[PATCH] mfd: twl6040: Optional clk32k clock handling

[PATCH] mfd: twl6040: Optional clk32k clock handling

[Peter Ujfalusi]

In certain boards the source for the clk32k clock can be gated. In these
boards the clk32k clock can be provided to the driver and it is going to be
enabled/disabled when it is needed.
If the clk32k clock is not provided the driver will assume that it is always
running.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 Documentation/devicetree/bindings/mfd/twl6040.txt |  2 ++
 drivers/mfd/twl6040.c                             | 10 ++++++++++
 include/linux/mfd/twl6040.h                       |  2 ++
 3 files changed, 14 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/twl6040.txt b/Documentation/devicetree/bindings/mfd/twl6040.txt
index 0f5dd709d752..a41157b5d930 100644
--- a/Documentation/devicetree/bindings/mfd/twl6040.txt
+++ b/Documentation/devicetree/bindings/mfd/twl6040.txt
@@ -19,6 +19,8 @@ Required properties:
 
 Optional properties, nodes:
 - enable-active-high: To power on the twl6040 during boot.
+- clocks: phandle to the clk32k clock provider
+- clock-names: Must be "clk32k"
 
 Vibra functionality
 Required properties:
diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
index 2e6504a8e1e3..12b314ea48dc 100644
--- a/drivers/mfd/twl6040.c
+++ b/drivers/mfd/twl6040.c
@@ -291,6 +291,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
 		if (twl6040->power_count++)
 			goto out;
 
+		clk_prepare_enable(twl6040->clk32k);
+
 		/* Allow writes to the chip */
 		regcache_cache_only(twl6040->regmap, false);
 
@@ -346,6 +348,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
 
 		twl6040->sysclk = 0;
 		twl6040->mclk = 0;
+
+		clk_disable_unprepare(twl6040->clk32k);
 	}
 
 out:
@@ -644,6 +648,12 @@ static int twl6040_probe(struct i2c_client *client,
 
 	i2c_set_clientdata(client, twl6040);
 
+	twl6040->clk32k = devm_clk_get(&client->dev, "clk32k");
+	if (IS_ERR(twl6040->clk32k)) {
+		dev_info(&client->dev, "clk32k is not handled\n");
+		twl6040->clk32k = NULL;
+	}
+
 	twl6040->supplies[0].supply = "vio";
 	twl6040->supplies[1].supply = "v2v1";
 	ret = devm_regulator_bulk_get(&client->dev, TWL6040_NUM_SUPPLIES,
diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
index a69d16b30c18..8f9fc3d26e6d 100644
--- a/include/linux/mfd/twl6040.h
+++ b/include/linux/mfd/twl6040.h
@@ -28,6 +28,7 @@
 #include <linux/interrupt.h>
 #include <linux/mfd/core.h>
 #include <linux/regulator/consumer.h>
+#include <linux/clk.h>
 
 #define TWL6040_REG_ASICID		0x01
 #define TWL6040_REG_ASICREV		0x02
@@ -223,6 +224,7 @@ struct twl6040 {
 	struct regmap *regmap;
 	struct regmap_irq_chip_data *irq_data;
 	struct regulator_bulk_data supplies[2]; /* supplies for vio, v2v1 */
+	struct clk *clk32k;
 	struct mutex mutex;
 	struct mutex irq_mutex;
 	struct mfd_cell cells[TWL6040_CELLS];
-- 
1.9.1

[PATCH] mfd: twl6040: Optional clk32k clock handling

[Peter Ujfalusi]

