Hi,
On Thu, Apr 14, 2022 at 5:51 PM Dmitry Baryshkov dmitry.baryshkov@linaro.org wrote:
On 09/04/2022 05:36, Douglas Anderson wrote:
Let's add support for being able to read the HPD pin even if it's hooked directly to the controller. This will allow us to get more accurate delays also lets us take away the waiting in the AUX transfer functions of the eDP controller drivers.
Signed-off-by: Douglas Anderson dianders@chromium.org
drivers/gpu/drm/panel/panel-edp.c | 37 ++++++++++++++++++++++++++----- 1 file changed, 31 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c index 1732b4f56e38..4a143eb9544b 100644 --- a/drivers/gpu/drm/panel/panel-edp.c +++ b/drivers/gpu/drm/panel/panel-edp.c @@ -417,6 +417,19 @@ static int panel_edp_get_hpd_gpio(struct device *dev, struct panel_edp *p) return 0; }
+static bool panel_edp_can_read_hpd(struct panel_edp *p) +{
return !p->no_hpd && (p->hpd_gpio || (p->aux && p->aux->is_hpd_asserted));+}
+static bool panel_edp_read_hpd(struct panel_edp *p) +{
if (p->hpd_gpio)return gpiod_get_value_cansleep(p->hpd_gpio);return p->aux->is_hpd_asserted(p->aux);+}
- static int panel_edp_prepare_once(struct panel_edp *p) { struct device *dev = p->base.dev;
@@ -441,13 +454,21 @@ static int panel_edp_prepare_once(struct panel_edp *p) if (delay) msleep(delay);
if (p->hpd_gpio) {
if (panel_edp_can_read_hpd(p)) { if (p->desc->delay.hpd_absent) hpd_wait_us = p->desc->delay.hpd_absent * 1000UL; else hpd_wait_us = 2000000;
err = readx_poll_timeout(gpiod_get_value_cansleep, p->hpd_gpio,
/** Extra max delay, mostly to account for ps8640. ps8640* is crazy and the bridge chip driver itself has over 200 ms* of delay if it needs to do the pm_runtime resume of the* bridge chip to read the HPD.*/hpd_wait_us += 3000000;I think this should come in a separate commit and ideally this should be configurable somehow. Other hosts wouldn't need such 'additional' delay.
With this change removed:
Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org
What would you think about changing the API slightly? Instead of is_hpd_asserted(), we change it to wait_hpd_asserted() and it takes a timeout in microseconds. If you pass 0 for the timeout the function is defined to behave the same as is_hpd_asserted() today--AKA a single poll of the line.
-Doug