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Date: Fri, 5 Jul 2013 00:05:12 +0300 From: Luciano Coelho <coelho@...com> To: <mturquette@...aro.org> CC: <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>, <balbi@...com>, <coelho@...com> Subject: [RFC] clk: add flags to distinguish xtal clocks Add a flag that indicate whether the clock is a crystal or not. Since no clocks set this flag right now, include an additional flag that indicates whether the type is set or not. If the CLK_IS_TYPE_DEFINED flag is not set, the value of the CLK_IS_TYPE_XTAL flag is undefined. This ensures backwards compatibility. Additionally, parse a new device tree binding in clk-fixed-rate to set this flag. Signed-off-by: Luciano Coelho <coelho@...com> --- I'm not familiar with the common clock framework and I'm not entirely sure the flags can be used in such a way, but to me it looks reasonable, since some clock consumers may need to know what type of clock is being provided. Specifically, the wl12xx firmware needs to know if the clock is XTAL or not to handle the stabilization and boosts properly. My main idea is that I need to pass this information in the device tree definition of the clocks, so that the driver can pass this information on to the firmware. Please let me know if this looks ok or not. If not, please let me know if you have any other ideas on how to solve my problem (of knowing whether the clock attached to the WiLink chip is XTAL or not). drivers/clk/clk-fixed-rate.c | 6 +++++- include/linux/clk-provider.h | 2 ++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/clk/clk-fixed-rate.c b/drivers/clk/clk-fixed-rate.c index dc58fbd..4003a82 100644 --- a/drivers/clk/clk-fixed-rate.c +++ b/drivers/clk/clk-fixed-rate.c @@ -90,13 +90,17 @@ void of_fixed_clk_setup(struct device_node *node) struct clk *clk; const char *clk_name = node->name; u32 rate; + unsigned long flags = CLK_IS_ROOT; if (of_property_read_u32(node, "clock-frequency", &rate)) return; + if (of_property_read_bool(node, "clock-xtal")) + flags |= CLK_IS_TYPE_DEFINED | CLK_IS_TYPE_XTAL; + of_property_read_string(node, "clock-output-names", &clk_name); - clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT, rate); + clk = clk_register_fixed_rate(NULL, clk_name, NULL, flags, rate); if (!IS_ERR(clk)) of_clk_add_provider(node, of_clk_src_simple_get, clk); } diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 1186098..034320b 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -27,6 +27,8 @@ #define CLK_IS_ROOT BIT(4) /* root clk, has no parent */ #define CLK_IS_BASIC BIT(5) /* Basic clk, can't do a to_clk_foo() */ #define CLK_GET_RATE_NOCACHE BIT(6) /* do not use the cached clk rate */ +#define CLK_IS_TYPE_DEFINED BIT(7) /* the clock type is defined */ +#define CLK_IS_TYPE_XTAL BIT(8) /* this is a crystal clock */ struct clk_hw; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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