Re: [PATCH v13 13/14] drm/mediatek: dpi: Add dp_intf support

On Tue, 2022-06-21 at 14:11 +0200, AngeloGioacchino Del Regno wrote:

Il 21/06/22 13:37, Bo-Chen Chen ha scritto:

...

From: Guillaume Ranquet granquet@baylibre.com

Dpintf is the displayport interface hardware unit. This unit is similar to dpi and can reuse most of the code.

This patch adds support for mt8195-dpintf to this dpi driver. Main differences are:

• 4 pixels for one round for dp_intf while dpi is 1 pixel for one

round. Therefore, we add a new config "round_pixels" to control setting of

Okay, I like where this is going, but "round_pixels" explains itself like "the pixels are round" (which doesn't make sense).

So... is this "4 pixels per iteration" (computation of 4 pixels per iteration), or "outputs 4 pixels at a time"? I can give you some ideas about a better name for this struct member, I think... ...something like "output_4pixel"?

Alternatively, we can do something even cleaner here: u8 pixels_per_round;

...where we define it like...

static const struct mtk_dpi_conf mt8195_dpintf_conf = { .pixels_per_round = 4, .......... }

static const struct mtk_dpi_conf mt8192_conf = { .pixels_per_round = 1, ......... }

... and then, in function mtk_dpi_set_display_mode(), we would have something like

/*

* Depending on the IP version, we may output a different

amount

* of pixels for each (choose: round/iteration): divide the

clock

* by this number and adjust the display porches accordingly.

*/

	vm.pixelclock = pll_rate / factor;

vm.pixelclock /= dpi->conf->pixels_per_round;

......

	hsync.sync_width = vm.hsync_len / dpi->conf->pixels_per_round;

	hsync.back_porch = vm.hback_porch / dpi->conf-

...

pixels_per_round;

	hsync.front_porch = vm.hfront_porch / dpi->conf-

...

pixels_per_round;

This would also eliminate any need to check if the IP has 4 pixels per round or if it has just 1, as in the latter case, we'd be dividing by 1 (hence, we would not be dividing anything).

Do you like this solution? :-)

Cheers, Angelo

Hello Angelo,

Thanks for the advise! After syncing with CK, I will use mothod of "pixels_per_round". This soultion is pretty good and more clear for this config.

Thanks again!

BRs, Bo-Chen

...

pixel clock and timing parameter for dp_intf.

• Input of dp_intf is two pixels per round, so we add a new

config "input_2pixel" to control this.

• Some register contents differ slightly between the two

components. To work around this I added register bits/masks with a DPINTF_ prefix and use them where different.

Based on a separate driver for dpintf created by Jitao shi jitao.shi@mediatek.com.

Signed-off-by: Markus Schneider-Pargmann msp@baylibre.com Signed-off-by: Guillaume Ranquet granquet@baylibre.com [Bo-Chen: Modify reviewers' comments.] Signed-off-by: Bo-Chen Chen rex-bc.chen@mediatek.com

---

drivers/gpu/drm/mediatek/mtk_dpi.c | 62 +++++++++++++++++++++ drivers/gpu/drm/mediatek/mtk_dpi_regs.h | 12 ++++ drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 4 ++ drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h | 1 + drivers/gpu/drm/mediatek/mtk_drm_drv.c | 3 + 5 files changed, 82 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c index ef7f828a4b1e..e562f0d55cc2 100644 --- a/drivers/gpu/drm/mediatek/mtk_dpi.c +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c @@ -131,6 +131,11 @@ struct mtk_dpi_yc_limit {

• @color_fmt_trans_support: Enable color format transfer.
• @support_direct_pin: Dpi can directly connect pins, and enable

this config

• 	to do this.
  

• • @round_pixels: Dp_intf is 4 pixels for one round while dpi is

one pixel for

• •   one round, so we need to enable this config for
    

dp_intf to do

• •   corresponding settings.
    

• • @input_2pixel: Input pixel of dp_intf is 2 pixel per round, so

enable this

• •   config to enable this feature.
    

  • @dimension_mask: Mask used for HWIDTH, HPORCH, VSYNC_WIDTH and

VSYNC_PORCH

•     (no shift).
  

• @hvsize_mask: Mask of HSIZE and VSIZE mask (no shift).

