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author | James Hogan <james.hogan@imgtec.com> | 2013-01-15 15:27:45 +0000 |
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committer | James Hogan <james.hogan@imgtec.com> | 2013-06-13 12:54:41 +0100 |
commit | caa279dda4d9a442d824cd333e8b72078b83e855 (patch) | |
tree | 609d39ecdf728bc759ab4a3e8775475b1e4636b7 /arch/metag/kernel | |
parent | c24d2976c7834aa948f9d8a48ad4285cfbaf1c3a (diff) | |
download | linux-caa279dda4d9a442d824cd333e8b72078b83e855.tar.gz linux-caa279dda4d9a442d824cd333e8b72078b83e855.tar.bz2 linux-caa279dda4d9a442d824cd333e8b72078b83e855.zip |
metag: init common clk and use "core" clk
If the common clock framework is enabled, call of_clk_init(NULL) in
time_init() to register device tree clocks with the clock framework.
After this time_init() calls a new function init_metag_clocks(), which
looks for a clock named "core" in the node compatible with "img,meta"
(usually the root node). If found the get_core_freq machine callback is
overridden to obtain the core clock frequency using that clock.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: devicetree-discuss@lists.ozlabs.org
Diffstat (limited to 'arch/metag/kernel')
-rw-r--r-- | arch/metag/kernel/clock.c | 57 | ||||
-rw-r--r-- | arch/metag/kernel/time.c | 14 |
2 files changed, 68 insertions, 3 deletions
diff --git a/arch/metag/kernel/clock.c b/arch/metag/kernel/clock.c index defc84056f18..8bfd6a5deac9 100644 --- a/arch/metag/kernel/clock.c +++ b/arch/metag/kernel/clock.c @@ -8,8 +8,10 @@ * published by the Free Software Foundation. */ +#include <linux/clk.h> #include <linux/delay.h> #include <linux/io.h> +#include <linux/of.h> #include <asm/param.h> #include <asm/clock.h> @@ -34,8 +36,61 @@ static unsigned long get_core_freq_default(void) #endif } +static struct clk *clk_core; + +/* Clk based get_core_freq callback. */ +static unsigned long get_core_freq_clk(void) +{ + return clk_get_rate(clk_core); +} + +/** + * init_metag_core_clock() - Set up core clock from devicetree. + * + * Checks to see if a "core" clock is provided in the device tree, and overrides + * the get_core_freq callback to use it. + */ +static void __init init_metag_core_clock(void) +{ + /* + * See if a core clock is provided by the devicetree (and + * registered by the init callback above). + */ + struct device_node *node; + node = of_find_compatible_node(NULL, NULL, "img,meta"); + if (!node) { + pr_warn("%s: no compatible img,meta DT node found\n", + __func__); + return; + } + + clk_core = of_clk_get_by_name(node, "core"); + if (IS_ERR(clk_core)) { + pr_warn("%s: no core clock found in DT\n", + __func__); + return; + } + + /* + * Override the core frequency callback to use + * this clk. + */ + _meta_clock.get_core_freq = get_core_freq_clk; +} + +/** + * init_metag_clocks() - Set up clocks from devicetree. + * + * Set up important clocks from device tree. In particular any needed for clock + * sources. + */ +void __init init_metag_clocks(void) +{ + init_metag_core_clock(); +} + /** - * setup_meta_clocks() - Set up the Meta clock. + * setup_meta_clocks() - Early set up of the Meta clock. * @desc: Clock descriptor usually provided by machine description * * Ensures all callbacks are valid. diff --git a/arch/metag/kernel/time.c b/arch/metag/kernel/time.c index 17dc10733b2f..f1c8c53dace7 100644 --- a/arch/metag/kernel/time.c +++ b/arch/metag/kernel/time.c @@ -5,11 +5,21 @@ * */ -#include <linux/init.h> - #include <clocksource/metag_generic.h> +#include <linux/clk-provider.h> +#include <linux/init.h> +#include <asm/clock.h> void __init time_init(void) { +#ifdef CONFIG_COMMON_CLK + /* Init clocks from device tree */ + of_clk_init(NULL); +#endif + + /* Init meta clocks, particularly the core clock */ + init_metag_clocks(); + + /* Set up the timer clock sources */ metag_generic_timer_init(); } |