OMAPDSS: HDMI: clean up PHY power handling

The TRM tells to set PHY to TXON only after getting LINK_CONNECT, and to
set PHY to OFF or LDOON after getting LINK_DISCONNECT, in order to avoid
damage to the PHY.

We don't currently do it quite like that. Instead of using the HDMI
interrupts, we use HPD signal. This works, but is not actually quite
correct, as HPD comes at a different time than LINK_CONNECT and
LINK_DISCONNECT interrupts. Also, the HPD GPIO is a property of the TPD
level shifter, not HDMI IP, so handling the GPIO in the HDMI driver is
wrong.

This patch implements the PHY power handling correctly, using the
interrupts.

There is a corner case that causes some additional difficulties: we may
get both LINK_CONNECT and LINK_DISCONNECT interrupts at the same time.
This is handled in the code by retrying: turning off the PHY, clearing
the interrupt status, and re-enabling the PHY. This causes a new
LINK_CONNECT interrupt to happen if a cable is connected.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap2/dss/hdmi.c

@@ -1072,6 +1072,12 @@ static int omapdss_hdmihw_probe(struct platform_device *pdev)
 	if (IS_ERR(hdmi.ip_data.base_wp))
 		return PTR_ERR(hdmi.ip_data.base_wp);
 
+	hdmi.ip_data.irq = platform_get_irq(pdev, 0);
+	if (hdmi.ip_data.irq < 0) {
+		DSSERR("platform_get_irq failed\n");
+		return -ENODEV;
+	}
+
 	r = hdmi_get_clocks(pdev);
 	if (r) {
 		DSSERR("can't get clocks\n");

drivers/video/omap2/dss/ti_hdmi.h

@@ -155,6 +155,7 @@ struct hdmi_ip_data {
 	unsigned long	core_av_offset;
 	unsigned long	pll_offset;
 	unsigned long	phy_offset;
+	int		irq;
 	const struct ti_hdmi_ip_ops *ops;
 	struct hdmi_config cfg;
 	struct hdmi_pll_info pll_data;

drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c

@@ -38,6 +38,9 @@
 #include "dss.h"
 #include "dss_features.h"
 
+#define HDMI_IRQ_LINK_CONNECT		(1 << 25)
+#define HDMI_IRQ_LINK_DISCONNECT	(1 << 26)
+
 static inline void hdmi_write_reg(void __iomem *base_addr,
 				const u16 idx, u32 val)
 {
@@ -233,37 +236,39 @@ void ti_hdmi_4xxx_pll_disable(struct hdmi_ip_data *ip_data)
 	hdmi_set_pll_pwr(ip_data, HDMI_PLLPWRCMD_ALLOFF);
 }
 
-static int hdmi_check_hpd_state(struct hdmi_ip_data *ip_data)
+static irqreturn_t hdmi_irq_handler(int irq, void *data)
 {
-	bool hpd;
-	int r;
+	struct hdmi_ip_data *ip_data = data;
+	void __iomem *wp_base = hdmi_wp_base(ip_data);
+	u32 irqstatus;
 
-	mutex_lock(&ip_data->lock);
+	irqstatus = hdmi_read_reg(wp_base, HDMI_WP_IRQSTATUS);
+	hdmi_write_reg(wp_base, HDMI_WP_IRQSTATUS, irqstatus);
+	/* flush posted write */
+	hdmi_read_reg(wp_base, HDMI_WP_IRQSTATUS);
 
-	hpd = gpio_get_value(ip_data->hpd_gpio);
+	if ((irqstatus & HDMI_IRQ_LINK_CONNECT) &&
+			irqstatus & HDMI_IRQ_LINK_DISCONNECT) {
+		/*
+		 * If we get both connect and disconnect interrupts at the same
+		 * time, turn off the PHY, clear interrupts, and restart, which
+		 * raises connect interrupt if a cable is connected, or nothing
+		 * if cable is not connected.
+		 */
+		hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_OFF);
 
