[RFC PATCH 7/8] drm: bridge: analogix_dp: try force hpd after plug in lookup failed

Yakir Yang
2015-08-06T14:26:40Z

Some edp screen do not have hpd signal, so we can't just return
failed when hpd plug in detect failed.

Besides TRM indicate that if HPD_STATUS(RO) is 0, AUX CH will not
work, so we need to give a force hpd action to set HPD_STATUS manually.

Signed-off-by: Yakir Yang <ykk@rock-chips.com>
---
drivers/gpu/drm/bridge/analogix_dp_core.c | 28 +++++++++++++++++++++++-----
drivers/gpu/drm/bridge/analogix_dp_core.h | 1 +
drivers/gpu/drm/bridge/analogix_dp_reg.c | 9 +++++++++
3 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix_dp_core.c
index 28724d4..7e67f19 100644
--- a/drivers/gpu/drm/bridge/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix_dp_core.c
@@ -68,15 +68,33 @@ static int analogix_dp_detect_hpd(struct analogix_dp_device *dp)
{
int timeout_loop = 0;

- while (analogix_dp_get_plug_in_status(dp) != 0) {
+ while (timeout_loop < DP_TIMEOUT_LOOP_COUNT) {
+ if (analogix_dp_get_plug_in_status(dp) == 0)
+ return 0;
+
timeout_loop++;
- if (DP_TIMEOUT_LOOP_COUNT < timeout_loop) {
- dev_err(dp->dev, "failed to get hpd plug status\n");
- return -ETIMEDOUT;
- }
usleep_range(10, 11);
}

+ /*
+ * Some edp screen do not have hpd signal, so we can't just
+ * return failed when hpd plug in detect failed.
+ *
+ * Besides TRM indicate that if HPD_STATUS(RO) is 0, AUX CH
+ * will not work, so we need to give a force hpd action to
+ * set HPD_STATUS manually.
+ */
+ dev_dbg(dp->dev, "failed to get hpd plug status, try to force hpd\n");
+
+ analogix_dp_force_hpd(dp);
+
+ if (analogix_dp_get_plug_in_status(dp) != 0) {
+ dev_err(dp->dev, "failed to get hpd plug in status\n");
+ return -ETIMEDOUT;
+ }
+
+ dev_dbg(dp->dev, "success to get plug in status after force hpd\n");
+
return 0;
}

diff --git a/drivers/gpu/drm/bridge/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix_dp_core.h
index fe72695..43cec77 100644
--- a/drivers/gpu/drm/bridge/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix_dp_core.h
@@ -183,6 +183,7 @@ void analogix_dp_set_analog_power_down(struct analogix_dp_device *dp,
bool enable);
void analogix_dp_init_analog_func(struct analogix_dp_device *dp);
void analogix_dp_init_hpd(struct analogix_dp_device *dp);
+void analogix_dp_force_hpd(struct analogix_dp_device *dp);
enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp);
void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp);
void analogix_dp_reset_aux(struct analogix_dp_device *dp);
diff --git a/drivers/gpu/drm/bridge/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix_dp_reg.c
index 4d6e08a..3fb215b 100644
--- a/drivers/gpu/drm/bridge/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix_dp_reg.c
@@ -366,6 +366,15 @@ void analogix_dp_init_hpd(struct analogix_dp_device *dp)
writel(reg, dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
}

+void analogix_dp_force_hpd(struct analogix_dp_device *dp)
+{
+ u32 reg;
+
+ reg = readl(dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
+ reg = (F_HPD | HPD_CTRL);
+ writel(reg, dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
+}
+
enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp)
{
u32 reg;
--
2.1.2