Re: [PATCH v2] thermal: exynos: add special clock support

[Eduardo Valentin <edubezval@gmail.com>]

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Abhilash,

On Wed, Nov 26, 2014 at 08:34:19PM +0530, Abhilash Kesavan wrote:
> Hi Eduardo,
> 
> On Wed, Nov 26, 2014 at 8:15 PM, Eduardo Valentin <edubezval@gmail.com> wrote:
> >
> > Abhilash,
> >
> > On Wed, Nov 26, 2014 at 06:21:10AM +0530, Abhilash Kesavan wrote:
> >> Exynos7 has a special clock required for the functional operation
> >> of the TMU that is not present in earlier SoCs. Add support for
> >> this clock and update the binding documentation.
> >>
> >> Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
> >> ---
> >> Changes since v1:
> >>       - Added a per-soc flag to indicate the presence of special clock
> >>       - Changed the name of special clock from "tmu_sclk" to "sclk"
> >>       - Fixed the error handling for sclk
> >>
> >> Tested on 5420 and 5800 based chromebooks, no change in existing behavior.
> >>
> >>  .../devicetree/bindings/thermal/exynos-thermal.txt |    3 ++
> >>  drivers/thermal/samsung/exynos_tmu.c               |   31 ++++++++++++++++----
> >>  2 files changed, 29 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/thermal/exynos-thermal.txt b/Documentation/devicetree/bindings/thermal/exynos-thermal.txt
> >> index ae738f5..acf4705 100644
> >> --- a/Documentation/devicetree/bindings/thermal/exynos-thermal.txt
> >> +++ b/Documentation/devicetree/bindings/thermal/exynos-thermal.txt
> >> @@ -32,10 +32,13 @@
> >>  - clocks : The main clocks for TMU device
> >>       -- 1. operational clock for TMU channel
> >>       -- 2. optional clock to access the shared registers of TMU channel
> >> +     -- 3. optional special clock for functional operation
> >>  - clock-names : Thermal system clock name
> >>       -- "tmu_apbif" operational clock for current TMU channel
> >>       -- "tmu_triminfo_apbif" clock to access the shared triminfo register
> >>               for current TMU channel
> >> +     -- "sclk" clock for functional operation of the current TMU
> >> +             channel
> >>  - vtmu-supply: This entry is optional and provides the regulator node supplying
> >>               voltage to TMU. If needed this entry can be placed inside
> >>               board/platform specific dts file.
> >> diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
> >> index d44d91d..8ed8409 100644
> >> --- a/drivers/thermal/samsung/exynos_tmu.c
> >> +++ b/drivers/thermal/samsung/exynos_tmu.c
> >> @@ -123,11 +123,14 @@
> >>   * @base: base address of the single instance of the TMU controller.
> >>   * @base_second: base address of the common registers of the TMU controller.
> >>   * @irq: irq number of the TMU controller.
> >> + * @needs_sclk: SoC specific flag indicating that sclk is required for
> >> +     functional operation of the TMU controller.
> >>   * @soc: id of the SOC type.
> >>   * @irq_work: pointer to the irq work structure.
> >>   * @lock: lock to implement synchronization.
> >>   * @clk: pointer to the clock structure.
> >>   * @clk_sec: pointer to the clock structure for accessing the base_second.
> >> + * @sclk: pointer to the clock structure for accessing the tmu special clock.
> >>   * @temp_error1: fused value of the first point trim.
> >>   * @temp_error2: fused value of the second point trim.
> >>   * @regulator: pointer to the TMU regulator structure.
> >> @@ -144,10 +147,11 @@ struct exynos_tmu_data {
> >>       void __iomem *base;
> >>       void __iomem *base_second;
> >>       int irq;
> >> +     bool needs_sclk;
> >>       enum soc_type soc;
> >>       struct work_struct irq_work;
> >>       struct mutex lock;
> >> -     struct clk *clk, *clk_sec;
> >> +     struct clk *clk, *clk_sec, *sclk;
> >>       u8 temp_error1, temp_error2;
> >>       struct regulator *regulator;
> >>       struct thermal_sensor_conf *reg_conf;
> >> @@ -883,10 +887,24 @@ static int exynos_tmu_probe(struct platform_device *pdev)
> >>               goto err_clk_sec;
> >>       }
> >>
> >> +     if (data->needs_sclk) {
> >
> > Based on the trend we see from Bartlomiej's and Lukasz' works, you
> > should be asking for SoC version, not adding a flag. Can you please
> > crosscheck with them?
> 
> I planned to populate this flag as true for Exynos7 in
> exynos_map_dt_data() where other soc specific methods are being setup.

