From a856c5bdf40c218ef1875147455d9d24d01c11c9 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Wed, 13 May 2015 10:35:25 +0300 Subject: [PATCH] drm/i915/dsi: add support for DSI PLL N1 divisor values MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Currently DSI PLL N1 is hardcoded off. Make it possible to use it later. This should have no functional changes for now. v2: s/ffz(~(n))/ffs(n) - 1/ (Ville) Signed-off-by: Jani Nikula Reviewed-by: Ville Syrjälä Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_dsi_pll.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c index cfd527765156..9688d996af31 100644 --- a/drivers/gpu/drm/i915/intel_dsi_pll.c +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c @@ -165,7 +165,7 @@ static u32 dsi_clk_from_pclk(u32 pclk, int pixel_format, int lane_count) static int dsi_calc_mnp(int target_dsi_clk, struct dsi_mnp *dsi_mnp) { unsigned int calc_m = 0, calc_p = 0; - unsigned int m, n, p; + unsigned int m, n = 1, p; int ref_clk = 25000; int delta = target_dsi_clk; u32 m_seed; @@ -182,7 +182,7 @@ static int dsi_calc_mnp(int target_dsi_clk, struct dsi_mnp *dsi_mnp) * Find the optimal m and p divisors with minimal delta * +/- the required clock */ - int calc_dsi_clk = (m * ref_clk) / p; + int calc_dsi_clk = (m * ref_clk) / (p * n); int d = abs(target_dsi_clk - calc_dsi_clk); if (d < delta) { delta = d; @@ -192,10 +192,11 @@ static int dsi_calc_mnp(int target_dsi_clk, struct dsi_mnp *dsi_mnp) } } + /* register has log2(N1), this works fine for powers of two */ + n = ffs(n) - 1; m_seed = lfsr_converts[calc_m - 62]; - n = 1; dsi_mnp->dsi_pll_ctrl = 1 << (DSI_PLL_P1_POST_DIV_SHIFT + calc_p - 2); - dsi_mnp->dsi_pll_div = (n - 1) << DSI_PLL_N1_DIV_SHIFT | + dsi_mnp->dsi_pll_div = n << DSI_PLL_N1_DIV_SHIFT | m_seed << DSI_PLL_M1_DIV_SHIFT; return 0; @@ -312,7 +313,7 @@ u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp) struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base); u32 dsi_clock, pclk; u32 pll_ctl, pll_div; - u32 m = 0, p = 0; + u32 m = 0, p = 0, n; int refclk = 25000; int i; @@ -327,6 +328,10 @@ u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp) pll_ctl &= DSI_PLL_P1_POST_DIV_MASK; pll_ctl = pll_ctl >> (DSI_PLL_P1_POST_DIV_SHIFT - 2); + /* N1 divisor */ + n = (pll_div & DSI_PLL_N1_DIV_MASK) >> DSI_PLL_N1_DIV_SHIFT; + n = 1 << n; /* register has log2(N1) */ + /* mask out the other bits and extract the M1 divisor */ pll_div &= DSI_PLL_M1_DIV_MASK; pll_div = pll_div >> DSI_PLL_M1_DIV_SHIFT; @@ -354,7 +359,7 @@ u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp) m = i + 62; - dsi_clock = (m * refclk) / p; + dsi_clock = (m * refclk) / (p * n); /* pixel_format and pipe_bpp should agree */ assert_bpp_mismatch(intel_dsi->pixel_format, pipe_bpp); -- 2.20.1