Re: [PATCH] thermal: exynos: Support for TMU regulator defined atdevice tree

[amit daniel kachhap]

Hi Sylwester,

On Thu, May 2, 2013 at 2:57 PM, Sylwester Nawrocki
<s.nawrocki@xxxxxxxxxxx> wrote:
> Hi,
>
> On 05/02/2013 07:37 AM, Amit Daniel Kachhap wrote:
>> TMU probe function now checks for a device tree defined regulator.
>> For compatibility reasons it is allowed to probe driver even without
>> this regulator defined.
>>
>> Signed-off-by: Lukasz Majewski <l.majewski@xxxxxxxxxxx>
>> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
>> Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
>> ---
>>
>> This patch is repost of the patch posted by Lukasz Majewski
>> (https://patchwork.kernel.org/patch/2488211/). I have rebased this
>> patch on top of my TMU re-structured patch series
>> (http://lwn.net/Articles/548634/). Although I thought of handling
>> regulator as one type of feature (newly added) but could not do
>> so as regulator is a board/platform property and not SOC property so
>> leaving the device tree to define and handle it.
>>
>>  .../devicetree/bindings/thermal/exynos-thermal.txt |    4 ++++
>>  drivers/thermal/samsung/exynos_tmu.c               |   17 +++++++++++++++++
>>  2 files changed, 21 insertions(+), 0 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/thermal/exynos-thermal.txt b/Documentation/devicetree/bindings/thermal/exynos-thermal.txt
>> index 970eeba..ff62f7a 100644
>> --- a/Documentation/devicetree/bindings/thermal/exynos-thermal.txt
>> +++ b/Documentation/devicetree/bindings/thermal/exynos-thermal.txt
>> @@ -14,6 +14,9 @@
>>  - interrupts : Should contain interrupt for thermal system
>>  - clocks : The main clock for TMU device
>>  - clock-names : Thermal system clock name
>> +- 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.
>>
>>  Example 1):
>>
>> @@ -25,6 +28,7 @@ Example 1):
>>               clocks = <&clock 383>;
>>               clock-names = "tmu_apbif";
>>               status = "disabled";
>> +             vtmu-supply = <&tmu_regulator_node>;
>>       };
>>
>>  Example 2):
>> diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
>> index 72446c9..45b50c1 100644
>> --- a/drivers/thermal/samsung/exynos_tmu.c
>> +++ b/drivers/thermal/samsung/exynos_tmu.c
>> @@ -32,6 +32,7 @@
>>  #include <linux/of_address.h>
>>  #include <linux/of_irq.h>
>>  #include <linux/platform_device.h>
>> +#include <linux/regulator/consumer.h>
>>  #include <linux/slab.h>
>>  #include <linux/workqueue.h>
>>  #include "exynos_thermal_common.h"
>> @@ -52,6 +53,7 @@
>>   * @clk: pointer to the clock structure.
>>   * @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.
>>   * @reg_conf: pointer to structure to register with core thermal.
>>   */
>>  struct exynos_tmu_data {
>> @@ -65,6 +67,7 @@ struct exynos_tmu_data {
>>       struct mutex lock;
>>       struct clk *clk;
>>       u8 temp_error1, temp_error2;
>> +     struct regulator *regulator;
>>       struct thermal_sensor_conf *reg_conf;
>>  };
>>
>> @@ -501,10 +504,21 @@ static int exynos_map_dt_data(struct platform_device *pdev)
>>       struct exynos_tmu_data *data = platform_get_drvdata(pdev);
>>       struct exynos_tmu_platform_data *pdata = data->pdata;
>>       struct resource res;
>> +     int ret;
>>
>>       if (!data)
>>               return -ENODEV;
>>
>> +     /* Try enabling the regulator if found */
>> +     data->regulator = devm_regulator_get(&pdev->dev, "vtmu");
>
> Wouldn't it better to require vtmu-supply property always ?
> This way any errors would have not been ignored. And board/platform
> would have to specify real or dummy regulator supply.
Yes it makes sense but then it involves adding many lines in the
current DT nodes.
>
> However, if the DT binding is already defined it might be too late to
> add a required property. Nevertless some log might be useful in case
> regulator_get fails and the driver runs without the regulator's control.
Yes correct will re-submit with some logs in error path.
>
>> +     if (!IS_ERR(data->regulator)) {
>> +             ret = regulator_enable(data->regulator);
>> +             if (ret) {
>> +                     dev_err(&pdev->dev, "failed to enable vtmu\n");
>> +                     return ret;
>> +             }
>> +     }
>> +
>>       data->id = of_alias_get_id(pdev->dev.of_node, "tmuctrl");
>>       if (data->id < 0)
>>               data->id = 0;
>> @@ -669,6 +683,9 @@ static int exynos_tmu_remove(struct platform_device *pdev)
>>
>>       clk_unprepare(data->clk);
>>
>> +     if (data->regulator)
>
> Shouldn't this be:
>
>         if (!IS_ERR(data->regulator))
Yes correct.

Thanks,
Amit Daniel
>
> You probably want to set data->regulator to some ERR_PTR() value
> in probe, unless regulator get is first thing done there.
>
>> +             regulator_disable(data->regulator);
>> +
>>       platform_set_drvdata(pdev, NULL);
>>
>>       return 0;
>>
>
> Regards,
> Sylwester
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/