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

[Lee Jones]

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?

> > 	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@xxxxxxxxxxxx>
> > Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
> > Cc: Lee Jones <lee.jones@xxxxxxxxxx>
> > Cc: devicetree@xxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: Milo Kim <milo.kim@xxxxxx>
> 
> Acked-by: Jingoo Han <jingoohan1@xxxxxxxxx>
> 
> 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 â Open source software for ARM SoCs
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