In certain boards the source for the clk32k clock can be gated. In these
boards the clk32k clock can be provided to the driver and it is going to be
enabled/disabled when it is needed.
If the clk32k clock is not provided the driver will assume that it is always
running.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi-l0cyMroinI0@public.gmane.org>
---
 Documentation/devicetree/bindings/mfd/twl6040.txt |  2 ++
 drivers/mfd/twl6040.c                             | 10 ++++++++++
 include/linux/mfd/twl6040.h                       |  2 ++
 3 files changed, 14 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/twl6040.txt b/Documentation/devicetree/bindings/mfd/twl6040.txt
index 0f5dd709d752..a41157b5d930 100644
--- a/Documentation/devicetree/bindings/mfd/twl6040.txt
+++ b/Documentation/devicetree/bindings/mfd/twl6040.txt
@@ -19,6 +19,8 @@ Required properties:
 
 Optional properties, nodes:
 - enable-active-high: To power on the twl6040 during boot.
+- clocks: phandle to the clk32k clock provider
+- clock-names: Must be "clk32k"
 
 Vibra functionality
 Required properties:
diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
index 2e6504a8e1e3..12b314ea48dc 100644
--- a/drivers/mfd/twl6040.c
+++ b/drivers/mfd/twl6040.c
@@ -291,6 +291,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
 		if (twl6040->power_count++)
 			goto out;
 
+		clk_prepare_enable(twl6040->clk32k);
+
 		/* Allow writes to the chip */
 		regcache_cache_only(twl6040->regmap, false);
 
@@ -346,6 +348,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
 
 		twl6040->sysclk = 0;
 		twl6040->mclk = 0;
+
+		clk_disable_unprepare(twl6040->clk32k);
 	}
 
 out:
@@ -644,6 +648,12 @@ static int twl6040_probe(struct i2c_client *client,
 
 	i2c_set_clientdata(client, twl6040);
 
+	twl6040->clk32k = devm_clk_get(&client->dev, "clk32k");
+	if (IS_ERR(twl6040->clk32k)) {
+		dev_info(&client->dev, "clk32k is not handled\n");
+		twl6040->clk32k = NULL;
+	}
+
 	twl6040->supplies[0].supply = "vio";
 	twl6040->supplies[1].supply = "v2v1";
 	ret = devm_regulator_bulk_get(&client->dev, TWL6040_NUM_SUPPLIES,
diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
index a69d16b30c18..8f9fc3d26e6d 100644
--- a/include/linux/mfd/twl6040.h
+++ b/include/linux/mfd/twl6040.h
@@ -28,6 +28,7 @@
 #include <linux/interrupt.h>
 #include <linux/mfd/core.h>
 #include <linux/regulator/consumer.h>
+#include <linux/clk.h>
 
 #define TWL6040_REG_ASICID		0x01
 #define TWL6040_REG_ASICREV		0x02
@@ -223,6 +224,7 @@ struct twl6040 {
 	struct regmap *regmap;
 	struct regmap_irq_chip_data *irq_data;
 	struct regulator_bulk_data supplies[2]; /* supplies for vio, v2v1 */
+	struct clk *clk32k;
 	struct mutex mutex;
 	struct mutex irq_mutex;
 	struct mfd_cell cells[TWL6040_CELLS];
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] mfd: twl6040: Optional clk32k clock handling

[Peter Ujfalusi]

Lee,

On 04/03/2014 01:54 PM, Peter Ujfalusi wrote:
> In certain boards the source for the clk32k clock can be gated. In these
> boards the clk32k clock can be provided to the driver and it is going to be
> enabled/disabled when it is needed.
> If the clk32k clock is not provided the driver will assume that it is always
> running.

Do you want me to resend this patch, it seams to be missing from next still.

