[PATCH v2] drm/bridge:anx7625: Enable DSC feature
Xin Ji
xji at analogixsemi.com
Mon Mar 31 05:44:58 UTC 2025
> > 4K30(3840x2160 30Hz) timing pixel clock around 297M, for 24bits RGB
> > pixel data format, total transport bandwidth need 297M*24(at least
> > 7.2Gbps) more than anx7625 mipi rx lane bandwidth(maximum 6Gbps,
> > 4lanes, each lane 1.5Gbps). Without DSC function, anx7625 cannot
> > receive 4K30 video timing.
> >
> > When display pixel clock exceed 250M, driver will enable DSC feature,
> > and the compression ratio is 3:1, eg: 4K30's pixel clock around 297M,
> > bandwidth 7.2G will be compressed to 7.2G/3 = 2.4G. Then anx7625 can
> > receive 4K30 video timing and do decompress, then package video data
> > and send to sink device through DP link.
> >
> > Anx7625 is bridge IC, sink monitor only receive normal DP signal from
> > anx7625, sink device didn't know DSC information between SOC and
> > anx7625
> >
> > v2:
> > 1. Add more commit message
> > 2. Remove unused code
> > 3. Add more comment
>
> This part is useless, it adds no information. It is as good as 'changed it'.
OK, I'll remove it
>
> > 4. Remove dsc_en flag
> >
> > Signed-off-by: Xin Ji <xji at analogixsemi.com>
> > ---
> > drivers/gpu/drm/bridge/analogix/anx7625.c | 299
> > ++++++++++++++++++---- drivers/gpu/drm/bridge/analogix/anx7625.h |
> > 31 +++
> > 2 files changed, 274 insertions(+), 56 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > index 4be34d5c7a3b..bae76d9a665f 100644
> > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > @@ -9,6 +9,7 @@
> > #include <linux/interrupt.h>
> > #include <linux/iopoll.h>
> > #include <linux/kernel.h>
> > +#include <linux/math64.h>
> > #include <linux/module.h>
> > #include <linux/mutex.h>
> > #include <linux/pm_runtime.h>
> > @@ -22,6 +23,7 @@
> >
> > #include <drm/display/drm_dp_aux_bus.h> #include
> > <drm/display/drm_dp_helper.h>
> > +#include <drm/display/drm_dsc_helper.h>
> > #include <drm/display/drm_hdcp_helper.h> #include
> > <drm/drm_atomic_helper.h> #include <drm/drm_bridge.h> @@ -476,11
> > +478,159 @@ static int anx7625_set_k_value(struct anx7625_data *ctx)
> > MIPI_DIGITAL_ADJ_1, 0x3D); }
> >
> > +static bool anx7625_dsc_check(struct anx7625_data *ctx) {
> > + if (ctx->dt.pixelclock.min > DSC_PIXEL_CLOCK)
> > + return true;
>
> So, now DSC is enabled unconditionally just because the clock is too high. Let's
> see...
Yes
>
> > +
> > + return false;
> > +}
> > +
> > +static inline int anx7625_h_timing_reg_write(struct anx7625_data *ctx,
> > + struct i2c_client *client,
> > + u8 reg_addr, u16 val,
> > + bool dsc_check) {
> > + int ret;
> > +
> > + if (dsc_check && anx7625_dsc_check(ctx))
> > + val = dsc_div(val);
> > +
> > + ret = anx7625_reg_write(ctx, client, reg_addr, val);
> > + ret |= anx7625_reg_write(ctx, client, reg_addr + 1, val >> 8);
> > +
> > + return ret;
> > +}
> > +
> > +static int anx7625_h_timing_write(struct anx7625_data *ctx,
> > + struct i2c_client *client,
> > + bool rx_h_timing) {
> > + u16 htotal;
> > + int ret;
> > +
> > + htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > + ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > + /* Htotal */
> > + ret = anx7625_h_timing_reg_write(ctx, client,
> HORIZONTAL_TOTAL_PIXELS_L,
> > + htotal, rx_h_timing);
> > + /* Hactive */
> > + ret |= anx7625_h_timing_reg_write(ctx, client,
> HORIZONTAL_ACTIVE_PIXELS_L,
> > + ctx->dt.hactive.min, rx_h_timing);
> > + /* HFP */
> > + ret |= anx7625_h_timing_reg_write(ctx, client,
> HORIZONTAL_FRONT_PORCH_L,
> > + ctx->dt.hfront_porch.min, rx_h_timing);
> > + /* HWS */
> > + ret |= anx7625_h_timing_reg_write(ctx, client,
> HORIZONTAL_SYNC_WIDTH_L,
> > + ctx->dt.hsync_len.min, rx_h_timing);
> > + /* HBP */
> > + ret |= anx7625_h_timing_reg_write(ctx, client,
> HORIZONTAL_BACK_PORCH_L,
> > + ctx->dt.hback_porch.min,
> > + rx_h_timing);
> > +
> > + return ret;
> > +}
> > +
> > +static int anx7625_v_timing_write(struct anx7625_data *ctx,
> > + struct i2c_client *client) {
> > + int ret;
> > +
> > + /* Vactive */
> > + ret = anx7625_reg_write(ctx, client, ACTIVE_LINES_L,
> > + ctx->dt.vactive.min);
> > + ret |= anx7625_reg_write(ctx, client, ACTIVE_LINES_H,
> > + ctx->dt.vactive.min >> 8);
> > + /* VFP */
> > + ret |= anx7625_reg_write(ctx, client, VERTICAL_FRONT_PORCH,
> > + ctx->dt.vfront_porch.min);
> > + /* VWS */
> > + ret |= anx7625_reg_write(ctx, client, VERTICAL_SYNC_WIDTH,
