[PATCH V2] GPIO PL061: Adding Clk framework support

[PATCH V2] GPIO PL061: Adding Clk framework support

[Viresh KUMAR]

From: Viresh KUMAR <viresh.kumar@st.com>

GPIO Clk is never enabled on Platforms, like: SPEAr, which are based upon clock
framework and use PL061 driver. This patch adds support for Clk enabling and
disabling as and when gpios are requested and freed.

Modifications since V1:
 - Removed usage_count, as already done by clk framework.
 - Checking error case of clk_enable.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
---
 drivers/gpio/pl061.c |   37 ++++++++++++++++++++++++++++++++++---
 1 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/pl061.c b/drivers/gpio/pl061.c
index 105701a..fd37349 100644
--- a/drivers/gpio/pl061.c
+++ b/drivers/gpio/pl061.c
@@ -11,7 +11,10 @@
  *
  * Data sheet: ARM DDI 0190B, September 2000
  */
+
+#include <linux/clk.h>
 #include <linux/spinlock.h>
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/list.h>
@@ -56,8 +59,26 @@ struct pl061_gpio {
 	void __iomem		*base;
 	unsigned		irq_base;
 	struct gpio_chip	gc;
+	struct clk		*clk;
 };
 
+static int pl061_request(struct gpio_chip *gc, unsigned offset)
+{
+	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
+
+	if (offset >= gc->ngpio)
+		return -EINVAL;
+
+	return clk_enable(chip->clk);
+}
+
+static void pl061_free(struct gpio_chip *gc, unsigned offset)
+{
+	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
+
+	clk_disable(chip->clk);
+}
+
 static int pl061_direction_input(struct gpio_chip *gc, unsigned offset)
 {
 	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
@@ -260,10 +281,18 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 		goto release_region;
 	}
 
+	chip->clk = clk_get(&dev->dev, NULL);
+	if (IS_ERR(chip->clk)) {
+		ret = PTR_ERR(chip->clk);
+		goto iounmap;
+	}
+
 	spin_lock_init(&chip->lock);
 	spin_lock_init(&chip->irq_lock);
 	INIT_LIST_HEAD(&chip->list);
 
+	chip->gc.request = pl061_request;
+	chip->gc.free = pl061_free;
 	chip->gc.direction_input = pl061_direction_input;
 	chip->gc.direction_output = pl061_direction_output;
 	chip->gc.get = pl061_get_value;
@@ -279,7 +308,7 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 
 	ret = gpiochip_add(&chip->gc);
 	if (ret)
-		goto iounmap;
+		goto free_clk;
 
 	/*
 	 * irq_chip support
@@ -292,7 +321,7 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 	irq = dev->irq[0];
 	if (irq < 0) {
 		ret = -ENODEV;
-		goto iounmap;
+		goto free_clk;
 	}
 	set_irq_chained_handler(irq, pl061_irq_handler);
 	if (!test_and_set_bit(irq, init_irq)) { /* list initialized? */
@@ -300,7 +329,7 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 		if (chip_list == NULL) {
 			clear_bit(irq, init_irq);
 			ret = -ENOMEM;
-			goto iounmap;
+			goto free_clk;
 		}
 		INIT_LIST_HEAD(chip_list);
 		set_irq_data(irq, chip_list);
@@ -323,6 +352,8 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 
 	return 0;
 
+free_clk:
+	clk_put(chip->clk);
 iounmap:
 	iounmap(chip->base);
 release_region:
-- 
1.6.0.2

[PATCH V2] GPIO PL061: Adding Clk framework support

[Rabin Vincent]

On Mon, Jun 21, 2010 at 12:27:43PM +0530, Viresh KUMAR wrote:
> GPIO Clk is never enabled on Platforms, like: SPEAr, which are based upon clock
> framework and use PL061 driver. This patch adds support for Clk enabling and
> disabling as and when gpios are requested and freed.
[...]
> +	chip->clk = clk_get(&dev->dev, NULL);
> +	if (IS_ERR(chip->clk)) {
> +		ret = PTR_ERR(chip->clk);
> +		goto iounmap;
> +	}

Have you verified that all platforms using this driver already have
clocks with the appropriate names?   Otherwise this patch will break
those platforms.

Rabin

[PATCH V2] GPIO PL061: Adding Clk framework support

[Linus Walleij]

2010/6/21 Rabin Vincent <rabin@rab.in>:
> On Mon, Jun 21, 2010 at 12:27:43PM +0530, Viresh KUMAR wrote:
>> GPIO Clk is never enabled on Platforms, like: SPEAr, which are based upon clock
>> framework and use PL061 driver. This patch adds support for Clk enabling and
>> disabling as and when gpios are requested and freed.
> [...]
>> + ? ? chip->clk = clk_get(&dev->dev, NULL);
>> + ? ? if (IS_ERR(chip->clk)) {
>> + ? ? ? ? ? ? ret = PTR_ERR(chip->clk);
>> + ? ? ? ? ? ? goto iounmap;
>> + ? ? }
>
> Have you verified that all platforms using this driver already have
> clocks with the appropriate names? ? Otherwise this patch will break
> those platforms.

