Quoting Philip Chen (2021-10-21 14:05:59) > Fit ps8640 driver into runtime power management framework: > > First, break _poweron() to 3 parts: (1) turn on power and wait for > ps8640's internal MCU to finish init (2) check panel HPD (which is > proxied by GPIO9) (3) the other configs. As runtime_resume() can be > called before panel is powered, we only add (1) to _resume() and leave > (2)(3) to _pre_enable(). We also add (2) to _aux_transfer() as we want > to ensure panel HPD is asserted before we start AUX CH transactions. > > The original driver has a mysterious delay of 50 ms between (2) and > (3). Since Parade's support can't explain what the delay is for, and we > don't see removing the delay break any boards at hand, remove the dalay s/dalay/delay/ > to fit into this driver change. > > Besides, rename "powered" to "pre_enabled" and don't check for it in "Besides" doesn't make sense here. Probably "In addition" or "Also"? > the pm_runtime calls. The pm_runtime calls are already refcounted so > there's no reason to check there. The other user of "powered", > _get_edid(), only cares if pre_enable() has already been called. > > Lastly, change some existing DRM_...() logging to dev_...() along the > way, since DRM_...() seem to be deprecated in [1]. > > [1] https://patchwork.freedesktop.org/patch/454760/ > > Signed-off-by: Philip Chen <philipchen@xxxxxxxxxxxx> > Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > --- > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c > index 3aaa90913bf8..220ca3b03d24 100644 > --- a/drivers/gpu/drm/bridge/parade-ps8640.c > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c > @@ -148,6 +149,25 @@ static inline struct ps8640 *aux_to_ps8640(struct drm_dp_aux *aux) > return container_of(aux, struct ps8640, aux); > } > > +static void ps8640_ensure_hpd(struct ps8640 *ps_bridge) > +{ > + 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); > + > + if (ret < 0) > + dev_warn(dev, "HPD didn't go high: %d", ret); Missing newline on the print message. > +} > + > static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux, > struct drm_dp_aux_msg *msg) > { > @@ -171,6 +191,9 @@ static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux, > if (msg->address & ~SWAUX_ADDR_MASK) > return -EINVAL; > > + pm_runtime_get_sync(dev); > + ps8640_ensure_hpd(ps_bridge); Shouldn't we bail out of here with an error if we can't ensure hpd? > + > switch (request) { > case DP_AUX_NATIVE_WRITE: > case DP_AUX_NATIVE_READ: > @@ -180,14 +203,15 @@ static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux, > case DP_AUX_I2C_READ: > break; > default: > - return -EINVAL; > + ret = -EINVAL; > + goto exit; > } > > ret = regmap_write(map, PAGE0_AUXCH_CFG3, AUXCH_CFG3_RESET); > if (ret) { > DRM_DEV_ERROR(dev, "failed to write PAGE0_AUXCH_CFG3: %d\n", > ret); > - return ret; > + goto exit; > } > > /* Assume it's good */ > @@ -213,7 +237,7 @@ static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux, > DRM_DEV_ERROR(dev, > "failed to write WDATA: %d\n", > ret); > - return ret; > + goto exit; > } > } > } > @@ -228,7 +252,7 @@ static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux, > if (ret) { > DRM_DEV_ERROR(dev, "failed to read PAGE0_SWAUX_STATUS: %d\n", > ret); > - return ret; > + goto exit; > } > > switch (data & SWAUX_STATUS_MASK) { > @@ -250,9 +274,11 @@ static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux, > len = data & SWAUX_M_MASK; > break; > case SWAUX_STATUS_INVALID: > - return -EOPNOTSUPP; > + ret = -EOPNOTSUPP; > + goto exit; > case SWAUX_STATUS_TIMEOUT: > - return -ETIMEDOUT; > + ret = -ETIMEDOUT; > + goto exit; > } > > if (len && (request == DP_AUX_NATIVE_READ || It may be simpler to understand the diff if the transfer function still exited the same way and a small wrapper function was put around this to do the runtime PM operations. pm_runtime_get_sync(); if (ps8640_hpd_asserted()) ret = ps8640_aux_transfer_msg(); pm_runtime_mark_last_busy(); pm_runtime_put_autosuspend(); return ret; > @@ -587,6 +611,13 @@ static int ps8640_probe(struct i2c_client *client) > ps_bridge->aux.transfer = ps8640_aux_transfer; > drm_dp_aux_init(&ps_bridge->aux); > > + pm_runtime_enable(dev); > + pm_runtime_set_autosuspend_delay(dev, 500); Presumably 500 is chosen because the message transfer speed is faster than that? Can we get a comment in the code for that? > + pm_runtime_use_autosuspend(dev); > + ret = devm_add_action_or_reset(dev, ps8640_runtime_disable, dev); > + if (ret) > + return ret; > + > drm_bridge_add(&ps_bridge->bridge); > > return 0;
