OMAPDSS: HDMI: PHY burnout fix

commit c49d005b6cc8491fad5b24f82805be2d6bcbd3dd upstream.

A hardware bug in the OMAP4 HDMI PHY causes physical damage to the board
if the HDMI PHY is kept powered on when the cable is not connected.

This patch solves the problem by adding hot-plug-detection into the HDMI
IP driver. This is not a real HPD support in the sense that nobody else
than the IP driver gets to know about the HPD events, but is only meant
to fix the HW bug.

The strategy is simple: If the display device is turned off by the user,
the PHY power is set to OFF. When the display device is turned on by the
user, the PHY power is set either to LDOON or TXON, depending on whether
the HDMI cable is connected.

The reason to avoid PHY OFF when the display device is on, but the cable
is disconnected, is that when the PHY is turned OFF, the HDMI IP is not
"ticking" and thus the DISPC does not receive pixel clock from the HDMI
IP. This would, for example, prevent any VSYNCs from happening, and
would thus affect the users of omapdss. By using LDOON when the cable is
disconnected we'll avoid the HW bug, but keep the HDMI working as usual
from the user's point of view.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm/mach-omap2/board-4430sdp.c b/arch/arm/mach-omap2/board-4430sdp.c
index 5c2aaa0260474ac1ce059dbdf1b0b677d68a29f2..02cd29ae35065c1fa7265014f84acbc0909252f8 100644 (file)
--- a/arch/arm/mach-omap2/board-4430sdp.c
+++ b/arch/arm/mach-omap2/board-4430sdp.c
@@ -742,6 +742,10 @@ static void sdp4430_lcd_init(void)
                pr_err("%s: Could not get lcd2_reset_gpio\n", __func__);
 }
 
+static struct omap_dss_hdmi_data sdp4430_hdmi_data = {
+       .hpd_gpio = HDMI_GPIO_HPD,
+};
+
 static struct omap_dss_device sdp4430_hdmi_device = {
        .name = "hdmi",
        .driver_name = "hdmi_panel",
@@ -749,6 +753,7 @@ static struct omap_dss_device sdp4430_hdmi_device = {
        .platform_enable = sdp4430_panel_enable_hdmi,
        .platform_disable = sdp4430_panel_disable_hdmi,
        .channel = OMAP_DSS_CHANNEL_DIGIT,
+       .data = &sdp4430_hdmi_data,
 };
 
 static struct picodlp_panel_data sdp4430_picodlp_pdata = {

diff --git a/arch/arm/mach-omap2/board-omap4panda.c b/arch/arm/mach-omap2/board-omap4panda.c
index e913c80060ec4af086e922f992c205c729bdb471..51b1c93837b23eb67936bbb1ce0af658a85cf3ac 100644 (file)
--- a/arch/arm/mach-omap2/board-omap4panda.c
+++ b/arch/arm/mach-omap2/board-omap4panda.c
@@ -513,6 +513,10 @@ static void omap4_panda_panel_disable_hdmi(struct omap_dss_device *dssdev)
        gpio_free_array(panda_hdmi_gpios, ARRAY_SIZE(panda_hdmi_gpios));
 }
 
+static struct omap_dss_hdmi_data omap4_panda_hdmi_data = {
+       .hpd_gpio = HDMI_GPIO_HPD,
+};
+
 static struct omap_dss_device  omap4_panda_hdmi_device = {
        .name = "hdmi",
        .driver_name = "hdmi_panel",
@@ -520,6 +524,7 @@ static struct omap_dss_device  omap4_panda_hdmi_device = {
        .platform_enable = omap4_panda_panel_enable_hdmi,
        .platform_disable = omap4_panda_panel_disable_hdmi,
        .channel = OMAP_DSS_CHANNEL_DIGIT,
+       .data = &omap4_panda_hdmi_data,
 };
 
 static struct omap_dss_device *omap4_panda_dss_devices[] = {

diff --git a/drivers/video/omap2/dss/hdmi.c b/drivers/video/omap2/dss/hdmi.c
index c56378c555b0907255048e32384c1b5b191bc14f..7099c31f3ae1d5b7f4f5d10a6ef41c4bafe96a73 100644 (file)
--- a/drivers/video/omap2/dss/hdmi.c
+++ b/drivers/video/omap2/dss/hdmi.c
@@ -490,6 +490,7 @@ bool omapdss_hdmi_detect(void)
 
 int omapdss_hdmi_display_enable(struct omap_dss_device *dssdev)
 {
+       struct omap_dss_hdmi_data *priv = dssdev->data;
        int r = 0;
 