> > + ctx->dt.vsync_len.min);
> > + /* VBP */
> > + ret |= anx7625_reg_write(ctx, client, VERTICAL_BACK_PORCH,
> > + ctx->dt.vback_porch.min);
> > +
> > + return ret;
> > +}
> > +
> > +static int anx7625_set_dsc_params(struct anx7625_data *ctx) {
> > + int ret, i;
> > + u16 htotal, vtotal;
> > +
> > + if (!anx7625_dsc_check(ctx))
> > + return 0;
> > +
> > + /* Video Horizontal timing */
> > + ret = anx7625_h_timing_write(ctx, ctx->i2c.tx_p2_client, false);
> > +
> > + /* Video Vertical timing */
> > + ret |= anx7625_v_timing_write(ctx, ctx->i2c.tx_p2_client);
> > +
> > + /* Vtotal */
> > + vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> > + ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_L,
> > + vtotal);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_H,
> > + vtotal >> 8);
> > + /* Htotal */
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_L_7E,
> > + htotal);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_H_7E,
> > + htotal >> 8);
> > + /* Hactive */
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> > + /* HFP */
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + HORIZON_FRONT_PORCH_L_7E,
> > + ctx->dt.hfront_porch.min);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + HORIZON_FRONT_PORCH_H_7E,
> > + ctx->dt.hfront_porch.min >> 8);
> > + /* HWS */
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + HORIZON_SYNC_WIDTH_L_7E,
> > + ctx->dt.hsync_len.min);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + HORIZON_SYNC_WIDTH_H_7E,
> > + ctx->dt.hsync_len.min >> 8);
> > + /* HBP */
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + HORIZON_BACK_PORCH_L_7E,
> > + ctx->dt.hback_porch.min);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + HORIZON_BACK_PORCH_H_7E,
> > + ctx->dt.hback_porch.min >> 8);
> > +
> > + /* Config DSC decoder internal blank timing for decoder to start */
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > + H_BLANK_L,
> > + dsc_div(htotal - ctx->dt.hactive.min));
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > + H_BLANK_H,
> > + dsc_div(htotal - ctx->dt.hactive.min)
> > + >> 8);
> > +
> > + /* Compress ratio RATIO bit[7:6] */
> > + ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1, 0x3F);
> > + ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > + (5 - DSC_COMPRESS_RATIO) << 6);
> > + /*PPS table*/
> > + for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> > + ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> > + R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
> > + &ctx->pps_table[i]);
> > +
> > + return ret;
> > +}
> > +
> > static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
> > {
> > struct device *dev = ctx->dev;
> > unsigned long m, n;
> > - u16 htotal;
> > int ret;
> > u8 post_divider = 0;
> >
> > @@ -506,48 +656,12 @@ static int anx7625_dsi_video_timing_config(struct
> anx7625_data *ctx)
> > ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> > MIPI_LANE_CTRL_0, ctx->pdata.mipi_lanes
> > - 1);
> >
> > - /* Htotal */
> > - htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > - ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > - /* Hactive */
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min & 0xFF);
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> > - /* HFP */
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min);
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_FRONT_PORCH_H,
> > - ctx->dt.hfront_porch.min >> 8);
> > - /* HWS */
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >> 8);
> > - /* HBP */
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >> 8);
> > - /* Vactive */
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_L,
> > - ctx->dt.vactive.min);
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_H,
> > - ctx->dt.vactive.min >> 8);
> > - /* VFP */
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> > - /* VWS */
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> > - /* VBP */
> > - ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > - VERTICAL_BACK_PORCH, ctx->dt.vback_porch.min);
> > + /* Video Horizontal timing */
> > + ret |= anx7625_h_timing_write(ctx, ctx->i2c.rx_p2_client, true);
> > +
> > + /* Video Vertical timing */
> > + ret |= anx7625_v_timing_write(ctx, ctx->i2c.rx_p2_client);
> > +
>
> Please split this part into two commits: one refactoring timing programming into
> two functions and another one introducing DSC support.
