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Date: Wed, 24 Oct 2012 12:40:19 +0800
From: Hongbo Zhang <hongbo.zhang@...aro.org>
To: Francesco Lavra <francescolavra.fl@...il.com>
Cc: linaro-dev@...ts.linaro.org, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org, STEricsson_nomadik_linux@...t.st.com,
kernel@...oocommunity.org, linaro-kernel@...ts.linaro.org,
"hongbo.zhang" <hongbo.zhang@...aro.com>, patches@...aro.org
Subject: Re: [PATCH 5/5] Thermal: Add ST-Ericsson db8500 thermal dirver.
On 23 October 2012 02:51, Francesco Lavra <francescolavra.fl@...il.com> wrote:
> On 10/22/2012 02:02 PM, Hongbo Zhang wrote:
> [...]
>>>> +static irqreturn_t prcmu_low_irq_handler(int irq, void *irq_data)
>>>> +{
>>>> + struct db8500_thermal_zone *pzone = irq_data;
>>>> + struct db8500_thsens_platform_data *ptrips;
>>>> + unsigned long next_low, next_high;
>>>> + unsigned int idx;
>>>> +
>>>> + ptrips = pzone->trip_tab;
>>>> + idx = pzone->cur_index;
>>>> + if (unlikely(idx == 0))
>>>> + /* Meaningless for thermal management, ignoring it */
>>>> + return IRQ_HANDLED;
>>>> +
>>>> + if (idx == 1) {
>>>> + next_high = ptrips->trip_points[0].temp;
>>>> + next_low = PRCMU_DEFAULT_LOW_TEMP;
>>>> + } else {
>>>> + next_high = ptrips->trip_points[idx-1].temp;
>>>> + next_low = ptrips->trip_points[idx-2].temp;
>>>> + }
>>>> +
>>>> + pzone->cur_index -= 1;
>>>> + pzone->cur_temp_pseudo = (next_high + next_low)/2;
>>>> +
>>>> + prcmu_stop_temp_sense();
>>>> + prcmu_config_hotmon((u8)(next_low/1000), (u8)(next_high/1000));
>>>> + prcmu_start_temp_sense(PRCMU_DEFAULT_MEASURE_TIME);
>>>> +
>>>> + pr_debug("PRCMU set max %ld, set min %ld\n", next_high, next_low);
>>>> +
>>>> + pzone->trend = THERMAL_TREND_DROPPING;
>>>> + schedule_work(&pzone->therm_work);
>>>> +
>>>> + return IRQ_HANDLED;
>>>> +}
>>>> +
>>>> +static irqreturn_t prcmu_high_irq_handler(int irq, void *irq_data)
>>>> +{
>>>> + struct db8500_thermal_zone *pzone = irq_data;
>>>> + struct db8500_thsens_platform_data *ptrips;
>>>> + unsigned long next_low, next_high;
>>>> + unsigned int idx;
>>>> +
>>>> + ptrips = pzone->trip_tab;
>>>> + idx = pzone->cur_index;
>>>> +
>>>> + if (idx < ptrips->num_trips - 1) {
>>>> + next_high = ptrips->trip_points[idx+1].temp;
>>>> + next_low = ptrips->trip_points[idx].temp;
>>>> +
>>>> + pzone->cur_index += 1;
>>>> + pzone->cur_temp_pseudo = (next_high + next_low)/2;
>>>> +
>>>> + prcmu_stop_temp_sense();
>>>> + prcmu_config_hotmon((u8)(next_low/1000), (u8)(next_high/1000));
>>>> + prcmu_start_temp_sense(PRCMU_DEFAULT_MEASURE_TIME);
>>>> +
>>>> + pr_debug("PRCMU set max %ld, min %ld\n", next_high, next_low);
>>>> + }
>>>> +
>>>> + if (idx == ptrips->num_trips - 1)
>>>
>>> } else if ()
>> There is no else condition here, because it it the highest critical
>> trip point, system will be shut down in thermal_work.
>> But I'd like to add some comments here to state this situation.
>
> I didn't mean adding a new else condition, what I meant is that if the
> first condition (idx < ptrips->num_trips - 1) is verified, then there is
> no need to check for the second condition (idx == ptrips->num_trips -
> 1). So I was thinking of changing the code to:
>
> if (idx < ptrips->num_trips - 1)
> ...
