From: Hans de Goede <hdegoede@xxxxxxxxxx> [ Upstream commit 2c39a01154ea57d596470afa1d278e3be3b37f6a ] The TrekStor SurfTab duo W1 10.1 has a hw bug where turning eldo2 back on after having turned it off causes the CPLM3218 ambient-light-sensor on the front camera sensor's I2C bus to crash, hanging the bus. Add a DMI quirk table for systems on which to leave eldo2 on. Note an alternative fix is to turn off the CPLM3218 ambient-light-sensor as long as the camera sensor is being used, this is what Windows seems to do as a workaround (based on analyzing the DSDT). But that is not easy to do cleanly under Linux. Link: https://lore.kernel.org/linux-media/20220116215204.307649-10-hdegoede@xxxxxxxxxx Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- .../media/atomisp/pci/atomisp_gmin_platform.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c index 34480ca16474..c9ee85037644 100644 --- a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c +++ b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c @@ -729,6 +729,21 @@ static int axp_regulator_set(struct device *dev, struct gmin_subdev *gs, return 0; } +/* + * Some boards contain a hw-bug where turning eldo2 back on after having turned + * it off causes the CPLM3218 ambient-light-sensor on the image-sensor's I2C bus + * to crash, hanging the bus. Do not turn eldo2 off on these systems. + */ +static const struct dmi_system_id axp_leave_eldo2_on_ids[] = { + { + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "TrekStor"), + DMI_MATCH(DMI_PRODUCT_NAME, "SurfTab duo W1 10.1 (VT4)"), + }, + }, + { } +}; + static int axp_v1p8_on(struct device *dev, struct gmin_subdev *gs) { int ret; @@ -763,6 +778,9 @@ static int axp_v1p8_off(struct device *dev, struct gmin_subdev *gs) if (ret) return ret; + if (dmi_check_system(axp_leave_eldo2_on_ids)) + return 0; + ret = axp_regulator_set(dev, gs, gs->eldo2_sel_reg, gs->eldo2_1p8v, ELDO_CTRL_REG, gs->eldo2_ctrl_shift, false); return ret; -- 2.34.1
