On 07/29/2014 02:57 AM, YoungJun Cho wrote: > Hi Andrzej, > > On 07/29/2014 01:09 AM, Andrzej Hajda wrote: >> On 07/28/2014 04:00 AM, Inki Dae wrote: >>> This patch adds below two flags for LPM transfer, and it attaches LPM flags >>> to a msg in accordance with master's mode_flags set by LCD Panel driver. >>> >>> MIPI_DSI_MODE_CMD_LPM >>> - If this flag is set by Panel driver, MIPI-DSI controller will tranfer >>> command data to Panel device in Low Power Mode. >> What do you mean by command data? It could be: >> - all transfer in command mode of operations, >> - transfer initialized by the driver by writing to DSIM registers. > The 2nd one. > >>> MIPI_DSI_MODE_VIDEO_LPM >>> - If this flag is set by Panel driver, MIPI-DSI controller will tranfer >>> image data to Panel device in Low Power Mode. >> What is the meaning of this flag in case of command mode of operation? > I'm also not sure that there is a case to transfer image data in Low > Power Mode, but this flag is not related with 'command mode' only. > Inki may consider generic condition. > >> Maybe it would be better to create flags based on source of data/FIFOs: >> - commands send by SFR registers, >> - commands generated from data sent from Display Controller. >> >> >>> And above two flags can be combined together to transfer command and video >>> data to Panel device. >>> >>> MIPI DSI spec says, >>> "the host processor controls the desired mode of clock operation. >>> Host protocol and applications control Clock Lane operating mode >>> (High Speed or Low Power mode). System designers are responsible >>> for understanding the clock requirements for peripherals attached >>> to DSI and controlling clock behavior in accordance with those >>> requirements." >>> >>> Some LCD Panel devices, nt35502a, would need LPM transfer support >>> because they should receive some initial commands with LPM by default >>> hardware setting. >> >> Is this requirement for initial commands, or for all commands. >> Btw what is the mode of operation of nt35502a? What flags do you need >> for it? >> > The nt35502a panel is video(RGB) mode panel and it requires low power > mode for initial commands, which means to initialize nt35502a panel, the > initial commands are transferred by LP mode(Not HS mode). > And after initialization, its other features like gamma control or etc > could be controlled in HS mode. It sounds similar to my tc358764 bridge driver [1]. The difference is that it uses only MIPI_DSI_GENERIC_LONG_(WRITE|READ) in LPM. As I understand nt35502a requires also different driving of TxRequestHSClk signal and this seems to me unrelated to LPM. As LPM is not related at all with HS clock, AFAIK. Regards Andrzej [1]: http://permalink.gmane.org/gmane.linux.drivers.devicetree/61559 > > Thank you. > Best regards YJ > >> >>> Changelog v2: just add more descriptions. >>> >>> Signed-off-by: Inki Dae <inki.dae@xxxxxxxxxxx> >>> Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> >>> --- >>> drivers/gpu/drm/drm_mipi_dsi.c | 3 +++ >>> include/drm/drm_mipi_dsi.h | 4 ++++ >>> 2 files changed, 7 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c >>> index e633df2..6b2bbda 100644 >>> --- a/drivers/gpu/drm/drm_mipi_dsi.c >>> +++ b/drivers/gpu/drm/drm_mipi_dsi.c >>> @@ -232,6 +232,9 @@ int mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel, >>> break; >>> } >>> >>> + if (dsi->mode_flags & MIPI_DSI_MODE_CMD_LPM) >>> + msg.flags = MIPI_DSI_MSG_USE_LPM; >>> + >>> return ops->transfer(dsi->host, &msg); >>> } >> Shouldn't this be also the same for dcs read? >> >> Anyway I think check in the DSIM should be used instead, as panel driver >> can issue other dsi transfers without MIPI_DSI_MSG_USE_LPM flag set. >> >> Regards >> Andrzej >> >> >>> EXPORT_SYMBOL(mipi_dsi_dcs_write); >>> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h >>> index 944f33f..1c41e49 100644 >>> --- a/include/drm/drm_mipi_dsi.h >>> +++ b/include/drm/drm_mipi_dsi.h >>> @@ -94,6 +94,10 @@ void mipi_dsi_host_unregister(struct mipi_dsi_host *host); >>> #define MIPI_DSI_MODE_VSYNC_FLUSH BIT(8) >>> /* disable EoT packets in HS mode */ >>> #define MIPI_DSI_MODE_EOT_PACKET BIT(9) >>> +/* command low power mode */ >>> +#define MIPI_DSI_MODE_CMD_LPM BIT(10) >>> +/* video low power mode */ >>> +#define MIPI_DSI_MODE_VIDEO_LPM BIT(11) >>> >>> enum mipi_dsi_pixel_format { >>> MIPI_DSI_FMT_RGB888, >>> >> _______________________________________________ >> dri-devel mailing list >> dri-devel@xxxxxxxxxxxxxxxxxxxxx >> http://lists.freedesktop.org/mailman/listinfo/dri-devel >> > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
