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Date: Mon, 6 Jul 2015 16:33:05 +0900
From: Jingoo Han <jingoohan1@...il.com>
To: Lee Jones <lee.jones@...aro.org>, Milo Kim <milo.kim@...com>
Cc: Sean Paul <seanpaul@...omium.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"jingoohan1@...il.com" <jingoohan1@...il.com>
Subject: Re: [PATCH] backlight: lp855x: use private data for regulator control
On 2015. 7. 6., at PM 3:54, Lee Jones <lee.jones@...aro.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@...02000 {
>>> (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@...omium.org>
>>> Cc: Jingoo Han <jingoohan1@...il.com>
>>> Cc: Lee Jones <lee.jones@...aro.org>
>>> Cc: devicetree@...r.kernel.org
>>> Cc: linux-kernel@...r.kernel.org
>>> Signed-off-by: Milo Kim <milo.kim@...com>
>>
>> Acked-by: Jingoo Han <jingoohan1@...il.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 ĶĒ Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog
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