Thanks,
Péter

> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi-l0cyMroinI0@public.gmane.org>
> ---
>  Documentation/devicetree/bindings/mfd/twl6040.txt |  2 ++
>  drivers/mfd/twl6040.c                             | 10 ++++++++++
>  include/linux/mfd/twl6040.h                       |  2 ++
>  3 files changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/twl6040.txt b/Documentation/devicetree/bindings/mfd/twl6040.txt
> index 0f5dd709d752..a41157b5d930 100644
> --- a/Documentation/devicetree/bindings/mfd/twl6040.txt
> +++ b/Documentation/devicetree/bindings/mfd/twl6040.txt
> @@ -19,6 +19,8 @@ Required properties:
>  
>  Optional properties, nodes:
>  - enable-active-high: To power on the twl6040 during boot.
> +- clocks: phandle to the clk32k clock provider
> +- clock-names: Must be "clk32k"
>  
>  Vibra functionality
>  Required properties:
> diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
> index 2e6504a8e1e3..12b314ea48dc 100644
> --- a/drivers/mfd/twl6040.c
> +++ b/drivers/mfd/twl6040.c
> @@ -291,6 +291,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
>  		if (twl6040->power_count++)
>  			goto out;
>  
> +		clk_prepare_enable(twl6040->clk32k);
> +
>  		/* Allow writes to the chip */
>  		regcache_cache_only(twl6040->regmap, false);
>  
> @@ -346,6 +348,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
>  
>  		twl6040->sysclk = 0;
>  		twl6040->mclk = 0;
> +
> +		clk_disable_unprepare(twl6040->clk32k);
>  	}
>  
>  out:
> @@ -644,6 +648,12 @@ static int twl6040_probe(struct i2c_client *client,
>  
>  	i2c_set_clientdata(client, twl6040);
>  
> +	twl6040->clk32k = devm_clk_get(&client->dev, "clk32k");
> +	if (IS_ERR(twl6040->clk32k)) {
> +		dev_info(&client->dev, "clk32k is not handled\n");
> +		twl6040->clk32k = NULL;
> +	}
> +
>  	twl6040->supplies[0].supply = "vio";
>  	twl6040->supplies[1].supply = "v2v1";
>  	ret = devm_regulator_bulk_get(&client->dev, TWL6040_NUM_SUPPLIES,
> diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
> index a69d16b30c18..8f9fc3d26e6d 100644
> --- a/include/linux/mfd/twl6040.h
> +++ b/include/linux/mfd/twl6040.h
> @@ -28,6 +28,7 @@
>  #include <linux/interrupt.h>
>  #include <linux/mfd/core.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/clk.h>
>  
>  #define TWL6040_REG_ASICID		0x01
>  #define TWL6040_REG_ASICREV		0x02
> @@ -223,6 +224,7 @@ struct twl6040 {
>  	struct regmap *regmap;
>  	struct regmap_irq_chip_data *irq_data;
>  	struct regulator_bulk_data supplies[2]; /* supplies for vio, v2v1 */
> +	struct clk *clk32k;
>  	struct mutex mutex;
>  	struct mutex irq_mutex;
>  	struct mfd_cell cells[TWL6040_CELLS];
> 
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] mfd: twl6040: Optional clk32k clock handling

[Lee Jones]

> In certain boards the source for the clk32k clock can be gated. In these
> boards the clk32k clock can be provided to the driver and it is going to be
> enabled/disabled when it is needed.
> If the clk32k clock is not provided the driver will assume that it is always
> running.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
>  Documentation/devicetree/bindings/mfd/twl6040.txt |  2 ++
>  drivers/mfd/twl6040.c                             | 10 ++++++++++
>  include/linux/mfd/twl6040.h                       |  2 ++
>  3 files changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/twl6040.txt b/Documentation/devicetree/bindings/mfd/twl6040.txt
> index 0f5dd709d752..a41157b5d930 100644
> --- a/Documentation/devicetree/bindings/mfd/twl6040.txt
> +++ b/Documentation/devicetree/bindings/mfd/twl6040.txt
> @@ -19,6 +19,8 @@ Required properties:
>  
>  Optional properties, nodes:
>  - enable-active-high: To power on the twl6040 during boot.
> +- clocks: phandle to the clk32k clock provider
> +- clock-names: Must be "clk32k"
>  
>  Vibra functionality
>  Required properties:
> diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
> index 2e6504a8e1e3..12b314ea48dc 100644
> --- a/drivers/mfd/twl6040.c
> +++ b/drivers/mfd/twl6040.c
> @@ -291,6 +291,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
>  		if (twl6040->power_count++)
>  			goto out;
>  
> +		clk_prepare_enable(twl6040->clk32k);
> +
>  		/* Allow writes to the chip */
>  		regcache_cache_only(twl6040->regmap, false);
>  
> @@ -346,6 +348,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
>  
>  		twl6040->sysclk = 0;
>  		twl6040->mclk = 0;
> +
> +		clk_disable_unprepare(twl6040->clk32k);
>  	}
>  
>  out:
> @@ -644,6 +648,12 @@ static int twl6040_probe(struct i2c_client *client,
>  
>  	i2c_set_clientdata(client, twl6040);
>  
> +	twl6040->clk32k = devm_clk_get(&client->dev, "clk32k");
> +	if (IS_ERR(twl6040->clk32k)) {
> +		dev_info(&client->dev, "clk32k is not handled\n");
> +		twl6040->clk32k = NULL;

