From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67DE3EB64DD for ; Mon, 3 Jul 2023 08:59:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230080AbjGCI74 (ORCPT ); Mon, 3 Jul 2023 04:59:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230205AbjGCI7y (ORCPT ); Mon, 3 Jul 2023 04:59:54 -0400 Received: from mout-p-201.mailbox.org (mout-p-201.mailbox.org [80.241.56.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A77093; Mon, 3 Jul 2023 01:59:50 -0700 (PDT) Received: from smtp102.mailbox.org (smtp102.mailbox.org [10.196.197.102]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 4Qvfxv02dpz9spf; Mon, 3 Jul 2023 10:59:47 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oltmanns.dev; s=MBO0001; t=1688374787; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=IgizOrynAySv2dLicDLGl13lYDf7Baoa0hm2ZdTCH8M=; b=hzqyvIoY1GLE4APTwgDMqFjTi1N9S0Tr21AZF0v44cOHMOKfT/Sl5UikMRTfTCpR+ZlIKv fwWiBr810bLDuL6G0UzbM8DjZzfLmSRJ5YlEof0laYNWHcREuEFkibFe2PejX6+Azx9bhA fO9hEx09A8YK5zEOVA8XLmveqfDYJLIFfHXqAJkPcQmJ0InSlPvTrg2akkW7OWS7EBX5Ud x/V3GLefSYRBmeYmVAcT5jmbf7pMX73tVpQHUFJMxstF8YVdcMDmXFGp3JIgZdKDcWULLl Xl1Iq3KVa3wy2lDMb05t0L90XNzlZUNmc06lmXsBLcTvRadFWLKgF8BJxG8P1w== References: <20230702-pll-mipi_set_rate_parent-v3-0-46dcb8aa9cbc@oltmanns.dev> <20230702-pll-mipi_set_rate_parent-v3-5-46dcb8aa9cbc@oltmanns.dev> <87wmzhsbu0.fsf@oltmanns.dev> From: Frank Oltmanns To: Maxime Ripard Cc: Michael Turquette , Stephen Boyd , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Andre Przywara , Roman Beranek , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 5/8] clk: sunxi-ng: nkm: Support finding closest rate In-reply-to: Date: Mon, 03 Jul 2023 10:59:43 +0200 Message-ID: <87jzvhs740.fsf@oltmanns.dev> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org On 2023-07-03 at 09:25:59 +0200, Maxime Ripard wrote: > [[PGP Signed Part:Undecided]] > On Mon, Jul 03, 2023 at 09:17:43AM +0200, Frank Oltmanns wrote: >> >> On 2023-07-02 at 19:55:24 +0200, Frank Oltmanns wrote: >> > When finding the best rate for a NKM clock, consider rates that are >> > higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is >> > set. >> > >> > Accommodate ccu_mux_helper_determine_rate to this change. >> > >> > Signed-off-by: Frank Oltmanns >> > --- >> > drivers/clk/sunxi-ng/ccu_mux.c | 23 +++++++++++++++----- >> > drivers/clk/sunxi-ng/ccu_nkm.c | 48 +++++++++++++++++++++++++++++++----------- >> > 2 files changed, 54 insertions(+), 17 deletions(-) >> > >> > diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c >> > index 1d557e323169..8594d6a4addd 100644 >> > --- a/drivers/clk/sunxi-ng/ccu_mux.c >> > +++ b/drivers/clk/sunxi-ng/ccu_mux.c >> > @@ -113,7 +113,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common, >> > } >> > >> > for (i = 0; i < clk_hw_get_num_parents(hw); i++) { >> > - unsigned long tmp_rate, parent_rate; >> > + unsigned long tmp_rate, parent_rate, best_diff = ULONG_MAX; >> > struct clk_hw *parent; >> > >> > parent = clk_hw_get_parent_by_index(hw, i); >> > @@ -139,10 +139,23 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common, >> > goto out; >> > } >> > >> > - if ((req->rate - tmp_rate) < (req->rate - best_rate)) { >> > - best_rate = tmp_rate; >> > - best_parent_rate = parent_rate; >> > - best_parent = parent; >> > + if (common->features & CCU_FEATURE_CLOSEST_RATE) { >> > + unsigned long tmp_diff = req->rate > tmp_rate ? >> > + req->rate - tmp_rate : >> > + tmp_rate - req->rate; >> > + >> > + if (tmp_diff < best_diff) { >> > + best_rate = tmp_rate; >> > + best_parent_rate = parent_rate; >> > + best_parent = parent; >> > + best_diff = tmp_diff; >> > + } >> > + } else { >> > + if ((req->rate - tmp_rate) < (req->rate - best_rate)) { >> > + best_rate = tmp_rate; >> > + best_parent_rate = parent_rate; >> > + best_parent = parent; >> > + } >> > } >> > } >> > >> > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c >> > index d83843e69c25..36d9e987e4d8 100644 >> > --- a/drivers/clk/sunxi-ng/ccu_nkm.c >> > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c >> > @@ -18,9 +18,11 @@ struct _ccu_nkm { >> > }; >> > >> > static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, unsigned long rate, >> > - struct _ccu_nkm *nkm, struct clk_hw *phw) >> > + struct _ccu_nkm *nkm, struct clk_hw *phw, >> > + unsigned long features) >> > { >> > - unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent; >> > + unsigned long best_rate = 0, best_parent_rate = 0, tmp_parent = *parent; >> > + unsigned long best_diff = ULONG_MAX; >> > unsigned long best_n = 0, best_k = 0, best_m = 0; >> > unsigned long _n, _k, _m; >> > >> > @@ -28,16 +30,26 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un >> > for (_n = nkm->min_n; _n <= nkm->max_n; _n++) { >> > for (_m = nkm->min_m; _m <= nkm->max_m; _m++) { >> > unsigned long tmp_rate; >> > + unsigned long tmp_diff; >> > >> > 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)) { >> > + if (features & CCU_FEATURE_CLOSEST_RATE) { >> > + tmp_diff = rate > tmp_rate ? >> > + rate - tmp_rate : >> > + tmp_rate - rate; >> > + } else { >> > + if (tmp_rate > rate) >> > + continue; >> > + tmp_diff = rate - tmp_diff; >> >> Sorry, this should of course be tmp_diff = rate - tmp_rate. I'll fix >> that in v4. Also I'll do tests on my phone where >> CCU_FEATURE_CLOSEST_RATE is not set (i.e., without PATCH 8), so see if >> it replicates the old behaviour. I'll also look into adding kunit tests, >> so that this doesn't happen again. I'm not sure if this is feasible, but >> I'll ask here for advise, if/when I encounter obstacles. > > While this would obviously be great, I don't think we have the > infrastructure just yet to allow to easily add kunit tests for entire > clocks. I think, clk_test.c provides a good blueprint. I tried to do that for clk-fractional-divider [1], but Stephen wanted to go a different route, so I dropped it. You could look at clk_fd_test_init() in [1]. A similar approach might work for the sunxi-ng clocks. I don't see any real blockers, but maybe that's me being naive. [1]: https://lore.kernel.org/all/20230614185521.477924-3-frank@oltmanns.dev/ Best regards, Frank > > Maxime > > [[End of PGP Signed Part]]