Am Mittwoch, den 04.11.2015, 09:47 +0800 schrieb YH Huang: > On Tue, 2015-11-03 at 12:08 +0100, Philipp Zabel wrote: > > Hi YH, > > > > Am Dienstag, den 03.11.2015, 16:11 +0800 schrieb YH Huang: > > > > The reasoning is that devices where there is no phandle link pointing to > > > > the backlight (for example from a simple-panel node), we should keep the > > > > current default behaviour (enable during probe). > > > > > > I have a little problem for the current default behaviour. > > > Should we enable during probe? > > > > Here I mean enabling the backlight (at the end of the probe function), > > not enabling the GPIO already when requesting it. > > > > > Before this patch ( http://patchwork.ozlabs.org/patch/324690/ ), > > > we disable "enable-gpio" in the probe function. > > > > While before this patch the GPIO would be initialized in the disabled > > state, the call to backlight_update_status at the end of the probe > > function would still enable the backlight afterwards. > > Based on this, could we disable it initially and update in the > backlight_update_status function? > > Like this, > > if (pb->enable_gpio) { > if (phandle && > gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT && > gpiod_get_value(pb->enable_gpio) == 1) > gpiod_direction_output(pb->enable_gpio, 1); The gpiod_direction_output call is a no-op, since the direction is already output and the value is already 1. Also, I propose to set initial blanking to FB_BLANK_POWERDOWN in this case, and wait for the panel driver to enable the backlight at the appropriate time. regards Philipp -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
