From 2e9abc6ec108370ad341f98d0e05e02e4e165b5a Mon Sep 17 00:00:00 2001 From: Frank Oltmanns Date: Sat, 17 Jun 2023 15:10:40 +0200 Subject: [PATCH] clk: fractional-divider: Improve approximation when zero based and export Consider the CLK_FRAC_DIVIDER_ZERO_BASED flag when finding the best approximation for m and n. By doing so, increase the range of valid values for the numerator and denominator by 1. Furthermore, export the approximation function so that users of this function can be compiled as modules. Cc: A.s. Dong Signed-off-by: Frank Oltmanns Link: https://lore.kernel.org/r/20230617131041.18313-2-frank@oltmanns.dev Signed-off-by: Stephen Boyd --- drivers/clk/clk-fractional-divider.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c index 479297763e70..5067e067e906 100644 --- a/drivers/clk/clk-fractional-divider.c +++ b/drivers/clk/clk-fractional-divider.c @@ -123,6 +123,7 @@ void clk_fractional_divider_general_approximation(struct clk_hw *hw, unsigned long *m, unsigned long *n) { struct clk_fractional_divider *fd = to_clk_fd(hw); + unsigned long max_m, max_n; /* * Get rate closer to *parent_rate to guarantee there is no overflow @@ -138,10 +139,17 @@ void clk_fractional_divider_general_approximation(struct clk_hw *hw, rate <<= scale - fd->nwidth; } - rational_best_approximation(rate, *parent_rate, - GENMASK(fd->mwidth - 1, 0), GENMASK(fd->nwidth - 1, 0), - m, n); + if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) { + max_m = 1 << fd->mwidth; + max_n = 1 << fd->nwidth; + } else { + max_m = GENMASK(fd->mwidth - 1, 0); + max_n = GENMASK(fd->nwidth - 1, 0); + } + + rational_best_approximation(rate, *parent_rate, max_m, max_n, m, n); } +EXPORT_SYMBOL_GPL(clk_fractional_divider_general_approximation); static long clk_fd_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *parent_rate) @@ -169,13 +177,18 @@ static int clk_fd_set_rate(struct clk_hw *hw, unsigned long rate, { struct clk_fractional_divider *fd = to_clk_fd(hw); unsigned long flags = 0; - unsigned long m, n; + unsigned long m, n, max_m, max_n; u32 mmask, nmask; u32 val; - rational_best_approximation(rate, parent_rate, - GENMASK(fd->mwidth - 1, 0), GENMASK(fd->nwidth - 1, 0), - &m, &n); + if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) { + max_m = 1 << fd->mwidth; + max_n = 1 << fd->nwidth; + } else { + max_m = GENMASK(fd->mwidth - 1, 0); + max_n = GENMASK(fd->nwidth - 1, 0); + } + rational_best_approximation(rate, parent_rate, max_m, max_n, &m, &n); if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) { m--;