Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933951AbbGVNQw (ORCPT ); Wed, 22 Jul 2015 09:16:52 -0400 Received: from mail-wi0-f175.google.com ([209.85.212.175]:34025 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756770AbbGVNE1 (ORCPT ); Wed, 22 Jul 2015 09:04:27 -0400 From: Lee Jones To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: kernel@stlinux.com, mturquette@linaro.org, sboyd@codeaurora.org, devicetree@vger.kernel.org, geert@linux-m68k.org, maxime.ripard@free-electrons.com, s.hauer@pengutronix.de, Lee Jones Subject: [PATCH v7 4/5] clk: Provide critical clock support Date: Wed, 22 Jul 2015 14:04:14 +0100 Message-Id: <1437570255-21049-5-git-send-email-lee.jones@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1437570255-21049-1-git-send-email-lee.jones@linaro.org> References: <1437570255-21049-1-git-send-email-lee.jones@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2732 Lines: 88 Lots of platforms contain clocks which if turned off would prove fatal. The only way to recover from these catastrophic failures is to restart the board(s). Now, when a clock provider is registered with the framework it is possible for a list of critical clocks to be supplied which must be kept ungated. Each clock mentioned in the newly introduced 'critical-clock' property will be clk_prepare_enable()d where the normal references will be taken. This will prevent the common clk framework from attempting to gate them during the normal clk_disable_unused() and disable_clock() procedures. Note that it will still be possible for knowledgeable drivers to turn these clocks off using clk_{enable,disable}_critical() calls. Signed-off-by: Lee Jones --- drivers/clk/clk-conf.c | 45 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c index aad4796..f83c1c2 100644 --- a/drivers/clk/clk-conf.c +++ b/drivers/clk/clk-conf.c @@ -116,6 +116,45 @@ static int __set_clk_rates(struct device_node *node, bool clk_supplier) return 0; } +static int __set_critical_clocks(struct device_node *node, bool clk_supplier) +{ + struct of_phandle_args clkspec; + struct clk *clk; + struct property *prop; + const __be32 *cur; + uint32_t index; + int ret; + + if (!clk_supplier) + return 0; + + of_property_for_each_u32(node, "critical-clock", prop, cur, index) { + clkspec.np = node; + clkspec.args_count = 1; + clkspec.args[0] = index; + + clk = of_clk_get_from_provider(&clkspec); + if (IS_ERR(clk)) { + pr_err("clk: couldn't get clock %u for %s\n", + index, node->full_name); + return PTR_ERR(clk); + } + + clk_init_critical(clk); + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("Failed to enable clock %u for %s: %d\n", + index, node->full_name, ret); + return ret; + } + + pr_debug("Setting clock as critical %pC\n", clk); + } + + return 0; +} + /** * of_clk_set_defaults() - parse and set assigned clocks configuration * @node: device node to apply clock settings for @@ -139,6 +178,10 @@ int of_clk_set_defaults(struct device_node *node, bool clk_supplier) if (rc < 0) return rc; - return __set_clk_rates(node, clk_supplier); + rc = __set_clk_rates(node, clk_supplier); + if (rc < 0) + return rc; + + return __set_critical_clocks(node, clk_supplier); } EXPORT_SYMBOL_GPL(of_clk_set_defaults); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/