[PATCH v2 4/7] clk: Add simple gated clock
From: Richard Zhao <hidden>
Date: 2011-10-12 06:47:07
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On Thu, Sep 22, 2011 at 03:26:59PM -0700, Mike Turquette wrote:
From: Jeremy Kerr <redacted> Signed-off-by: Jeremy Kerr <redacted> Signed-off-by: Mark Brown <redacted> Signed-off-by: Jamie Iles <redacted> Signed-off-by: Mike Turquette <redacted> --- Changes since v1: Add copyright header Fold in Jamie's patch for set-to-disable clks Use BIT macro instead of shift drivers/clk/Kconfig | 4 ++ drivers/clk/Makefile | 1 + drivers/clk/clk-gate.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/clk.h | 13 ++++++++ 4 files changed, 96 insertions(+), 0 deletions(-) create mode 100644 drivers/clk/clk-gate.c
I feel hard to tell the tree the clk parent, at register/init time. For the simple gate clk, the only way is to set .get_parent. But normally, for clk without any divider we set .get_parent to NULL. Maybe we can put .parent to struct clk_hw? Thanks Richard
quoted hunk ↗ jump to hunk
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index d8313d7..a78967c 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig@@ -12,3 +12,7 @@ config GENERIC_CLK config GENERIC_CLK_FIXED bool depends on GENERIC_CLK + +config GENERIC_CLK_GATE + bool + depends on GENERIC_CLKdiff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 9a3325a..d186446 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile@@ -2,3 +2,4 @@ obj-$(CONFIG_CLKDEV_LOOKUP) += clkdev.o obj-$(CONFIG_GENERIC_CLK) += clk.o obj-$(CONFIG_GENERIC_CLK_FIXED) += clk-fixed.o +obj-$(CONFIG_GENERIC_CLK_GATE) += clk-gate.odiff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c new file mode 100644 index 0000000..a1d8e79 --- /dev/null +++ b/drivers/clk/clk-gate.c@@ -0,0 +1,78 @@ +/* + * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.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. + * + * Simple clk gate implementation + */ + +#include <linux/clk.h> +#include <linux/module.h> +#include <asm/io.h> + +#define to_clk_gate(clk) container_of(clk, struct clk_gate, hw) + +static unsigned long clk_gate_get_rate(struct clk_hw *clk) +{ + return clk_get_rate(clk_get_parent(clk->clk)); +} + +static void clk_gate_set_bit(struct clk_hw *clk) +{ + struct clk_gate *gate = to_clk_gate(clk); + u32 reg; + + reg = __raw_readl(gate->reg); + reg |= BIT(gate->bit_idx); + __raw_writel(reg, gate->reg); +} + +static void clk_gate_clear_bit(struct clk_hw *clk) +{ + struct clk_gate *gate = to_clk_gate(clk); + u32 reg; + + reg = __raw_readl(gate->reg); + reg &= ~BIT(gate->bit_idx); + __raw_writel(reg, gate->reg); +} + +static int clk_gate_enable_set(struct clk_hw *clk) +{ + clk_gate_set_bit(clk); + + return 0; +} + +static void clk_gate_disable_clear(struct clk_hw *clk) +{ + clk_gate_clear_bit(clk); +} + +struct clk_hw_ops clk_gate_set_enable_ops = { + .recalc_rate = clk_gate_get_rate, + .enable = clk_gate_enable_set, + .disable = clk_gate_disable_clear, +}; +EXPORT_SYMBOL_GPL(clk_gate_set_enable_ops); + +static int clk_gate_enable_clear(struct clk_hw *clk) +{ + clk_gate_clear_bit(clk); + + return 0; +} + +static void clk_gate_disable_set(struct clk_hw *clk) +{ + clk_gate_set_bit(clk); +} + +struct clk_hw_ops clk_gate_set_disable_ops = { + .recalc_rate = clk_gate_get_rate, + .enable = clk_gate_enable_clear, + .disable = clk_gate_disable_set, +}; +EXPORT_SYMBOL_GPL(clk_gate_set_disable_ops);diff --git a/include/linux/clk.h b/include/linux/clk.h index 1903dd8..626fd0d 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h@@ -124,6 +124,19 @@ extern struct clk_hw_ops clk_fixed_ops; #endif /* CONFIG_GENERIC_CLK_FIXED */ +#ifdef CONFIG_GENERIC_CLK_GATE + +struct clk_gate { + struct clk_hw hw; + void __iomem *reg; + u8 bit_idx; +}; + +extern struct clk_hw_ops clk_gate_set_enable_ops; +extern struct clk_hw_ops clk_gate_set_disable_ops; + +#endif /* CONFIG_GENERIC_CLK_GATE */ + /** * clk_register - register and initialize a new clock *-- 1.7.4.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel at lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel