Messages in this thread | | | Date | Tue, 2 Nov 2021 12:22:53 +0000 | From | Daniel Thompson <> | Subject | Re: [PATCH 3/3] backlight: lp855x: Add support ACPI enumeration |
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On Mon, Nov 01, 2021 at 07:55:17PM +0100, Hans de Goede wrote: > The Xiaomi Mi Pad 2 tablet uses an ACPI enumerated LP8556 backlight > controller for its LCD-panel, with a Xiaomi specific ACPI HID of > "XMCC0001", add support for this. > > Note the new "if (id)" check also fixes a NULL pointer deref when a user > tries to manually bind the driver from sysfs. > > When CONFIG_ACPI is disabled acpi_match_device() will always return NULL, > so the lp855x_parse_acpi() call will get optimized away. > > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- > drivers/video/backlight/lp855x_bl.c | 70 ++++++++++++++++++++++++----- > 1 file changed, 60 insertions(+), 10 deletions(-) > > diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c > index d1d27d5eb0f2..f075ec84acfb 100644 > --- a/drivers/video/backlight/lp855x_bl.c > +++ b/drivers/video/backlight/lp855x_bl.c > @@ -338,10 +339,6 @@ static int lp855x_parse_dt(struct lp855x *lp) > return -EINVAL; > } > > - pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); > - if (!pdata) > - return -ENOMEM; > - > of_property_read_string(node, "bl-name", &pdata->name); > of_property_read_u8(node, "dev-ctrl", &pdata->device_control); > of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
Shouldn't there be a removal of an `lp->pdata = pdata` from somewhere in this function?
> @@ -379,8 +376,31 @@ static int lp855x_parse_dt(struct lp855x *lp) > } > #endif > > +static int lp855x_parse_acpi(struct lp855x *lp) > +{ > + int ret; > + > + /* > + * On ACPI the device has already been initialized by the firmware
Perhaps nitpicking but ideally I'd like "and is in register mode" here since I presume it can also be assumed that everything with this HID has adopted that).
Other than these, LGTM.
Daniel.
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