Re: [U-Boot] [PATCH 0/8] video: Add support for SSD2828 (parallel LCD to MIPI bridge)
On Fri, 09 Jan 2015 16:35:09 +0100 Hans de Goede hdego...@redhat.com wrote: Hi, On 09-01-15 11:01, Siarhei Siamashka wrote: Hello, This patchset adds support for the Solomon Systech SSD2828 bridge chip, which is used to convert parallel LCD interface into MIPI DSI interface and drive MIPI LCD display in some tablets. In particular, this allows to have a working LCD display in my Allwinner A31s based MSI Primo81 tablet. The core of the SSD2828 support code is generic and should work with any SoC (as long as the hardware supports the standard u-boot GPIO API). It also does not have any hardcoded assumptions about the MSI Primo81 display and should be able to drive any MIPI LCD panel (as long as the number of data lanes and the bitrate per lane is provided in the config struct). The code tries to follow the standard power-up sequence described in the SSD2828 datasheet. However it has been tested only on my MSI Primo81 tablet so far. The sunxi specific part includes a small glue code in the sunxi display driver and the defconfig update for the MSI Primo81 tablet. This can be applied after http://lists.denx.de/pipermail/u-boot/2015-January/200753.html 'sunxi: video: Add lvds support' patchset to the 'next' branch in the u-boot-sunxi repository. And here is a bonus picture :-) http://linux-sunxi.org/File:MSI_Primo81_and_LCD_support_in_u-boot.jpg Cool :) Siarhei Siamashka (8): sunxi: axp221: Add ELDO[1-3] support include: Add header file with MIPI DSI constants from the Linux kernel video: Add support for SSD2828 (parallel LCD to MIPI bridge) video: sunxi: Hook up SSD2828 with the sunxi video driver sun6i: Add LCD display support for MSI Primo81 tablet video: ssd2828: Allow using 'pclk' as the PLL clock source video: sunxi: Switch from 'tx_clk' to 'pclk' for SSD2828 video: ssd2828: Use MIPI DCS commands to retrieve the LCD panel id Thanks for working on this! Overall this looks good. Looks like you did a better job then I did with the Hitachi tx18d42vm LCD panel support, esp. wrt making things generic rather then sunxi specific. So assuming the Ian will ack v2 of my lvds patch I suggest that we merge my lvds patch, then your patches (pending an ack from Anatolij) and then I respin my Hitachi tx18d42vm LCD panel patch following your patches as an example. I've also reviewed all of your patches. I've one change request, can you please move all of the board/sunxi/Kconfig changes except for the last hunk to drivers/video/Kconfig, if we go the generic route we should also make the Kconfig stuff generic. This also means dropping the select VIDEO_LCD_IF_PARALLEL from config VIDEO_LCD_SSD2828 and adding it to config VIDEO_LCD_PANEL_MIPI_4_LANE_513_MBPS_VIA_SSD2828, as that option is the only one which will stay in board/sunxi/Kconfig and VIDEO_LCD_IF_PARALLEL is sunxi specific. The changes to drivers/video/Kconfig should then become part of the video: Add support for SSD2828 (parallel LCD to MIPI bridge) commit. Thanks. This sounds like a good plan. Will do it. With that changed patches 1-7 are: Acked-by: Hans de Goede hdego...@redhat.com I'm not 100% sure about patch 8, I can see this being useful for debugging but not for normal use, and as you said it may (theoretically) be unsafe with some panels. Maybe keep the patch, but #ifdef DEBUG the entire code block it adds ? I'm also somewhat disappointed by the panel id reading functionality provided by MIPI. I surely had better expectations. But the standard MIPI_DCS_GET_DISPLAY_ID and MIPI_DCS_READ_DDB_START commands still could be safely used, even though they do not happen to return anything interesting on MSI Primo81. The non-standard commands are indeed potentially unsafe and could be probably hidden under a Kconfig option (are we adding too many of them?) or under #ifdef DEBUG. After posting the patch series, I have also noticed that the http://linux-sunxi.org/ICOU_Fatty_I tablet is also using SSD2828. Appears that 'lcd_if=4' in the A20 FEX dialect means the same as 'lcd_if=6' in the A31 FEX dialect. This Fatty tablet is using 6 gpio pins for LCD configuration (compared to just 4 pins in Primo81). One is an extra reset pin (ssd2828 reset and lcd panel reset are handled separately). One more pin is set as output and driven low (maybe something related to enabling ssd2828 power on A20?). I have contacted the tablet owner to ask about this tablet whereabouts and would really like to get test results from this Fatty tablet before landing the ssd2828 patches. Hopefully it's a matter of a few days at most. Additionally, the Allwinner reference A20 tablet schematics (a20_pad_std_v1_1.pdf on the Internet) has a page dedicated to the use of SSD2828QN4, which is very insightful. I wish I had discovered this earlier. -- Best regards, Siarhei Siamashka ___ U-Boot mailing
