by Keerthy

[permalink] [raw]

Subject: Re: [PATCH v5 7/8] pwm: pwm-omap-dmtimer: Adapt driver to utilize dmtimer pdata ops

On Tuesday 19 December 2017 08:51 PM, Ladislav Michl wrote:
> On Tue, Dec 19, 2017 at 01:55:48PM +0530, Keerthy wrote:
>> On Tuesday 19 December 2017 10:28 AM, Keerthy wrote:
>>> On Monday 18 December 2017 06:25 PM, Keerthy wrote:
>>>> On Monday 18 December 2017 03:01 PM, Ladislav Michl wrote:
>>>>> Keerthy,
>>>>>
>>>>> On Tue, Dec 12, 2017 at 11:42:16AM +0530, Keerthy wrote:
>>>>>> Adapt driver to utilize dmtimer pdata ops instead of pdata-quirks.
>>>>>>
>>>>>> Signed-off-by: Keerthy <[email protected]>
>>>>>> ---
>>>>>>
>>>>>> Changes in v4:
>>>>>>
>>>>>> * Switched to dev_get_platdata.
>>>>>
>>>>> Where do you expect dev.platform_data to be set? PWM driver is failing
>>>>> with:
>>>>> omap-dmtimer-pwm dmtimer-pwm: dmtimer pdata structure NULL
>>>>> omap-dmtimer-pwm: probe of dmtimer-pwm failed with error -22
>>>>>
>>>>> Which I fixed with patch bellow, to be able to test your patchset.
>>>>
>>>> Thanks! I will make the below patch part of my series.
>>>>
>>>>>
>>>>> Also I'm running a bit out of time, so I'll send few clean up
>>>>> patches and event capture code to get some feedback early.
>>>>>
>>>>> Regards,
>>>>> ladis
>>>>>
>>>>> diff --git a/drivers/clocksource/timer-dm.c b/drivers/clocksource/timer-dm.c
>>>>> index 39be39e6a8dd..d3d8a49cae0d 100644
>>>>> --- a/drivers/clocksource/timer-dm.c
>>>>> +++ b/drivers/clocksource/timer-dm.c
>>>>> @@ -773,6 +773,7 @@ static int omap_dm_timer_probe(struct platform_device *pdev)
>>>>> dev_err(dev, "%s: no platform data.\n", __func__);
>>>>> return -ENODEV;
>>>>> }
>>>>> + dev->platform_data = pdata;
>>>
>>> drivers/clocksource/timer-dm.c: In function 'omap_dm_timer_probe':
>>> drivers/clocksource/timer-dm.c:744:21: warning: assignment discards
>>> 'const' qualifier from pointer target type
>>>
>>> This cannot be done as we are assigning a const pointer to a non-const
>>> pointer.
>
> Oh, I didn't even assume it as proper fix, just to show what is missing :)
>
> But technically 'struct dmtimer_platform_data *pdata' is a constant which
> should not be changed. Also look how all that of_populate chain works -
> at the end const pointer is assigned to void* platform_data by simple
> (void *) overcast.
>
>>> I will figure out a different way for this fix.
>>
>> Ladis,
>>
>> I fixed that:
>>
>> diff --git a/drivers/clocksource/timer-dm.c b/drivers/clocksource/timer-dm.c
>> index 1cbd954..e58f555 100644
>> --- a/drivers/clocksource/timer-dm.c
>> +++ b/drivers/clocksource/timer-dm.c
>> @@ -807,17 +807,21 @@ static int omap_dm_timer_probe(struct
>> platform_device *pdev)
>> struct resource *mem, *irq;
>> struct device *dev = &pdev->dev;
>> const struct of_device_id *match;
>> - const struct dmtimer_platform_data *pdata;
>> + struct dmtimer_platform_data *pdata;
>> int ret;
>>
>> match = of_match_device(of_match_ptr(omap_timer_match), dev);
>> - pdata = match ? match->data : dev->platform_data;
>> + pdata = match ? (struct dmtimer_platform_data *)match->data :
>> + dev->platform_data;
>
> All that seems needlesly complicated, what about patch bellow?
>
>> if (!pdata && !dev->of_node) {
>> dev_err(dev, "%s: no platform data.\n", __func__);
>> return -ENODEV;
>> }
>>
>> + if (!dev->platform_data)
>> + dev->platform_data = pdata;
>
> Does the above condition bring us anything?

That was to avoid assigning the same thing.

>
>> irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
>> if (unlikely(!irq)) {
>> dev_err(dev, "%s: no IRQ resource.\n", __func__);
>> @@ -946,7 +950,7 @@ static int omap_dm_timer_remove(struct
>> platform_device *pdev)
>> .write_status = omap_dm_timer_write_status,
>> };
>>
>> -static const struct dmtimer_platform_data omap3plus_pdata = {
>> +static struct dmtimer_platform_data omap3plus_pdata = {
>> .timer_errata = OMAP_TIMER_ERRATA_I103_I767,
>> .timer_ops = &dmtimer_ops,
>> };
>>
>> Can you check at your end if this works for you?
>
> Note, it is untested as I ran out of time and will continue after New Year.
>
> diff --git a/drivers/clocksource/timer-dm.c b/drivers/clocksource/timer-dm.c
> index 1cbd95420914..85024f11773a 100644
> --- a/drivers/clocksource/timer-dm.c
> +++ b/drivers/clocksource/timer-dm.c
> @@ -806,14 +806,16 @@ static int omap_dm_timer_probe(struct platform_device *pdev)
> struct omap_dm_timer *timer;
> struct resource *mem, *irq;
> struct device *dev = &pdev->dev;
> - const struct of_device_id *match;
> const struct dmtimer_platform_data *pdata;
> int ret;
>
> - match = of_match_device(of_match_ptr(omap_timer_match), dev);
> - pdata = match ? match->data : dev->platform_data;
> + pdata = of_device_get_match_data(dev);
> + if (!pdata)
> + pdata = dev_get_platdata(dev);
> + else
> + dev->platform_data = (void *) pdata;
>
> - if (!pdata && !dev->of_node) {
> + if (!pdata) {
> dev_err(dev, "%s: no platform data.\n", __func__);
> return -ENODEV;
> }

Ladis,

I have tested this on AM437 for dmtimer only. But i have checked that
pdata gets neatly assigned to dev->platform_data. So i believe that was
what was lacking. I will pick the above patch from you and post v6 with
your Tested-by as the pdata hooking was the only missing link for pwm.

Thanks for the patch once again.

Regards,
Keerthy
>