drm: sti: remove gpio for HDMI hot plug detection

gpio used for HDMI hot plug detection is useless,
HDMI_STI register contains an hot plug detection status bit.
Fix binding documentation.

Signed-off-by: Benjamin Gaignard <[e-mail]>

Documentation/devicetree/bindings/gpu/st,stih4xx.txt

···
     number of clocks may depend of the SoC type.
   - clock-names: names of the clocks listed in clocks property in the same
     order.
-  - hdmi,hpd-gpio: gpio id to detect if an hdmi cable is plugged or not.
   - ddc: phandle of an I2C controller used for DDC EDID probing
 
 sti-hda:
···
 				interrupt-names	= "irq";
 				clock-names	= "pix", "tmds", "phy", "audio";
 				clocks          = <&clockgen_c_vcc CLK_S_PIX_HDMI>, <&clockgen_c_vcc CLK_S_TMDS_HDMI>, <&clockgen_c_vcc CLK_S_HDMI_REJECT_PLL>, <&clockgen_b1 CLK_S_PCM_0>;
-				hdmi,hpd-gpio	= <&PIO2 5>;
 			};
 
 			sti-hda@fe85a000 {

drivers/gpu/drm/sti/sti_hdmi.c

···
 
 	/* Hot plug/unplug IRQ */
 	if (hdmi->irq_status & HDMI_INT_HOT_PLUG) {
-		/* read gpio to get the status */
-		hdmi->hpd = gpio_get_value(hdmi->hpd_gpio);
+		hdmi->hpd = readl(hdmi->regs + HDMI_STA) & HDMI_STA_HOT_PLUG;
 		if (hdmi->drm_dev)
 			drm_helper_hpd_irq_event(hdmi->drm_dev);
 	}
···
 		return PTR_ERR(hdmi->clk_audio);
 	}
 
-	hdmi->hpd_gpio = of_get_named_gpio(np, "hdmi,hpd-gpio", 0);
-	if (hdmi->hpd_gpio < 0) {
-		DRM_ERROR("Failed to get hdmi hpd-gpio\n");
-		return -EIO;
-	}
-
-	hdmi->hpd = gpio_get_value(hdmi->hpd_gpio);
+	hdmi->hpd = readl(hdmi->regs + HDMI_STA) & HDMI_STA_HOT_PLUG;
 
 	init_waitqueue_head(&hdmi->wait_event);
 

drivers/gpu/drm/sti/sti_hdmi.h

···
 #define HDMI_STA           0x0010
 #define HDMI_STA_DLL_LCK   BIT(5)
 
+#define HDMI_STA_HOT_PLUG_SHIFT 4
+#define HDMI_STA_HOT_PLUG	(1 << HDMI_STA_HOT_PLUG_SHIFT)
+
 struct sti_hdmi;
 
 struct hdmi_phy_ops {
···
  * @irq_status: interrupt status register
  * @phy_ops: phy start/stop operations
  * @enabled: true if hdmi is enabled else false
- * @hpd_gpio: hdmi hot plug detect gpio number
  * @hpd: hot plug detect status
  * @wait_event: wait event
  * @event_received: wait event status
···
 	u32 irq_status;
 	struct hdmi_phy_ops *phy_ops;
 	bool enabled;
-	int hpd_gpio;
 	bool hpd;
 	wait_queue_head_t wait_event;
 	bool event_received;