[PATCH] drm/msm/dsi: add support for dsi test pattern generator

[Marijn Suijten]

On 6/29/21 9:04 PM, Abhinav Kumar wrote:
> During board bringups its useful to have a DSI test pattern
> generator to isolate a DPU vs a DSI issue and focus on the relevant
> hardware block.
> 
> To facilitate this, add an API which triggers the DSI controller
> test pattern. The expected output is a rectangular checkered pattern.
> 
> This has been validated on a single DSI video mode panel by calling it
> right after drm_panel_enable() which is also the ideal location to use
> this as the DSI host and the panel have been initialized by then.
> 
> Further validation on dual DSI and command mode panel is pending.
> If there are any fix ups needed for those, it shall be applied on top
> of this change.
> 
> Signed-off-by: Abhinav Kumar <abhinavk at codeaurora.org>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>


Tested-by: Marijn Suijten <marijn.suijten at somainline.org>

[...]
> +static void msm_dsi_host_cmd_test_pattern_setup(struct msm_dsi_host *msm_host)
> +{
> +	u32 reg;
> +
> +	reg = dsi_read(msm_host, REG_DSI_TEST_PATTERN_GEN_CTRL);
> +
> +	dsi_write(msm_host, REG_DSI_TEST_PATTERN_GEN_CMD_MDP_INIT_VAL0, 0xff);
> +
> +	reg |= (0x3 << 0x8);
> +	dsi_write(msm_host, REG_DSI_TEST_PATTERN_GEN_CTRL, reg);
> +	/* draw checkered rectangle pattern */
> +	dsi_write(msm_host, REG_DSI_TPG_MAIN_CONTROL2, (0x1 << 0x7));


How about BIT(7)?

On SM6125 this seems to change the color intensity of the pattern; it is 
always colored lines of a few pixels wide alternating R, B and G from 
left to right.  Is it possible to document the meaning and available 
values of these registers, especially if they differ between SoC / DSI 
block?

Kind regards,
Marijn

> +	DBG("Cmd test pattern setup done\n");
> +}
[...]