> It is hard to review timing programming otherwise.
OK
>
> > /* M value */
> > ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > MIPI_PLL_M_NUM_23_16, (m >> 16) & 0xff); @@
> > -663,9 +777,15 @@ static int anx7625_dsi_config(struct anx7625_data
> > *ctx)
> >
> > DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> >
> > - /* DSC disable */
> > - ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > - R_DSC_CTRL_0, ~DSC_EN);
> > + ret = anx7625_set_dsc_params(ctx);
> > + if (anx7625_dsc_check(ctx))
> > + /* DSC enable */
> > + ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > + R_DSC_CTRL_0, DSC_EN);
> > + else
> > + /* DSC disable */
> > + ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > + R_DSC_CTRL_0, ~DSC_EN);
> >
> > ret |= anx7625_api_dsi_config(ctx);
> >
> > @@ -2083,6 +2203,7 @@ static int anx7625_setup_dsi_device(struct
> anx7625_data *ctx)
> > MIPI_DSI_MODE_VIDEO_HSE |
> > MIPI_DSI_HS_PKT_END_ALIGNED;
> >
> > + dsi->dsc = &ctx->dsc;
> > ctx->dsi = dsi;
> >
> > return 0;
> > @@ -2187,19 +2308,69 @@ anx7625_bridge_mode_valid(struct drm_bridge
> *bridge,
> > struct device *dev = ctx->dev;
> >
> > DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> > + if (mode->clock > SUPPORT_PIXEL_CLOCK)
> > + return MODE_CLOCK_HIGH;
> > +
> > + if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> > + return MODE_CLOCK_LOW;
> >
> > - /* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> > - if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> > - DRM_DEV_DEBUG_DRIVER(dev,
> > - "drm mode invalid, pixelclock too high.\n");
>
> Any reason for dropping debug message?
I'll keep this message.
>
> > + /*
> > + * If hdisplay cannot be divided by DSC compress ratio, then display
> > + * will have overlap/shift issue
> > + */
> > + if (mode->clock > DSC_PIXEL_CLOCK &&
> > + (mode->hdisplay % DSC_COMPRESS_RATIO != 0))
>
>
> ... and there still no check that the DSI host supports generating DSC data. Nor
> there is an atomic_check() that will check if the mode can be enabled.
I cannot know whether the DSI host supports DSC or not. Anx7625 driver force
enable DSC feature if pixel clock higher than DSC_PIXEL_CLOCK.
>
> > return MODE_CLOCK_HIGH;
> > - }
> >
> > DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> >
> > return MODE_OK;
> > }
> >
> > +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en) {
> > + int ret;
> > + struct device *dev = ctx->dev;
> > +
> > + if (en) {
> > + ctx->dsc.dsc_version_major = 1;
> > + ctx->dsc.dsc_version_minor = 1;
> > + ctx->dsc.slice_height = 8;
> > + ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
> > + ctx->dsc.slice_count = DSC_SLICE_NUM;
> > + ctx->dsc.bits_per_component = 8;
> > + ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> > + ctx->dsc.block_pred_enable = true;
> > + ctx->dsc.native_420 = false;
> > + ctx->dsc.native_422 = false;
> > + ctx->dsc.simple_422 = false;
> > + ctx->dsc.vbr_enable = false;
> > + ctx->dsc.convert_rgb = 1;
> > + ctx->dsc.vbr_enable = 0;
>
> Aren't those 'false' and '0' defaults? If so, you don't need to write those fields.
