Messages in this thread | | | Date | Thu, 2 Jun 2022 17:56:13 +0300 | Subject | Re: [PATCH v3 4/4] drm/bridge: parade-ps8640: Provide wait_hpd_asserted() in struct drm_dp_aux | From | Dmitry Baryshkov <> |
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On 18/04/2022 20:17, Douglas Anderson wrote: > This implements the callback added by the patch ("drm/dp: Add > wait_hpd_asserted() callback to struct drm_dp_aux"). > > With this change and all the two "DP AUX Endpoint" drivers changed to > use wait_hpd_asserted(), we no longer need to have an long delay in > the AUX transfer function. It's up to the panel code to make sure that > the panel is powered now. If someone tried to call the aux transfer > function without making sure the panel is powered we'll just get a > normal transfer failure. > > We'll still keep the wait for HPD in the pre_enable() function. Though > it's probably not actually needed there, this driver is used in the > old mode (pre-DP AUX Endpoints) and it may be important for those > cases. If nothing else, it shouldn't cause any big problems. > > Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Minor nit below
> --- > > (no changes since v2) > > Changes in v2: > - Change is_hpd_asserted() to wait_hpd_asserted() > > drivers/gpu/drm/bridge/parade-ps8640.c | 34 ++++++++++++++++---------- > 1 file changed, 21 insertions(+), 13 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c > index 9766cbbd62ad..2f19a8c89880 100644 > --- a/drivers/gpu/drm/bridge/parade-ps8640.c > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c > @@ -168,23 +168,30 @@ static bool ps8640_of_panel_on_aux_bus(struct device *dev) > return true; > } > > -static int ps8640_ensure_hpd(struct ps8640 *ps_bridge) > +static int _ps8640_wait_hpd_asserted(struct ps8640 *ps_bridge, unsigned long wait_us) > { > struct regmap *map = ps_bridge->regmap[PAGE2_TOP_CNTL]; > - struct device *dev = &ps_bridge->page[PAGE2_TOP_CNTL]->dev; > int status; > - int ret; > > /* > * Apparently something about the firmware in the chip signals that > * HPD goes high by reporting GPIO9 as high (even though HPD isn't > * actually connected to GPIO9). > */ > - ret = regmap_read_poll_timeout(map, PAGE2_GPIO_H, status, > - status & PS_GPIO9, 20 * 1000, 200 * 1000); > + return regmap_read_poll_timeout(map, PAGE2_GPIO_H, status, > + status & PS_GPIO9, wait_us / 10, wait_us); > +} > > - if (ret < 0) > - dev_warn(dev, "HPD didn't go high: %d\n", ret); > +static int ps8640_wait_hpd_asserted(struct drm_dp_aux *aux, unsigned long wait_us) > +{ > + struct ps8640 *ps_bridge = aux_to_ps8640(aux); > + struct device *dev = &ps_bridge->page[PAGE0_DP_CNTL]->dev; > + int ret; > + > + pm_runtime_get_sync(dev); > + ret = _ps8640_wait_hpd_asserted(ps_bridge, wait_us); > + pm_runtime_mark_last_busy(dev); > + pm_runtime_put_autosuspend(dev);
I'd add a note here, that the called should have already woken up the device.
> > return ret; > } > @@ -323,9 +330,7 @@ static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux, > int ret; > > pm_runtime_get_sync(dev); > - ret = ps8640_ensure_hpd(ps_bridge); > - if (!ret) > - ret = ps8640_aux_transfer_msg(aux, msg); > + ret = ps8640_aux_transfer_msg(aux, msg); > pm_runtime_mark_last_busy(dev); > pm_runtime_put_autosuspend(dev); > > @@ -369,8 +374,8 @@ static int __maybe_unused ps8640_resume(struct device *dev) > * Mystery 200 ms delay for the "MCU to be ready". It's unclear if > * this is truly necessary since the MCU will already signal that > * things are "good to go" by signaling HPD on "gpio 9". See > - * ps8640_ensure_hpd(). For now we'll keep this mystery delay just in > - * case. > + * _ps8640_wait_hpd_asserted(). For now we'll keep this mystery delay > + * just in case. > */ > msleep(200); > > @@ -406,7 +411,9 @@ static void ps8640_pre_enable(struct drm_bridge *bridge) > int ret; > > pm_runtime_get_sync(dev); > - ps8640_ensure_hpd(ps_bridge); > + ret = _ps8640_wait_hpd_asserted(ps_bridge, 200 * 1000); > + if (ret < 0) > + dev_warn(dev, "HPD didn't go high: %d\n", ret); > > /* > * The Manufacturer Command Set (MCS) is a device dependent interface > @@ -652,6 +659,7 @@ static int ps8640_probe(struct i2c_client *client) > ps_bridge->aux.name = "parade-ps8640-aux"; > ps_bridge->aux.dev = dev; > ps_bridge->aux.transfer = ps8640_aux_transfer; > + ps_bridge->aux.wait_hpd_asserted = ps8640_wait_hpd_asserted; > drm_dp_aux_init(&ps_bridge->aux); > > pm_runtime_enable(dev);
-- With best wishes Dmitry
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