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SubjectRE: [PATCH v4] Thermal: exynos: Add sysfs node supporting exynos's emulation mode.
Date
Hi Rui,


> -----Original Message-----
> From: Zhang, Rui
> Sent: Wednesday, November 07, 2012 12:07 PM
> To: R, Durgadoss
> Cc: Jonghwa Lee; linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org;
> Brown, Len; Rafael J. Wysocki; Amit Dinel Kachhap; MyungJoo Ham;
> Kyungmin Park
> Subject: RE: [PATCH v4] Thermal: exynos: Add sysfs node supporting
> exynos's emulation mode.
>
> On Thu, 2012-11-01 at 23:13 -0600, R, Durgadoss wrote:
> > Hi Lee,
> >
> > > -----Original Message-----
> > > From: Jonghwa Lee [mailto:jonghwa3.lee@samsung.com]
> > > Sent: Friday, November 02, 2012 7:55 AM
> > > To: linux-pm@vger.kernel.org
> > > Cc: linux-kernel@vger.kernel.org; Brown, Len; R, Durgadoss; Rafael J.
> > > Wysocki; Amit Dinel Kachhap; MyungJoo Ham; Kyungmin Park; Jonghwa
> Lee
> > > Subject: [PATCH v4] Thermal: exynos: Add sysfs node supporting
> exynos's
> > > emulation mode.
> > >
> > > This patch supports exynos's emulation mode with newly created sysfs
> node.
> > > Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for
> thermal
> > > management unit. Thermal emulation mode supports software debug for
> > > TMU's
> > > operation. User can set temperature manually with software code and
> TMU
> > > will read current temperature from user value not from sensor's value.
> > > This patch includes also documentary placed under
> > > Documentation/thermal/.
> > >
> >
> first of all, what would happen if overheat happens during emulation?
>
> I just had a thought about if we can introduce this to the generic
> thermal layer.

Sure, we can.

> to do this, we only need to:
> 1) introduce tz->emulation
> 2) introduce thermal_get_temp()
> static int thermal_get_temp(tz) {
> if (tz->emulation)
> return tz->emulation;
> else
> return tz->ops->get_temp(tz);
> }
> 3) replace tz->ops->get_temp() with thermal_get_temp() in thermal layer
> 4) introduce /sys/class/thermal/thermal_zoneX/emulation
> 5) when setting /sys/class/thermal/thermal_zoneX/emulation,
> a) set tz->emulation
> b) invoke thermal_zone_device_update();
> this is a pure software emulation solution but it would work on all
> generic thermal layer users.
>
> do you think this proposal would work properly?

Yes, this should work..
But, I am working on (top of your -next tree) to add multiple sensor support to
thermal framework.(What we discussed in Plumbers this year).
This changes APIs quite a bit in the thermal framework.
So, we will add this emulation support after the above changes are
in. What do you think ?

