| Message ID | 1400520171-6698-3-git-send-email-s.nawrocki@samsung.com |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 19/05/14 19:22, Sylwester Nawrocki wrote: > @@ -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); There is an error in this patch, this line should read: + of_clk_set_defaults(clk_provider->np, true); > list_del(&clk_provider->node); > kfree(clk_provider); > is_init_done = true; -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Quoting Sylwester Nawrocki (2014-05-19 10:22:51) > 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 s/frequecies/frequencies/ > +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. Is it worthwhile to show an example of this? I guess the outcome will depend on whether or not we support "assigned-clocks" property, which I just revisited in the V5 thread. Regards, Mike -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 05/19/2014 10:52 PM, Sylwester Nawrocki wrote: > 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@samsung.com> [ ... ] > 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; > + of_clk_set_defaults() is not getting called when the related driver is not registered through platform_driver_register(). I came across this issue while testing this patch on peach-pit board with following dts change. max98090 audio codec driver is registered through module_i2c_driver(). * arch/arm/boot/dts/exynos5420-peach-pit.dts &hsi2c_7 { status = "okay"; max98090: codec@10 { compatible = "maxim,max98090"; reg = <0x10>; interrupts = <2 0>; interrupt-parent = <&gpx0>; pinctrl-names = "default"; pinctrl-0 = <&max98090_irq>; + clocks = <&pmu_system_controller 0>; + clock-names = "mclk"; + clock-parents = <&clock CLK_FIN_PLL>; + clock-rates = <24000000>; }; };
On 27/05/14 12:28, Tushar Behera wrote: > On 05/19/2014 10:52 PM, Sylwester Nawrocki wrote: >> 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@samsung.com> > > [ ... ] > >> 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; >> + > > of_clk_set_defaults() is not getting called when the related driver is > not registered through platform_driver_register(). > > I came across this issue while testing this patch on peach-pit board with > following dts change. max98090 audio codec driver is registered through > module_i2c_driver(). Yes, that shouldn't be surprising, since now in this RFC the clocks setting is done only for platform bus devices. Similarly the above call would need to be added to i2c, amba, spi and maybe other busses. We just need to be careful to avoid attempting to set up clocks of a clock provider device before it is probed and actually registers its clocks. I'm still not sure if we should carry on with this approach or do all the clocks set up in one place, similarly to disabling unused clocks. I'm afraid when attempting to set up all clocks at one point in time the clock parent/rate dependencies may get even more hairy. The deferred probe mechanism helps to resolve the dependencies when the clock defaults setting is done before or within a driver probe() call. Either for clock supplier and consumer nodes or a supplier only. > * arch/arm/boot/dts/exynos5420-peach-pit.dts > > &hsi2c_7 { > > status = "okay"; > > max98090: codec@10 { > compatible = "maxim,max98090"; > reg = <0x10>; > interrupts = <2 0>; > interrupt-parent = <&gpx0>; > pinctrl-names = "default"; > pinctrl-0 = <&max98090_irq>; > + clocks = <&pmu_system_controller 0>; > + clock-names = "mclk"; > + clock-parents = <&clock CLK_FIN_PLL>; > + clock-rates = <24000000>; > }; > }; -- Regards, Sylwester -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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@samsung.com> + * + * 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@samsung.com> + * + * 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
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@samsung.com> --- 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 -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html