-	if (hpd)
-		r = hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_TXON);
-	else
-		r = hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_LDOON);
+		hdmi_write_reg(wp_base, HDMI_WP_IRQSTATUS,
+			HDMI_IRQ_LINK_CONNECT | HDMI_IRQ_LINK_DISCONNECT);
+		/* flush posted write */
+		hdmi_read_reg(wp_base, HDMI_WP_IRQSTATUS);
 
-	if (r) {
-		DSSERR("Failed to %s PHY TX power\n",
-				hpd ? "enable" : "disable");
-		goto err;
+		hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_LDOON);
+	} else if (irqstatus & HDMI_IRQ_LINK_CONNECT) {
+		hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_TXON);
+	} else if (irqstatus & HDMI_IRQ_LINK_DISCONNECT) {
+		hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_LDOON);
 	}
 
-err:
-	mutex_unlock(&ip_data->lock);
-	return r;
-}
-
-static irqreturn_t hpd_irq_handler(int irq, void *data)
-{
-	struct hdmi_ip_data *ip_data = data;
-
-	hdmi_check_hpd_state(ip_data);
-
 	return IRQ_HANDLED;
 }
 
@@ -272,6 +277,12 @@ int ti_hdmi_4xxx_phy_enable(struct hdmi_ip_data *ip_data)
 	u16 r = 0;
 	void __iomem *phy_base = hdmi_phy_base(ip_data);
 
+	hdmi_write_reg(hdmi_wp_base(ip_data), HDMI_WP_IRQENABLE_CLR,
+			0xffffffff);
+
+	hdmi_write_reg(hdmi_wp_base(ip_data), HDMI_WP_IRQSTATUS,
+			HDMI_IRQ_LINK_CONNECT | HDMI_IRQ_LINK_DISCONNECT);
+
 	r = hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_LDOON);
 	if (r)
 		return r;
@@ -297,29 +308,23 @@ int ti_hdmi_4xxx_phy_enable(struct hdmi_ip_data *ip_data)
 	/* Write to phy address 3 to change the polarity control */
 	REG_FLD_MOD(phy_base, HDMI_TXPHY_PAD_CFG_CTRL, 0x1, 27, 27);
 
-	r = request_threaded_irq(gpio_to_irq(ip_data->hpd_gpio),
-				 NULL, hpd_irq_handler,
-				 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
-				 IRQF_ONESHOT, "hpd", ip_data);
+	r = request_threaded_irq(ip_data->irq, NULL, hdmi_irq_handler,
+				 IRQF_ONESHOT, "OMAP HDMI", ip_data);
 	if (r) {
-		DSSERR("HPD IRQ request failed\n");
+		DSSERR("HDMI IRQ request failed\n");
 		hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_OFF);
 		return r;
 	}
 
-	r = hdmi_check_hpd_state(ip_data);
-	if (r) {
-		free_irq(gpio_to_irq(ip_data->hpd_gpio), ip_data);
-		hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_OFF);
-		return r;
-	}
+	hdmi_write_reg(hdmi_wp_base(ip_data), HDMI_WP_IRQENABLE_SET,
+			HDMI_IRQ_LINK_CONNECT | HDMI_IRQ_LINK_DISCONNECT);
 
 	return 0;
 }
 
 void ti_hdmi_4xxx_phy_disable(struct hdmi_ip_data *ip_data)
 {
-	free_irq(gpio_to_irq(ip_data->hpd_gpio), ip_data);
+	free_irq(ip_data->irq, ip_data);
 
 	hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_OFF);
 }

drivers/video/omap2/dss/ti_hdmi_4xxx_ip.h

@@ -33,6 +33,7 @@
 #define HDMI_WP_IRQSTATUS			0x28
 #define HDMI_WP_PWR_CTRL			0x40
 #define HDMI_WP_IRQENABLE_SET			0x2C
+#define HDMI_WP_IRQENABLE_CLR			0x30
 #define HDMI_WP_VIDEO_CFG			0x50
 #define HDMI_WP_VIDEO_SIZE			0x60
 #define HDMI_WP_VIDEO_TIMING_H			0x68