Quoting Nishanth Menon (2013-05-08 12:06:11) <snip> > Overall strategy introduced here is simple: a clock node described in > device tree blob is used to identify the exact clock provided in the > SoC specific data. This is then linked back using of_clk_add_provider > to the device node to be accessible by of_clk_get. > FYI, I'm working on moving the OMAP clocks over to DT which is a better alternative than this patch. I'll share what I have on the list, hopefully next week. Regards, Mike > Based on discussion contributions from Roger Quadros, Grygorii Strashko > and others. > > Cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> > Cc: Mike Turquette <mturquette@xxxxxxxxxx> > Cc: Paul Walmsley <paul@xxxxxxxxx> > [tony@xxxxxxxxxxx: co-developed] > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> > Signed-off-by: Nishanth Menon <nm@xxxxxx> > --- > Changes in this version: > - review comments incorporated. > Previous version of this patch was discussed in: > http://marc.info/?t=136580758500001&r=1&w=2 > > .../devicetree/bindings/clock/omap-clock.txt | 40 +++++++++ > drivers/clk/Makefile | 1 + > drivers/clk/omap/Makefile | 1 + > drivers/clk/omap/clk.c | 91 ++++++++++++++++++++ > 4 files changed, 133 insertions(+) > create mode 100644 Documentation/devicetree/bindings/clock/omap-clock.txt > create mode 100644 drivers/clk/omap/Makefile > create mode 100644 drivers/clk/omap/clk.c > > diff --git a/Documentation/devicetree/bindings/clock/omap-clock.txt b/Documentation/devicetree/bindings/clock/omap-clock.txt > new file mode 100644 > index 0000000..047c1e7 > --- /dev/null > +++ b/Documentation/devicetree/bindings/clock/omap-clock.txt > @@ -0,0 +1,40 @@ > +Device Tree Clock bindings for Texas Instrument's OMAP compatible platforms > + > +This binding is an initial minimal binding that may be enhanced as part of > +transitioning OMAP clock data out of kernel image. > + > +This binding uses the common clock binding[1]. > + > +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt > + > +Required properties: > +- compatible : shall be "ti,omap-clock" > +- #clock-cells : from common clock binding; shall be set to 0. > +NOTE: > +node name should map to clock database in arch/arm/mach-omap2/cclock<SoC>_data.c > +Since all clocks are described with _ck, the node name is optimized to drop the > +usage of _ck. For example, a clock called dpll1_ck will be defined as dpll1. > + > +Example #1: describing clock node for CPU on OMAP34xx platform: > +Ref: arch/arm/mach-omap2/cclock3xxx_data.c > +describes the CPU clock to be as follows > + CLK(NULL, "dpll1_ck", &dpll1_ck, CK_3XXX), > +Corresponding binding will be: > + dpll1: dpll1 { > + #clock-cells = <0>; > + compatible = "ti,omap-clock"; > + }; > +And it's usage will be: > + clocks = <&dpll1>; > + > +Example #2: describing clock node for auxilary clock #3 on OMAP443x platform: > +Ref: arch/arm/mach-omap2/cclock44xx_data.c > +describes the auxclk3 clock to be as follows: > + CLK(NULL, "auxclk3_ck", &auxclk3_ck, CK_443X), > +Corresponding binding will be: > + auxclk3: auxclk3 { > + #clock-cells = <0>; > + compatible = "ti,omap-clock"; > + }; > +And it's usage will be: > + clocks = <&auxclk3>; > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile > index 137d3e7..1d5a2ec 100644 > --- a/drivers/clk/Makefile > +++ b/drivers/clk/Makefile > @@ -30,6 +30,7 @@ obj-$(CONFIG_ARCH_VT8500) += clk-vt8500.o > obj-$(CONFIG_ARCH_ZYNQ) += clk-zynq.o > obj-$(CONFIG_ARCH_TEGRA) += tegra/ > obj-$(CONFIG_PLAT_SAMSUNG) += samsung/ > +obj-$(CONFIG_ARCH_OMAP) += omap/ > > obj-$(CONFIG_X86) += x86/ > > diff --git a/drivers/clk/omap/Makefile b/drivers/clk/omap/Makefile > new file mode 100644 > index 0000000..8195931 > --- /dev/null > +++ b/drivers/clk/omap/Makefile > @@ -0,0 +1 @@ > +obj-y += clk.o > diff --git a/drivers/clk/omap/clk.c b/drivers/clk/omap/clk.c > new file mode 100644 > index 0000000..5a3c6d9 > --- /dev/null > +++ b/drivers/clk/omap/clk.c > @@ -0,0 +1,91 @@ > +/* > + * Texas Instruments OMAP Clock driver > + * > + * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com/ > + * Nishanth Menon <nm@xxxxxx> > + * Tony Lindgren <tony@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. > + * > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any > + * kind, whether express or implied; without even the implied warranty > + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/clkdev.h> > +#include <linux/clk-provider.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/string.h> > + > +static const struct of_device_id omap_clk_of_match[] = { > + {.compatible = "ti,omap-clock",}, > + {}, > +}; > + > +/** > + * omap_clk_src_get() - Get OMAP clock from node name when needed > + * @clkspec: clkspec argument > + * @data: unused > + * > + * REVISIT: We assume the following: > + * 1. omap clock names end with _ck > + * 2. omap clock names are under 32 characters in length > + */ > +static struct clk *omap_clk_src_get(struct of_phandle_args *clkspec, void *data) > +{ > + struct clk *clk; > + char clk_name[32]; > + struct device_node *np = clkspec->np; > + > + snprintf(clk_name, 32, "%s_ck", np->name); > + clk = clk_get(NULL, clk_name); > + if (IS_ERR(clk)) > + pr_err("%s: could not get clock %s(%ld)\n", __func__, > + clk_name, PTR_ERR(clk)); > + > + return clk; > +} > + > +/** > + * omap_clk_probe() - create link from DT definition to clock data > + * @pdev: device node > + * > + * NOTE: we look up the clock lazily when the consumer driver does > + * of_clk_get() and initialize a NULL clock here. > + */ > +static int omap_clk_probe(struct platform_device *pdev) > +{ > + int res; > + struct device_node *np = pdev->dev.of_node; > + > + /* This allows the driver to of_clk_get() */ > + res = of_clk_add_provider(np, omap_clk_src_get, NULL); > + if (res) > + dev_err(&pdev->dev, "could not add provider(%d)\n", res); > + > + return res; > +} > + > +static struct platform_driver omap_clk_driver = { > + .probe = omap_clk_probe, > + .driver = { > + .name = "omap_clk", > + .of_match_table = of_match_ptr(omap_clk_of_match), > + }, > +}; > + > +static int __init omap_clk_init(void) > +{ > + return platform_driver_register(&omap_clk_driver); > +} > +arch_initcall(omap_clk_init); > + > +MODULE_DESCRIPTION("OMAP Clock driver"); > +MODULE_AUTHOR("Texas Instruments Inc."); > +MODULE_LICENSE("GPL v2"); > -- > 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
