The ADV7511 family of bridges supports two modes for CEC RX: legacy and
non-legacy mode. The only difference is whether the chip uses a single
CEC RX buffer, or uses all three available RX buffers. Currently the
adv7511 driver uses legacy mode.
While debugging a stall in CEC RX on an ADV7535, we reached out to
Analog Devices, who suggested to use non-legacy mode instead. According
to the programming guide for the ADV7511 [1], and the register control
manual of the ADV7535 [2], this is the default behaviour on reset. As
previously stated, the adv7511 driver currently overrides this to legacy
mode.
This patch updates the adv7511 driver to instead use non-legacy mode
with all three CEC RX buffers. As a result of this change, we no longer
experience any stalling of CEC RX with the ADV7535. It is not known why
non-legacy mode solves this particular issue, but besides this, no
functional change is to be expected by this patch. Please note that this
has only been tested on an ADV7535.
What follows is a brief description of the non-legacy mode interrupt
handling behaviour. The programming guide in [1] gives a more detailed
explanation.
With three RX buffers, the interrupt handler checks the CEC_RX_STATUS
register (renamed from CEC_RX_ENABLE in this patch), which contains
2-bit psuedo-timestamps for each of the RX buffers. The RX timestamps
for each buffer represent the time of arrival for the CEC frame held in
a given buffer, with lower timestamp values indicating chronologically
older frames. A special value of 0 indicates that the given RX buffer
is inactive and should be skipped. The interrupt handler parses these
timestamps and then reads the active RX buffers in the prescribed order
using the same logic as before. Changes have been made to ensure that
the correct RX buffer is cleared after processing. This clearing
procesure also sets the timestamp of the given RX buffer to 0 to mark it
as inactive.
[1] https://www.analog.com/media/en/technical-documentation/user-guides/ADV7511_Programming_Guide.pdf
cf. CEC Map, register 0x4A, bit 3, default value 1:
0 = Use only buffer 0 to store CEC frames (Legacy mode)
1 = Use all 3 buffers to stores the CEC frames (Non-legacy mode)
[2] The ADV7535 register control manual is under NDA, but trust me when
I say that non-legacy CEC RX mode is the default here too. Here the
register is offset by 0x70 and has an address of 0xBA in the DSI_CEC
regiser map.
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220423120854.1503163-3-alvin@pqrs.dk
The mode and ajusted_mode passed to the bridge .mode_set() operation
should never be modified by the bridge (and are not in any of the
existing bridge drivers). Make them const to make this clear.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The adv7511 driver keeps a private copy of the EDID in its driver state
struct. But this copy is only used in adv7511_get_modes() where it is also
retrieved, so there is no need to keep this extra copy around.
If a need to access the EDID elsewhere in the driver ever arises the copy
that is stored in the connector can be used. This copy is accessible
through drm_connector_get_edid().
Note, this patch removes the NULL check of the EDID before passing it to
drm_detect_hdmi_monitor(), but that is fine since the function correctly
handles the case where the EDID is NULL.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20170905121018.11477-2-lars@metafoo.de
Lower modes on ADV7533 require lower number of DSI lanes for correct
operation. If ADV7533 is being used with 4 DSI lanes, then switch the
lanes to 3 when the target mode's pixel clock is less than 80 Mhz.
Based on patch by Andy Green <andy.green@linaro.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
ADV7533 provides an internal timing generator for certain modes that it
can't use the DSI clock directly.
We've observed that HDMI is more stable with the internal timing
generator, especially if there are instabilities in the DSI clock source.
The data spec also seems to recommend the usage of the timing generator
for all modes.
However, on some platforms, it's reported that enabling the timing
generator causes instabilities with the HDMI output.
Create a DT parameter that lets a platform explicitly disable the timing
generator. The timing generator is enabled by default.
Signed-off-by: Archit Taneja <architt@codeaurora.org>
In order to pass DSI specific parameters to the DSI host, we need the
driver to create a mipi_dsi_device DSI device that attaches to the
host.
Use of_graph helpers to get the DSI host DT node. Create a MIPI DSI
device using this host. Finally, attach this device to the DSI host.
Populate DT parameters (number of data lanes for now) that are required
for DSI RX to work correctly. Hardcode few other parameters (rgb,
embedded_sync) for now.
Select DRM_MIPI_DSI config option only when ADV7533 support is enabled.
Signed-off-by: Archit Taneja <architt@codeaurora.org>
ADV7533 is a DSI to HDMI encoder chip. It is a derivative of ADV7511,
with additional blocks to translate input DSI data to parallel RGB
data. Besides the ADV7511 I2C register map, it has additional registers
that require to be configured to activate the DSI Rx block.
Create a new config that enables ADV7533 support. Use DT compatible
strings to populate the ADV7533 type enum. Add minimal register
configurations belonging to the DSI/CEC register map. Keep the ADV7533
code in a separate file.
Originally worked on by Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
The driver has been converted to use drm_bridge instead of
drm_i2c_slave_encoder. We can now move it to the bridge folder.
Create a separate folder since we already have a couple of files and
expect more when we support audio and ADV7533.
Rename the driver to adv7511_drv.c. This will come in handy later
when the driver module will need to be built from multiple object
files.
Signed-off-by: Archit Taneja <architt@codeaurora.org>
