[V3,3/4] usb: dwc3: of-simple: Add support to get resets for the device

Submitted by Vivek Gautam on April 18, 2017, 11:21 a.m.

Details

Message ID 1492514488-27385-4-git-send-email-vivek.gautam@codeaurora.org
State New
Headers show

Commit Message

Vivek Gautam April 18, 2017, 11:21 a.m.
Add support to get a list of resets available for the device.
These resets must be kept de-asserted until the device is
in use.

Cc: Felipe Balbi <balbi@kernel.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
---
 drivers/usb/dwc3/dwc3-of-simple.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

Comments

Philipp Zabel April 19, 2017, 10:32 a.m.
On Tue, 2017-04-18 at 16:51 +0530, Vivek Gautam wrote:
> Add support to get a list of resets available for the device.
> These resets must be kept de-asserted until the device is
> in use.
> 
> Cc: Felipe Balbi <balbi@kernel.org>
> Cc: Philipp Zabel <p.zabel@pengutronix.de>
> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
> ---
>  drivers/usb/dwc3/dwc3-of-simple.c | 36 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-of-simple.c b/drivers/usb/dwc3/dwc3-of-simple.c
> index fe414e7a9c78..9116df649f0b 100644
> --- a/drivers/usb/dwc3/dwc3-of-simple.c
> +++ b/drivers/usb/dwc3/dwc3-of-simple.c
> @@ -29,13 +29,39 @@
>  #include <linux/of.h>
>  #include <linux/of_platform.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
>  
>  struct dwc3_of_simple {
>  	struct device		*dev;
>  	struct clk		**clks;
>  	int			num_clocks;
> +	struct reset_control_array *resets;
>  };
>  
> +static int dwc3_of_simple_reset_init(struct dwc3_of_simple *simple)
> +{
> +	struct device		*dev = simple->dev;
> +	int			ret;
> +
> +	simple->resets = of_reset_control_array_get_exclusive(dev->of_node);
> +	if (IS_ERR(simple->resets)) {
> +		ret = PTR_ERR(simple->resets);
> +		if (ret == -ENOENT)
> +			/* not all controllers required resets */
> +			return 0;

If you use the of_reset_control_array_get_optional_exclusive variant,
you can remove the three lines directly above.

> +		dev_err(dev, "failed to get device resets\n");

It would be nice to print the error code here.

> +		return ret;
> +	}
> +
> +	ret = reset_control_array_deassert(simple->resets);
> +	if (ret) {
> +		reset_control_array_put(simple->resets);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  static int dwc3_of_simple_clk_init(struct dwc3_of_simple *simple, int count)
>  {
>  	struct device		*dev = simple->dev;
> @@ -100,6 +126,10 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	ret = dwc3_of_simple_reset_init(simple);
> +	if (ret)
> +		return ret;
> +

I would just move the contents of dwc3_of_simple_reset_init here and add
a goto error path at the end of dwc3_of_simple_clk_init to handle the
reset control cleanup as needed.

>  	ret = of_platform_populate(np, NULL, NULL, dev);
>  	if (ret) {
>  		for (i = 0; i < simple->num_clocks; i++) {
> @@ -107,6 +137,9 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
>  			clk_put(simple->clks[i]);
>  		}
>  
> +		reset_control_array_assert(simple->resets);
> +		reset_control_array_put(simple->resets);
> +
>  		return ret;
>  	}
>  
> @@ -128,6 +161,9 @@ static int dwc3_of_simple_remove(struct platform_device *pdev)
>  		clk_put(simple->clks[i]);
>  	}
>  
> +	reset_control_array_assert(simple->resets);
> +	reset_control_array_put(simple->resets);
> +

Must the reset be asserted before of_platform_depopulate?

>  	of_platform_depopulate(dev);

Given the order above, I'd expect the reset cleanup here.

>  	pm_runtime_put_sync(dev);

regards
Philipp

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Vivek Gautam April 19, 2017, 12:02 p.m.
On 04/19/2017 04:02 PM, Philipp Zabel wrote:
> On Tue, 2017-04-18 at 16:51 +0530, Vivek Gautam wrote:
>> Add support to get a list of resets available for the device.
>> These resets must be kept de-asserted until the device is
>> in use.
>>
>> Cc: Felipe Balbi <balbi@kernel.org>
>> Cc: Philipp Zabel <p.zabel@pengutronix.de>
>> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
>> ---
>>   drivers/usb/dwc3/dwc3-of-simple.c | 36 ++++++++++++++++++++++++++++++++++++
>>   1 file changed, 36 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/dwc3-of-simple.c b/drivers/usb/dwc3/dwc3-of-simple.c
>> index fe414e7a9c78..9116df649f0b 100644
>> --- a/drivers/usb/dwc3/dwc3-of-simple.c
>> +++ b/drivers/usb/dwc3/dwc3-of-simple.c
>> @@ -29,13 +29,39 @@
>>   #include <linux/of.h>
>>   #include <linux/of_platform.h>
>>   #include <linux/pm_runtime.h>
>> +#include <linux/reset.h>
>>   
>>   struct dwc3_of_simple {
>>   	struct device		*dev;
>>   	struct clk		**clks;
>>   	int			num_clocks;
>> +	struct reset_control_array *resets;
>>   };
>>   
>> +static int dwc3_of_simple_reset_init(struct dwc3_of_simple *simple)
>> +{
>> +	struct device		*dev = simple->dev;
>> +	int			ret;
>> +
>> +	simple->resets = of_reset_control_array_get_exclusive(dev->of_node);
>> +	if (IS_ERR(simple->resets)) {
>> +		ret = PTR_ERR(simple->resets);
>> +		if (ret == -ENOENT)
>> +			/* not all controllers required resets */
>> +			return 0;
> If you use the of_reset_control_array_get_optional_exclusive variant,
> you can remove the three lines directly above.

No, it's a little tricky here.
of_reset_control_get_count() returns an error code, that we then return from
of_reset_control_array_get().

This is something that tegra/pmc driver required (return errorno in case 
count
of reset controls is zero.

So we handle that error separately here.

>
>> +		dev_err(dev, "failed to get device resets\n");
> It would be nice to print the error code here.

Sure.

>
>> +		return ret;
>> +	}
>> +
>> +	ret = reset_control_array_deassert(simple->resets);
>> +	if (ret) {
>> +		reset_control_array_put(simple->resets);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>   static int dwc3_of_simple_clk_init(struct dwc3_of_simple *simple, int count)
>>   {
>>   	struct device		*dev = simple->dev;
>> @@ -100,6 +126,10 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
>>   	if (ret)
>>   		return ret;
>>   
>> +	ret = dwc3_of_simple_reset_init(simple);
>> +	if (ret)
>> +		return ret;
>> +
> I would just move the contents of dwc3_of_simple_reset_init here and add
> a goto error path at the end of dwc3_of_simple_clk_init to handle the
> reset control cleanup as needed.

Okay, i can restructure it.

>
>>   	ret = of_platform_populate(np, NULL, NULL, dev);
>>   	if (ret) {
>>   		for (i = 0; i < simple->num_clocks; i++) {
>> @@ -107,6 +137,9 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
>>   			clk_put(simple->clks[i]);
>>   		}
>>   
>> +		reset_control_array_assert(simple->resets);
>> +		reset_control_array_put(simple->resets);
>> +
>>   		return ret;
>>   	}
>>   
>> @@ -128,6 +161,9 @@ static int dwc3_of_simple_remove(struct platform_device *pdev)
>>   		clk_put(simple->clks[i]);
>>   	}
>>   
>> +	reset_control_array_assert(simple->resets);
>> +	reset_control_array_put(simple->resets);
>> +
> Must the reset be asserted before of_platform_depopulate?

Right, the order must be taken care of here. Will change this.

>
>>   	of_platform_depopulate(dev);
> Given the order above, I'd expect the reset cleanup here.

Sure.

>
>>   	pm_runtime_put_sync(dev);
> regards
> Philipp

Thanks for reviewing.

Best Regards
Vivek

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diff --git a/drivers/usb/dwc3/dwc3-of-simple.c b/drivers/usb/dwc3/dwc3-of-simple.c
index fe414e7a9c78..9116df649f0b 100644
--- a/drivers/usb/dwc3/dwc3-of-simple.c
+++ b/drivers/usb/dwc3/dwc3-of-simple.c
@@ -29,13 +29,39 @@ 
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 
 struct dwc3_of_simple {
 	struct device		*dev;
 	struct clk		**clks;
 	int			num_clocks;
+	struct reset_control_array *resets;
 };
 
+static int dwc3_of_simple_reset_init(struct dwc3_of_simple *simple)
+{
+	struct device		*dev = simple->dev;
+	int			ret;
+
+	simple->resets = of_reset_control_array_get_exclusive(dev->of_node);
+	if (IS_ERR(simple->resets)) {
+		ret = PTR_ERR(simple->resets);
+		if (ret == -ENOENT)
+			/* not all controllers required resets */
+			return 0;
+		dev_err(dev, "failed to get device resets\n");
+		return ret;
+	}
+
+	ret = reset_control_array_deassert(simple->resets);
+	if (ret) {
+		reset_control_array_put(simple->resets);
+		return ret;
+	}
+
+	return 0;
+}
+
 static int dwc3_of_simple_clk_init(struct dwc3_of_simple *simple, int count)
 {
 	struct device		*dev = simple->dev;
@@ -100,6 +126,10 @@  static int dwc3_of_simple_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = dwc3_of_simple_reset_init(simple);
+	if (ret)
+		return ret;
+
 	ret = of_platform_populate(np, NULL, NULL, dev);
 	if (ret) {
 		for (i = 0; i < simple->num_clocks; i++) {
@@ -107,6 +137,9 @@  static int dwc3_of_simple_probe(struct platform_device *pdev)
 			clk_put(simple->clks[i]);
 		}
 
+		reset_control_array_assert(simple->resets);
+		reset_control_array_put(simple->resets);
+
 		return ret;
 	}
 
@@ -128,6 +161,9 @@  static int dwc3_of_simple_remove(struct platform_device *pdev)
 		clk_put(simple->clks[i]);
 	}
 
+	reset_control_array_assert(simple->resets);
+	reset_control_array_put(simple->resets);
+
 	of_platform_depopulate(dev);
 
 	pm_runtime_put_sync(dev);