From patchwork Thu Jun 13 16:06:02 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Hogan X-Patchwork-Id: 2717551 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 8FE689F967 for ; Thu, 13 Jun 2013 16:17:09 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5847C2039D for ; Thu, 13 Jun 2013 16:17:08 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D05E320426 for ; Thu, 13 Jun 2013 16:17:06 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UnAAV-0008T5-TD; Thu, 13 Jun 2013 16:14:37 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UnAA6-0000MP-B3; Thu, 13 Jun 2013 16:14:10 +0000 Received: from multi.imgtec.com ([194.200.65.239]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UnA9W-0000HQ-QM for linux-arm-kernel@lists.infradead.org; Thu, 13 Jun 2013 16:13:37 +0000 From: James Hogan To: Mike Turquette , Subject: [PATCH v5 5/5] clk: clk-mux: implement remuxing on set_rate Date: Thu, 13 Jun 2013 17:06:02 +0100 Message-ID: <1371139562-305-6-git-send-email-james.hogan@imgtec.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1371139562-305-1-git-send-email-james.hogan@imgtec.com> References: <1371139562-305-1-git-send-email-james.hogan@imgtec.com> MIME-Version: 1.0 X-SEF-Processed: 7_3_0_01192__2013_06_13_17_13_08 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130613_121335_013091_01EBB5BC X-CRM114-Status: GOOD ( 13.50 ) X-Spam-Score: -2.3 (--) Cc: James Hogan , Saravana Kannan , Stephen Boyd , linux-kernel@vger.kernel.org, Doug Anderson X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Implement clk-mux remuxing if the CLK_SET_RATE_NO_REPARENT flag isn't set. This implements determine_rate for clk-mux to propagate to each parent and to choose the best one (like clk-divider this chooses the parent which provides the fastest rate <= the requested rate). The determine_rate op is implemented as a core helper function so that it can be easily used by more complex clocks which incorporate muxes. Signed-off-by: James Hogan Reviewed-by: Stephen Boyd Cc: Mike Turquette Cc: linux-arm-kernel@lists.infradead.org --- Changes in v4: * never pass NULL to determine_rate's best_parent_clk parameter. Changes in v3: * rename/invert CLK_SET_RATE_REMUX to CLK_SET_RATE_NO_REPARENT and move to patch 3. drivers/clk/clk-mux.c | 1 + drivers/clk/clk.c | 49 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/clk-provider.h | 3 +++ 3 files changed, 53 insertions(+) diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c index 25b1734..cecfa01 100644 --- a/drivers/clk/clk-mux.c +++ b/drivers/clk/clk-mux.c @@ -100,6 +100,7 @@ static int clk_mux_set_parent(struct clk_hw *hw, u8 index) const struct clk_ops clk_mux_ops = { .get_parent = clk_mux_get_parent, .set_parent = clk_mux_set_parent, + .determine_rate = __clk_mux_determine_rate, }; EXPORT_SYMBOL_GPL(clk_mux_ops); diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 52abc3f..30aaaef 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -692,6 +692,55 @@ struct clk *__clk_lookup(const char *name) return NULL; } +/* + * Helper for finding best parent to provide a given frequency. This can be used + * directly as a determine_rate callback (e.g. for a mux), or from a more + * complex clock that may combine a mux with other operations. + */ +long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, + struct clk **best_parent_p) +{ + struct clk *clk = hw->clk, *parent, *best_parent = NULL; + int i, num_parents; + unsigned long parent_rate, best = 0; + + /* if NO_REPARENT flag set, pass through to current parent */ + if (clk->flags & CLK_SET_RATE_NO_REPARENT) { + parent = clk->parent; + if (clk->flags & CLK_SET_RATE_PARENT) + best = __clk_round_rate(parent, rate); + else if (parent) + best = __clk_get_rate(parent); + else + best = __clk_get_rate(clk); + goto out; + } + + /* find the parent that can provide the fastest rate <= rate */ + num_parents = clk->num_parents; + for (i = 0; i < num_parents; i++) { + parent = clk_get_parent_by_index(clk, i); + if (!parent) + continue; + if (clk->flags & CLK_SET_RATE_PARENT) + parent_rate = __clk_round_rate(parent, rate); + else + parent_rate = __clk_get_rate(parent); + if (parent_rate <= rate && parent_rate > best) { + best_parent = parent; + best = parent_rate; + } + } + +out: + if (best_parent) + *best_parent_p = best_parent; + *best_parent_rate = best; + + return best; +} + /*** clk api ***/ void __clk_unprepare(struct clk *clk) diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 5500af6..c94385b 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -419,6 +419,9 @@ unsigned long __clk_get_flags(struct clk *clk); bool __clk_is_prepared(struct clk *clk); bool __clk_is_enabled(struct clk *clk); struct clk *__clk_lookup(const char *name); +long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, + struct clk **best_parent_p); /* * FIXME clock api without lock protection