This patch adds a helper function to configure clock parents and rates as specified in clock-parents, clock-rates DT properties for a consumer device and a call to it before driver is bound to a device. Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx> --- Changes since v5: - updated the DT binding description (dropped 'assigned-clocks' node); - fixed detecting of null phandles (ENOENT error handling); - modified of_clk_init() to account for that the clocks property may now contain a clock specifier with a phandle that points to our node; Changes since v4: - added note explaining how to skip setting parent and rate of a clock, - moved of_clk_dev_init() calls to the platform bus, - added missing call to of_node_put(), - dropped debug traces. Changes since v3: - added detailed description of the assigned-clocks subnode, - added missing 'static inline' to the function stub definition, - clk-conf.c is now excluded when CONFIG_OF is not set, - s/of_clk_device_setup/of_clk_device_init. Changes since v2: - edited in clock-bindings.txt, added note about 'assigned-clocks' subnode which may be used to specify "global" clocks configuration at a clock provider node, - moved of_clk_device_setup() function declaration from clk-provider.h to clk-conf.h so required function stubs are available when CONFIG_COMMON_CLK is not enabled, Changes since v1: - the helper function to parse and set assigned clock parents and rates made public so it is available to clock providers to call directly; - dropped the platform bus notification and call of_clk_device_setup() is is now called from the driver core, rather than from the notification callback; - s/of_clk_get_list_entry/of_clk_get_by_property. --- .../devicetree/bindings/clock/clock-bindings.txt | 32 +++++ drivers/base/platform.c | 5 + drivers/clk/Makefile | 3 + drivers/clk/clk-conf.c | 141 ++++++++++++++++++++ drivers/clk/clk.c | 27 +++- include/linux/clk/clk-conf.h | 20 +++ 6 files changed, 225 insertions(+), 3 deletions(-) create mode 100644 drivers/clk/clk-conf.c create mode 100644 include/linux/clk/clk-conf.h diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt index 700e7aa..bee649b 100644 --- a/Documentation/devicetree/bindings/clock/clock-bindings.txt +++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt @@ -132,3 +132,35 @@ clock signal, and a UART. ("pll" and "pll-switched"). * The UART has its baud clock connected the external oscillator and its register clock connected to the PLL clock (the "pll-switched" signal) + +==Assigned clock parents and rates== + +Some platforms require static initial configuration of default parent clocks +and clock frequecies. Such a configuration can be specified in a device node +through clock-parents and clock-rates DT properties. The former should contain +a list of parent clocks in form of phandle and clock specifier pairs, the +latter the list of assigned clock frequency values (one cell each). +To skip setting parent or rate of a clock its corresponding entry should be +set to 0, or can be omitted if it is not followed by any non-zero entry. + + uart@a000 { + compatible = "fsl,imx-uart"; + reg = <0xa000 0x1000>; + ... + clocks = <&clkcon 0>, <&clkcon 3>; + clock-names = "baud", "mux"; + + clock-parents = <0>, <&pll 1>; + clock-rates = <460800>; + }; + +In this example the pll is set as parent of "mux" clock and frequency of +"baud" clock is specified as 460800 Hz. + +Configuring a clock's parent and rate through the device node that consumes +the clock can be done only for clocks that have a single user. Specifying +conflicting parent or rate configuration in multiple consumer nodes for +a shared clock is forbidden. + +Configuration of common clocks, which affect multiple consumer devices can +be similarly specified in the clock provider node. diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 5b47210..f622733 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -23,6 +23,7 @@ #include <linux/pm_runtime.h> #include <linux/idr.h> #include <linux/acpi.h> +#include <linux/clk/clk-conf.h> #include "base.h" #include "power/power.h" @@ -486,6 +487,10 @@ static int platform_drv_probe(struct device *_dev) struct platform_device *dev = to_platform_device(_dev); int ret; + ret = of_clk_set_defaults(_dev->of_node, false); + if (ret < 0) + return ret; + acpi_dev_pm_attach(_dev, true); ret = drv->probe(dev); diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 5f8a287..45598f7 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -8,6 +8,9 @@ obj-$(CONFIG_COMMON_CLK) += clk-fixed-rate.o obj-$(CONFIG_COMMON_CLK) += clk-gate.o obj-$(CONFIG_COMMON_CLK) += clk-mux.o obj-$(CONFIG_COMMON_CLK) += clk-composite.o +ifeq ($(CONFIG_OF), y) +obj-$(CONFIG_COMMON_CLK) += clk-conf.o +endif # hardware specific clock types # please keep this section sorted lexicographically by file/directory path name diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c new file mode 100644 index 0000000..0bf26d5 --- /dev/null +++ b/drivers/clk/clk-conf.c @@ -0,0 +1,141 @@ +/* + * Copyright (C) 2014 Samsung Electronics Co., Ltd. + * Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/device.h> +#include <linux/of.h> +#include <linux/printk.h> +#include "clk.h" + +static int __set_clk_parents(struct device_node *node, bool self_consumer) +{ + struct of_phandle_args clkspec; + int index, rc, num_parents; + struct clk *clk, *pclk; + + num_parents = of_count_phandle_with_args(node, "clock-parents", + "#clock-cells"); + if (num_parents == -EINVAL) + pr_err("clk: invalid value of clock-parents property at %s\n", + node->full_name); + + for (index = 0; index < num_parents; index++) { + rc = of_parse_phandle_with_args(node, "clock-parents", + "#clock-cells", index, &clkspec); + if (rc < 0) { + /* skip empty (null) phandles */ + if (rc == -ENOENT) + continue; + else + return rc; + } + if (clkspec.np == node && !self_consumer) + return 0; + pclk = of_clk_get_by_clkspec(&clkspec); + if (IS_ERR(pclk)) { + pr_warn("clk: couldn't get parent clock %d for %s\n", + index, node->full_name); + return PTR_ERR(pclk); + } + + rc = of_parse_phandle_with_args(node, "clocks", "#clock-cells", + index, &clkspec); + if (rc < 0) + goto err; + if (clkspec.np == node && !self_consumer) { + rc = 0; + goto err; + } + clk = of_clk_get_by_clkspec(&clkspec); + if (IS_ERR(pclk)) { + pr_warn("clk: couldn't get parent clock %d for %s\n", + index, node->full_name); + rc = PTR_ERR(pclk); + goto err; + } + + rc = clk_set_parent(clk, pclk); + if (rc < 0) + pr_err("clk: failed to reparent %s to %s: %d\n", + __clk_get_name(clk), __clk_get_name(pclk), rc); + clk_put(clk); + clk_put(pclk); + } + return 0; +err: + clk_put(pclk); + return rc; +} + +static int __set_clk_rates(struct device_node *node, bool self_consumer) +{ + struct of_phandle_args clkspec; + struct property *prop; + const __be32 *cur; + int rc, index = 0; + struct clk *clk; + u32 rate; + + of_property_for_each_u32(node, "clock-rates", prop, cur, rate) { + if (rate) { + rc = of_parse_phandle_with_args(node, "clocks", + "#clock-cells", index, &clkspec); + if (rc < 0) { + /* skip empty (null) phandles */ + if (rc == -ENOENT) + continue; + else + return rc; + } + if (clkspec.np == node && !self_consumer) + return 0; + + clk = of_clk_get_by_clkspec(&clkspec); + if (IS_ERR(clk)) { + pr_warn("clk: couldn't get clock %d for %s\n", + index, node->full_name); + return PTR_ERR(clk); + } + + rc = clk_set_rate(clk, rate); + if (rc < 0) + pr_err("clk: couldn't set %s clock rate: %d\n", + __clk_get_name(clk), rc); + clk_put(clk); + } + index++; + } + return 0; +} + +/** + * of_clk_set_defaults() - parse and set assigned clocks configuration + * @node: device node to apply clock settings for + * @self_consumer: true to indicate @node may also consume clocks it supplies + * + * This function parses 'clock-parents' and 'clock-rates' properties and sets + * any specified clock parents and rates. The @self_consumer argument should be + * set to true if @node may be also a clock supplier of any clock listed in its + * 'clocks' or 'clock-parents' properties. Otherwise the functions exits as soon + * as it determines the @node is also a supplier of any of the clocks. + */ +int of_clk_set_defaults(struct device_node *node, bool self_consumer) +{ + int rc; + + if (!node) + return 0; + + rc = __set_clk_parents(node, self_consumer); + if (rc < 0) + return rc; + + return __set_clk_rates(node, self_consumer); +} diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index dff0373..3a8947d 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -10,6 +10,7 @@ */ #include <linux/clk-private.h> +#include <linux/clk/clk-conf.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/spinlock.h> @@ -2429,6 +2430,7 @@ int of_clk_add_provider(struct device_node *np, void *data) { struct of_clk_provider *cp; + int ret; cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL); if (!cp) @@ -2443,7 +2445,11 @@ int of_clk_add_provider(struct device_node *np, mutex_unlock(&of_clk_mutex); pr_debug("Added clock from %s\n", np->full_name); - return 0; + ret = of_clk_set_defaults(np, true); + if (ret < 0) + of_clk_del_provider(np); + + return ret; } EXPORT_SYMBOL_GPL(of_clk_add_provider); @@ -2558,10 +2564,23 @@ static LIST_HEAD(clk_provider_list); */ static int parent_ready(struct device_node *np) { + struct of_phandle_args clkspec; int i = 0; while (true) { - struct clk *clk = of_clk_get(np, i); + struct clk *clk; + + int rc = of_parse_phandle_with_args(np, "clocks", + "#clock-cells", i, &clkspec); + if (!rc) { + if (clkspec.np == np) { + i++; + continue; + } + clk = of_clk_get_by_clkspec(&clkspec); + } else { + clk = ERR_PTR(rc); + } /* this parent is ready we can check the next one */ if (!IS_ERR(clk)) { @@ -2620,7 +2639,10 @@ void __init of_clk_init(const struct of_device_id *matches) list_for_each_entry_safe(clk_provider, next, &clk_provider_list, node) { if (force || parent_ready(clk_provider->np)) { + clk_provider->clk_init_cb(clk_provider->np); + of_clk_set_defaults(np, true); + list_del(&clk_provider->node); kfree(clk_provider); is_init_done = true; @@ -2635,7 +2657,6 @@ void __init of_clk_init(const struct of_device_id *matches) */ if (!is_init_done) force = true; - } } #endif diff --git a/include/linux/clk/clk-conf.h b/include/linux/clk/clk-conf.h new file mode 100644 index 0000000..0a1f311 --- /dev/null +++ b/include/linux/clk/clk-conf.h @@ -0,0 +1,20 @@ +/* + * Copyright (C) 2014 Samsung Electronics Co., Ltd. + * Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +struct device_node; + +#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) +int of_clk_set_defaults(struct device_node *node, bool self_consumer); +#else +static inline int of_clk_set_defaults(struct device_node *node, + bool self_consumer) +{ + return 0; +} +#endif -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html