The ARM Versatiles and RealViews are always clocked I think,
so clock support should be optional.

When I added a clock lookup to the PL08x block recently I used
a construct like this for an optional clock:

chip->clk = clk_get(&dev->dev, NULL);
if (IS_ERR(chip->clk)) {
       ret = PTR_ERR(chip->clk);
       if (ret == -ENOENT)
          /* No block clock in this platform */
          chip->clk = NULL;
       else
          goto iounmap;
}

This will work whenever clkdevice is used, since that
returns -ENOENT for nonexisting entries.

Then:

if (chip->clk)
  clk_enable(chip->clk);

etc

Yours,
Linus Walleij

[PATCH V2] GPIO PL061: Adding Clk framework support

[Baruch Siach]

Hi Viresh,

On Mon, Jun 21, 2010 at 12:27:43PM +0530, Viresh KUMAR wrote:
> From: Viresh KUMAR <viresh.kumar@st.com>
> 
> GPIO Clk is never enabled on Platforms, like: SPEAr, which are based upon clock
> framework and use PL061 driver. This patch adds support for Clk enabling and
> disabling as and when gpios are requested and freed.
> 
> Modifications since V1:
>  - Removed usage_count, as already done by clk framework.
>  - Checking error case of clk_enable.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@st.com>

Acked-by: Baruch Siach <baruch@tkos.co.il>


-- 
                                                     ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

[PATCH V2] GPIO PL061: Adding Clk framework support

[Viresh KUMAR]

On 6/21/2010 11:04 PM, Linus Walleij wrote:
> 2010/6/21 Rabin Vincent <rabin@rab.in>:
>> On Mon, Jun 21, 2010 at 12:27:43PM +0530, Viresh KUMAR wrote:
>>> +     chip->clk = clk_get(&dev->dev, NULL);
>>> +     if (IS_ERR(chip->clk)) {
>>> +             ret = PTR_ERR(chip->clk);
>>> +             goto iounmap;
>>> +     }
>>
>> Have you verified that all platforms using this driver already have
>> clocks with the appropriate names?   Otherwise this patch will break
>> those platforms.
> 
> The ARM Versatiles and RealViews are always clocked I think,
> so clock support should be optional.
> 
> When I added a clock lookup to the PL08x block recently I used
> a construct like this for an optional clock:
> 
> chip->clk = clk_get(&dev->dev, NULL);
> if (IS_ERR(chip->clk)) {
>        ret = PTR_ERR(chip->clk);
>        if (ret == -ENOENT)
>           /* No block clock in this platform */
>           chip->clk = NULL;
>        else
>           goto iounmap;
> }
> 
> This will work whenever clkdevice is used, since that
> returns -ENOENT for nonexisting entries.
> 
> Then:
> 
> if (chip->clk)
>   clk_enable(chip->clk);
> 

Will modify it, as suggested.

thanks
viresh.

[PATCH V2] GPIO PL061: Adding Clk framework support

[Viresh KUMAR]

On 6/21/2010 11:11 PM, Baruch Siach wrote:
> Hi Viresh,
> 
> On Mon, Jun 21, 2010 at 12:27:43PM +0530, Viresh KUMAR wrote:
>> From: Viresh KUMAR <viresh.kumar@st.com>
>>
>> GPIO Clk is never enabled on Platforms, like: SPEAr, which are based upon clock
>> framework and use PL061 driver. This patch adds support for Clk enabling and
>> disabling as and when gpios are requested and freed.
>>
>> Modifications since V1:
>>  - Removed usage_count, as already done by clk framework.
>>  - Checking error case of clk_enable.
>>
>> Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
> 
> Acked-by: Baruch Siach <baruch@tkos.co.il>
> 

Baruch,

Sorry, but you need to review another version.

viresh.

[PATCH v2] GPIO PL061: Adding Clk framework support

[Viresh KUMAR]

From: Viresh KUMAR <viresh.kumar@st.com>

GPIO Clk is never enabled on Platforms, like: SPEAr, which are based upon clock
framework and use PL061 driver. This patch adds support for Clk enabling and
disabling as and when gpios are requested and freed.

modifications since V2:
 - if clk_get returns -ENOENT, then work without clk enable/disable.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
---
 drivers/gpio/pl061.c |   47 ++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/pl061.c b/drivers/gpio/pl061.c
index 105701a..b2a556b 100644
--- a/drivers/gpio/pl061.c
+++ b/drivers/gpio/pl061.c
@@ -11,7 +11,10 @@
  *
  * Data sheet: ARM DDI 0190B, September 2000
  */
+
+#include <linux/clk.h>
 #include <linux/spinlock.h>
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/list.h>
@@ -56,8 +59,31 @@ struct pl061_gpio {
 	void __iomem		*base;
 	unsigned		irq_base;
 	struct gpio_chip	gc;
+	struct clk		*clk;
 };
 
+static int pl061_request(struct gpio_chip *gc, unsigned offset)
+{
+	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
+	int ret;
+
+	if (offset >= gc->ngpio)
+		return -EINVAL;
+
+	if (chip->clk)
+		ret = clk_enable(chip->clk);
+
+	return ret
+}
+
+static void pl061_free(struct gpio_chip *gc, unsigned offset)
+{
+	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
+
+	if (chip->clk)
+		clk_disable(chip->clk);
+}
+
 static int pl061_direction_input(struct gpio_chip *gc, unsigned offset)
 {
 	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
@@ -260,10 +286,22 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 		goto release_region;
 	}
 
+	chip->clk = clk_get(&dev->dev, NULL);
+	if (IS_ERR(chip->clk)) {
+		ret = PTR_ERR(chip->clk);
+		/* clk Not present */
+		if (ret == -ENOENT)
+			chip->clk = NULL;
+		else
+			goto iounmap;
+	}
+
 	spin_lock_init(&chip->lock);
 	spin_lock_init(&chip->irq_lock);
 	INIT_LIST_HEAD(&chip->list);
 
+	chip->gc.request = pl061_request;
+	chip->gc.free = pl061_free;
 	chip->gc.direction_input = pl061_direction_input;
 	chip->gc.direction_output = pl061_direction_output;
 	chip->gc.get = pl061_get_value;
@@ -279,7 +317,7 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 
 	ret = gpiochip_add(&chip->gc);
 	if (ret)
-		goto iounmap;
+		goto free_clk;
 
 	/*
 	 * irq_chip support
@@ -292,7 +330,7 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 	irq = dev->irq[0];
 	if (irq < 0) {
 		ret = -ENODEV;
-		goto iounmap;
+		goto free_clk;
 	}
 	set_irq_chained_handler(irq, pl061_irq_handler);
 	if (!test_and_set_bit(irq, init_irq)) { /* list initialized? */
@@ -300,7 +338,7 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 		if (chip_list == NULL) {
 			clear_bit(irq, init_irq);
 			ret = -ENOMEM;
-			goto iounmap;
+			goto free_clk;
 		}
 		INIT_LIST_HEAD(chip_list);
 		set_irq_data(irq, chip_list);
@@ -323,6 +361,9 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 
 	return 0;
 
+free_clk:
+	if (chip->clk)
+		clk_put(chip->clk);
 iounmap:
 	iounmap(chip->base);
 release_region:
-- 
1.6.0.2

[PATCH v2] GPIO PL061: Adding Clk framework support

[Rabin Vincent]

On Tue, Jun 22, 2010 at 9:37 AM, Viresh KUMAR <viresh.kumar@st.com> wrote:
> +static int pl061_request(struct gpio_chip *gc, unsigned offset)
> +{
> + ? ? ? struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
> + ? ? ? int ret;
> +
> + ? ? ? if (offset >= gc->ngpio)
> + ? ? ? ? ? ? ? return -EINVAL;
> +
> + ? ? ? if (chip->clk)
> + ? ? ? ? ? ? ? ret = clk_enable(chip->clk);
> +
> + ? ? ? return ret

Missing semicolon.

Also, returning uninitialized values when chip->clk is not set.

You can probably just not register these callbacks for the
!chip->clk case.

Rabin

[PATCH v2] GPIO PL061: Adding Clk framework support

[Viresh KUMAR]

On 6/22/2010 9:51 AM, Rabin Vincent wrote:
> On Tue, Jun 22, 2010 at 9:37 AM, Viresh KUMAR <viresh.kumar@st.com> wrote:
>> +static int pl061_request(struct gpio_chip *gc, unsigned offset)
>> +{
>> +       struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
>> +       int ret;
>> +
>> +       if (offset >= gc->ngpio)
>> +               return -EINVAL;
>> +
>> +       if (chip->clk)
>> +               ret = clk_enable(chip->clk);
>> +
>> +       return ret
> 
> Also, returning uninitialized values when chip->clk is not set.
> 
> You can probably just not register these callbacks for the
> !chip->clk case.
> 

Sorry. Will correct it.