From patchwork Wed Jul 23 10:44:33 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Walmsley X-Patchwork-Id: 4609701 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 1D0F5C0514 for ; Wed, 23 Jul 2014 10:47:47 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 439F620158 for ; Wed, 23 Jul 2014 10:47:46 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 572AA201C0 for ; Wed, 23 Jul 2014 10:47:45 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1X9u2e-0000Pr-I7; Wed, 23 Jul 2014 10:45:00 +0000 Received: from utopia.booyaka.com ([74.50.51.50]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1X9u2a-0000Nl-7B for linux-arm-kernel@lists.infradead.org; Wed, 23 Jul 2014 10:44:58 +0000 Received: (qmail 5236 invoked by uid 1019); 23 Jul 2014 10:44:33 -0000 Date: Wed, 23 Jul 2014 10:44:33 +0000 (UTC) From: Paul Walmsley To: linux-omap@vger.kernel.org Subject: [PATCH] ARM: OMAP2+: clock: allow omap2_dpll_round_rate() to round to next-lowest rate Message-ID: User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140723_034456_381480_E8ACF6C8 X-CRM114-Status: GOOD ( 16.53 ) X-Spam-Score: -0.0 (/) Cc: tomi.valkeinen@ti.com, mturquette@linaro.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 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=-1.9 required=5.0 tests=BAYES_00,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 Change the behavior of omap2_dpll_round_rate() to round to either the exact rate requested, or the next lowest rate that the clock is able to provide. This is not an ideal fix, but is intended to provide a relatively safe way for drivers to set PLL rates, until a better solution can be implemented. For the time being, omap3_noncore_dpll_set_rate() is still allowed to set its rate to something other than what the caller requested; but will warn when this occurs. Cc: Tomi Valkeinen Cc: Mike Turquette Signed-off-by: Paul Walmsley --- arch/arm/mach-omap2/clkt_dpll.c | 28 +++++++++++++++++++++------- arch/arm/mach-omap2/dpll3xxx.c | 12 ++++++++++-- 2 files changed, 31 insertions(+), 9 deletions(-) diff --git a/arch/arm/mach-omap2/clkt_dpll.c b/arch/arm/mach-omap2/clkt_dpll.c index 332af927f4d3..85701142c5fc 100644 --- a/arch/arm/mach-omap2/clkt_dpll.c +++ b/arch/arm/mach-omap2/clkt_dpll.c @@ -293,10 +293,13 @@ long omap2_dpll_round_rate(struct clk_hw *hw, unsigned long target_rate, { struct clk_hw_omap *clk = to_clk_hw_omap(hw); int m, n, r, scaled_max_m; + int min_delta_m = INT_MAX, min_delta_n = INT_MAX; unsigned long scaled_rt_rp; unsigned long new_rate = 0; struct dpll_data *dd; unsigned long ref_rate; + long delta; + long prev_min_delta = LONG_MAX; const char *clk_name; if (!clk || !clk->dpll_data) @@ -342,23 +345,34 @@ long omap2_dpll_round_rate(struct clk_hw *hw, unsigned long target_rate, if (r == DPLL_MULT_UNDERFLOW) continue; + /* skip rates above our target rate */ + delta = target_rate - new_rate; + if (delta < 0) + continue; + + if (delta < prev_min_delta) { + prev_min_delta = delta; + min_delta_m = m; + min_delta_n = n; + } + pr_debug("clock: %s: m = %d: n = %d: new_rate = %lu\n", clk_name, m, n, new_rate); - if (target_rate == new_rate) { - dd->last_rounded_m = m; - dd->last_rounded_n = n; - dd->last_rounded_rate = target_rate; + if (delta == 0) break; - } } - if (target_rate != new_rate) { + if (prev_min_delta == LONG_MAX) { pr_debug("clock: %s: cannot round to rate %lu\n", clk_name, target_rate); return ~0; } - return target_rate; + dd->last_rounded_m = min_delta_m; + dd->last_rounded_n = min_delta_n; + dd->last_rounded_rate = target_rate - prev_min_delta; + + return dd->last_rounded_rate; } diff --git a/arch/arm/mach-omap2/dpll3xxx.c b/arch/arm/mach-omap2/dpll3xxx.c index fcd8036af910..839a13e1208b 100644 --- a/arch/arm/mach-omap2/dpll3xxx.c +++ b/arch/arm/mach-omap2/dpll3xxx.c @@ -469,6 +469,7 @@ int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate, { struct clk_hw_omap *clk = to_clk_hw_omap(hw); struct clk *new_parent = NULL; + unsigned long rrate; u16 freqsel = 0; struct dpll_data *dd; int ret; @@ -496,8 +497,15 @@ int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate, __clk_prepare(dd->clk_ref); clk_enable(dd->clk_ref); - if (dd->last_rounded_rate != rate) - rate = __clk_round_rate(hw->clk, rate); + if (dd->last_rounded_rate != rate) { + rrate = __clk_round_rate(hw->clk, rate); + if (rrate != rate) { + pr_warn("%s: %s: final rate %lu does not match desired rate %lu\n", + __func__, __clk_get_name(hw->clk), + rrate, rate); + rate = rrate; + } + } if (dd->last_rounded_rate == 0) return -EINVAL;