From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kim, Milo" Date: Thu, 27 Nov 2014 01:32:51 +0000 Subject: Re: [PATCH 2/2] backlight/lp855x: Add supply regulator to lp855x Message-Id: <54767F43.2060901@ti.com> List-Id: References: <1417029064-12460-1-git-send-email-seanpaul@chromium.org> <1417029064-12460-2-git-send-email-seanpaul@chromium.org> In-Reply-To: <1417029064-12460-2-git-send-email-seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Sean Paul , linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: =?UTF-8?B?U3TDqXBoYW5lIE1hcmNoZXNpbg==?= , Aaron Durbin , jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, cooloney-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org (Looping backlight class subsystem maintainers) Hi Sean, Please see my comments below. Thanks! On 11/27/2014 4:11 AM, Sean Paul wrote: > This patch adds a supply regulator to the lp855x platform data to facilit= ate > powering on/off the 3V rail attached to the controller. > > Cc: St=C3=A9phane Marchesin > Cc: Aaron Durbin > Signed-off-by: Sean Paul > --- > .../devicetree/bindings/video/backlight/lp855x.txt | 2 ++ > drivers/video/backlight/lp855x_bl.c | 17 ++++++++++= +++++++ > include/linux/platform_data/lp855x.h | 2 ++ > 3 files changed, 21 insertions(+) > > diff --git a/Documentation/devicetree/bindings/video/backlight/lp855x.txt= b/Documentation/devicetree/bindings/video/backlight/lp855x.txt > index 96e83a5..0a3ecbc 100644 > --- a/Documentation/devicetree/bindings/video/backlight/lp855x.txt > +++ b/Documentation/devicetree/bindings/video/backlight/lp855x.txt > @@ -12,6 +12,7 @@ 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: > > @@ -56,6 +57,7 @@ Example: > backlight@2c { > compatible =3D "ti,lp8557"; > reg =3D <0x2c>; > + power-supply =3D <&backlight_vdd>; > > dev-ctrl =3D /bits/ 8 <0x41>; > init-brt =3D /bits/ 8 <0x0a>; > diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backligh= t/lp855x_bl.c > index 257b3ba..8021009 100644 > --- a/drivers/video/backlight/lp855x_bl.c > +++ b/drivers/video/backlight/lp855x_bl.c > @@ -17,6 +17,7 @@ > #include > #include > #include > +#include > > /* LP8550/1/2/3/6 Registers */ > #define LP855X_BRIGHTNESS_CTRL 0x00 > @@ -383,6 +384,13 @@ static int lp855x_parse_dt(struct lp855x *lp) > pdata->rom_data =3D &rom[0]; > } > > + pdata->supply =3D devm_regulator_get(dev, "power"); > + if (IS_ERR(pdata->supply)) { > + if (PTR_ERR(pdata->supply) =3D -EPROBE_DEFER) > + return -EPROBE_DEFER; > + pdata->supply =3D NULL; This optional data, 'supply' is set to NULL. Please refer to my comments below. > + } > + > lp->pdata =3D pdata; > > return 0; > @@ -423,6 +431,14 @@ static int lp855x_probe(struct i2c_client *cl, const= struct i2c_device_id *id) > else > lp->mode =3D REGISTER_BASED; > > + if (lp->pdata->supply) { > + ret =3D regulator_enable(lp->pdata->supply); > + if (ret < 0) { > + dev_err(&cl->dev, "failed to enable supply: %d\n", ret); > + return ret; > + } > + } > + > i2c_set_clientdata(cl, lp); > > ret =3D lp855x_configure(lp); > @@ -454,6 +470,7 @@ static int lp855x_remove(struct i2c_client *cl) > > lp->bl->props.brightness =3D 0; > backlight_update_status(lp->bl); > + regulator_disable(lp->pdata->supply); The 'lp->pdata->supply' is optional, what happens if it is NULL? This will cause the kernel OOPS inside regulator_disable() API. int regulator_disable(struct regulator *regulator) { struct regulator_dev *rdev =3D regulator->rdev; ... } > sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); > > return 0; > diff --git a/include/linux/platform_data/lp855x.h b/include/linux/platfor= m_data/lp855x.h > index 1b2ba24..9c7fd1e 100644 > --- a/include/linux/platform_data/lp855x.h > +++ b/include/linux/platform_data/lp855x.h > @@ -136,6 +136,7 @@ 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; > @@ -144,6 +145,7 @@ struct lp855x_platform_data { > unsigned int period_ns; > int size_program; > struct lp855x_rom_data *rom_data; > + struct regulator *supply; > }; > > #endif > Best regards, Milo