drm/panel: simple: Allow GPIO accesses to sleep

The enable GPIO for panels may be provided by GPIO expanders on slow
busses (such as I2C), and therefore toggling the GPIO may sleep. Since
these accesses don't happen in interrupt context, use the *_cansleep()
variants of the GPIO API.
Signed-off-by: NThierry Reding <treding@nvidia.com>

drivers/gpu/drm/panel/panel-simple.c

@@ -106,7 +106,7 @@ static int panel_simple_disable(struct drm_panel *panel)
 	}
 
 	if (p->enable_gpio)
-		gpiod_set_value(p->enable_gpio, 0);
+		gpiod_set_value_cansleep(p->enable_gpio, 0);
 
 	regulator_disable(p->supply);
 	p->enabled = false;
@@ -129,7 +129,7 @@ static int panel_simple_enable(struct drm_panel *panel)
 	}
 
 	if (p->enable_gpio)
-		gpiod_set_value(p->enable_gpio, 1);
+		gpiod_set_value_cansleep(p->enable_gpio, 1);
 
 	if (p->backlight) {
 		p->backlight->props.power = FB_BLANK_UNBLANK;