So what happens if you pass a NULL clk reference to clk_prepare_enable()?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH] mfd: twl6040: Optional clk32k clock handling

[Peter Ujfalusi]

On 04/28/2014 01:36 PM, Lee Jones wrote:
>> In certain boards the source for the clk32k clock can be gated. In these
>> boards the clk32k clock can be provided to the driver and it is going to be
>> enabled/disabled when it is needed.
>> If the clk32k clock is not provided the driver will assume that it is always
>> running.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>> ---
>>  Documentation/devicetree/bindings/mfd/twl6040.txt |  2 ++
>>  drivers/mfd/twl6040.c                             | 10 ++++++++++
>>  include/linux/mfd/twl6040.h                       |  2 ++
>>  3 files changed, 14 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/twl6040.txt b/Documentation/devicetree/bindings/mfd/twl6040.txt
>> index 0f5dd709d752..a41157b5d930 100644
>> --- a/Documentation/devicetree/bindings/mfd/twl6040.txt
>> +++ b/Documentation/devicetree/bindings/mfd/twl6040.txt
>> @@ -19,6 +19,8 @@ Required properties:
>>  
>>  Optional properties, nodes:
>>  - enable-active-high: To power on the twl6040 during boot.
>> +- clocks: phandle to the clk32k clock provider
>> +- clock-names: Must be "clk32k"
>>  
>>  Vibra functionality
>>  Required properties:
>> diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
>> index 2e6504a8e1e3..12b314ea48dc 100644
>> --- a/drivers/mfd/twl6040.c
>> +++ b/drivers/mfd/twl6040.c
>> @@ -291,6 +291,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
>>  		if (twl6040->power_count++)
>>  			goto out;
>>  
>> +		clk_prepare_enable(twl6040->clk32k);
>> +
>>  		/* Allow writes to the chip */
>>  		regcache_cache_only(twl6040->regmap, false);
>>  
>> @@ -346,6 +348,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
>>  
>>  		twl6040->sysclk = 0;
>>  		twl6040->mclk = 0;
>> +
>> +		clk_disable_unprepare(twl6040->clk32k);
>>  	}
>>  
>>  out:
>> @@ -644,6 +648,12 @@ static int twl6040_probe(struct i2c_client *client,
>>  
>>  	i2c_set_clientdata(client, twl6040);
>>  
>> +	twl6040->clk32k = devm_clk_get(&client->dev, "clk32k");
>> +	if (IS_ERR(twl6040->clk32k)) {
>> +		dev_info(&client->dev, "clk32k is not handled\n");
>> +		twl6040->clk32k = NULL;
> 
> So what happens if you pass a NULL clk reference to clk_prepare_enable()?

We have checks for !clk in all cases within the clk_* API. If we pass NULL,
nothing will happen and from the calling driver point of view it will look
like a success.
AFAIK this is the way to handle non esential/optional clocks without if()s in
the driver code around the clock handling.

