From patchwork Tue Feb 15 08:44:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 12746708 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 7D882C433F5 for ; Tue, 15 Feb 2022 08:44:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234596AbiBOIou (ORCPT ); Tue, 15 Feb 2022 03:44:50 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:53526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234609AbiBOIot (ORCPT ); Tue, 15 Feb 2022 03:44:49 -0500 Received: from phobos.denx.de (phobos.denx.de [IPv6:2a01:238:438b:c500:173d:9f52:ddab:ee01]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FDE0111F8F; Tue, 15 Feb 2022 00:44:40 -0800 (PST) Received: from tr.lan (ip-89-176-112-137.net.upcbroadband.cz [89.176.112.137]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id 6581F810EC; Tue, 15 Feb 2022 09:44:38 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1644914678; bh=+gsN6CS5cyJLY35Hog/hYyWdo7/b8jO3oJkqkV1ZkA8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xaqXWGPta6BEfycX+/MshsKf11jMwd3ffznruP5GZhr+URixgBLqemD4DwJywwZ5I CP6AL2c2s8hm04SiHFq5tLQliPkwjP6fLOHybyuIRtWj53N/ki8sN5Q1OYngfNcv6k NUW0obIycWlbeh0xdRSWKVjG82l1j0bsC9OQZ4zfxDoFR/GmH/AQLYnpQOgfErchAW 45KEw1MQ53EcPypVhkvs1hJz9NYnaHDQl1z91F/FuNObiMz0k+l9H11k3IQ+ph3YPT 3UGi1QxCJ3/cEWiMXyMdgUXSTTleSAFIeFFxGgEyvKdQKfsCjVtxIIQ0qZ397BL5bw eN8UEp1hmHLIg== From: Marek Vasut To: linux-clk@vger.kernel.org Cc: Marek Vasut , Matti Vaittinen , Michael Turquette , Rob Herring , Stephen Boyd , devicetree@vger.kernel.org, linux-power@fi.rohmeurope.com Subject: [PATCH 2/3] clk: Introduce 'critical-clocks' property Date: Tue, 15 Feb 2022 09:44:11 +0100 Message-Id: <20220215084412.8090-2-marex@denx.de> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220215084412.8090-1-marex@denx.de> References: <20220215084412.8090-1-marex@denx.de> MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.103.5 at phobos.denx.de X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org Some platforms require clock to be always running, e.g. because those clock supply devices which are not otherwise attached to the system. One example is a system where the SoC serves as a crystal oscillator replacement for a programmable logic device. The critical-clock property of a clock controller allows listing clock which must never be turned off. The implementation here is similar to "protected-clock", except protected clock property is currently driver specific. This patch attempts to make a generic implementation of "critical-clock" instead. Unlike "assigned-clocks", the "critical-clock" must be parsed much earlier in __clk_register() to assign CLK_IS_CRITICAL flag to clk_init_data .flags field. The parsing code obviously need to be cleaned up and factor out into separate function. The new match_clkspec() callback is used to determine whether struct clk_hw that is currently being registered matches the clock specifier in the DT "critical-clock" property, and if so, then the CLK_IS_CRITICAL is added to these newly registered clock. This callback is currently driver specific, although I suspect a common and/or generic version of the callback could be added. Also, this new callback could possibly be used to replace (*get) argument of of_clk_add_hw_provider() later on too. Signed-off-by: Marek Vasut Cc: Matti Vaittinen Cc: Michael Turquette Cc: Rob Herring Cc: Stephen Boyd Cc: devicetree@vger.kernel.org Cc: linux-power@fi.rohmeurope.com To: linux-clk@vger.kernel.org Reported-by: kernel test robot Reported-by: kernel test robot --- drivers/clk/clk.c | 41 ++++++++++++++++++++++++++++++++++++ include/linux/clk-provider.h | 3 +++ 2 files changed, 44 insertions(+) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 8de6a22498e70..1e1686fa76e01 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -3872,6 +3872,45 @@ static void clk_core_free_parent_map(struct clk_core *core) kfree(core->parents); } +static void +__clk_register_critical_clock(struct device_node *np, struct clk_core *core, + struct clk_hw *hw) +{ + struct of_phandle_args clkspec; + u32 clksize, clktotal; + int ret, i, index; + + if (!np) + return; + + if (!core->ops->match_clkspec) + return; + + if (of_property_read_u32(np, "#clock-cells", &clksize)) + return; + + /* Clock node with #clock-cells = <0> uses critical-clocks; */ + if (clksize == 0) { + if (of_property_read_bool(np, "critical-clocks") && + !core->ops->match_clkspec(hw, &clkspec)) + core->flags |= CLK_IS_CRITICAL; + return; + } + + clkspec.np = np; + clktotal = of_property_count_u32_elems(np, "critical-clocks"); + clktotal /= clksize; + for (index = 0; index < clktotal; index++) { + for (i = 0; i < clksize; i++) { + ret = of_property_read_u32_index(np, "critical-clocks", + (index * clksize) + i, + &(clkspec.args[i])); + } + if (!core->ops->match_clkspec(hw, &clkspec)) + core->flags |= CLK_IS_CRITICAL; + } +} + static struct clk * __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw) { @@ -3916,6 +3955,8 @@ __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw) core->min_rate = 0; core->max_rate = ULONG_MAX; + __clk_register_critical_clock(np, core, hw); + ret = clk_core_populate_parent_map(core, init); if (ret) goto fail_parents; diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 2faa6f7aa8a87..8bc0eedfeb2fd 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -205,6 +205,8 @@ struct clk_duty { * directory is provided as an argument. Called with * prepare_lock held. Returns 0 on success, -EERROR otherwise. * + * @match_clkspec: Check whether clk_hw matches DT clock specifier. + * Returns 0 on success, -EERROR otherwise. * * The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow * implementations to split any work between atomic (enable) and sleepable @@ -252,6 +254,7 @@ struct clk_ops { int (*init)(struct clk_hw *hw); void (*terminate)(struct clk_hw *hw); void (*debug_init)(struct clk_hw *hw, struct dentry *dentry); + int (*match_clkspec)(struct clk_hw *hw, struct of_phandle_args *clkspec); }; /**