linux-kernel - Re: [PATCH 4/4] mfd: 88pm800: allocate pdata->rtc if not allocated earlier

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Message-ID: <556D71F6.4030608@linaro.org>
Date:	Tue, 02 Jun 2015 14:35:58 +0530
From:	Vaibhav Hiremath <vaibhav.hiremath@...aro.org>
To:	Lee Jones <lee.jones@...aro.org>
CC:	linux-arm-kernel@...ts.infradead.org, robh+dt@...nel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	rtc-linux@...glegroups.com, sameo@...ux.intel.com,
	a.zummo@...ertech.it, alexandre.belloni@...e-electrons.com,
	Chao Xie <chao.xie@...vell.com>
Subject: Re: [PATCH 4/4] mfd: 88pm800: allocate pdata->rtc if not allocated
 earlier



On Tuesday 02 June 2015 01:10 PM, Lee Jones wrote:
> On Tue, 02 Jun 2015, Vaibhav Hiremath wrote:
>> On Monday 01 June 2015 01:52 PM, Lee Jones wrote:
>>> On Sat, 30 May 2015, Vaibhav Hiremath wrote:
>>>
>>>> RTC in pmic 88PM800 can run even the core is powered off, and user
>>>> can set alarm in RTC. When the alarm is timed out, the PMIC will power up
>>>> the core, and the whole system will boot up. And during PMIC driver probe,
>>>> it will read some register to find out whether this boot is caused by RTC
>>>> timeout or not, and pass on this information to the RTC driver.
>>>>
>>>> So we need rtc platform data to be existed in PMIC driver to pass this
>>>> information.
>>>>
>>>> Signed-off-by: Chao Xie <chao.xie@...vell.com>
>>>> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@...aro.org>
>>>> ---
>>>>   drivers/mfd/88pm800.c | 19 +++++++++++++++++++
>>>>   1 file changed, 19 insertions(+)
>>>>
>>>> diff --git a/drivers/mfd/88pm800.c b/drivers/mfd/88pm800.c
>>>> index 8ea4467..34546a1 100644
>>>> --- a/drivers/mfd/88pm800.c
>>>> +++ b/drivers/mfd/88pm800.c
>>>> @@ -586,6 +586,25 @@ static int pm800_probe(struct i2c_client *client,
>>>>   			return ret;
>>>>   	}
>>>>
>>>> +	/*
>>>> +	 * RTC in pmic can run even the core is powered off, and user can set
>>>> +	 * alarm in RTC. When the alarm is time out, the PMIC will power up
>>>> +	 * the core, and the whole system will boot up. When PMIC driver is
>>>> +	 * probed, it will read out some register to find out whether this
>>>> +	 * boot is caused by RTC timeout or not, and it need pass this
>>>> +	 * information to RTC driver.
>>>> +	 * So we need rtc platform data to be existed to pass this information.
>>>> +	 */
>>>> +	if (!pdata->rtc) {
>>>> +		pdata->rtc = devm_kzalloc(&client->dev,
>>>> +					  sizeof(*(pdata->rtc)), GFP_KERNEL);
>>>> +		if (!pdata->rtc) {
>>>> +			dev_err(&client->dev,
>>>> +					"failed to allocate memory for rtc\n");
>>>> +			return -ENOMEM;
>>>> +		}
>>>> +	}
>>>> +
>>>
>>> Where is this memory first used?
>>>
>>
>> In the same file, look for field "rtc_wakeup".
>>
>> FYI,
>>
>> This field is used in two files,
>>
>> drivers/mfd/88pm800.c
>> and
>> drivers/rtc/rtc-88pm800.c	[sets the "platform_data" field]
>
> Then were is the platform_data field subsequently used?
>


Currently not used, but it is for future use, where we would be
interested to know that the wakeup is really from reset or RTC wakeup.

> Looking at the RTC platform data declaration I see:
>
> struct pm80x_rtc_pdata {
>      int             vrtc;
>      int             rtc_wakeup;
> };
>
> Is 'vrtc' even used?  If so, where?
>


No, it is not.

Thanks,
Vaibhav
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