[RFC PATCH 1/3] arm: plat-omap: dmtimer: Add clock source from DT

[RFC PATCH 1/3] arm: plat-omap: dmtimer: Add clock source from DT

[Neil Armstrong]

Add a function which sets the timer source from the clocks
binding on dm_timer_prepare call.

In case the clocks property is not valid, it falls back to
the set_source() with 32_KHZ clock as default.

Suggested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 arch/arm/plat-omap/dmtimer.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c
index 8ca94d3..5e8aece 100644
--- a/arch/arm/plat-omap/dmtimer.c
+++ b/arch/arm/plat-omap/dmtimer.c
@@ -137,9 +137,33 @@ static int omap_dm_timer_reset(struct omap_dm_timer *timer)
 	return 0;
 }

+static int omap_dm_timer_of_set_source(struct omap_dm_timer *timer)
+{
+	int ret;
+	struct clk *parent;
+
+	if (unlikely(!timer))
+		return -EINVAL;
+
+	if (IS_ERR(timer->fclk))
+		return -EINVAL;
+
+	parent = clk_get(&timer->pdev->dev, NULL);
+	if (IS_ERR(parent))
+		return -ENODEV;
+
+	ret = clk_set_parent(timer->fclk, parent);
+	if (ret < 0)
+		pr_err("%s: failed to set parent\n", __func__);
+
+	clk_put(parent);
+
+	return ret;
+}
+
 static int omap_dm_timer_prepare(struct omap_dm_timer *timer)
 {
-	int rc;
+	int rc, ret;

 	/*
 	 * FIXME: OMAP1 devices do not use the clock framework for dmtimers so
@@ -166,7 +190,11 @@ static int omap_dm_timer_prepare(struct omap_dm_timer *timer)
 	__omap_dm_timer_enable_posted(timer);
 	omap_dm_timer_disable(timer);

-	return omap_dm_timer_set_source(timer, OMAP_TIMER_SRC_32_KHZ);
+	ret = omap_dm_timer_of_set_source(timer);
+	if (ret < 0 && ret == -ENODEV)
+		return omap_dm_timer_set_source(timer, OMAP_TIMER_SRC_32_KHZ);
+
+	return ret;
 }

 static inline u32 omap_dm_timer_reserved_systimer(int id)
-- 
1.9.1

[RFC PATCH 1/3] arm: plat-omap: dmtimer: Add clock source from DT

[Felipe Balbi]

Hi,

Neil Armstrong <narmstrong@baylibre.com> writes:
> Add a function which sets the timer source from the clocks
> binding on dm_timer_prepare call.
>
> In case the clocks property is not valid, it falls back to
> the set_source() with 32_KHZ clock as default.
>
> Suggested-by: Tony Lindgren <tony@atomide.com>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>  arch/arm/plat-omap/dmtimer.c | 32 ++++++++++++++++++++++++++++++--
>  1 file changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c
> index 8ca94d3..5e8aece 100644
> --- a/arch/arm/plat-omap/dmtimer.c
> +++ b/arch/arm/plat-omap/dmtimer.c
> @@ -137,9 +137,33 @@ static int omap_dm_timer_reset(struct omap_dm_timer *timer)
>  	return 0;
>  }
>
> +static int omap_dm_timer_of_set_source(struct omap_dm_timer *timer)
> +{
> +	int ret;
> +	struct clk *parent;
> +
> +	if (unlikely(!timer))
> +		return -EINVAL;

IMO, let this crash. If this happens we have bigger problems.

> +	if (IS_ERR(timer->fclk))
> +		return -EINVAL;

We bail out if we can't get fclk, this check is unnecessary.

> +	parent = clk_get(&timer->pdev->dev, NULL);

why NULL ? You could use something more descriptive, but no strong
feelings.

> +	if (IS_ERR(parent))
> +		return -ENODEV;
> +
> +	ret = clk_set_parent(timer->fclk, parent);
> +	if (ret < 0)
> +		pr_err("%s: failed to set parent\n", __func__);
> +
> +	clk_put(parent);
> +
> +	return ret;
> +}
> +
>  static int omap_dm_timer_prepare(struct omap_dm_timer *timer)
>  {
> -	int rc;
> +	int rc, ret;

doesn't seem like you need this extra 'ret' variable. Just use 'rc'.

> @@ -166,7 +190,11 @@ static int omap_dm_timer_prepare(struct omap_dm_timer *timer)
>  	__omap_dm_timer_enable_posted(timer);
>  	omap_dm_timer_disable(timer);
>
> -	return omap_dm_timer_set_source(timer, OMAP_TIMER_SRC_32_KHZ);
> +	ret = omap_dm_timer_of_set_source(timer);
> +	if (ret < 0 && ret == -ENODEV)

this < 0 check is pointless if you're going to check for equality to -ENODEV

> +		return omap_dm_timer_set_source(timer, OMAP_TIMER_SRC_32_KHZ);
> +
> +	return ret;
>  }
>
>  static inline u32 omap_dm_timer_reserved_systimer(int id)
> -- 
> 1.9.1
>
> --
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-- 
balbi
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[RFC PATCH 1/3] arm: plat-omap: dmtimer: Add clock source from DT

[Neil Armstrong]

Hi,

On 10/16/2015 05:40 PM, Felipe Balbi wrote:
>> +static int omap_dm_timer_of_set_source(struct omap_dm_timer *timer)
>> +{
>> +	int ret;
>> +	struct clk *parent;
>> +
>> +	if (unlikely(!timer))
>> +		return -EINVAL;
> 
> IMO, let this crash. If this happens we have bigger problems.
> 
>> +	if (IS_ERR(timer->fclk))
>> +		return -EINVAL;
> 
> We bail out if we can't get fclk, this check is unnecessary.

Sure, I will remove the checks.
This was also breaking OMAP1, fclk must be checked against NULL here to detect OMAP1 and return -ENODEV;

> 
>> +	parent = clk_get(&timer->pdev->dev, NULL);
> 
> why NULL ? You could use something more descriptive, but no strong
> feelings.


Actually, I just wanted the "default" clock for this device, NULL will select the first OF clock found.
If we specify a name, we should also specify it in the DT as clock-names, is it desired ?
If you feel I should name it somehow... I don't want it to conflict all the HWMOD clk namings actually.

> 
>> +	if (IS_ERR(parent))
>> +		return -ENODEV;
>> +
>> +	ret = clk_set_parent(timer->fclk, parent);
>> +	if (ret < 0)
>> +		pr_err("%s: failed to set parent\n", __func__);
>> +
>> +	clk_put(parent);
>> +
>> +	return ret;
>> +}
>> +
>>  static int omap_dm_timer_prepare(struct omap_dm_timer *timer)
>>  {
>> -	int rc;
>> +	int rc, ret;
> 
> doesn't seem like you need this extra 'ret' variable. Just use 'rc'.
> 
>> @@ -166,7 +190,11 @@ static int omap_dm_timer_prepare(struct omap_dm_timer *timer)
>>  	__omap_dm_timer_enable_posted(timer);
>>  	omap_dm_timer_disable(timer);
>>
>> -	return omap_dm_timer_set_source(timer, OMAP_TIMER_SRC_32_KHZ);
>> +	ret = omap_dm_timer_of_set_source(timer);
>> +	if (ret < 0 && ret == -ENODEV)
> 
> this < 0 check is pointless if you're going to check for equality to -ENODEV

Sure, I was certainly tired, this was a so stupid mistake...

Neil