drm/sti: remove deprecated legacy vtg slave

stih416 chip family is no more supported in Linux v4.9.
It is then useless to keep vtg slave field since it not used at all for
the stih407/10 chip family supported by sti driver.
Signed-off-by: Vincent Abriou <vincent.abriou@st.com>

drivers/gpu/drm/sti/sti_vtg.c

@@ -17,7 +17,6 @@
 #include "sti_vtg.h"
 
 #define VTG_MODE_MASTER         0
-#define VTG_MODE_SLAVE_BY_EXT0  1
 
 /* registers offset */
 #define VTG_MODE            0x0000
@@ -132,7 +131,6 @@ struct sti_vtg_sync_params {
  * @irq_status: store the IRQ status value
  * @notifier_list: notifier callback
  * @crtc: the CRTC for vblank event
- * @slave: slave vtg
  * @link: List node to link the structure in lookup list
  */
 struct sti_vtg {
@@ -144,7 +142,6 @@ struct sti_vtg {
 	u32 irq_status;
 	struct raw_notifier_head notifier_list;
 	struct drm_crtc *crtc;
-	struct sti_vtg *slave;
 	struct list_head link;
 };
 
@@ -166,10 +163,6 @@ struct sti_vtg *of_vtg_find(struct device_node *np)
 
 static void vtg_reset(struct sti_vtg *vtg)
 {
-	/* reset slave and then master */
-	if (vtg->slave)
-		vtg_reset(vtg->slave);
-
 	writel(1, vtg->regs + VTG_DRST_AUTOC);
 }
 
@@ -259,10 +252,6 @@ static void vtg_set_mode(struct sti_vtg *vtg,
 {
 	unsigned int i;
 
-	if (vtg->slave)
-		vtg_set_mode(vtg->slave, VTG_MODE_SLAVE_BY_EXT0,
-			     vtg->sync_params, mode);
-
 	/* Set the number of clock cycles per line */
 	writel(mode->htotal, vtg->regs + VTG_CLKLN);
 
@@ -318,10 +307,6 @@ void sti_vtg_set_config(struct sti_vtg *vtg,
 
 	vtg_reset(vtg);
 
-	/* enable irq for the vtg vblank synchro */
-	if (vtg->slave)
-		vtg_enable_irq(vtg->slave);
-	else
 	vtg_enable_irq(vtg);
 }
 
@@ -365,18 +350,12 @@ u32 sti_vtg_get_pixel_number(struct drm_display_mode mode, int x)
 int sti_vtg_register_client(struct sti_vtg *vtg, struct notifier_block *nb,
 			    struct drm_crtc *crtc)
 {
-	if (vtg->slave)
-		return sti_vtg_register_client(vtg->slave, nb, crtc);
-
 	vtg->crtc = crtc;
 	return raw_notifier_chain_register(&vtg->notifier_list, nb);
 }
 
 int sti_vtg_unregister_client(struct sti_vtg *vtg, struct notifier_block *nb)
 {
-	if (vtg->slave)
-		return sti_vtg_unregister_client(vtg->slave, nb);
-
 	return raw_notifier_chain_unregister(&vtg->notifier_list, nb);
 }
 
@@ -434,14 +413,6 @@ static int vtg_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	np = of_parse_phandle(pdev->dev.of_node, "st,slave", 0);
-	if (np) {
-		vtg->slave = of_vtg_find(np);
-		of_node_put(np);
-
-		if (!vtg->slave)
-			return -EPROBE_DEFER;
-	} else {
 	vtg->irq = platform_get_irq(pdev, 0);
 	if (vtg->irq < 0) {
 		DRM_ERROR("Failed to get VTG interrupt\n");
@@ -457,7 +428,6 @@ static int vtg_probe(struct platform_device *pdev)
 		DRM_ERROR("Failed to register VTG interrupt\n");
 		return ret;
 	}
-	}
 
 	vtg_register(vtg);
 	platform_set_drvdata(pdev, vtg);