From 58922910add18583d5273c2edcdb9fd7bf4eca02 Mon Sep 17 00:00:00 2001 From: Taniya Das Date: Sun, 27 Feb 2022 23:25:35 +0530 Subject: clk: qcom: clk-rcg2: Update logic to calculate D value for RCG The display pixel clock has a requirement on certain newer platforms to support M/N as (2/3) and the final D value calculated results in underflow errors. As the current implementation does not check for D value is within the accepted range for a given M & N value. Update the logic to calculate the final D value based on the range. Fixes: 99cbd064b059f ("clk: qcom: Support display RCG clocks") Signed-off-by: Taniya Das Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20220227175536.3131-1-tdas@codeaurora.org --- drivers/clk/qcom/clk-rcg2.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c index e1b1b426fae4..b831975a9606 100644 --- a/drivers/clk/qcom/clk-rcg2.c +++ b/drivers/clk/qcom/clk-rcg2.c @@ -264,7 +264,7 @@ static int clk_rcg2_determine_floor_rate(struct clk_hw *hw, static int __clk_rcg2_configure(struct clk_rcg2 *rcg, const struct freq_tbl *f) { - u32 cfg, mask; + u32 cfg, mask, d_val, not2d_val, n_minus_m; struct clk_hw *hw = &rcg->clkr.hw; int ret, index = qcom_find_src_index(hw, rcg->parent_map, f->src); @@ -283,8 +283,17 @@ static int __clk_rcg2_configure(struct clk_rcg2 *rcg, const struct freq_tbl *f) if (ret) return ret; + /* Calculate 2d value */ + d_val = f->n; + + n_minus_m = f->n - f->m; + n_minus_m *= 2; + + d_val = clamp_t(u32, d_val, f->m, n_minus_m); + not2d_val = ~d_val & mask; + ret = regmap_update_bits(rcg->clkr.regmap, - RCG_D_OFFSET(rcg), mask, ~f->n); + RCG_D_OFFSET(rcg), mask, not2d_val); if (ret) return ret; } -- cgit v1.2.3-59-g8ed1b