
> ---
>  drivers/pwm/pwm-omap-dmtimer.c |   92 +++++++++++++++++++++++----------------
>  1 file changed, 53 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
> index cc485d9946f3..81c79e41a167 100644
> --- a/drivers/pwm/pwm-omap-dmtimer.c
> +++ b/drivers/pwm/pwm-omap-dmtimer.c
> @@ -40,6 +40,7 @@ struct pwm_omap_dmtimer_chip {
>  	pwm_omap_dmtimer *dm_timer;
>  	struct omap_dm_timer_ops *pdata;
>  	struct platform_device *dm_timer_pdev;
> +	unsigned long freq;
>  };
>  
>  static inline struct pwm_omap_dmtimer_chip *
> @@ -48,9 +49,10 @@ to_pwm_omap_dmtimer_chip(struct pwm_chip *chip)
>  	return container_of(chip, struct pwm_omap_dmtimer_chip, chip);
>  }
>  
> -static u32 pwm_omap_dmtimer_get_clock_cycles(unsigned long clk_rate, int ns)
> +static inline u32
> +pwm_omap_dmtimer_get_clock_cycles(struct pwm_omap_dmtimer_chip *omap, int ns)
>  {
> -	return DIV_ROUND_CLOSEST_ULL((u64)clk_rate * ns, NSEC_PER_SEC);
> +	return DIV_ROUND_CLOSEST_ULL((u64)omap->freq * ns, NSEC_PER_SEC);
>  }
>  
>  static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap)
> @@ -99,8 +101,6 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
>  	struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
>  	u32 period_cycles, duty_cycles;
>  	u32 load_value, match_value;
> -	struct clk *fclk;
> -	unsigned long clk_rate;
>  	bool timer_active;
>  
>  	dev_dbg(chip->dev, "requested duty cycle: %d ns, period: %d ns\n",
> @@ -114,19 +114,6 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
>  		return 0;
>  	}
>  
> -	fclk = omap->pdata->get_fclk(omap->dm_timer);
> -	if (!fclk) {
> -		dev_err(chip->dev, "invalid pmtimer fclk\n");
> -		goto err_einval;
> -	}
> -
> -	clk_rate = clk_get_rate(fclk);
> -	if (!clk_rate) {
> -		dev_err(chip->dev, "invalid pmtimer fclk rate\n");
> -		goto err_einval;
> -	}
> -
> -	dev_dbg(chip->dev, "clk rate: %luHz\n", clk_rate);
>  
>  	/*
>  	 * Calculate the appropriate load and match values based on the
> @@ -144,35 +131,35 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
>  	 *   OMAP4430/60/70 TRM sections 22.2.4.10 and 22.2.4.11
>  	 *   AM335x Sitara TRM sections 20.1.3.5 and 20.1.3.6
>  	 */
> -	period_cycles = pwm_omap_dmtimer_get_clock_cycles(clk_rate, period_ns);
> -	duty_cycles = pwm_omap_dmtimer_get_clock_cycles(clk_rate, duty_ns);
> +	period_cycles = pwm_omap_dmtimer_get_clock_cycles(omap, period_ns);
> +	duty_cycles = pwm_omap_dmtimer_get_clock_cycles(omap, duty_ns);
>  
>  	if (period_cycles < 2) {
>  		dev_info(chip->dev,
>  			 "period %d ns too short for clock rate %lu Hz\n",
> -			 period_ns, clk_rate);
> +			 period_ns, omap->freq);
>  		goto err_einval;
>  	}
>  
>  	if (duty_cycles < 1) {
>  		dev_dbg(chip->dev,
>  			"duty cycle %d ns is too short for clock rate %lu Hz\n",
> -			duty_ns, clk_rate);
> +			duty_ns, omap->freq);
>  		dev_dbg(chip->dev, "using minimum of 1 clock cycle\n");
>  		duty_cycles = 1;
>  	} else if (duty_cycles >= period_cycles) {
>  		dev_dbg(chip->dev,
>  			"duty cycle %d ns is too long for period %d ns at clock rate %lu Hz\n",
> -			duty_ns, period_ns, clk_rate);
> +			duty_ns, period_ns, omap->freq);
>  		dev_dbg(chip->dev, "using maximum of 1 clock cycle less than period\n");
