Re: [PATCH] backlight: lp855x: use private data for regulator control

[Jingoo Han <jingoohan1@gmail.com>]

On 2015. 7. 6., at PM 3:54, Lee Jones <lee.jones@linaro.org> wrote:
> 
>> On Sun, 05 Jul 2015, Jingoo Han wrote:
>> 
>>> On Tuesday, June 30, 2015 3:16 PM, Milo Kim wrote:
>>> 
>>> LP855x backlight device can be enabled by external VDD input.
>>> The 'supply' data is used for this purpose.
>>> It's kind of private data which runs internally, so there is no reason to
>>> expose to the platform data.
>>> 
>>> And LP855x DT property, 'power-supply' is unnecessary.
>>> If a regulator is registered correctly, then lp855x driver can get
>>> regulator resource by using devm_regulator_get().
>>> So devm_regulator_get() is moved from _parse_dt() to _probe().
>>> Ex) The following device tree works without 'power-supply' property.
> 
> Even if it's not 'required', I think it would be good to have it in
> DT, as it describes the hardware, right?

OK, I see.
If the 'regulator-name' is changed from 'power' to other names,
lp855x driver will not find the regulator. However, when 'power-supply' is added, it is more noticeable.

To Milo,

Would you send the patch v2 that
does not remove dt property from lp855x.txt?

Best regards,
Jingoo Han

>>>    i2c0: i2c@10002000 {
>>>        (snip)
>>> 
>>>        backlight@2c {
>>>            compatible = "ti,lp8556";
>>>            reg = <0x2c>;
>>> 
>>>            bl-name = "lcd-bl";
>>>            dev-ctrl = /bits/ 8 <0x85>;
>>>            init-brt = /bits/ 8 <0x10>;
>>>        };
>>>    };
>>> 
>>>    /* 'power' regulator for LP8556 VDD */
>>>    bl_vdd: fixed-regulator@1 {
>>>        compatible = "regulator-fixed";
>>>        regulator-name = "power";
>>>        regulator-min-microvolt = <3300000>;
>>>        regulator-max-microvolt = <3300000>;
>>> 
>>>        (snip)
>>>    };
>>> 
>>> Cc: Sean Paul <seanpaul@chromium.org>
>>> Cc: Jingoo Han <jingoohan1@gmail.com>
>>> Cc: Lee Jones <lee.jones@linaro.org>
>>> Cc: devicetree@vger.kernel.org
>>> Cc: linux-kernel@vger.kernel.org
>>> Signed-off-by: Milo Kim <milo.kim@ti.com>
>> 
>> Acked-by: Jingoo Han <jingoohan1@gmail.com>
>> 
>> Best regards,
>> Jingoo Han
>> 
>>> ---
>>> .../devicetree/bindings/video/backlight/lp855x.txt   |  2 --
>>> drivers/video/backlight/lp855x_bl.c                  | 20 +++++++++-----------
>>> include/linux/platform_data/lp855x.h                 |  2 --
>>> 3 files changed, 9 insertions(+), 15 deletions(-)
>>> 
>>> diff --git a/Documentation/devicetree/bindings/video/backlight/lp855x.txt
>>> b/Documentation/devicetree/bindings/video/backlight/lp855x.txt
>>> index 0a3ecbc..96e83a5 100644
>>> --- a/Documentation/devicetree/bindings/video/backlight/lp855x.txt
>>> +++ b/Documentation/devicetree/bindings/video/backlight/lp855x.txt
>>> @@ -12,7 +12,6 @@ Optional properties:
>>>   - pwm-period: PWM period value. Set only PWM input mode used (u32)
>>>   - rom-addr: Register address of ROM area to be updated (u8)
>>>   - rom-val: Register value to be updated (u8)
>>> -  - power-supply: Regulator which controls the 3V rail
>>> 
>>> Example:
>>> 
>>> @@ -57,7 +56,6 @@ Example:
>>>    backlight@2c {
>>>        compatible = "ti,lp8557";
>>>        reg = <0x2c>;
>>> -        power-supply = <&backlight_vdd>;
>>> 
>>>        dev-ctrl = /bits/ 8 <0x41>;
>>>        init-brt = /bits/ 8 <0x0a>;
>>> diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
>>> index a26d3bb..277d5ca 100644
>>> --- a/drivers/video/backlight/lp855x_bl.c
>>> +++ b/drivers/video/backlight/lp855x_bl.c
>>> @@ -73,6 +73,7 @@ struct lp855x {
>>>    struct device *dev;
>>>    struct lp855x_platform_data *pdata;
>>>    struct pwm_device *pwm;
>>> +    struct regulator *supply;    /* regulator for VDD input */
>>> };
>>> 
>>> static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
>>> @@ -384,13 +385,6 @@ static int lp855x_parse_dt(struct lp855x *lp)
>>>        pdata->rom_data = &rom[0];
>>>    }
>>> 
>>> -    pdata->supply = devm_regulator_get(dev, "power");
>>> -    if (IS_ERR(pdata->supply)) {
>>> -        if (PTR_ERR(pdata->supply) == -EPROBE_DEFER)
>>> -            return -EPROBE_DEFER;
>>> -        pdata->supply = NULL;
>>> -    }
>>> -
>>>    lp->pdata = pdata;
>>> 
>>>    return 0;
>>> @@ -431,8 +425,12 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
>>>    else
>>>        lp->mode = REGISTER_BASED;
>>> 
>>> -    if (lp->pdata->supply) {
>>> -        ret = regulator_enable(lp->pdata->supply);
>>> +    lp->supply = devm_regulator_get(lp->dev, "power");
>>> +    if (IS_ERR(lp->supply))
>>> +        lp->supply = NULL;
>>> +
>>> +    if (lp->supply) {
>>> +        ret = regulator_enable(lp->supply);
>>>        if (ret < 0) {
>>>            dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
>>>            return ret;
>>> @@ -470,8 +468,8 @@ static int lp855x_remove(struct i2c_client *cl)
>>> 
>>>    lp->bl->props.brightness = 0;
>>>    backlight_update_status(lp->bl);
>>> -    if (lp->pdata->supply)
>>> -        regulator_disable(lp->pdata->supply);
>>> +    if (lp->supply)
>>> +        regulator_disable(lp->supply);
>>>    sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
>>> 
>>>    return 0;
>>> diff --git a/include/linux/platform_data/lp855x.h b/include/linux/platform_data/lp855x.h
>>> index 9c7fd1e..1b2ba24 100644
>>> --- a/include/linux/platform_data/lp855x.h
>>> +++ b/include/linux/platform_data/lp855x.h
>>> @@ -136,7 +136,6 @@ struct lp855x_rom_data {
>>>        Only valid when mode is PWM_BASED.
>>>  * @size_program : total size of lp855x_rom_data
>>>  * @rom_data : list of new eeprom/eprom registers
>>> - * @supply : regulator that supplies 3V input
>>>  */
>>> struct lp855x_platform_data {
>>>    const char *name;
>>> @@ -145,7 +144,6 @@ struct lp855x_platform_data {
>>>    unsigned int period_ns;
>>>    int size_program;
>>>    struct lp855x_rom_data *rom_data;
>>> -    struct regulator *supply;
>>> };
>>> 
>>> #endif
> 
> -- 
> Lee Jones
> Linaro STMicroelectronics Landing Team Lead
> Linaro.org │ Open source software for ARM SoCs
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