Re: [U-Boot] [PATCH 0/8] video: Add support for SSD2828 (parallel LCD to MIPI bridge)
Hi, On 09-01-15 16:35, Hans de Goede wrote: Hi, On 09-01-15 11:01, Siarhei Siamashka wrote: Hello, This patchset adds support for the Solomon Systech SSD2828 bridge chip, which is used to convert parallel LCD interface into MIPI DSI interface and drive MIPI LCD display in some tablets. In particular, this allows to have a working LCD display in my Allwinner A31s based MSI Primo81 tablet. The core of the SSD2828 support code is generic and should work with any SoC (as long as the hardware supports the standard u-boot GPIO API). It also does not have any hardcoded assumptions about the MSI Primo81 display and should be able to drive any MIPI LCD panel (as long as the number of data lanes and the bitrate per lane is provided in the config struct). The code tries to follow the standard power-up sequence described in the SSD2828 datasheet. However it has been tested only on my MSI Primo81 tablet so far. The sunxi specific part includes a small glue code in the sunxi display driver and the defconfig update for the MSI Primo81 tablet. This can be applied after http://lists.denx.de/pipermail/u-boot/2015-January/200753.html 'sunxi: video: Add lvds support' patchset to the 'next' branch in the u-boot-sunxi repository. And here is a bonus picture :-) http://linux-sunxi.org/File:MSI_Primo81_and_LCD_support_in_u-boot.jpg Cool :) I've just pushed v2 of my lvds-patch to u-boot-sunxi/next with Anatolij's ack, and I see that Anatolij has also reviewed this series, when you do a v2 please base it on top of u-boot-sunxi/next. Thanks, Hans ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 0/8] video: Add support for SSD2828 (parallel LCD to MIPI bridge)
On Fri, 2015-01-09 at 16:35 +0100, Hans de Goede wrote: So assuming the Ian will ack v2 of my lvds patch Just done, assuming those were the patches you meant... With that changed patches 1-7 are: Acked-by: Hans de Goede hdego...@redhat.com Hence I wasn't planning on looking into this series further, please let me know if my opinion is wanted... Ian. ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 0/8] video: Add support for SSD2828 (parallel LCD to MIPI bridge)
Hi, On 09-01-15 11:01, Siarhei Siamashka wrote: Hello, This patchset adds support for the Solomon Systech SSD2828 bridge chip, which is used to convert parallel LCD interface into MIPI DSI interface and drive MIPI LCD display in some tablets. In particular, this allows to have a working LCD display in my Allwinner A31s based MSI Primo81 tablet. The core of the SSD2828 support code is generic and should work with any SoC (as long as the hardware supports the standard u-boot GPIO API). It also does not have any hardcoded assumptions about the MSI Primo81 display and should be able to drive any MIPI LCD panel (as long as the number of data lanes and the bitrate per lane is provided in the config struct). The code tries to follow the standard power-up sequence described in the SSD2828 datasheet. However it has been tested only on my MSI Primo81 tablet so far. The sunxi specific part includes a small glue code in the sunxi display driver and the defconfig update for the MSI Primo81 tablet. This can be applied after http://lists.denx.de/pipermail/u-boot/2015-January/200753.html 'sunxi: video: Add lvds support' patchset to the 'next' branch in the u-boot-sunxi repository. And here is a bonus picture :-) http://linux-sunxi.org/File:MSI_Primo81_and_LCD_support_in_u-boot.jpg Cool :) Siarhei Siamashka (8): sunxi: axp221: Add ELDO[1-3] support include: Add header file with MIPI DSI constants from the Linux kernel video: Add support for SSD2828 (parallel LCD to MIPI bridge) video: sunxi: Hook up SSD2828 with the sunxi video driver sun6i: Add LCD display support for MSI Primo81 tablet video: ssd2828: Allow using 'pclk' as the PLL clock source video: sunxi: Switch from 'tx_clk' to 'pclk' for SSD2828 video: ssd2828: Use MIPI DCS commands to retrieve the LCD panel id Thanks for working on this! Overall this looks good. Looks like you did a better job then I did with the Hitachi tx18d42vm LCD panel support, esp. wrt making things generic rather then sunxi specific. So assuming the Ian will ack v2 of my lvds patch I suggest that we merge my lvds patch, then your patches (pending an ack from Anatolij) and then I respin my Hitachi tx18d42vm LCD panel patch following your patches as an example. I've also reviewed all of your patches. I've one change request, can you please move all of the board/sunxi/Kconfig changes except for the last hunk to drivers/video/Kconfig, if we go the generic route we should also make the Kconfig stuff generic. This also means dropping the select VIDEO_LCD_IF_PARALLEL from config VIDEO_LCD_SSD2828 and adding it to config VIDEO_LCD_PANEL_MIPI_4_LANE_513_MBPS_VIA_SSD2828, as that option is the only one which will stay in board/sunxi/Kconfig and VIDEO_LCD_IF_PARALLEL is sunxi specific. The changes to drivers/video/Kconfig should then become part of the video: Add support for SSD2828 (parallel LCD to MIPI bridge) commit. With that changed patches 1-7 are: Acked-by: Hans de Goede hdego...@redhat.com I'm not 100% sure about patch 8, I can see this being useful for debugging but not for normal use, and as you said it may (theoretically) be unsafe with some panels. Maybe keep the patch, but #ifdef DEBUG the entire code block it adds ? Regards, Hans ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
[U-Boot] [PATCH 0/8] video: Add support for SSD2828 (parallel LCD to MIPI bridge)
Hello, This patchset adds support for the Solomon Systech SSD2828 bridge chip, which is used to convert parallel LCD interface into MIPI DSI interface and drive MIPI LCD display in some tablets. In particular, this allows to have a working LCD display in my Allwinner A31s based MSI Primo81 tablet. The core of the SSD2828 support code is generic and should work with any SoC (as long as the hardware supports the standard u-boot GPIO API). It also does not have any hardcoded assumptions about the MSI Primo81 display and should be able to drive any MIPI LCD panel (as long as the number of data lanes and the bitrate per lane is provided in the config struct). The code tries to follow the standard power-up sequence described in the SSD2828 datasheet. However it has been tested only on my MSI Primo81 tablet so far. The sunxi specific part includes a small glue code in the sunxi display driver and the defconfig update for the MSI Primo81 tablet. This can be applied after http://lists.denx.de/pipermail/u-boot/2015-January/200753.html 'sunxi: video: Add lvds support' patchset to the 'next' branch in the u-boot-sunxi repository. And here is a bonus picture :-) http://linux-sunxi.org/File:MSI_Primo81_and_LCD_support_in_u-boot.jpg Siarhei Siamashka (8): sunxi: axp221: Add ELDO[1-3] support include: Add header file with MIPI DSI constants from the Linux kernel video: Add support for SSD2828 (parallel LCD to MIPI bridge) video: sunxi: Hook up SSD2828 with the sunxi video driver sun6i: Add LCD display support for MSI Primo81 tablet video: ssd2828: Allow using 'pclk' as the PLL clock source video: sunxi: Switch from 'tx_clk' to 'pclk' for SSD2828 video: ssd2828: Use MIPI DCS commands to retrieve the LCD panel id board/sunxi/Kconfig | 60 + board/sunxi/board.c | 1 + configs/MSI_Primo81_defconfig | 9 + drivers/power/Kconfig | 10 + drivers/power/axp221.c | 51 drivers/video/Makefile | 1 + drivers/video/ssd2828.c | 575 drivers/video/ssd2828.h | 128 + drivers/video/sunxi_display.c | 3 + drivers/video/sunxi_lcd_panel.c | 37 +++ drivers/video/sunxi_lcd_panel.h | 3 + include/axp221.h| 9 + include/mipi_display.h | 130 + 13 files changed, 1017 insertions(+) create mode 100644 drivers/video/ssd2828.c create mode 100644 drivers/video/ssd2828.h create mode 100644 include/mipi_display.h -- 2.0.5 ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 0/8] video: Add support for SSD2828 (parallel LCD to MIPI bridge)
On Fri, 9 Jan 2015 12:01:08 +0200 Siarhei Siamashka siarhei.siamas...@gmail.com wrote: Hello, This patchset adds support for the Solomon Systech SSD2828 bridge chip, which is used to convert parallel LCD interface into MIPI DSI interface and drive MIPI LCD display in some tablets. In particular, this allows to have a working LCD display in my Allwinner A31s based MSI Primo81 tablet. The core of the SSD2828 support code is generic and should work with any SoC (as long as the hardware supports the standard u-boot GPIO API). It also does not have any hardcoded assumptions about the MSI Primo81 display and should be able to drive any MIPI LCD panel (as long as the number of data lanes and the bitrate per lane is provided in the config struct). The code tries to follow the standard power-up sequence described in the SSD2828 datasheet. However it has been tested only on my MSI Primo81 tablet so far. The sunxi specific part includes a small glue code in the sunxi display driver and the defconfig update for the MSI Primo81 tablet. This can be applied after http://lists.denx.de/pipermail/u-boot/2015-January/200753.html 'sunxi: video: Add lvds support' patchset to the 'next' branch in the u-boot-sunxi repository. And here is a bonus picture :-) http://linux-sunxi.org/File:MSI_Primo81_and_LCD_support_in_u-boot.jpg Siarhei Siamashka (8): sunxi: axp221: Add ELDO[1-3] support include: Add header file with MIPI DSI constants from the Linux kernel video: Add support for SSD2828 (parallel LCD to MIPI bridge) video: sunxi: Hook up SSD2828 with the sunxi video driver sun6i: Add LCD display support for MSI Primo81 tablet video: ssd2828: Allow using 'pclk' as the PLL clock source video: sunxi: Switch from 'tx_clk' to 'pclk' for SSD2828 video: ssd2828: Use MIPI DCS commands to retrieve the LCD panel id board/sunxi/Kconfig | 60 + board/sunxi/board.c | 1 + configs/MSI_Primo81_defconfig | 9 + drivers/power/Kconfig | 10 + drivers/power/axp221.c | 51 drivers/video/Makefile | 1 + drivers/video/ssd2828.c | 575 drivers/video/ssd2828.h | 128 + drivers/video/sunxi_display.c | 3 + drivers/video/sunxi_lcd_panel.c | 37 +++ drivers/video/sunxi_lcd_panel.h | 3 + include/axp221.h| 9 + include/mipi_display.h | 130 + 13 files changed, 1017 insertions(+) create mode 100644 drivers/video/ssd2828.c create mode 100644 drivers/video/ssd2828.h create mode 100644 include/mipi_display.h Also a short recap of the events from the last days, which led to this patch set: 1. Trying to see what needs to be done to support LCD on the MSI Primo81 tablet, I had a look into the Allwinner android kernel code from the A31 SDK. That code was pushing a small semi-magic blob through SPI, interleaved with a few magic delays. In fact the Allwinner code supports two different LCD panels in this way (768x1024 and another one 1280x800), each panel having its own blob. 2. The most useful part of the Allwinner code was a reference to ssd2828_rst, which gave away the name of the chip. Having the documentation for the hardware is great, because it allows to at least convert the magic numbers into proper named constants. 3. Also it turned out that the MISO pin is actually wired up in the MSI Primo81 tablet, even though the Allwinner android code never uses it and there are no references to this pin in the FEX file. So the SSD2828 hardware can actually talk back, and it was really easy to confirm that the hardware was indeed SSD2828. 4. If the SSD2828 chip can talk back, then maybe the LCD panel can talk back too? The B079XAN01.0 LCD panel datasheet had a teaser notice in the Power ON/OFF Sequence section: HS clock enable to vendor ID reading. 5. Now the question is: how to do this vendor ID reading? In fact MIPI specifies some standard commands exactly for this. So everything is supposedly very easy. Except that trying to use the standard panel id retrieval commands resulted in the panel just responding with a single zero byte. This (mis)led me to believe that there might have been something wrong with the clock speed setting, PHY tuning delays or other things, which could cause some sort of transmission failures in the reverse direction. Especially considering the hints that tLPX(MASTER) and tLPX(SLAVE) must be accurately matched. 6. Been reading a mountain of various MIPI related information about the communication protocol on both the PHY and higher level... 7. As nothing seemed to be obviously wrong, tried to search for the MIPI vendor ID reading methods again. Found hints that the vendors tend to be (ab)using the DCS commands and inventing something of their own. Such as