@@ -149,6 +154,8 @@ struct mtk_dpi_conf { bool swap_input_support; bool color_fmt_trans_support; bool support_direct_pin;

• bool round_pixels;
• bool input_2pixel; u32 dimension_mask; u32 hvsize_mask; u32 channel_swap_shift;

@@ -560,6 +567,14 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi, pll_rate = clk_get_rate(dpi->tvd_clk);

vm.pixelclock = pll_rate / factor;

• /*

• * For dp_intf, we need to divide clock by 4 because it's
  

• * 4 pixels for one round while dpi is 1 pixel for one round.
  

• */
  

• if (dpi->conf->round_pixels)

• vm.pixelclock /= 4;
  

• if ((dpi->output_fmt == MEDIA_BUS_FMT_RGB888_2X12_LE) || (dpi->output_fmt == MEDIA_BUS_FMT_RGB888_2X12_BE)) clk_set_rate(dpi->pixel_clk, vm.pixelclock * 2);

@@ -581,6 +596,17 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi, hsync.sync_width = vm.hsync_len; hsync.back_porch = vm.hback_porch; hsync.front_porch = vm.hfront_porch;

• /*

• * For dp_intf, we need to divide everything by 4 because it's
  

• * 4 pixels for one round while dpi is 1 pixel for one round.
  

• */
  

• if (dpi->conf->round_pixels) {

• hsync.sync_width = vm.hsync_len / 4;
  

• hsync.back_porch = vm.hback_porch / 4;
  

• hsync.front_porch = vm.hfront_porch / 4;
  

• }
• hsync.shift_half_line = false; vsync_lodd.sync_width = vm.vsync_len; vsync_lodd.back_porch = vm.vback_porch;

@@ -629,6 +655,10 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi, mtk_dpi_dual_edge(dpi); mtk_dpi_config_disable_edge(dpi); }

• if (dpi->conf->input_2pixel) {

• mtk_dpi_mask(dpi, DPI_CON, DPINTF_INPUT_2P_EN,
  

• 	     DPINTF_INPUT_2P_EN);
  

• } mtk_dpi_sw_reset(dpi, false);

  return 0;

@@ -869,6 +899,16 @@ static unsigned int mt8183_calculate_factor(int clock) return 2; }

+static unsigned int mt8195_dpintf_calculate_factor(int clock) +{

• if (clock < 70000)

• return 4;
  

• else if (clock < 200000)

• return 2;
  

• else

• return 1;
  

+}

• static const u32 mt8173_output_fmts[] = { MEDIA_BUS_FMT_RGB888_1X24, };

@@ -878,6 +918,11 @@ static const u32 mt8183_output_fmts[] = { MEDIA_BUS_FMT_RGB888_2X12_BE, };

+static const u32 mt8195_output_fmts[] = {

• MEDIA_BUS_FMT_RGB888_1X24,
• MEDIA_BUS_FMT_YUYV8_1X16,

+};

• static const struct mtk_dpi_conf mt8173_conf = { .cal_factor = mt8173_calculate_factor, .reg_h_fre_con = 0xe0,

@@ -943,6 +988,20 @@ static const struct mtk_dpi_conf mt8192_conf = { .csc_enable_bit = CSC_ENABLE, };

+static const struct mtk_dpi_conf mt8195_dpintf_conf = {

• .cal_factor = mt8195_dpintf_calculate_factor,
• .max_clock_khz = 600000,
• .output_fmts = mt8195_output_fmts,
• .num_output_fmts = ARRAY_SIZE(mt8195_output_fmts),
• .round_pixels = true,
• .input_2pixel = true,
• .dimension_mask = DPINTF_HPW_MASK,
• .hvsize_mask = DPINTF_HSIZE_MASK,
• .channel_swap_shift = DPINTF_CH_SWAP,
• .yuv422_en_bit = DPINTF_YUV422_EN,
• .csc_enable_bit = DPINTF_CSC_ENABLE,

+};

• static int mtk_dpi_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev;

@@ -1065,6 +1124,9 @@ static const struct of_device_id mtk_dpi_of_ids[] = { { .compatible = "mediatek,mt8192-dpi", .data = &mt8192_conf, },

• { .compatible = "mediatek,mt8195-dp-intf",

•  .data = &mt8195_dpintf_conf,
  

• }, { }, }; MODULE_DEVICE_TABLE(of, mtk_dpi_of_ids);