From: Manjunath Hadli <manjunath.hadli@xxxxxx> Add documentation on the Davinci VPFE driver. Document the subdevs, and private IOTCLs the driver implements Signed-off-by: Manjunath Hadli <manjunath.hadli@xxxxxx> Signed-off-by: Lad, Prabhakar <prabhakar.lad@xxxxxx> Cc: Rob Landley <rob@xxxxxxxxxxx> Cc: <linux-doc@xxxxxxxxxxxxxxx> --- Documentation/video4linux/davinci-vpfe-mc.txt | 95 +++++++++++++++++++++++++ 1 files changed, 95 insertions(+), 0 deletions(-) create mode 100644 Documentation/video4linux/davinci-vpfe-mc.txt diff --git a/Documentation/video4linux/davinci-vpfe-mc.txt b/Documentation/video4linux/davinci-vpfe-mc.txt new file mode 100644 index 0000000..9dfc4f9 --- /dev/null +++ b/Documentation/video4linux/davinci-vpfe-mc.txt @@ -0,0 +1,95 @@ +Davinci Video processing Front End (VPFE) driver + +Copyright (C) 2012 Texas Instruments Inc + +Contacts: Manjunath Hadli <manjunath.hadli@xxxxxx> + + +Introduction +============ + +This file documents the Texas Instruments Davinci Video processing Front End +(VPFE) driver located under drivers/media/platform/davinci. The original driver +exists for Davinci VPFE, which is now being changed to Media Controller +Framework. + +Currently the driver has been successfully used on the following +version of Davinci: + + DM365/DM368 + +The driver implements V4L2, Media controller and v4l2_subdev interfaces. Sensor, +lens and flash drivers using the v4l2_subdev interface in the kernel are +supported. + + +Split to subdevs +================ + +The Davinci VPFE is split into V4L2 subdevs, each of the blocks inside the VPFE +having one subdev to represent it. Each of the subdevs provide a V4L2 subdev +interface to userspace. + + DAVINCI CCDC + DAVINCI PREVIEWER + DAVINCI RESIZER + +Each possible link in the VPFE is modeled by a link in the Media controller +interface. For an example program see [1]. + + +Private IOCTLs +============== + +The Davinci Video processing Front End (VPFE) driver supports standard V4L2 +IOCTLs and controls where possible and practical. Much of the functions provided +by the VPFE, however, does not fall under the standard IOCTL's. + +In general, there is a private ioctl for configuring each of the blocks +containing hardware-dependent functions. + +The following private IOCTLs are supported: + + VIDIOC_VPFE_CCDC_[S/G]_RAW_PARAMS + VIDIOC_VPFE_PRV_[S/G]_CONFIG + VIDIOC_VPFE_RSZ_[S/G]_CONFIG + +The parameter structures used by these ioctl's are described in +include/linux/davinci_vpfe.h and include/linux/dm365_ccdc.h. + +The VIDIOC_VPFE_CCDC_S_RAW_PARAMS, VIDIOC_VPFE_PRV_S_CONFIG and +VIDIOC_VPFE_RSZ_S_CONFIG are used to configure, enable and disable functions in +the CCDC, preview and resizer blocks respectively. These IOCTL's control several +functions in the blocks they control. VIDIOC_VPFE_CCDC_S_RAW_PARAMS IOCTL +accepts a pointer to struct ccdc_config_params_raw as its argument. Similarly +VIDIOC_VPFE_PRV_S_CONFIG accepts a pointer to struct vpfe_prev_config. And +VIDIOC_VPFE_RSZ_S_CONFIG accepts a pointer to struct vpfe_rsz_config as its +argument. Similarly VIDIOC_VPFE_CCDC_G_RAW_PARAMS, VIDIOC_VPFE_PRV_G_CONFIG and +VIDIOC_VPFE_RSZ_G_CONFIG are used to get the current configuration set +in the CCDC, preview and resizer blocks respectively. + +The detailed functions of the VPFE itself related to a given VPFE block is +described in the Technical Reference Manuals (TRMs) --- see the end of the +document for those. + + +Technical reference manuals (TRMs) and other documentation +========================================================== + +Davinci DM365 TRM: +<URL:http://www.ti.com/lit/ds/sprs457e/sprs457e.pdf> +Referenced MARCH 2009-REVISED JUNE 2011 + +Davinci DM368 TRM: +<URL:http://www.ti.com/lit/ds/sprs668c/sprs668c.pdf> +Referenced APRIL 2010-REVISED JUNE 2011 + +Davinci Video Processing Front End (VPFE) DM36x +<URL:http://www.ti.com/lit/ug/sprufg8c/sprufg8c.pdf> + + +References +========== + +[1] http://git.ideasonboard.org/?p=media-ctl.git;a=summary +[2] include/linux/davinci_vpfe.h & include/linux/dm365_ccdc.h -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
