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Date: Thu, 9 Jul 2015 09:53:25 -0400
From: Sean Paul <seanpaul@...omium.org>
To: Lee Jones <lee.jones@...aro.org>
Cc: Jingoo Han <jingoohan1@...il.com>, Milo Kim <milo.kim@...com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] backlight: lp855x: use private data for regulator control
On Mon, Jul 6, 2015 at 2:54 AM, 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?
>
Yeah. I think it's common practice to specify regulator input in DT.
I'd rather this patch was not merged.
Sean
>> > 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 │ Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog
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