Thanks a lot for your comments.
On Wed, Jan 17, 2018 at 04:47:41PM +0000, Daniel Thompson wrote:
> On 17/01/18 14:01, Daniel Vetter wrote:
> > Leaking driver internal tracking into the already massively confusing
> > backlight power tracking is really confusing.
> >
> > Stop that by allocating a tiny driver private data structure instead.
> >
> > Cc: Lee Jones <lee.jones@xxxxxxxxxx>
> > Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
> > Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
> > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> > ---
> > drivers/video/backlight/pandora_bl.c | 26 +++++++++++++++++++-------
> > 1 file changed, 19 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/video/backlight/pandora_bl.c b/drivers/video/backlight/pandora_bl.c
> > index a186bc677c7d..6bd159946a47 100644
> > --- a/drivers/video/backlight/pandora_bl.c
> > +++ b/drivers/video/backlight/pandora_bl.c
> > @@ -35,11 +35,15 @@
> > #define MAX_VALUE 63
> > #define MAX_USER_VALUE (MAX_VALUE - MIN_VALUE)
> > -#define PANDORABL_WAS_OFF BL_CORE_DRIVER1
> > +struct pandora_private {
> > + unsigned old_state;
> > +#define PANDORABL_WAS_OFF 1
>
> Nit, but we using old_state like a bitfield so, BIT(0)?
>
>
> > +};
> > static int pandora_backlight_update_status(struct backlight_device *bl)
> > {
> > int brightness = bl->props.brightness;
> > + struct pandora_private *priv = bl_get_data(bl);
> > u8 r;
> > if (bl->props.power != FB_BLANK_UNBLANK)
> > @@ -53,7 +57,7 @@ static int pandora_backlight_update_status(struct backlight_device *bl)
> > brightness = MAX_USER_VALUE;
> > if (brightness == 0) {
> > - if (bl->props.state & PANDORABL_WAS_OFF)
> > + if (priv->old_state & PANDORABL_WAS_OFF)
> > goto done;
> > /* first disable PWM0 output, then clock */
> > @@ -66,7 +70,7 @@ static int pandora_backlight_update_status(struct backlight_device *bl)
> > goto done;
> > }
> > - if (bl->props.state & PANDORABL_WAS_OFF) {
> > + if (priv->old_state & PANDORABL_WAS_OFF) {
> > /*
> > * set PWM duty cycle to max. TPS61161 seems to use this
> > * to calibrate it's PWM sensitivity when it starts.
> > @@ -93,9 +97,9 @@ static int pandora_backlight_update_status(struct backlight_device *bl)
> > done:
> > if (brightness != 0)
> > - bl->props.state &= ~PANDORABL_WAS_OFF;
> > + priv->old_state 0;
> > else
> > - bl->props.state |= PANDORABL_WAS_OFF;
> > + priv->old_state = PANDORABL_WAS_OFF;
>
> Well, we were using it like a bitfield until this bit...
I had a simple boolean first (because that's all we neeed), but that made
the code less readable. Should I s/1/true/ in the #define? The entire C99
bool tends to be a bit a bikeshed sometimes :-)
>
>
> > return 0;
> > }
> > @@ -109,15 +113,23 @@ static int pandora_backlight_probe(struct platform_device *pdev)
> > {
> > struct backlight_properties props;
> > struct backlight_device *bl;
> > + struct pandora_private *priv;
> > u8 r;
> > + priv = devm_kmalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv) {
> > + dev_err(&pdev->dev, "failed to allocate driver private data\n");
> > + return -ENOMEM;
> > + }
> > +
> > memset(&props, 0, sizeof(props));
> > props.max_brightness = MAX_USER_VALUE;
> > props.type = BACKLIGHT_RAW;
> > bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev,
> > - NULL, &pandora_backlight_ops, &props);
> > + priv, &pandora_backlight_ops, &props);
> > if (IS_ERR(bl)) {
> > dev_err(&pdev->dev, "failed to register backlight\n");
> > + kfree(priv);
>
> Why can't we rely on devres for cleanup?
Argh, I had kmalloc first and then changed to devm_kmalloc. The kfree here
needs to go indeed.
Cheers, Daniel
>
>
> > return PTR_ERR(bl);
> > }
> > @@ -126,7 +138,7 @@ static int pandora_backlight_probe(struct platform_device *pdev)
> > /* 64 cycle period, ON position 0 */
> > twl_i2c_write_u8(TWL_MODULE_PWM, 0x80, TWL_PWM0_ON);
> > - bl->props.state |= PANDORABL_WAS_OFF;
> > + priv->old_state = PANDORABL_WAS_OFF;
> > bl->props.brightness = MAX_USER_VALUE;
> > backlight_update_status(bl);
> >
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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