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Subject[PATCH v2] drm/mediatek: fixed the calc method of data rate per lane
Date
Tune dsi frame rate by pixel clock, dsi add some extra signal (i.e. Tlpx,
Ths-prepare, Ths-zero, Ths-trail,Ths-exit) when enter and exit LP mode, this
signal will cause h-time larger than normal and reduce FPS.
Need to multiply a coefficient to offset the extra signal's effect.
coefficient = ((htotal*bpp/lane_number)+Tlpx+Ths_prep+Ths_zero+Ths_trail+
Ths_exit)/(htotal*bpp/lane_number))

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
Change since v1:
- phy_timing2 and phy_timing3 refer clock cycle time.
- define values of LPX HS_PRPR HS_ZERO HS_TRAIL TA_GO TA_SURE TA_GET DA_HS_EXIT
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 103 +++++++++++++++++++++++-------------
1 file changed, 67 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 28b2044..ade6f46 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -85,16 +85,16 @@
#define LD0_WAKEUP_EN BIT(2)

#define DSI_PHY_TIMECON0 0x110
-#define LPX (0xff << 0)
-#define HS_PRPR (0xff << 8)
-#define HS_ZERO (0xff << 16)
-#define HS_TRAIL (0xff << 24)
+#define LPX (5 << 0)
+#define HS_PRPR (6 << 8)
+#define HS_ZERO (10 << 16)
+#define HS_TRAIL (8 << 24)

#define DSI_PHY_TIMECON1 0x114
-#define TA_GO (0xff << 0)
-#define TA_SURE (0xff << 8)
-#define TA_GET (0xff << 16)
-#define DA_HS_EXIT (0xff << 24)
+#define TA_GO (20 << 0)
+#define TA_SURE (7 << 8)
+#define TA_GET (25 << 16)
+#define DA_HS_EXIT (7 << 24)

#define DSI_PHY_TIMECON2 0x118
#define CONT_DET (0xff << 0)
@@ -158,28 +158,14 @@ static void mtk_dsi_mask(struct mtk_dsi *dsi, u32 offset, u32 mask, u32 data)
writel((temp & ~mask) | (data & mask), dsi->regs + offset);
}

-static void dsi_phy_timconfig(struct mtk_dsi *dsi)
+static void dsi_phy_timconfig(struct mtk_dsi *dsi, u32 phy_timing0,
+ u32 phy_timing1, u32 phy_timing2,
+ u32 phy_timing3)
{
- u32 timcon0, timcon1, timcon2, timcon3;
- unsigned int ui, cycle_time;
- unsigned int lpx;
-
- ui = 1000 / dsi->data_rate + 0x01;
- cycle_time = 8000 / dsi->data_rate + 0x01;
- lpx = 5;
-
- timcon0 = (8 << 24) | (0xa << 16) | (0x6 << 8) | lpx;
- timcon1 = (7 << 24) | (5 * lpx << 16) | ((3 * lpx) / 2) << 8 |
- (4 * lpx);
- timcon2 = ((NS_TO_CYCLE(0x64, cycle_time) + 0xa) << 24) |
- (NS_TO_CYCLE(0x150, cycle_time) << 16);
- timcon3 = (2 * lpx) << 16 | NS_TO_CYCLE(80 + 52 * ui, cycle_time) << 8 |
- NS_TO_CYCLE(0x40, cycle_time);
-
- writel(timcon0, dsi->regs + DSI_PHY_TIMECON0);
- writel(timcon1, dsi->regs + DSI_PHY_TIMECON1);
- writel(timcon2, dsi->regs + DSI_PHY_TIMECON2);
- writel(timcon3, dsi->regs + DSI_PHY_TIMECON3);
+ writel(phy_timing0, dsi->regs + DSI_PHY_TIMECON0);
+ writel(phy_timing1, dsi->regs + DSI_PHY_TIMECON1);
+ writel(phy_timing2, dsi->regs + DSI_PHY_TIMECON2);
+ writel(phy_timing3, dsi->regs + DSI_PHY_TIMECON3);
}

static void mtk_dsi_enable(struct mtk_dsi *dsi)
@@ -202,19 +188,51 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
{
struct device *dev = dsi->dev;
int ret;
+ u64 bit_clock, total_bits;
+ u32 htotal, htotal_bits, bit_per_pixel, overhead_cycles, overhead_bits;
+ u32 phy_timing0, phy_timing1, phy_timing2, phy_timing3;
+ u32 ui, cycle_time;

if (++dsi->refcount != 1)
return 0;

