From 4e7cf74fa3b28fcb43531ca6bc350bf8636e3de6 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 12 Aug 2021 20:00:22 +0300 Subject: [PATCH] clk: fractional-divider: Export approximation algorithm to the CCF users At least one user currently duplicates some functions that are provided by fractional divider module. Let's export approximation algorithm and replace the open-coded variant. As a bonus the exported function will get better documentation in place. Signed-off-by: Andy Shevchenko Tested-by: Heiko Stuebner Acked-by: Heiko Stuebner Link: https://lore.kernel.org/r/20210812170025.67074-1-andriy.shevchenko@linux.intel.com [sboyd@kernel.org: Add header guard because why not] Signed-off-by: Stephen Boyd --- drivers/clk/clk-fractional-divider.c | 11 +++++++---- drivers/clk/clk-fractional-divider.h | 13 +++++++++++++ drivers/clk/rockchip/clk.c | 17 +++-------------- 3 files changed, 23 insertions(+), 18 deletions(-) create mode 100644 drivers/clk/clk-fractional-divider.h diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c index b1e556f..535d299 100644 --- a/drivers/clk/clk-fractional-divider.c +++ b/drivers/clk/clk-fractional-divider.c @@ -14,6 +14,8 @@ #include #include +#include "clk-fractional-divider.h" + static inline u32 clk_fd_readl(struct clk_fractional_divider *fd) { if (fd->flags & CLK_FRAC_DIVIDER_BIG_ENDIAN) @@ -68,9 +70,10 @@ static unsigned long clk_fd_recalc_rate(struct clk_hw *hw, return ret; } -static void clk_fd_general_approximation(struct clk_hw *hw, unsigned long rate, - unsigned long *parent_rate, - unsigned long *m, unsigned long *n) +void clk_fractional_divider_general_approximation(struct clk_hw *hw, + unsigned long rate, + unsigned long *parent_rate, + unsigned long *m, unsigned long *n) { struct clk_fractional_divider *fd = to_clk_fd(hw); unsigned long scale; @@ -102,7 +105,7 @@ static long clk_fd_round_rate(struct clk_hw *hw, unsigned long rate, if (fd->approximation) fd->approximation(hw, rate, parent_rate, &m, &n); else - clk_fd_general_approximation(hw, rate, parent_rate, &m, &n); + clk_fractional_divider_general_approximation(hw, rate, parent_rate, &m, &n); ret = (u64)*parent_rate * m; do_div(ret, n); diff --git a/drivers/clk/clk-fractional-divider.h b/drivers/clk/clk-fractional-divider.h new file mode 100644 index 0000000..a05649e --- /dev/null +++ b/drivers/clk/clk-fractional-divider.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _CLK_FRACTIONAL_DIV_H +#define _CLK_FRACTIONAL_DIV_H + +struct clk_hw; + +void clk_fractional_divider_general_approximation(struct clk_hw *hw, + unsigned long rate, + unsigned long *parent_rate, + unsigned long *m, + unsigned long *n); + +#endif diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c index 049e5e0..b7be7e1 100644 --- a/drivers/clk/rockchip/clk.c +++ b/drivers/clk/rockchip/clk.c @@ -22,6 +22,8 @@ #include #include #include + +#include "../clk-fractional-divider.h" #include "clk.h" /* @@ -178,10 +180,8 @@ static void rockchip_fractional_approximation(struct clk_hw *hw, unsigned long rate, unsigned long *parent_rate, unsigned long *m, unsigned long *n) { - struct clk_fractional_divider *fd = to_clk_fd(hw); unsigned long p_rate, p_parent_rate; struct clk_hw *p_parent; - unsigned long scale; p_rate = clk_hw_get_rate(clk_hw_get_parent(hw)); if ((rate * 20 > p_rate) && (p_rate % rate != 0)) { @@ -190,18 +190,7 @@ static void rockchip_fractional_approximation(struct clk_hw *hw, *parent_rate = p_parent_rate; } - /* - * Get rate closer to *parent_rate to guarantee there is no overflow - * for m and n. In the result it will be the nearest rate left shifted - * by (scale - fd->nwidth) bits. - */ - scale = fls_long(*parent_rate / rate - 1); - if (scale > fd->nwidth) - rate <<= scale - fd->nwidth; - - rational_best_approximation(rate, *parent_rate, - GENMASK(fd->mwidth - 1, 0), GENMASK(fd->nwidth - 1, 0), - m, n); + clk_fractional_divider_general_approximation(hw, rate, parent_rate, m, n); } static struct clk *rockchip_clk_register_frac_branch( -- 2.7.4