From 44d4c6eebb2ef04f698c292bb6eda5f2e80c663b Mon Sep 17 00:00:00 2001 From: Shobhit Kumar Date: Tue, 10 Dec 2013 12:14:56 +0530 Subject: drm/i915: Compute dsi_clk from pixel clock 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 v3: Removed the unused mnp calculation from static table Signed-off-by: Vijayakumar Balakrishnan Signed-off-by: Shobhit Kumar Reviewed-by: Jani Nikula Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_dsi_pll.c | 89 +++++++++++++----------------------- 1 file changed, 31 insertions(+), 58 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_dsi_pll.c') diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c index 44279b2ade8..0d1b17fee01 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; @@ -129,64 +131,37 @@ static u32 dsi_rr_formula(const struct drm_display_mode *mode, return dsi_clk; } -#ifdef MNP_FROM_TABLE - -struct dsi_clock_table { - u32 freq; - u8 m; - u8 p; -}; - -static const struct dsi_clock_table dsi_clk_tbl[] = { - {300, 72, 6}, {313, 75, 6}, {323, 78, 6}, {333, 80, 6}, - {343, 82, 6}, {353, 85, 6}, {363, 87, 6}, {373, 90, 6}, - {383, 92, 6}, {390, 78, 5}, {393, 79, 5}, {400, 80, 5}, - {401, 80, 5}, {402, 80, 5}, {403, 81, 5}, {404, 81, 5}, - {405, 81, 5}, {406, 81, 5}, {407, 81, 5}, {408, 82, 5}, - {409, 82, 5}, {410, 82, 5}, {411, 82, 5}, {412, 82, 5}, - {413, 83, 5}, {414, 83, 5}, {415, 83, 5}, {416, 83, 5}, - {417, 83, 5}, {418, 84, 5}, {419, 84, 5}, {420, 84, 5}, - {430, 86, 5}, {440, 88, 5}, {450, 90, 5}, {460, 92, 5}, - {470, 75, 4}, {480, 77, 4}, {490, 78, 4}, {500, 80, 4}, - {510, 82, 4}, {520, 83, 4}, {530, 85, 4}, {540, 86, 4}, - {550, 88, 4}, {560, 90, 4}, {570, 91, 4}, {580, 70, 3}, - {590, 71, 3}, {600, 72, 3}, {610, 73, 3}, {620, 74, 3}, - {630, 76, 3}, {640, 77, 3}, {650, 78, 3}, {660, 79, 3}, - {670, 80, 3}, {680, 82, 3}, {690, 83, 3}, {700, 84, 3}, - {710, 85, 3}, {720, 86, 3}, {730, 88, 3}, {740, 89, 3}, - {750, 90, 3}, {760, 91, 3}, {770, 92, 3}, {780, 62, 2}, - {790, 63, 2}, {800, 64, 2}, {880, 70, 2}, {900, 72, 2}, - {1000, 80, 2}, /* dsi clock frequency in Mhz*/ -}; +#else -static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp *dsi_mnp) +/* Get DSI clock from pixel clock */ +static u32 dsi_clk_from_pclk(const struct drm_display_mode *mode, + int pixel_format, int lane_count) { - unsigned int i; - u8 m; - u8 n; - u8 p; - u32 m_seed; - - if (dsi_clk < 300 || dsi_clk > 1000) - return -ECHRNG; + u32 dsi_clk_khz; + u32 bpp; - for (i = 0; i <= ARRAY_SIZE(dsi_clk_tbl); i++) { - if (dsi_clk_tbl[i].freq > dsi_clk) - break; + 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; } - m = dsi_clk_tbl[i].m; - p = dsi_clk_tbl[i].p; - m_seed = lfsr_converts[m - 62]; - n = 1; - dsi_mnp->dsi_pll_ctrl = 1 << (DSI_PLL_P1_POST_DIV_SHIFT + p - 2); - dsi_mnp->dsi_pll_div = (n - 1) << DSI_PLL_N1_DIV_SHIFT | - m_seed << DSI_PLL_M1_DIV_SHIFT; + /* 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 0; + return dsi_clk_khz; } -#else +#endif static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp *dsi_mnp) { @@ -200,13 +175,14 @@ 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; @@ -235,8 +211,6 @@ static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp *dsi_mnp) return 0; } -#endif - /* * XXX: The muxing and gating is hard coded for now. Need to add support for * sharing PLLs with two DSI outputs. @@ -251,9 +225,8 @@ 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) { -- cgit v1.2.3 From 8e1eed5aa8fe6cdd2c445b7aded42498523ad4dd Mon Sep 17 00:00:00 2001 From: Shobhit Kumar Date: Tue, 10 Dec 2013 12:14:57 +0530 Subject: drm/i915: Try harder to get best m, n, p values with minimal error Basically check for both +ive and -ive deviation from target clock and pick the one with minimal error. If we get a direct match, break from loop to acheive some optimization. v2: Use signed variable for target and calculated dsi clock values Signed-off-by: Vijayakumar Balakrishnan Signed-off-by: Shobhit Kumar Reviewed-by: Jani Nikula Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_dsi_pll.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_dsi_pll.c') diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c index 0d1b17fee01..ba79ec19da3 100644 --- a/drivers/gpu/drm/i915/intel_dsi_pll.c +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c @@ -169,8 +169,8 @@ static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp *dsi_mnp) u32 ref_clk; u32 error; u32 tmp_error; - u32 target_dsi_clk; - u32 calc_dsi_clk; + int target_dsi_clk; + int calc_dsi_clk; u32 calc_m; u32 calc_p; u32 m_seed; @@ -184,22 +184,32 @@ static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp *dsi_mnp) ref_clk = 25000; target_dsi_clk = dsi_clk; error = 0xFFFFFFFF; + tmp_error = 0xFFFFFFFF; calc_m = 0; calc_p = 0; for (m = 62; m <= 92; m++) { for (p = 2; p <= 6; p++) { - + /* Find the optimal m and p divisors + with minimal error +/- the required clock */ calc_dsi_clk = (m * ref_clk) / p; - if (calc_dsi_clk >= target_dsi_clk) { - tmp_error = calc_dsi_clk - target_dsi_clk; - if (tmp_error < error) { - error = tmp_error; - calc_m = m; - calc_p = p; - } + if (calc_dsi_clk == target_dsi_clk) { + calc_m = m; + calc_p = p; + error = 0; + break; + } else + tmp_error = abs(target_dsi_clk - calc_dsi_clk); + + if (tmp_error < error) { + error = tmp_error; + calc_m = m; + calc_p = p; } } + + if (error == 0) + break; } m_seed = lfsr_converts[calc_m - 62]; -- cgit v1.2.3