[v6,1/6] clk: Add of_clk_get_by_name_optional() function

Message ID	20181116145937.27660-2-phil.edworthy@renesas.com (mailing list archive)
State	Superseded, archived
Headers	show Return-Path: <linux-clk-owner@kernel.org> From: Phil Edworthy <phil.edworthy@renesas.com> To: Stephen Boyd <sboyd@kernel.org>, Michael Turquette <mturquette@baylibre.com>, Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Russell King <linux@armlinux.org.uk> Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Phil Edworthy <phil.edworthy@renesas.com>, Geert Uytterhoeven <geert@linux-m68k.org>, =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>, linux-arm-kernel@lists.infradead.org Subject: [PATCH v6 1/6] clk: Add of_clk_get_by_name_optional() function Date: Fri, 16 Nov 2018 14:59:32 +0000 Message-Id: <20181116145937.27660-2-phil.edworthy@renesas.com> In-Reply-To: <20181116145937.27660-1-phil.edworthy@renesas.com> References: <20181116145937.27660-1-phil.edworthy@renesas.com> Sender: linux-clk-owner@vger.kernel.org Precedence: bulk
Series	clk: Add functions to get optional clocks \| expand [v6,0/6] clk: Add functions to get optional clocks [v6,1/6] clk: Add of_clk_get_by_name_optional() function [v6,2/6] clk: Add (devm_)clk_get_optional() functions [v6,3/6] m68k: coldfire: Add clk_get_optional() function [v6,4/6] MIPS: AR7: Add clk_get_optional() function [v6,5/6] MIPS: Loongson 2F: Add clk_get_optional() function [v6,6/6] arch/unicore32/kernel/clock.c: Add clk_get_optional() function

diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c index 9ab3db8b3988..0c655d1ba1d9 100644 --- a/drivers/clk/clkdev.c +++ b/drivers/clk/clkdev.c @@ -52,9 +52,19 @@ struct clk *of_clk_get(struct device_node *np, int index) } EXPORT_SYMBOL(of_clk_get); +/* + * This function tries to find a clock provider. + * If a name is provided, the function looks for a clock with that name in the + * OF node's "clock-names" property. If not found, the function will try the + * parent node and so on until a matching property is found or we reach the + * top of the tree. + * When no clock provider is found, if optional is true, the function will + * return NULL, otherwise return -ENOENT. + */ static struct clk *__of_clk_get_by_name(struct device_node *np, const char *dev_id, - const char *name) + const char *name, + bool optional) { struct clk *clk = ERR_PTR(-ENOENT); @@ -65,18 +75,33 @@ static struct clk *__of_clk_get_by_name(struct device_node *np, /* * For named clocks, first look up the name in the * "clock-names" property. If it cannot be found, then - * index will be an error code, and of_clk_get() will fail. + * index will be an error code. */ if (name) index = of_property_match_string(np, "clock-names", name); - clk = __of_clk_get(np, index, dev_id, name); - if (!IS_ERR(clk)) { - break; - } else if (name && index >= 0) { - if (PTR_ERR(clk) != -EPROBE_DEFER) - pr_err("ERROR: could not get clock %pOF:%s(%i)\n", - np, name ? name : "", index); - return clk; + + /* + * If we are looking for an unnamed clock, or we have found the + * named clock in the node, try to get the clock provider. + */ + if (index >= 0) { + clk = __of_clk_get(np, index, dev_id, name); + if (!IS_ERR(clk)) + return clk; + + /* + * If the node specifies the clock name, do not walk up + * the tree looking in parent nodes. + */ + if (name) { + /* Optional clock that's not there? */ + if (optional && PTR_ERR(clk) == -ENOENT) + clk = NULL; + else if (PTR_ERR(clk) != -EPROBE_DEFER) + pr_err("ERROR: could not get clock %pOF:%s(%i)\n", + np, name, index); + return clk; + } } /* @@ -89,6 +114,9 @@ static struct clk *__of_clk_get_by_name(struct device_node *np, break; } + if (optional && PTR_ERR(clk) == -ENOENT) + clk = NULL; + return clk; } @@ -106,15 +134,37 @@ struct clk *of_clk_get_by_name(struct device_node *np, const char *name) if (!np) return ERR_PTR(-ENOENT); - return __of_clk_get_by_name(np, np->full_name, name); + return __of_clk_get_by_name(np, np->full_name, name, false); } EXPORT_SYMBOL(of_clk_get_by_name); +/** + * of_clk_get_by_name_optional() - Parse and lookup an optional clock referenced + * by a device node + * @np: pointer to clock consumer node + * @name: name of consumer's clock input, or NULL for the first clock reference + * + * This function parses the clocks and clock-names properties, and uses them to + * look up the struct clk from the registered list of clock providers. + * It behaves the same as of_clk_get_by_name(), except when np is NULL or no + * clock provider is found, when it then returns NULL. + */ +struct clk *of_clk_get_by_name_optional(struct device_node *np, + const char *name) +{ + if (!np) + return NULL; + + return __of_clk_get_by_name(np, np->full_name, name, true); +} +EXPORT_SYMBOL(of_clk_get_by_name_optional); + #else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */ static struct clk *__of_clk_get_by_name(struct device_node *np, const char *dev_id, - const char *name) + const char *name, + bool optional) { return ERR_PTR(-ENOENT); } @@ -197,7 +247,7 @@ struct clk *clk_get(struct device *dev, const char *con_id) struct clk *clk; if (dev && dev->of_node) { - clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id); + clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id, false); if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER) return clk; } diff --git a/include/linux/clk.h b/include/linux/clk.h index a7773b5c0b9f..84512b3ecf5c 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -865,6 +865,7 @@ static inline void clk_bulk_disable_unprepare(int num_clks, #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) struct clk *of_clk_get(struct device_node *np, int index); struct clk *of_clk_get_by_name(struct device_node *np, const char *name); +struct clk *of_clk_get_by_name_optional(struct device_node *np, const char *name); struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec); #else static inline struct clk *of_clk_get(struct device_node *np, int index) @@ -876,6 +877,11 @@ static inline struct clk *of_clk_get_by_name(struct device_node *np, { return ERR_PTR(-ENOENT); } +static inline struct clk *of_clk_get_by_name_optional(struct device_node *np, + const char *name) +{ + return NULL; +} static inline struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) { return ERR_PTR(-ENOENT);

[v6,1/6] clk: Add of_clk_get_by_name_optional() function

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