Well, that I wouldn't expect different, otherwise how your code is
supposed to work, right?

> 
> Bartlomiej/Lukasz can you kindly comment on if you would prefer the
> check to be based on the SoC version.
> 


Have a look on how Bartz has removed the flag based code in my -linus
branch. Here is an example:
https://git.kernel.org/cgit/linux/kernel/git/evalenti/linux-soc-thermal.git/commit/?h=linus&id=ef3f80fc7f79c32a1b015afcbffce2a2630011a4

> Regards,
> Abhilash
> >
> > Cheers,
> >
> > Eduardo Valentin
> >
> >> +             data->sclk = devm_clk_get(&pdev->dev, "sclk");
> >> +             if (IS_ERR(data->sclk)) {
> >> +                     dev_err(&pdev->dev, "Failed to get sclk\n");
> >> +                     goto err_clk;
> >> +             } else {
> >> +                     ret = clk_prepare_enable(data->sclk);
> >> +                     if (ret) {
> >> +                             dev_err(&pdev->dev, "Failed to enable sclk\n");
> >> +                             goto err_clk;
> >> +                     }
> >> +             }
> >> +     }
> >> +
> >>       ret = exynos_tmu_initialize(pdev);
> >>       if (ret) {
> >>               dev_err(&pdev->dev, "Failed to initialize TMU\n");
> >> -             goto err_clk;
> >> +             goto err_sclk;
> >>       }
> >>
> >>       exynos_tmu_control(pdev, true);
> >> @@ -896,7 +914,7 @@ static int exynos_tmu_probe(struct platform_device *pdev)
> >>                               sizeof(struct thermal_sensor_conf), GFP_KERNEL);
> >>       if (!sensor_conf) {
> >>               ret = -ENOMEM;
> >> -             goto err_clk;
> >> +             goto err_sclk;
> >>       }
> >>       sprintf(sensor_conf->name, "therm_zone%d", data->id);
> >>       sensor_conf->read_temperature = (int (*)(void *))exynos_tmu_read;
> >> @@ -928,7 +946,7 @@ static int exynos_tmu_probe(struct platform_device *pdev)
> >>       ret = exynos_register_thermal(sensor_conf);
> >>       if (ret) {
> >>               dev_err(&pdev->dev, "Failed to register thermal interface\n");
> >> -             goto err_clk;
> >> +             goto err_sclk;
> >>       }
> >>       data->reg_conf = sensor_conf;
> >>
> >> @@ -936,10 +954,12 @@ static int exynos_tmu_probe(struct platform_device *pdev)
> >>               IRQF_TRIGGER_RISING | IRQF_SHARED, dev_name(&pdev->dev), data);
> >>       if (ret) {
> >>               dev_err(&pdev->dev, "Failed to request irq: %d\n", data->irq);
> >> -             goto err_clk;
> >> +             goto err_sclk;
> >>       }
> >>
> >>       return 0;
> >> +err_sclk:
> >> +     clk_disable_unprepare(data->sclk);
> >>  err_clk:
> >>       clk_unprepare(data->clk);
> >>  err_clk_sec:
> >> @@ -956,6 +976,7 @@ static int exynos_tmu_remove(struct platform_device *pdev)
> >>
> >>       exynos_tmu_control(pdev, false);
> >>
> >> +     clk_disable_unprepare(data->sclk);
> >>       clk_unprepare(data->clk);
> >>       if (!IS_ERR(data->clk_sec))
> >>               clk_unprepare(data->clk_sec);
> >> --
> >> 1.7.9.5
> >>

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