Hi Rob, On Mon, Sep 26, 2011 at 01:33:08PM -0500, Rob Herring wrote: > Mike, > > On 09/22/2011 05:26 PM, Mike Turquette wrote: > > From: Jeremy Kerr <jeremy.k...@canonical.com> > > > > Signed-off-by: Jeremy Kerr <jeremy.k...@canonical.com> > > Signed-off-by: Mark Brown <broo...@opensource.wolfsonmicro.com> > > Signed-off-by: Jamie Iles <ja...@jamieiles.com> > > Signed-off-by: Mike Turquette <mturque...@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 > > > > 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.k...@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> > > use linux/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); > > Don't these read-mod-writes need a spinlock around it? > > It's possible to have an enable bits and dividers in the same register. > If you did a set_rate and while doing an enable/disable, there would be > a problem. Also, it may be 2 different clocks in the same register, so > the spinlock needs to be shared and not per clock.
Well the prepare lock will be held here and I believe that would be sufficient. > > +} > > + > > +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 = { > > const? Yup. > > + .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); > > +} > > Are these wrapper functions really needed? Just assign set_bit and > clear_bit functions directly to the ops structs. Only the ops struct > name is exposed to the user. I used the wrappers because the .enable method has to return an int, but the disable needs to return void. It's either that or open code the set/clear in each. > > + > > +struct clk_hw_ops clk_gate_set_disable_ops = { > > const? Yes. Jamie _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev