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    Subject[PATCH v8 01/10] drm/sun4i: sun6i_mipi_dsi: Compute burst mode loop N1 instruction delay
    Date
    Loop N1 instruction delay varies between burst and non-burst video modes.

    1) for burst mode panels it is computed based on the panel pixel clock
    along with horizontal sync and porch timings.
    2) for non-burst mode panels, it is same as existing (50 - 1)

    Reference code is available in BSP (from linux-sunxi
    drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c)

    dsi_dev[sel]->dsi_inst_loop_num.bits.loop_n1=
    (panel->lcd_ht-panel->lcd_x)*(150)/(panel->lcd_dclk_freq*8) - 50;
    => (((mode->htotal - mode->hdisplay) * 150) /
    ((mode->clock / 1000) * 8)) - 50;

    This patch add loop N1 computation for burst mode by simplifying
    existing code to support all possible modes.

    Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
    Tested-by: Merlijn Wajer <merlijn@wizzup.org>
    ---
    drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 20 +++++++++++++++++++-
    1 file changed, 19 insertions(+), 1 deletion(-)

    diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
    index 3a28d70dbdc1..8184fbcfd9fd 100644
    --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
    +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
    @@ -355,6 +355,24 @@ static void sun6i_dsi_inst_init(struct sun6i_dsi *dsi,
    SUN6I_DSI_INST_JUMP_CFG_NUM(1));
    };

    +static u16 sun6i_dsi_setup_inst_delay(struct sun6i_dsi *dsi,
    + struct drm_display_mode *mode)
    +{
    + struct mipi_dsi_device *device = dsi->device;
    + u32 hsync_porch, dclk;
    + u16 delay;
    +
    + hsync_porch = (mode->htotal - mode->hdisplay);
    + dclk = (mode->clock / 1000);
    +
    + if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
    + delay = ((hsync_porch * 150) / (dclk * 8)) - 50;
    + else
    + delay = 50 - 1;
    +
    + return delay;
    +}
    +
    static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi,
    struct drm_display_mode *mode)
    {
    @@ -401,7 +419,7 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
    static void sun6i_dsi_setup_inst_loop(struct sun6i_dsi *dsi,
    struct drm_display_mode *mode)
    {
    - u16 delay = 50 - 1;
    + u16 delay = sun6i_dsi_setup_inst_delay(dsi, mode);

    regmap_write(dsi->regs, SUN6I_DSI_INST_LOOP_NUM_REG(0),
    SUN6I_DSI_INST_LOOP_NUM_N0(50 - 1) |
    --
    2.18.0.321.gffc6fa0e3
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