For the eDP case we can support using aux-bus on MediaTek DP: this
gives us the possibility to declare our panel as generic "panel-edp"
which will automatically configure the timings and available modes
via the EDID that we read from it.
To do this, move the panel parsing at the end of the probe function
so that the hardware is initialized beforehand and also initialize
the DPTX AUX block and power both on as, when we populate the
aux-bus, the panel driver will trigger an EDID read to perform
panel detection.
Last but not least, since now the AUX transfers can happen in the
separated aux-bus, it was necessary to add an exclusion for the
cable_plugged_in check in `mtk_dp_aux_transfer()` and the easiest
way to do this is to simply ignore checking that when the bridge
type is eDP.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
---
drivers/gpu/drm/mediatek/Kconfig | 1 +
drivers/gpu/drm/mediatek/mtk_dp.c | 92 ++++++++++++++++++++++++++-----
2 files changed, 79 insertions(+), 14 deletions(-)
>> While digging through the code I realized that all the outputs and
>> pipelines
>> are harcoded. Doh. For all the mediatek SoCs. Looks like major
>> restriction
>> to
>> me. E.g. there is also DSI and HDMI output on the mt8195. I looked at
>> the
>> downstream linux and there, the output is not part of the pipeline.
>> Are you
>> aware of any work in that direction?
>
> I'm not sure I get what output and pipelines are hardcoded that you're
> referring
> to (besides the one in the mtk-dsi/dpi driver that you already sent the
> patch
> fixing).
Have a look at [1]. That main path ends with the DP_INTF0 which is the
eDP output. But from what I understand that path can also use the DSI
output. But that is a pattern for all the paths in that file. Looks like
all supported boards in the kernel will have the output type for a given
SoC/path (or maybe the mt8195 is the first one which supports different
output interfaces).
If you have a look at the mediatek kernel instead [2], there the last
part of the path is not fixed, but there is also a .conn_routes property
by which you seem to be able to choose the actual output interface.
I was just curious if you know of any development for that (or similar)
in the kernel.
-michael
> And I'm not familiar with the DSI and HDMI output support on MT8195, so
> I can't
> help with that.
>
> Thanks,
> Nícolas
[1]
https://elixir.bootlin.com/linux/v6.5/source/drivers/gpu/drm/mediatek/mtk_drm_drv.c#L210
[2]
https://gitlab.com/mediatek/aiot/bsp/linux/-/blob/mtk-v5.15-dev/drivers/gpu/drm/mediatek/mtk_drm_drv.c?ref_type=heads#L425
@@ -26,6 +26,7 @@ config DRM_MEDIATEK_DP
select PHY_MTK_DP
select DRM_DISPLAY_HELPER
select DRM_DISPLAY_DP_HELPER
+ select DRM_DP_AUX_BUS
help
DRM/KMS Display Port driver for MediaTek SoCs.
@@ -4,6 +4,7 @@
* Copyright (c) 2022 BayLibre
*/
+#include <drm/display/drm_dp_aux_bus.h>
#include <drm/display/drm_dp.h>
#include <drm/display/drm_dp_helper.h>
#include <drm/drm_atomic_helper.h>
@@ -1313,9 +1314,11 @@ static void mtk_dp_power_disable(struct mtk_dp *mtk_dp)
static void mtk_dp_initialize_priv_data(struct mtk_dp *mtk_dp)
{
+ bool plugged_in = (mtk_dp->bridge.type == DRM_MODE_CONNECTOR_eDP);
+
mtk_dp->train_info.link_rate = DP_LINK_BW_5_4;
mtk_dp->train_info.lane_count = mtk_dp->max_lanes;
- mtk_dp->train_info.cable_plugged_in = false;
+ mtk_dp->train_info.cable_plugged_in = plugged_in;
mtk_dp->info.format = DP_PIXELFORMAT_RGB;
memset(&mtk_dp->info.vm, 0, sizeof(struct videomode));
@@ -1617,6 +1620,16 @@ static int mtk_dp_parse_capabilities(struct mtk_dp *mtk_dp)
u8 val;
ssize_t ret;
+ /*
+ * If we're eDP and capabilities were already parsed we can skip
+ * reading again because eDP panels aren't hotpluggable hence the
