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SubjectRe: [PATCH v2 4/7] clk: Add simple gated clock
On Thu, Sep 22, 2011 at 03:26:59PM -0700, Mike Turquette wrote:
> From: Jeremy Kerr <jeremy.kerr@canonical.com>
>
> Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
> Signed-off-by: Jamie Iles <jamie@jamieiles.com>
> Signed-off-by: Mike Turquette <mturquette@ti.com>
> ---
> 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
>
> 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_CLK
> diff --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.o
> diff --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@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>



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