>  		duty_cycles = period_cycles - 1;
>  	}
>  
>  	dev_dbg(chip->dev, "effective duty cycle: %lld ns, period: %lld ns\n",
>  		DIV_ROUND_CLOSEST_ULL((u64)NSEC_PER_SEC * duty_cycles,
> -				      clk_rate),
> +				      omap->freq),
>  		DIV_ROUND_CLOSEST_ULL((u64)NSEC_PER_SEC * period_cycles,
> -				      clk_rate));
> +				      omap->freq));
>  
>  	load_value = (DM_TIMER_MAX - period_cycles) + 1;
>  	match_value = load_value + duty_cycles - 1;
> @@ -248,8 +235,9 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
>  	struct dmtimer_platform_data *timer_pdata;
>  	struct omap_dm_timer_ops *pdata;
>  	pwm_omap_dmtimer *dm_timer;
> +	struct clk *fclk;
>  	u32 v;
> -	int status, ret;
> +	int ret;
>  
>  	timer = of_parse_phandle(np, "ti,timers", 0);
>  	if (!timer)
> @@ -302,9 +290,8 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
>  
>  	omap = devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL);
>  	if (!omap) {
> -		pdata->free(dm_timer);
>  		ret = -ENOMEM;
> -		goto put;
> +		goto free;
>  	}
>  
>  	omap->pdata = pdata;
> @@ -315,15 +302,42 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
>  	 * Ensure that the timer is stopped before we allow PWM core to call
>  	 * pwm_enable.
>  	 */
> -	if (pm_runtime_active(&omap->dm_timer_pdev->dev))
> -		omap->pdata->stop(omap->dm_timer);
> -
> -	if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler", &v))
> -		omap->pdata->set_prescaler(omap->dm_timer, v);
> +	if (pm_runtime_active(&timer_pdev->dev))
> +		pdata->stop(dm_timer);
>  
>  	/* setup dmtimer clock source */
> -	if (!of_property_read_u32(pdev->dev.of_node, "ti,clock-source", &v))
> -		omap->pdata->set_source(omap->dm_timer, v);
> +	if (!of_property_read_u32(pdev->dev.of_node, "ti,clock-source", &v)) {
> +		ret = pdata->set_source(dm_timer, v);
> +		if (ret) {
> +			dev_err(&pdev->dev, "invalid clock-source\n");
> +			goto free;
> +		}
> +	}
> +
> +	fclk = pdata->get_fclk(dm_timer);
> +	if (!fclk) {
> +		dev_err(&pdev->dev, "invalid fclk\n");
> +		ret = -EINVAL;
> +		goto free;
> +	}
> +
> +	omap->freq = clk_get_rate(fclk);
> +	if (!omap->freq) {
> +		dev_err(&pdev->dev, "invalid fclk rate\n");
> +		ret = -EINVAL;
> +		goto free;
> +	}
> +
> +	if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler", &v)) {
> +		ret = pdata->set_prescaler(dm_timer, v);
> +		if (ret) {
> +			dev_err(&pdev->dev, "invalid prescaler\n");
> +			goto free;
> +		}
> +		omap->freq >>= v + 1;
> +	}
> +
> +	dev_dbg(&pdev->dev, "clk rate: %luHz\n", omap->freq);
>  
>  	omap->chip.dev = &pdev->dev;
>  	omap->chip.ops = &pwm_omap_dmtimer_ops;
> @@ -334,18 +348,18 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
>  
>  	mutex_init(&omap->mutex);
>  
> -	status = pwmchip_add(&omap->chip);
> -	if (status < 0) {
> +	ret = pwmchip_add(&omap->chip);
> +	if (ret < 0) {
>  		dev_err(&pdev->dev, "failed to register PWM\n");
> -		omap->pdata->free(omap->dm_timer);
> -		ret = status;
> -		goto put;
> +		goto free;
>  	}
>  
>  	platform_set_drvdata(pdev, omap);
From documentation: "of_parse_phandle(): Returns the device_node pointer with refcount
incremented. Use of_node_put() on it when done."
In case of success the of_node_put() should also be called as I see.

>  
>  	return 0;
>  
> +free:
> +	pdata->free(dm_timer);
>  put:
>  	of_node_put(timer);
>  
> 
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Ladislav Michl Jan. 22, 2018, 10:53 a.m. | #2
Dear Claudiu,

On Mon, Jan 22, 2018 at 11:17:08AM +0200, Claudiu Beznea wrote:
> On 17.01.2018 23:47, Ladislav Michl wrote:
> > @@ -334,18 +348,18 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
> >  
> >  	mutex_init(&omap->mutex);
> >  
> > -	status = pwmchip_add(&omap->chip);
> > -	if (status < 0) {
> > +	ret = pwmchip_add(&omap->chip);
> > +	if (ret < 0) {
> >  		dev_err(&pdev->dev, "failed to register PWM\n");
> > -		omap->pdata->free(omap->dm_timer);
> > -		ret = status;
> > -		goto put;
> > +		goto free;
> >  	}
> >  
> >  	platform_set_drvdata(pdev, omap);
> >From documentation: "of_parse_phandle(): Returns the device_node pointer with refcount
> incremented. Use of_node_put() on it when done."
> In case of success the of_node_put() should also be called as I see.

Based on you previous suggestions found here:
https://patchwork.kernel.org/patch/10140209/
I'd say this fix belongs to patch which introduces of_node_put() in the error
path. I'll then rebase this patches on top of the fix.

Thank you,
	ladis
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Keerthy Jan. 24, 2018, 5:26 a.m. | #3
On Monday 22 January 2018 04:23 PM, Ladislav Michl wrote:
> Dear Claudiu,
> 
> On Mon, Jan 22, 2018 at 11:17:08AM +0200, Claudiu Beznea wrote:
>> On 17.01.2018 23:47, Ladislav Michl wrote:
>>> @@ -334,18 +348,18 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
>>>  
>>>  	mutex_init(&omap->mutex);
>>>  
>>> -	status = pwmchip_add(&omap->chip);
>>> -	if (status < 0) {
>>> +	ret = pwmchip_add(&omap->chip);
>>> +	if (ret < 0) {
>>>  		dev_err(&pdev->dev, "failed to register PWM\n");
>>> -		omap->pdata->free(omap->dm_timer);
>>> -		ret = status;
>>> -		goto put;
>>> +		goto free;
>>>  	}
>>>  
>>>  	platform_set_drvdata(pdev, omap);
>> >From documentation: "of_parse_phandle(): Returns the device_node pointer with refcount
>> incremented. Use of_node_put() on it when done."
>> In case of success the of_node_put() should also be called as I see.
> 
> Based on you previous suggestions found here:
> https://patchwork.kernel.org/patch/10140209/
> I'd say this fix belongs to patch which introduces of_node_put() in the error
> path. I'll then rebase this patches on top of the fix.

Agreed. I missed the success path as i assumed only error paths needed
te of_node_put(). I will post v8 of this patch alone as other patches
can be left untouched. Hope that is okay.

Regards,
Keerthy
> 
> Thank you,
> 	ladis
> 
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Keerthy Jan. 24, 2018, 5:49 a.m. | #4
On Wednesday 24 January 2018 10:56 AM, Keerthy wrote:
> 
> 
> On Monday 22 January 2018 04:23 PM, Ladislav Michl wrote:
>> Dear Claudiu,
>>
>> On Mon, Jan 22, 2018 at 11:17:08AM +0200, Claudiu Beznea wrote:
>>> On 17.01.2018 23:47, Ladislav Michl wrote:
>>>> @@ -334,18 +348,18 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
>>>>  
>>>>  	mutex_init(&omap->mutex);
>>>>  
>>>> -	status = pwmchip_add(&omap->chip);
>>>> -	if (status < 0) {
>>>> +	ret = pwmchip_add(&omap->chip);
>>>> +	if (ret < 0) {
>>>>  		dev_err(&pdev->dev, "failed to register PWM\n");
>>>> -		omap->pdata->free(omap->dm_timer);
>>>> -		ret = status;
>>>> -		goto put;
>>>> +		goto free;
>>>>  	}
>>>>  
>>>>  	platform_set_drvdata(pdev, omap);
>>> >From documentation: "of_parse_phandle(): Returns the device_node pointer with refcount
>>> incremented. Use of_node_put() on it when done."
>>> In case of success the of_node_put() should also be called as I see.
>>
>> Based on you previous suggestions found here:
>> https://patchwork.kernel.org/patch/10140209/
>> I'd say this fix belongs to patch which introduces of_node_put() in the error
>> path. I'll then rebase this patches on top of the fix.
> 
> Agreed. I missed the success path as i assumed only error paths needed
> te of_node_put(). I will post v8 of this patch alone as other patches
> can be left untouched. Hope that is okay.

Ladis,

I posted v8 of the above mentioned patch alone.

https://marc.info/?l=linux-omap&m=151677273619960&w=2

Thanks,
Keerthy
> 
> Regards,
> Keerthy
>>
>> Thank you,
>> 	ladis
>>
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Patch

diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
index cc485d9946f3..81c79e41a167 100644
--- a/drivers/pwm/pwm-omap-dmtimer.c
+++ b/drivers/pwm/pwm-omap-dmtimer.c
@@ -40,6 +40,7 @@  struct pwm_omap_dmtimer_chip {
 	pwm_omap_dmtimer *dm_timer;
 	struct omap_dm_timer_ops *pdata;
 	struct platform_device *dm_timer_pdev;
+	unsigned long freq;
 };
 
 static inline struct pwm_omap_dmtimer_chip *
@@ -48,9 +49,10 @@  to_pwm_omap_dmtimer_chip(struct pwm_chip *chip)
 	return container_of(chip, struct pwm_omap_dmtimer_chip, chip);
 }
 
-static u32 pwm_omap_dmtimer_get_clock_cycles(unsigned long clk_rate, int ns)
+static inline u32
+pwm_omap_dmtimer_get_clock_cycles(struct pwm_omap_dmtimer_chip *omap, int ns)
 {
-	return DIV_ROUND_CLOSEST_ULL((u64)clk_rate * ns, NSEC_PER_SEC);
+	return DIV_ROUND_CLOSEST_ULL((u64)omap->freq * ns, NSEC_PER_SEC);
 }
 
 static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap)
@@ -99,8 +101,6 @@  static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
 	struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
 	u32 period_cycles, duty_cycles;
 	u32 load_value, match_value;
-	struct clk *fclk;
-	unsigned long clk_rate;
 	bool timer_active;
 
 	dev_dbg(chip->dev, "requested duty cycle: %d ns, period: %d ns\n",
@@ -114,19 +114,6 @@  static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
 		return 0;
 	}
 
-	fclk = omap->pdata->get_fclk(omap->dm_timer);
-	if (!fclk) {
-		dev_err(chip->dev, "invalid pmtimer fclk\n");
-		goto err_einval;
-	}
-
-	clk_rate = clk_get_rate(fclk);
-	if (!clk_rate) {
-		dev_err(chip->dev, "invalid pmtimer fclk rate\n");
-		goto err_einval;
-	}
-
-	dev_dbg(chip->dev, "clk rate: %luHz\n", clk_rate);
 
 	/*
 	 * Calculate the appropriate load and match values based on the
@@ -144,35 +131,35 @@  static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
 	 *   OMAP4430/60/70 TRM sections 22.2.4.10 and 22.2.4.11
 	 *   AM335x Sitara TRM sections 20.1.3.5 and 20.1.3.6
 	 */
-	period_cycles = pwm_omap_dmtimer_get_clock_cycles(clk_rate, period_ns);
-	duty_cycles = pwm_omap_dmtimer_get_clock_cycles(clk_rate, duty_ns);
+	period_cycles = pwm_omap_dmtimer_get_clock_cycles(omap, period_ns);
+	duty_cycles = pwm_omap_dmtimer_get_clock_cycles(omap, duty_ns);
 
 	if (period_cycles < 2) {
 		dev_info(chip->dev,
 			 "period %d ns too short for clock rate %lu Hz\n",
-			 period_ns, clk_rate);
+			 period_ns, omap->freq);
 		goto err_einval;
 	}
 