> else if (idx == ptrips->num_trips - 1)
> ...
>
> Sorry if I wasn't clear.
Got it, thanks.
>
>>>
>>>> + pzone->cur_temp_pseudo = ptrips->trip_points[idx].temp + 1;
>>>> +
>>>> + pzone->trend = THERMAL_TREND_RAISING;
>>>> + schedule_work(&pzone->therm_work);
>>>> +
>>>> + return IRQ_HANDLED;
>>>> +}
>>>> +
>>>> +static void db8500_thermal_work(struct work_struct *work)
>>>> +{
>>>> + enum thermal_device_mode cur_mode;
>>>> + struct db8500_thermal_zone *pzone;
>>>> +
>>>> + pzone = container_of(work, struct db8500_thermal_zone, therm_work);
>>>> +
>>>> + mutex_lock(&pzone->th_lock);
>>>> + cur_mode = pzone->mode;
>>>> + mutex_unlock(&pzone->th_lock);
>>>> +
>>>> + if (cur_mode == THERMAL_DEVICE_DISABLED) {
>>>> + pr_warn("Warning: thermal function disabled.\n");
>>>> + return;
>>>> + }
>>>> +
>>>> + thermal_zone_device_update(pzone->therm_dev);
>>>> + pr_debug("db8500_thermal_work finished.\n");
>>>> +}
>>>> +
>>>> +static int __devinit db8500_thermal_probe(struct platform_device *pdev)
>>>> +{
>>>> + struct db8500_thermal_zone *pzone = NULL;
>>>> + struct db8500_thsens_platform_data *ptrips;
>>>> + int low_irq, high_irq, ret = 0;
>>>> + unsigned long dft_low, dft_high;
>>>> +
>>>> + pzone = devm_kzalloc(&pdev->dev,
>>>> + sizeof(struct db8500_thermal_zone), GFP_KERNEL);
>>>> + if (!pzone)
>>>> + return -ENOMEM;
>>>> +
>>>> + pzone->thsens_pdev = pdev;
>>>> +
>>>> + low_irq = platform_get_irq_byname(pdev, "IRQ_HOTMON_LOW");
>>>> + if (low_irq < 0) {
>>>> + pr_err("Get IRQ_HOTMON_LOW failed.\n");
>>>> + return low_irq;
>>>> + }
>>>> +
>>>> + ret = devm_request_threaded_irq(&pdev->dev, low_irq, NULL,
>>>> + prcmu_low_irq_handler,
>>>> + IRQF_NO_SUSPEND | IRQF_ONESHOT, "dbx500_temp_low", pzone);
>>>> + if (ret < 0) {
>>>> + pr_err("Failed to allocate temp low irq.\n");
>>>> + return ret;
>>>> + }
>>>> +
>>>> + high_irq = platform_get_irq_byname(pdev, "IRQ_HOTMON_HIGH");
>>>> + if (high_irq < 0) {
>>>> + pr_err("Get IRQ_HOTMON_HIGH failed.\n");
>>>> + return high_irq;
>>>> + }
>>>> +
>>>> + ret = devm_request_threaded_irq(&pdev->dev, high_irq, NULL,
>>>> + prcmu_high_irq_handler,
>>>> + IRQF_NO_SUSPEND | IRQF_ONESHOT, "dbx500_temp_high", pzone);
>>>> + if (ret < 0) {
>>>> + pr_err("Failed to allocate temp high irq.\n");
>>>> + return ret;
>>>> + }
>>>> +
>>>> + pzone->low_irq = low_irq;
>>>> + pzone->high_irq = high_irq;
>>>> +
>>>> + pzone->mode = THERMAL_DEVICE_DISABLED;
>>>> +
>>>> + mutex_init(&pzone->th_lock);
>>>> +
>>>> + INIT_WORK(&pzone->therm_work, db8500_thermal_work);
>>>> +
>>>> + ptrips = pdev->dev.platform_data;
>>>> + pzone->trip_tab = ptrips;
>>>> +
>>>> + pzone->therm_dev = thermal_zone_device_register("db8500_thermal_zone",
>>>> + ptrips->num_trips, 0, pzone, &thdev_ops, 0, 0);
>>>> +
>>>> + if (IS_ERR(pzone->therm_dev)) {
>>>> + pr_err("Failed to register thermal zone device\n");
>>>> + return PTR_ERR(pzone->therm_dev);
>>>> + }
>>>> +
>>>> + dft_low = PRCMU_DEFAULT_LOW_TEMP;
>>>> + dft_high = ptrips->trip_points[0].temp;
>>>> +
>>>> + prcmu_stop_temp_sense();
>>>> + prcmu_config_hotmon((u8)(dft_low/1000), (u8)(dft_high/1000));
>>>> + prcmu_start_temp_sense(PRCMU_DEFAULT_MEASURE_TIME);
>>>> +
>>>> + pzone->cur_index = 0;
>>>> + pzone->cur_temp_pseudo = (dft_low + dft_high)/2;
>>>> + pzone->trend = THERMAL_TREND_STABLE;
>>>
>>> All the stuff from prcmu_stop_temp_sense() up to this line can race with
>>> the irq handlers, I would suggest doing it before requesting the irqs.
