From patchwork Mon Jul 17 13:34:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank Oltmanns X-Patchwork-Id: 13316466 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mout-p-202.mailbox.org ([80.241.56.172]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qLONE-0048RT-2G for linux-arm-kernel@lists.infradead.org; Mon, 17 Jul 2023 13:34:59 +0000 From: Frank Oltmanns Date: Mon, 17 Jul 2023 15:34:26 +0200 Subject: [PATCH v4 02/11] clk: sunxi-ng: nkm: consider alternative parent rates when determining rate MIME-Version: 1.0 Message-Id: <20230717-pll-mipi_set_rate_parent-v4-2-04acf1d39765@oltmanns.dev> References: <20230717-pll-mipi_set_rate_parent-v4-0-04acf1d39765@oltmanns.dev> In-Reply-To: <20230717-pll-mipi_set_rate_parent-v4-0-04acf1d39765@oltmanns.dev> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+lwn-linux-arm-kernel=archive.lwn.net@lists.infradead.org List-Archive: To: Maxime Ripard , Michael Turquette , Stephen Boyd , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Andre Przywara , Roman Beranek Cc: linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org, Frank Oltmanns In case the CLK_SET_RATE_PARENT flag is set, consider using a different parent rate when determining a new rate. To find the best match for the requested rate, perform the following steps for each NKM combination: - calculate the optimal parent rate, - find the best parent rate that the parent clock actually supports - use that parent rate to calculate the effective rate. In case the clk does not support setting the parent rate, use the same algorithm as before. Signed-off-by: Frank Oltmanns Acked-by: Maxime Ripard --- drivers/clk/sunxi-ng/ccu_nkm.c | 44 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 43 insertions(+), 1 deletion(-) diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c index f267142e58b3..750e2b8da24b 100644 --- a/drivers/clk/sunxi-ng/ccu_nkm.c +++ b/drivers/clk/sunxi-ng/ccu_nkm.c @@ -6,6 +6,7 @@ #include #include +#include #include "ccu_gate.h" #include "ccu_nkm.h" @@ -16,6 +17,44 @@ struct _ccu_nkm { unsigned long m, min_m, max_m; }; +static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struct _ccu_nkm *nkm, + unsigned long *parent, unsigned long rate) +{ + unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent; + unsigned long best_n = 0, best_k = 0, best_m = 0; + unsigned long _n, _k, _m; + + for (_k = nkm->min_k; _k <= nkm->max_k; _k++) { + for (_n = nkm->min_n; _n <= nkm->max_n; _n++) { + for (_m = nkm->min_m; _m <= nkm->max_m; _m++) { + unsigned long tmp_rate; + + tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k)); + + tmp_rate = tmp_parent * _n * _k / _m; + if (tmp_rate > rate) + continue; + + if ((rate - tmp_rate) < (rate - best_rate)) { + best_rate = tmp_rate; + best_parent_rate = tmp_parent; + best_n = _n; + best_k = _k; + best_m = _m; + } + } + } + } + + nkm->n = best_n; + nkm->k = best_k; + nkm->m = best_m; + + *parent = best_parent_rate; + + return best_rate; +} + static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate, struct _ccu_nkm *nkm) { @@ -124,7 +163,10 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux, if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV) rate *= nkm->fixed_post_div; - rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm); + if (!clk_hw_can_set_rate_parent(&nkm->common.hw)) + rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm); + else + rate = ccu_nkm_find_best_with_parent_adj(parent_hw, &_nkm, parent_rate, rate); if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV) rate /= nkm->fixed_post_div;