 	if (duty_cycles < 1) {
 		dev_dbg(chip->dev,
 			"duty cycle %d ns is too short for clock rate %lu Hz\n",
-			duty_ns, clk_rate);
+			duty_ns, omap->freq);
 		dev_dbg(chip->dev, "using minimum of 1 clock cycle\n");
 		duty_cycles = 1;
 	} else if (duty_cycles >= period_cycles) {
 		dev_dbg(chip->dev,
 			"duty cycle %d ns is too long for period %d ns at clock rate %lu Hz\n",
-			duty_ns, period_ns, clk_rate);
+			duty_ns, period_ns, omap->freq);
 		dev_dbg(chip->dev, "using maximum of 1 clock cycle less than period\n");
 		duty_cycles = period_cycles - 1;
 	}
 
 	dev_dbg(chip->dev, "effective duty cycle: %lld ns, period: %lld ns\n",
 		DIV_ROUND_CLOSEST_ULL((u64)NSEC_PER_SEC * duty_cycles,
-				      clk_rate),
+				      omap->freq),
 		DIV_ROUND_CLOSEST_ULL((u64)NSEC_PER_SEC * period_cycles,
-				      clk_rate));
+				      omap->freq));
 
 	load_value = (DM_TIMER_MAX - period_cycles) + 1;
 	match_value = load_value + duty_cycles - 1;
@@ -248,8 +235,9 @@  static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
 	struct dmtimer_platform_data *timer_pdata;
 	struct omap_dm_timer_ops *pdata;
 	pwm_omap_dmtimer *dm_timer;
+	struct clk *fclk;
 	u32 v;
-	int status, ret;
+	int ret;
 
 	timer = of_parse_phandle(np, "ti,timers", 0);
 	if (!timer)
@@ -302,9 +290,8 @@  static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
 
 	omap = devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL);
 	if (!omap) {
-		pdata->free(dm_timer);
 		ret = -ENOMEM;
-		goto put;
+		goto free;
 	}
 
 	omap->pdata = pdata;
@@ -315,15 +302,42 @@  static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
 	 * Ensure that the timer is stopped before we allow PWM core to call
 	 * pwm_enable.
 	 */
-	if (pm_runtime_active(&omap->dm_timer_pdev->dev))
-		omap->pdata->stop(omap->dm_timer);
-
-	if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler", &v))
-		omap->pdata->set_prescaler(omap->dm_timer, v);
+	if (pm_runtime_active(&timer_pdev->dev))
+		pdata->stop(dm_timer);
 
 	/* setup dmtimer clock source */
-	if (!of_property_read_u32(pdev->dev.of_node, "ti,clock-source", &v))
-		omap->pdata->set_source(omap->dm_timer, v);
+	if (!of_property_read_u32(pdev->dev.of_node, "ti,clock-source", &v)) {
+		ret = pdata->set_source(dm_timer, v);
+		if (ret) {
+			dev_err(&pdev->dev, "invalid clock-source\n");
+			goto free;
+		}
+	}
+
+	fclk = pdata->get_fclk(dm_timer);
+	if (!fclk) {
+		dev_err(&pdev->dev, "invalid fclk\n");
+		ret = -EINVAL;
+		goto free;
+	}
+
+	omap->freq = clk_get_rate(fclk);
+	if (!omap->freq) {
+		dev_err(&pdev->dev, "invalid fclk rate\n");
+		ret = -EINVAL;
+		goto free;
+	}
+
+	if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler", &v)) {
+		ret = pdata->set_prescaler(dm_timer, v);
+		if (ret) {
+			dev_err(&pdev->dev, "invalid prescaler\n");
+			goto free;
+		}
+		omap->freq >>= v + 1;
+	}
+
+	dev_dbg(&pdev->dev, "clk rate: %luHz\n", omap->freq);
 
 	omap->chip.dev = &pdev->dev;
 	omap->chip.ops = &pwm_omap_dmtimer_ops;
@@ -334,18 +348,18 @@  static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
 
 	mutex_init(&omap->mutex);
 
-	status = pwmchip_add(&omap->chip);
-	if (status < 0) {
+	ret = pwmchip_add(&omap->chip);
+	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to register PWM\n");
-		omap->pdata->free(omap->dm_timer);
-		ret = status;
-		goto put;
+		goto free;
 	}
 
 	platform_set_drvdata(pdev, omap);
 
 	return 0;
 
+free:
+	pdata->free(dm_timer);
 put:
 	of_node_put(timer);