-- 
Péter

Re: [PATCH] mfd: twl6040: Optional clk32k clock handling

[Lee Jones]

On Mon, 28 Apr 2014, Peter Ujfalusi wrote:

> On 04/28/2014 01:36 PM, Lee Jones wrote:
> >> In certain boards the source for the clk32k clock can be gated. In these
> >> boards the clk32k clock can be provided to the driver and it is going to be
> >> enabled/disabled when it is needed.
> >> If the clk32k clock is not provided the driver will assume that it is always
> >> running.
> >>
> >> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> >> ---
> >>  Documentation/devicetree/bindings/mfd/twl6040.txt |  2 ++
> >>  drivers/mfd/twl6040.c                             | 10 ++++++++++
> >>  include/linux/mfd/twl6040.h                       |  2 ++
> >>  3 files changed, 14 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/mfd/twl6040.txt b/Documentation/devicetree/bindings/mfd/twl6040.txt
> >> index 0f5dd709d752..a41157b5d930 100644
> >> --- a/Documentation/devicetree/bindings/mfd/twl6040.txt
> >> +++ b/Documentation/devicetree/bindings/mfd/twl6040.txt
> >> @@ -19,6 +19,8 @@ Required properties:
> >>  
> >>  Optional properties, nodes:
> >>  - enable-active-high: To power on the twl6040 during boot.
> >> +- clocks: phandle to the clk32k clock provider
> >> +- clock-names: Must be "clk32k"
> >>  
> >>  Vibra functionality
> >>  Required properties:
> >> diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
> >> index 2e6504a8e1e3..12b314ea48dc 100644
> >> --- a/drivers/mfd/twl6040.c
> >> +++ b/drivers/mfd/twl6040.c
> >> @@ -291,6 +291,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
> >>  		if (twl6040->power_count++)
> >>  			goto out;
> >>  
> >> +		clk_prepare_enable(twl6040->clk32k);
> >> +
> >>  		/* Allow writes to the chip */
> >>  		regcache_cache_only(twl6040->regmap, false);
> >>  
> >> @@ -346,6 +348,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
> >>  
> >>  		twl6040->sysclk = 0;
> >>  		twl6040->mclk = 0;
> >> +
> >> +		clk_disable_unprepare(twl6040->clk32k);
> >>  	}
> >>  
> >>  out:
> >> @@ -644,6 +648,12 @@ static int twl6040_probe(struct i2c_client *client,
> >>  
> >>  	i2c_set_clientdata(client, twl6040);
> >>  
> >> +	twl6040->clk32k = devm_clk_get(&client->dev, "clk32k");
> >> +	if (IS_ERR(twl6040->clk32k)) {
> >> +		dev_info(&client->dev, "clk32k is not handled\n");
> >> +		twl6040->clk32k = NULL;
> > 
> > So what happens if you pass a NULL clk reference to clk_prepare_enable()?
> 
> We have checks for !clk in all cases within the clk_* API. If we pass NULL,
> nothing will happen and from the calling driver point of view it will look
> like a success.
> AFAIK this is the way to handle non esential/optional clocks without if()s in
> the driver code around the clock handling.

Okay, so long as those checks are there, we're all good.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH] mfd: twl6040: Optional clk32k clock handling

[Lee Jones]

> In certain boards the source for the clk32k clock can be gated. In these
> boards the clk32k clock can be provided to the driver and it is going to be
> enabled/disabled when it is needed.
> If the clk32k clock is not provided the driver will assume that it is always
> running.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
>  Documentation/devicetree/bindings/mfd/twl6040.txt |  2 ++
>  drivers/mfd/twl6040.c                             | 10 ++++++++++
>  include/linux/mfd/twl6040.h                       |  2 ++
>  3 files changed, 14 insertions(+)

Applied, thanks.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog