lkml.org 
[lkml]   [2017]   [Apr]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH V3 3/4] usb: dwc3: of-simple: Add support to get resets for the device
From
Date


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

--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

\
 
 \ /
  Last update: 2017-04-19 14:03    [W:0.186 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site