Re: [PATCH v2 3/3] backlight: lp855x: Add support ACPI enumeration

On Tue, 02 Nov 2021, 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

Changes in v2:

• Remove `lp->pdata = pdata` assignment from lp855x_parse_dt()
• Add "and is in register mode" to the comment in lp855x_parse_acpi()

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drivers/video/backlight/lp855x_bl.c | 73 ++++++++++++++++++++++++----- 1 file changed, 61 insertions(+), 12 deletions(-)

Applied, thanks.