>>>
>>>> + pzone->mode = THERMAL_DEVICE_ENABLED;
>>>
>>> Shouldn't this be protected by pzone->th_lock? Otherwise it should be
>>> set before the thermal zone is registered.
>>>
>>>> +
>>>> + platform_set_drvdata(pdev, pzone);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int __devexit db8500_thermal_remove(struct platform_device *pdev)
>>>> +{
>>>> + struct db8500_thermal_zone *pzone;
>>>> + pzone = platform_get_drvdata(pdev);
>>>> +
>>>> + cancel_work_sync(&pzone->therm_work);
>>>> +
>>>> + if (pzone->therm_dev)
>>>> + thermal_zone_device_unregister(pzone->therm_dev);
>>>> +
>>>> + return 0;
>>>> +}
>>>
>>> mutex_destroy() should be called on pzone->th_lock
>>>
>>>> +
>>>> +static int db8500_thermal_suspend(struct platform_device *pdev,
>>>> + pm_message_t state)
>>>> +{
>>>> + struct db8500_thermal_zone *pzone;
>>>> + pzone = platform_get_drvdata(pdev);
>>>> +
>>>> + flush_work_sync(&pzone->therm_work);
>>>> + prcmu_stop_temp_sense();
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int db8500_thermal_resume(struct platform_device *pdev)
>>>> +{
>>>> + struct db8500_thermal_zone *pzone;
>>>> + struct db8500_thsens_platform_data *ptrips;
>>>> + unsigned long dft_low, dft_high;
>>>> +
>>>> + pzone = platform_get_drvdata(pdev);
>>>> + ptrips = pzone->trip_tab;
>>>> + dft_low = PRCMU_DEFAULT_LOW_TEMP;
>>>> + dft_high = ptrips->trip_points[0].temp;
>>>> +
>>>> + prcmu_config_hotmon((u8)(dft_low/1000), (u8)(dft_high/1000));
>>>> + prcmu_start_temp_sense(PRCMU_DEFAULT_MEASURE_TIME);
>>>
>>> Shouldn't cur_index and cur_temp_pseudo be updated as well? You may want
>>> to define a helper function with all the code shared by irq handlers
>>> (both high and low), probe and resume.
>> No, they cannot be update because we don't know the actual current
>> temp[1] after short or long time suspend, everything goes as
>> beginning.
>
> That's what I wanted to say, if everything is reset to a default value,
> then cur_index and cur_temp should be reset too, as it's done in the
> probe function. Otherwise you may have a current pseudo-temp and a
> current index unrelated to how the hotmon is configured.
Yes, right.
>
>> If a helper function is introduced, it can be only used in probe and
>> resume I think, different and a bit complicated algorithm in irq
>> handlers.
>
> I was thinking about a function which takes the new index and the new
> low and high parameters, and updates cur_index and cur_pseudo_temp and
> does the prcmu stuff. It seems to me this is (or should be) common to
> all the 4 functions.
I misunderstood this helper will do all the updates, but algorithm of
cur_index is different everywhere.
If cur_index is calculated outside this new helper function, it works.
I will do that.
>
>> [1] due to lack of corresponding interface, search "TODO" in this file
>> to get more explanation.
>
> --
> Francesco
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