Thanks,
Durga

> if yes, I'd like to see if it is valuable for the other platform thermal
> drivers.
>
> thanks,
> rui
> > Thanks for fixing the comments.
> > Please CC linux-acpi, when you submit thermal patches, going forward.
> > I am CCing Rui for now, for him to review/merge this patch.
> >
> > Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
> >
> > Thanks,
> > Durga
> >
> > > Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
> > > ---
> > > v4
> > > - Fix Typo.
> > > - Remove unnecessary codes.
> > > - Add comments about feature of exynos emulation operation to the
> > > document.
> > >
> > > v3
> > > - Remove unnecessay variables.
> > > - Do some code clean in exynos_tmu_emulation_store().
> > > - Make wrapping function of sysfs node creation function to use
> > > #ifdefs in minimum.
> > >
> > > v2
> > > exynos_thermal.c
> > > - Fix build error occured by wrong emulation control register name.
> > > - Remove exynos5410 dependent codes.
> > > exynos_thermal_emulation
> > > - Align indentation.
> > >
> > > Documentation/thermal/exynos_thermal_emulation | 56
> > > +++++++++++++++
> > > drivers/thermal/Kconfig | 9 +++
> > > drivers/thermal/exynos_thermal.c | 91
> > > ++++++++++++++++++++++++
> > > 3 files changed, 156 insertions(+), 0 deletions(-)
> > > create mode 100644
> Documentation/thermal/exynos_thermal_emulation
> > >
> > > diff --git a/Documentation/thermal/exynos_thermal_emulation
> > > b/Documentation/thermal/exynos_thermal_emulation
> > > new file mode 100644
> > > index 0000000..a6ea06f
> > > --- /dev/null
> > > +++ b/Documentation/thermal/exynos_thermal_emulation
> > > @@ -0,0 +1,56 @@
> > > +EXYNOS EMULATION MODE
> > > +========================
> > > +
> > > +Copyright (C) 2012 Samsung Electronics
> > > +
> > > +Written by Jonghwa Lee <jonghwa3.lee@samsung.com>
> > > +
> > > +Description
> > > +-----------
> > > +
> > > +Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for
> thermal
> > > management unit.
> > > +Thermal emulation mode supports software debug for TMU's
> operation.
> > > User can set temperature
> > > +manually with software code and TMU will read current temperature
> from
> > > user value not from
> > > +sensor's value.
> > > +
> > > +Enabling CONFIG_EXYNOS_THERMAL_EMUL option will make this
> support
> > > in available.
> > > +When it's enabled, sysfs node will be created under
> > > +/sys/bus/platform/devices/'exynos device name'/ with name of
> > > 'emulation'.
> > > +
> > > +The sysfs node, 'emulation', will contain value 0 for the initial state.
> When
> > > you input any
> > > +temperature you want to update to sysfs node, it automatically enable
> > > emulation mode and
> > > +current temperature will be changed into it.
> > > +(Exynos also supports user changable delay time which would be used
> to
> > > delay of
> > > + changing temperature. However, this node only uses same delay of real
> > > sensing time, 938us.)
> > > +
> > > +Exynos emulation mode requires synchronous of value changing and
> > > enabling. It means when you
> > > +want to update the any value of delay or next temperature, then you
> have
> > > to enable emulation
> > > +mode at the same time. (Or you have to keep the mode enabling.) If
> you
> > > don't, it fails to
> > > +change the value to updated one and just use last succeessful value
> > > repeatedly. That's why
> > > +this node gives users the right to change termerpature only. Just one
> > > interface makes it more
> > > +simply to use.
> > > +
> > > +Disabling emulation mode only requires writing value 0 to sysfs node.
> > > +
> > > +
> > > +TEMP 120 |
> > > + |
> > > + 100 |
> > > + |
> > > + 80 |
> > > + | +-----------
> > > + 60 | | |
> > > + | +-------------| |
> > > + 40 | | | |
> > > + | | | |
> > > + 20 | | | +----------
> > > + | | | | |
> > > + 0
> > >
> |______________|_____________|__________|__________|_______
> > > __
> > > + A A A A TIME
> > > + |<----->| |<----->| |<----->| |
> > > + | 938us | | | | | |
> > > +emulation : 0 50 | 70 | 20 | 0
> > > +current temp : sensor 50 70 20 sensor
> > > +
> > > +
> > > +
> > > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> > > index e1cb6bd..c02a66c 100644
> > > --- a/drivers/thermal/Kconfig
> > > +++ b/drivers/thermal/Kconfig
> > > @@ -55,3 +55,12 @@ config EXYNOS_THERMAL
> > > help
> > > If you say yes here you get support for TMU (Thermal Managment
> > > Unit) on SAMSUNG EXYNOS series of SoC.
> > > +
> > > +config EXYNOS_THERMAL_EMUL
> > > + bool "EXYNOS TMU emulation mode support"
> > > + depends on !CPU_EXYNOS4210 && EXYNOS_THERMAL
> > > + help
