From: Deepak M <m.dee...@intel.com>
For GEMINILAKE, dphy param reg values are programmed in terms
of HS byte clock count while for older platforms in terms of
HS ddr clk count.
v2: Added comments to clarify ddr clock count calculation
v3: Use multiplier variable instead of IS_GEMINILAKE()
check everywhere (Jani)
Signed-off-by: Deepak M <m.dee...@intel.com>
Signed-off-by: Madhav Chauhan <madhav.chau...@intel.com>
---
drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 31 +++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
index 8f683b8..d06e7f7 100644
--- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
+++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
@@ -571,6 +571,7 @@ struct drm_panel *vbt_panel_init(struct intel_dsi
*intel_dsi, u16 panel_id)
u32 tclk_prepare_clkzero, ths_prepare_hszero;
u32 lp_to_hs_switch, hs_to_lp_switch;
u32 pclk, computed_ddr;
+ u32 mul;
u16 burst_mode_ratio;
enum port port;
@@ -674,11 +675,6 @@ struct drm_panel *vbt_panel_init(struct intel_dsi
*intel_dsi, u16 panel_id)
break;
}
- /*
- * ui(s) = 1/f [f in hz]
- * ui(ns) = 10^9 / (f*10^6) [f in Mhz] -> 10^3/f(Mhz)
- */
-
/* in Kbps */
ui_num = NS_KHZ_RATIO;
ui_den = bitrate;
@@ -692,21 +688,26 @@ struct drm_panel *vbt_panel_init(struct intel_dsi
*intel_dsi, u16 panel_id)
*/
intel_dsi->lp_byte_clk = DIV_ROUND_UP(tlpx_ns * ui_den, 8 * ui_num);
- /* count values in UI = (ns value) * (bitrate / (2 * 10^6))
+ /* DDR clock period = 2 * UI
+ * UI(sec) = 1/(bitrate * 10^3) (bitrate is in KHZ)
+ * UI(nsec) = 10^6 / bitrate
+ * DDR clock period (nsec) = 2 * UI = (2 * 10^6)/ bitrate
+ * DDR clock count = ns_value / DDR clock period
*
- * Since txddrclkhs_i is 2xUI, all the count values programmed in
- * DPHY param register are divided by 2
- *
- * prepare count
+ * For GEMINILAKE dphy_param_reg will be programmed in terms of
+ * HS byte clock count for other platform in HS ddr clock count
*/
+ mul = IS_GEMINILAKE(dev_priv) ? 8 : 2;
ths_prepare_ns = max(mipi_config->ths_prepare,
mipi_config->tclk_prepare);
- prepare_cnt = DIV_ROUND_UP(ths_prepare_ns * ui_den, ui_num * 2);
+
+ /* prepare count */
+ prepare_cnt = DIV_ROUND_UP(ths_prepare_ns * ui_den, ui_num * mul);
/* exit zero count */
exit_zero_cnt = DIV_ROUND_UP(
(ths_prepare_hszero - ths_prepare_ns) * ui_den,
- ui_num * 2
+ ui_num * mul
);
/*
@@ -720,12 +721,12 @@ struct drm_panel *vbt_panel_init(struct intel_dsi
*intel_dsi, u16 panel_id)
/* clk zero count */
clk_zero_cnt = DIV_ROUND_UP(
- (tclk_prepare_clkzero - ths_prepare_ns)
- * ui_den, 2 * ui_num);
+ (tclk_prepare_clkzero - ths_prepare_ns)
+ * ui_den, ui_num * mul);
/* trail count */
tclk_trail_ns = max(mipi_config->tclk_trail, mipi_config->ths_trail);
- trail_cnt = DIV_ROUND_UP(tclk_trail_ns * ui_den, 2 * ui_num);
+ trail_cnt = DIV_ROUND_UP(tclk_trail_ns * ui_den, ui_num * mul);
if (prepare_cnt > PREPARE_CNT_MAX ||
exit_zero_cnt > EXIT_ZERO_CNT_MAX ||
--
1.9.1
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