+ switch (dsi->format) {
+ case MIPI_DSI_FMT_RGB565:
+ bit_per_pixel = 16;
+ break;
+ case MIPI_DSI_FMT_RGB666_PACKED:
+ bit_per_pixel = 18;
+ break;
+ case MIPI_DSI_FMT_RGB666:
+ case MIPI_DSI_FMT_RGB888:
+ default:
+ bit_per_pixel = 24;
+ break;
+ }
+ /**
+ * data_rate = (pixel_clock) * bit_per_pixel * mipi_ratio / lane_num;
+ * vm.pixelclock is Khz, data_rata unit is Hz, so need to multiply 1000
+ * mipi_ratio is (htotal * byte_per_pixel / lane_num + Tlpx + Ths_prep
+ * + Thstrail + Ths_exit + Ths_zero) /
+ * (htotal * byte_per_pixel /lane_number)
+ */
+ bit_clock = dsi->vm.pixelclock * 1000 * bit_per_pixel;
+ htotal = dsi->vm.hactive + dsi->vm.hback_porch + dsi->vm.hfront_porch +
+ dsi->vm.hsync_len;
+ htotal_bits = htotal * bit_per_pixel;
+
/**
- * data_rate = (pixel_clock / 1000) * pixel_dipth * mipi_ratio;
- * pixel_clock unit is Khz, data_rata unit is MHz, so need divide 1000.
- * mipi_ratio is mipi clk coefficient for balance the pixel clk in mipi.
- * we set mipi_ratio is 1.05.
+ * overhead = lpx + hs_prepare + hs_zero + hs_trail + hs_exit
*/
- dsi->data_rate = dsi->vm.pixelclock * 3 * 21 / (1 * 1000 * 10);
+ overhead_cycles = LPX + (HS_PRPR >> 8) + (HS_ZERO >> 16) +
+ (HS_TRAIL >> 24) + (DA_HS_EXIT >> 24);
+ overhead_bits = overhead_cycles * dsi->lanes * 8;
+ total_bits = htotal_bits + overhead_bits;

- ret = clk_set_rate(dsi->hs_clk, dsi->data_rate * 1000000);
+ dsi->data_rate = DIV_ROUND_UP_ULL(bit_clock * total_bits,
+ htotal_bits * dsi->lanes);
+
+ ret = clk_set_rate(dsi->hs_clk, dsi->data_rate);
if (ret < 0) {
dev_err(dev, "Failed to set data rate: %d\n", ret);
goto err_refcount;
@@ -236,7 +254,20 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)

mtk_dsi_enable(dsi);
mtk_dsi_reset(dsi);
- dsi_phy_timconfig(dsi);
+
+ ui = 1000 / dsi->data_rate + 0x01;
+ cycle_time = 8000 / dsi->data_rate + 0x01;
+
+ phy_timing0 = LPX | HS_PRPR | HS_ZERO | HS_TRAIL;
+ phy_timing1 = TA_GO | TA_SURE | TA_GET | DA_HS_EXIT;
+ phy_timing2 = ((NS_TO_CYCLE(0x64, cycle_time) + 0xa) << 24) |
+ (NS_TO_CYCLE(0x150, cycle_time) << 16);
+ phy_timing3 = (2 * LPX) << 16 |
+ NS_TO_CYCLE(80 + 52 * ui, cycle_time) << 8 |
+ NS_TO_CYCLE(0x40, cycle_time);
+
+ dsi_phy_timconfig(dsi, phy_timing0, phy_timing1, phy_timing2,
+ phy_timing3);

return 0;

--
1.7.9.5
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