Ok
>
> > +
> > + drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> > + drm_dsc_set_const_params(&ctx->dsc);
> > +
> > + ctx->dsc.initial_scale_value = drm_dsc_initial_scale_value(&ctx->dsc);
> > + ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
> > + ret = drm_dsc_setup_rc_params(&ctx->dsc, DRM_DSC_1_2_444);
> > + if (ret < 0)
> > + dev_warn(dev, "drm_dsc_setup_rc_params ret
> > + %d\n", ret);
> > +
> > + ret = drm_dsc_compute_rc_parameters(&ctx->dsc);
> > + if (ret)
> > + dev_warn(dev, "drm dsc compute rc parameters
> > + failed ret %d\n", ret);
> > +
> > + drm_dsc_pps_payload_pack((struct drm_dsc_picture_parameter_set
> *)&ctx->pps_table,
> > + &ctx->dsc);
> > + dev_dbg(dev, "anx7625 enable dsc\n");
> > + } else {
> > + ctx->dsc.dsc_version_major = 0;
> > + ctx->dsc.dsc_version_minor = 0;
> > + dev_dbg(dev, "anx7625 disable dsc\n");
> > + }
> > +}
> > +
> > static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> > const struct drm_display_mode *old_mode,
> > const struct drm_display_mode *mode)
> > @@ -2244,6 +2415,8 @@ static void anx7625_bridge_mode_set(struct
> drm_bridge *bridge,
> > DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> > mode->vsync_end,
> > mode->vtotal);
> > +
> > + anx7625_dsc_enable(ctx, anx7625_dsc_check(ctx));
> > }
> >
> > static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge, @@
> > -2258,10 +2431,6 @@ static bool anx7625_bridge_mode_fixup(struct
> > drm_bridge *bridge,
> >
> > DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
> >
> > - /* No need fixup for external monitor */
> > - if (!ctx->pdata.panel_bridge)
> > - return true;
> > -
> > hsync = mode->hsync_end - mode->hsync_start;
> > hfp = mode->hsync_start - mode->hdisplay;
> > hbp = mode->htotal - mode->hsync_end; @@ -2272,12 +2441,24 @@
> > static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
> > hsync, hfp, hbp, adj->clock);
> > DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> htot(%d)\n",
> > adj->hsync_start, adj->hsync_end,
> > adj->htotal);
> > -
> > adj_hfp = hfp;
> > adj_hsync = hsync;
> > adj_hbp = hbp;
> > adj_hblanking = hblanking;
> >
> > + if (mode->clock > DSC_PIXEL_CLOCK) {
> > + adj_hsync = DSC_HSYNC_LEN;
> > + adj_hfp = DSC_HFP_LEN;
> > + adj_hbp = DSC_HBP_LEN;
> > + vref = (u32)div_u64((u64)adj->clock * 1000 * 1000,
> > + adj->htotal * adj->vtotal);
> > + goto calculate_timing;
> > + }
> > +
> > + /* No need fixup for external monitor */
> > + if (!ctx->pdata.panel_bridge)
> > + return true;
> > +
> > /* HFP needs to be even */
> > if (hfp & 0x1) {
> > adj_hfp += 1;
> > @@ -2349,6 +2530,8 @@ static bool anx7625_bridge_mode_fixup(struct
> drm_bridge *bridge,
> > adj_hfp -= delta_adj;
> > }
> >
> > +calculate_timing:
> > +
> > DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> > DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> clock(%d)\n",
> > adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > @@ -2357,6 +2540,10 @@ static bool anx7625_bridge_mode_fixup(struct
> drm_bridge *bridge,
> > adj->hsync_start = adj->hdisplay + adj_hfp;
> > adj->hsync_end = adj->hsync_start + adj_hsync;
> > adj->htotal = adj->hsync_end + adj_hbp;
> > + if (mode->clock > DSC_PIXEL_CLOCK)
> > + adj->clock = (u32)div_u64((u64)vref * adj->htotal * adj->vtotal,
> > + 1000 * 1000);
> > +
> > DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> htot(%d)\n",
> > adj->hsync_start, adj->hsync_end,
> > adj->htotal);
> >
>
> --
> With best wishes
> Dmitry
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