> > > + Exynos 4412 and 4414 and 5 series has emulation mode on TMU.
> > > + Enable this option will be make sysfs node in exynos thermal
> > > platform
> > > + device directory to support emulation mode. With emulation mode
> > > sysfs
> > > + node, you can manually input temperature to TMU for simulation
> > > purpose.
> > > diff --git a/drivers/thermal/exynos_thermal.c
> > > b/drivers/thermal/exynos_thermal.c
> > > index fd03e85..eebd4e5 100644
> > > --- a/drivers/thermal/exynos_thermal.c
> > > +++ b/drivers/thermal/exynos_thermal.c
> > > @@ -99,6 +99,14 @@
> > > #define IDLE_INTERVAL 10000
> > > #define MCELSIUS 1000
> > >
> > > +#ifdef CONFIG_EXYNOS_THERMAL_EMUL
> > > +#define EXYNOS_EMUL_TIME 0x57F0
> > > +#define EXYNOS_EMUL_TIME_SHIFT 16
> > > +#define EXYNOS_EMUL_DATA_SHIFT 8
> > > +#define EXYNOS_EMUL_DATA_MASK 0xFF
> > > +#define EXYNOS_EMUL_ENABLE 0x1
> > > +#endif /* CONFIG_EXYNOS_THERMAL_EMUL */
> > > +
> > > /* CPU Zone information */
> > > #define PANIC_ZONE 4
> > > #define WARN_ZONE 3
> > > @@ -832,6 +840,82 @@ static inline struct exynos_tmu_platform_data
> > > *exynos_get_driver_data(
> > > return (struct exynos_tmu_platform_data *)
> > > platform_get_device_id(pdev)->driver_data;
> > > }
> > > +
> > > +#ifdef CONFIG_EXYNOS_THERMAL_EMUL
> > > +static ssize_t exynos_tmu_emulation_show(struct device *dev,
> > > + struct device_attribute *attr,
> > > + char *buf)
> > > +{
> > > + struct platform_device *pdev = container_of(dev,
> > > + struct platform_device, dev);
> > > + struct exynos_tmu_data *data = platform_get_drvdata(pdev);
> > > + unsigned int reg;
> > > + u8 temp_code;
> > > + int temp = 0;
> > > +
> > > + mutex_lock(&data->lock);
> > > + clk_enable(data->clk);
> > > + reg = readl(data->base + EXYNOS_EMUL_CON);
> > > + clk_disable(data->clk);
> > > + mutex_unlock(&data->lock);
> > > +
> > > + if (reg & EXYNOS_EMUL_ENABLE) {
> > > + reg >>= EXYNOS_EMUL_DATA_SHIFT;
> > > + temp_code = reg & EXYNOS_EMUL_DATA_MASK;
> > > + temp = code_to_temp(data, temp_code);
> > > + }
> > > +
> > > + return sprintf(buf, "%d\n", temp);
> > > +}
> > > +
> > > +static ssize_t exynos_tmu_emulation_store(struct device *dev,
> > > + struct device_attribute *attr,
> > > + const char *buf, size_t count)
> > > +{
> > > + struct platform_device *pdev = container_of(dev,
> > > + struct platform_device, dev);
> > > + struct exynos_tmu_data *data = platform_get_drvdata(pdev);
> > > + unsigned int reg;
> > > + int temp;
> > > +
> > > + if (!sscanf(buf, "%d\n", &temp) || temp < 0)
> > > + return -EINVAL;
> > > +
> > > + mutex_lock(&data->lock);
> > > + clk_enable(data->clk);
> > > +
> > > + reg = readl(data->base + EXYNOS_EMUL_CON);
> > > +
> > > + if (temp)
> > > + reg = (EXYNOS_EMUL_TIME << EXYNOS_EMUL_TIME_SHIFT)
> > > |
> > > + (temp_to_code(data, temp) <<
> > > EXYNOS_EMUL_DATA_SHIFT) |
> > > + EXYNOS_EMUL_ENABLE;
> > > + else
> > > + reg &= ~EXYNOS_EMUL_ENABLE;
> > > +
> > > + writel(reg, data->base + EXYNOS_EMUL_CON);
> > > +
> > > + clk_disable(data->clk);
> > > + mutex_unlock(&data->lock);
> > > +
> > > + return count;
> > > +}
> > > +
> > > +static DEVICE_ATTR(emulation, 0644, exynos_tmu_emulation_show,
> > > + exynos_tmu_emulation_store);
> > > +static int create_emulation_sysfs(struct device *dev)
> > > +{
> > > + return device_create_file(dev, &dev_attr_emulation);
> > > +}
> > > +static void remove_emulation_sysfs(struct device *dev)
> > > +{
> > > + device_remove_file(dev, &dev_attr_emulation);
> > > +}
> > > +#else
> > > +static inline int create_emulation_sysfs(struct device *dev) {return 0;}
> > > +static inline void remove_emulation_sysfs(struct device *dev){}
> > > +#endif
> > > +
> > > static int __devinit exynos_tmu_probe(struct platform_device *pdev)
> > > {
> > > struct exynos_tmu_data *data;
> > > @@ -930,6 +1014,11 @@ static int __devinit exynos_tmu_probe(struct
> > > platform_device *pdev)
> > > dev_err(&pdev->dev, "Failed to register thermal
> > > interface\n");
> > > goto err_clk;
> > > }
> > > +
> > > + ret = create_emulation_sysfs(&pdev->dev);
> > > + if (ret)
> > > + dev_err(&pdev->dev, "Failed to create emulation mode
> > > sysfs node\n");
> > > +
> > > return 0;
> > > err_clk:
> > > platform_set_drvdata(pdev, NULL);
> > > @@ -941,6 +1030,8 @@ static int __devexit exynos_tmu_remove(struct
> > > platform_device *pdev)
> > > {
> > > struct exynos_tmu_data *data = platform_get_drvdata(pdev);
> > >
> > > + remove_emulation_sysfs(&pdev->dev);
> > > +
> > > exynos_tmu_control(pdev, false);
> > >
> > > exynos_unregister_thermal();
> > > --
> > > 1.7.4.1
> >
>

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