        DSSDBG("ENTER hdmi_display_enable\n");
@@ -502,6 +503,8 @@ int omapdss_hdmi_display_enable(struct omap_dss_device *dssdev)
                goto err0;
        }
 
+       hdmi.ip_data.hpd_gpio = priv->hpd_gpio;
+
        r = omap_dss_start_device(dssdev);
        if (r) {
                DSSERR("failed to start device\n");

diff --git a/drivers/video/omap2/dss/ti_hdmi.h b/drivers/video/omap2/dss/ti_hdmi.h
index 2c3443dabb14c3505087fec3dd045d109cceabd9..ec337b5dcc860f7f052a205eec21c55241faf821 100644 (file)
--- a/drivers/video/omap2/dss/ti_hdmi.h
+++ b/drivers/video/omap2/dss/ti_hdmi.h
@@ -121,6 +121,10 @@ struct hdmi_ip_data {
        const struct ti_hdmi_ip_ops *ops;
        struct hdmi_config cfg;
        struct hdmi_pll_info pll_data;
+
+       /* ti_hdmi_4xxx_ip private data. These should be in a separate struct */
+       int hpd_gpio;
+       bool phy_tx_enabled;
 };
 int ti_hdmi_4xxx_phy_enable(struct hdmi_ip_data *ip_data);
 void ti_hdmi_4xxx_phy_disable(struct hdmi_ip_data *ip_data);

diff --git a/drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c b/drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c
index e1a6ce518af6c4c250f6d542e9a135e2927683ba..36834042b3410d44ccfc262cdc3050eb39000c52 100644 (file)
--- a/drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c
+++ b/drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c
@@ -28,6 +28,7 @@
 #include <linux/delay.h>
 #include <linux/string.h>
 #include <linux/seq_file.h>
+#include <linux/gpio.h>
 
 #include "ti_hdmi_4xxx_ip.h"
 #include "dss.h"
@@ -223,6 +224,49 @@ 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)
+{
+       unsigned long flags;
+       bool hpd;
+       int r;
+       /* this should be in ti_hdmi_4xxx_ip private data */
+       static DEFINE_SPINLOCK(phy_tx_lock);
+
+       spin_lock_irqsave(&phy_tx_lock, flags);
+
+       hpd = gpio_get_value(ip_data->hpd_gpio);
+
+       if (hpd == ip_data->phy_tx_enabled) {
+               spin_unlock_irqrestore(&phy_tx_lock, flags);
+               return 0;
+       }
+
+       if (hpd)
+               r = hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_TXON);
+       else
+               r = hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_LDOON);
+
+       if (r) {
+               DSSERR("Failed to %s PHY TX power\n",
+                               hpd ? "enable" : "disable");
+               goto err;
+       }
+
+       ip_data->phy_tx_enabled = hpd;
+err:
+       spin_unlock_irqrestore(&phy_tx_lock, flags);
+       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;
+}
+
 int ti_hdmi_4xxx_phy_enable(struct hdmi_ip_data *ip_data)
 {
        u16 r = 0;
@@ -232,10 +276,6 @@ int ti_hdmi_4xxx_phy_enable(struct hdmi_ip_data *ip_data)
        if (r)
                return r;
 
-       r = hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_TXON);
-       if (r)
-               return r;
-
        /*
         * Read address 0 in order to get the SCP reset done completed
         * Dummy access performed to make sure reset is done
@@ -257,12 +297,32 @@ 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_DISABLED | IRQF_TRIGGER_RISING |
+                       IRQF_TRIGGER_FALLING, "hpd", ip_data);
+       if (r) {
+               DSSERR("HPD 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;
+       }
+
        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);
+
        hdmi_set_phy_pwr(ip_data, HDMI_PHYPWRCMD_OFF);
+       ip_data->phy_tx_enabled = false;
 }
 
 static int hdmi_core_ddc_init(struct hdmi_ip_data *ip_data)

diff --git a/include/video/omapdss.h b/include/video/omapdss.h
index 378c7ed6760be0563b501971df2a60e03a672ea7..6582c4554028e1c5d0aeb749d1a3eafc6a0d2451 100644 (file)
--- a/include/video/omapdss.h
+++ b/include/video/omapdss.h
@@ -575,6 +575,11 @@ struct omap_dss_device {
        int (*get_backlight)(struct omap_dss_device *dssdev);
 };
 
+struct omap_dss_hdmi_data
+{
+       int hpd_gpio;
+};
+
 struct omap_dss_driver {
        struct device_driver driver;