+ * caps and training information won't ever change in a boot life
+ */
+ if (mtk_dp->bridge.type == DRM_MODE_CONNECTOR_eDP &&
+ mtk_dp->rx_cap[DP_MAX_LINK_RATE] &&
+ mtk_dp->train_info.sink_ssc)
+ return 0;
+
ret = drm_dp_read_dpcd_caps(&mtk_dp->aux, mtk_dp->rx_cap);
if (ret < 0)
return ret;
@@ -2030,15 +2043,14 @@ static struct edid *mtk_dp_get_edid(struct drm_bridge *bridge,
static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux,
struct drm_dp_aux_msg *msg)
{
- struct mtk_dp *mtk_dp;
+ struct mtk_dp *mtk_dp = container_of(mtk_aux, struct mtk_dp, aux);
bool is_read;
u8 request;
size_t accessed_bytes = 0;
int ret;
- mtk_dp = container_of(mtk_aux, struct mtk_dp, aux);
-
- if (!mtk_dp->train_info.cable_plugged_in) {
+ if (mtk_dp->bridge.type != DRM_MODE_CONNECTOR_eDP &&
+ !mtk_dp->train_info.cable_plugged_in) {
ret = -EAGAIN;
goto err;
}
@@ -2501,6 +2513,28 @@ static int mtk_dp_register_phy(struct mtk_dp *mtk_dp)
return 0;
}
+static int mtk_dp_edp_link_panel(struct drm_dp_aux *mtk_aux)
+{
+ struct mtk_dp *mtk_dp = container_of(mtk_aux, struct mtk_dp, aux);
+ struct device *dev = mtk_aux->dev;
+ int ret;
+
+ mtk_dp->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
+
+ /* Power off the DP and AUX: either detection is done, or no panel present */
+ mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
+ DP_PWR_STATE_BANDGAP_TPLL,
+ DP_PWR_STATE_MASK);
+ mtk_dp_power_disable(mtk_dp);
+
+ if (IS_ERR(mtk_dp->next_bridge)) {
+ ret = PTR_ERR(mtk_dp->next_bridge);
+ mtk_dp->next_bridge = NULL;
+ return ret;
+ }
+ return 0;
+}
+
static int mtk_dp_probe(struct platform_device *pdev)
{
struct mtk_dp *mtk_dp;
@@ -2519,21 +2553,14 @@ static int mtk_dp_probe(struct platform_device *pdev)
return dev_err_probe(dev, mtk_dp->irq,
"failed to request dp irq resource\n");
- mtk_dp->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
- if (IS_ERR(mtk_dp->next_bridge) &&
- PTR_ERR(mtk_dp->next_bridge) == -ENODEV)
- mtk_dp->next_bridge = NULL;
- else if (IS_ERR(mtk_dp->next_bridge))
- return dev_err_probe(dev, PTR_ERR(mtk_dp->next_bridge),
- "Failed to get bridge\n");
-
ret = mtk_dp_dt_parse(mtk_dp, pdev);
if (ret)
return dev_err_probe(dev, ret, "Failed to parse dt\n");
- drm_dp_aux_init(&mtk_dp->aux);
mtk_dp->aux.name = "aux_mtk_dp";
+ mtk_dp->aux.dev = dev;
mtk_dp->aux.transfer = mtk_dp_aux_transfer;
+ drm_dp_aux_init(&mtk_dp->aux);
spin_lock_init(&mtk_dp->irq_thread_lock);
@@ -2577,6 +2604,43 @@ static int mtk_dp_probe(struct platform_device *pdev)
mtk_dp->need_debounce = true;
timer_setup(&mtk_dp->debounce_timer, mtk_dp_debounce_timer, 0);
+ if (mtk_dp->bridge.type == DRM_MODE_CONNECTOR_eDP) {
+ /*
+ * Set the data lanes to idle in case the bootloader didn't
+ * properly close the eDP port to avoid stalls and then
+ * reinitialize, reset and power on the AUX block.
+ */
+ mtk_dp_set_idle_pattern(mtk_dp, true);
+ mtk_dp_initialize_aux_settings(mtk_dp);
+ mtk_dp_power_enable(mtk_dp);
+
+ /*
+ * Power on the AUX to allow reading the EDID from aux-bus:
+ * please note that it is necessary to call power off in the
+ * .done_probing() callback (mtk_dp_edp_link_panel), as only
+ * there we can safely assume that we finished reading EDID.
+ */
+ mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
+ DP_PWR_STATE_BANDGAP_TPLL_LANE,
+ DP_PWR_STATE_MASK);
+
+ ret = devm_of_dp_aux_populate_bus(&mtk_dp->aux, mtk_dp_edp_link_panel);
+ if (ret) {
+ /* -ENODEV this means that the panel is not on the aux-bus */
+ if (ret == -ENODEV) {
+ ret = mtk_dp_edp_link_panel(&mtk_dp->aux);
+ if (ret)
+ return ret;
+ } else {
+ mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
+ DP_PWR_STATE_BANDGAP_TPLL,
+ DP_PWR_STATE_MASK);
+ mtk_dp_power_disable(mtk_dp);
+ return ret;
+ }
+ }
+ }
+
pm_runtime_enable(dev);
pm_runtime_get_sync(dev);