Pixel clock based calculation is recommended in the MIPI host controller
documentation
v2: Based on review comments from Jani and Ville
- Use dsi_clk in KHz rather than converting in Hz and back to MHz
- RR formula is retained though not used but return dsi_clk in KHz now
- Moved the m-n-p changes into a separate patch
- Removed the parameter check for intel_dsi->dsi_clock_freq. This will be
bought back in if needed when appropriate panel drivers are done
Signed-off-by: Vijayakumar Balakrishnan <[email protected]>
Signed-off-by: Shobhit Kumar <[email protected]>
---
drivers/gpu/drm/i915/intel_dsi_pll.c | 46 +++++++++++++++++++++++++++++-----
1 file changed, 40 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c
b/drivers/gpu/drm/i915/intel_dsi_pll.c
index 44279b2..9f3e6b0 100644
--- a/drivers/gpu/drm/i915/intel_dsi_pll.c
+++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
@@ -50,6 +50,8 @@ static const u32 lfsr_converts[] = {
71, 35 /* 91 - 92 */
};
+#ifdef DSI_CLK_FROM_RR
+
static u32 dsi_rr_formula(const struct drm_display_mode *mode,
int pixel_format, int video_mode_format,
int lane_count, bool eotp)
@@ -121,7 +123,7 @@ static u32 dsi_rr_formula(const struct drm_display_mode
*mode,
/* the dsi clock is divided by 2 in the hardware to get dsi ddr clock */
dsi_bit_clock_hz = bytes_per_x_frames_x_lanes * 8;
- dsi_clk = dsi_bit_clock_hz / (1000 * 1000);
+ dsi_clk = dsi_bit_clock_hz / 1000;
if (eotp && video_mode_format == VIDEO_MODE_BURST)
dsi_clk *= 2;
@@ -129,6 +131,38 @@ static u32 dsi_rr_formula(const struct drm_display_mode
*mode,
return dsi_clk;
}
+#else
+
+/* Get DSI clock from pixel clock */
+static u32 dsi_clk_from_pclk(const struct drm_display_mode *mode,
+ int pixel_format, int lane_count)
+{
+ u32 dsi_clk_khz;
+ u32 bpp;
+
+ switch (pixel_format) {
+ default:
+ case VID_MODE_FORMAT_RGB888:
+ case VID_MODE_FORMAT_RGB666_LOOSE:
+ bpp = 24;
+ break;
+ case VID_MODE_FORMAT_RGB666:
+ bpp = 18;
+ break;
+ case VID_MODE_FORMAT_RGB565:
+ bpp = 16;
+ break;
+ }
+
+ /* DSI data rate = pixel clock * bits per pixel / lane count
+ pixel clock is converted from KHz to Hz */
+ dsi_clk_khz = DIV_ROUND_CLOSEST(mode->clock * bpp, lane_count);
+
+ return dsi_clk_khz;
+}
+
+#endif
+
#ifdef MNP_FROM_TABLE
struct dsi_clock_table {
@@ -200,13 +234,14 @@ static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp
*dsi_mnp)
u32 calc_p;
u32 m_seed;
- if (dsi_clk < 300 || dsi_clk > 1150) {
+ /* dsi_clk is expected in KHZ */
+ if (dsi_clk < 300000 || dsi_clk > 1150000) {
DRM_ERROR("DSI CLK Out of Range\n");
return -ECHRNG;
}
ref_clk = 25000;
- target_dsi_clk = dsi_clk * 1000;
+ target_dsi_clk = dsi_clk;
error = 0xFFFFFFFF;
calc_m = 0;
calc_p = 0;
@@ -251,9 +286,8 @@ static void vlv_configure_dsi_pll(struct intel_encoder
*encoder)
struct dsi_mnp dsi_mnp;
u32 dsi_clk;
- dsi_clk = dsi_rr_formula(mode, intel_dsi->pixel_format,
- intel_dsi->video_mode_format,
- intel_dsi->lane_count,
!intel_dsi->eot_disable);
+ dsi_clk = dsi_clk_from_pclk(mode, intel_dsi->pixel_format,
+ intel_dsi->lane_count);
ret = dsi_calc_mnp(dsi_clk, &dsi_mnp);
if (ret) {
--
1.7.9.5
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