drm/panel: boe-himax8279d: Stop tracking prepared/enabled

As talked about in commit d2aacaf0 ("drm/panel: Check for already
prepared/enabled in drm_panel"), we want to remove needless code from
panel drivers that was storing and double-checking the
prepared/enabled state. Even if someone was relying on the
double-check before, that double-check is now in the core and not
needed in individual drivers.

NOTE: as part of this, transition the panel's direct calls to its
disable/unprepare functions in shutdown/remove to call through DRM
panel.

Cc: Jerry Han <jerry.han.hq@gmail.com>
Cc: Jitao Shi <jitao.shi@mediatek.com>
Cc: Rock Wang <rock_wang@himax.com.cn>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240604172305.v3.1.Ia3f254ab6e04e4f7afba6c066454498c8fb01324@changeidSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240604172305.v3.1.Ia3f254ab6e04e4f7afba6c066454498c8fb01324@changeid

drivers/gpu/drm/panel/panel-boe-himax8279d.c

@@ -47,9 +47,6 @@ struct panel_info {
 	struct gpio_desc *enable_gpio;
 	struct gpio_desc *pp33_gpio;
 	struct gpio_desc *pp18_gpio;
-
-	bool prepared;
-	bool enabled;
 };
 
 static inline struct panel_info *to_panel_info(struct drm_panel *panel)
@@ -86,17 +83,12 @@ static int boe_panel_disable(struct drm_panel *panel)
 	struct panel_info *pinfo = to_panel_info(panel);
 	int err;
 
-	if (!pinfo->enabled)
-		return 0;
-
 	err = mipi_dsi_dcs_set_display_off(pinfo->link);
 	if (err < 0) {
 		dev_err(panel->dev, "failed to set display off: %d\n", err);
 		return err;
 	}
 
-	pinfo->enabled = false;
-
 	return 0;
 }
 
@@ -105,9 +97,6 @@ static int boe_panel_unprepare(struct drm_panel *panel)
 	struct panel_info *pinfo = to_panel_info(panel);
 	int err;
 
-	if (!pinfo->prepared)
-		return 0;
-
 	err = mipi_dsi_dcs_set_display_off(pinfo->link);
 	if (err < 0)
 		dev_err(panel->dev, "failed to set display off: %d\n", err);
@@ -121,8 +110,6 @@ static int boe_panel_unprepare(struct drm_panel *panel)
 
 	disable_gpios(pinfo);
 
-	pinfo->prepared = false;
-
 	return 0;
 }
 
@@ -131,9 +118,6 @@ static int boe_panel_prepare(struct drm_panel *panel)
 	struct panel_info *pinfo = to_panel_info(panel);
 	int err;
 
-	if (pinfo->prepared)
-		return 0;
-
 	gpiod_set_value(pinfo->pp18_gpio, 1);
 	/* T1: 5ms - 6ms */
 	usleep_range(5000, 6000);
@@ -180,8 +164,6 @@ static int boe_panel_prepare(struct drm_panel *panel)
 	/* T7: 20ms - 21ms */
 	usleep_range(20000, 21000);
 
-	pinfo->prepared = true;
-
 	return 0;
 
 poweroff:
@@ -194,9 +176,6 @@ static int boe_panel_enable(struct drm_panel *panel)
 	struct panel_info *pinfo = to_panel_info(panel);
 	int ret;
 
-	if (pinfo->enabled)
-		return 0;
-
 	usleep_range(120000, 121000);
 
 	ret = mipi_dsi_dcs_set_display_on(pinfo->link);
@@ -205,8 +184,6 @@ static int boe_panel_enable(struct drm_panel *panel)
 		return ret;
 	}
 
-	pinfo->enabled = true;
-
 	return 0;
 }
 
@@ -917,11 +894,11 @@ static void panel_remove(struct mipi_dsi_device *dsi)
 	struct panel_info *pinfo = mipi_dsi_get_drvdata(dsi);
 	int err;
 
-	err = boe_panel_disable(&pinfo->base);
+	err = drm_panel_disable(&pinfo->base);
 	if (err < 0)
 		dev_err(&dsi->dev, "failed to disable panel: %d\n", err);
 
-	err = boe_panel_unprepare(&pinfo->base);
+	err = drm_panel_unprepare(&pinfo->base);
 	if (err < 0)
 		dev_err(&dsi->dev, "failed to unprepare panel: %d\n", err);
 
@@ -936,8 +913,8 @@ static void panel_shutdown(struct mipi_dsi_device *dsi)
 {
 	struct panel_info *pinfo = mipi_dsi_get_drvdata(dsi);
 
-	boe_panel_disable(&pinfo->base);
-	boe_panel_unprepare(&pinfo->base);
+	drm_panel_disable(&pinfo->base);
+	drm_panel_unprepare(&pinfo->base);
 }
 
 static struct mipi_dsi_driver panel_driver = {