linux/drivers/clk/clk-mux.c

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/*
* Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
* Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
* Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
*
* 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 multiplexer clock implementation
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
/*
* DOC: basic adjustable multiplexer clock that cannot gate
*
* Traits of this clock:
* prepare - clk_prepare only ensures that parents are prepared
* enable - clk_enable only ensures that parents are enabled
* rate - rate is only affected by parent switching. No clk_set_rate support
* parent - parent is adjustable through clk_set_parent
*/
#define to_clk_mux(_hw) container_of(_hw, struct clk_mux, hw)
static u8 clk_mux_get_parent(struct clk_hw *hw)
{
struct clk_mux *mux = to_clk_mux(hw);
u32 val;
/*
* FIXME need a mux-specific flag to determine if val is bitwise or numeric
* e.g. sys_clkin_ck's clksel field is 3 bits wide, but ranges from 0x1
* to 0x7 (index starts at one)
* OTOH, pmd_trace_clk_mux_ck uses a separate bit for each clock, so
* val = 0x4 really means "bit 2, index starts at bit 0"
*/
val = readl(mux->reg) >> mux->shift;
val &= (1 << mux->width) - 1;
if (val && (mux->flags & CLK_MUX_INDEX_BIT))
val = ffs(val) - 1;
if (val && (mux->flags & CLK_MUX_INDEX_ONE))
val--;
if (val >= __clk_get_num_parents(hw->clk))
return -EINVAL;
return val;
}
static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
{
struct clk_mux *mux = to_clk_mux(hw);
u32 val;
unsigned long flags = 0;
if (mux->flags & CLK_MUX_INDEX_BIT)
index = (1 << ffs(index));
if (mux->flags & CLK_MUX_INDEX_ONE)
index++;
if (mux->lock)
spin_lock_irqsave(mux->lock, flags);
val = readl(mux->reg);
val &= ~(((1 << mux->width) - 1) << mux->shift);
val |= index << mux->shift;
writel(val, mux->reg);
if (mux->lock)
spin_unlock_irqrestore(mux->lock, flags);
return 0;
}
const struct clk_ops clk_mux_ops = {
.get_parent = clk_mux_get_parent,
.set_parent = clk_mux_set_parent,
};
EXPORT_SYMBOL_GPL(clk_mux_ops);
struct clk *clk_register_mux(struct device *dev, const char *name,
const char **parent_names, u8 num_parents, unsigned long flags,
void __iomem *reg, u8 shift, u8 width,
u8 clk_mux_flags, spinlock_t *lock)
{
struct clk_mux *mux;
struct clk *clk;
clk: Use a separate struct for holding init data. Create a struct clk_init_data to hold all data that needs to be passed from the platfrom specific driver to the common clock framework during clock registration. Add a pointer to this struct inside clk_hw. This has several advantages: * Completely hides struct clk from many clock platform drivers and static clock initialization code that don't care for static initialization of the struct clks. * For platforms that want to do complete static initialization, it removed the need to directly mess with the struct clk's fields while still allowing to statically allocate struct clk. This keeps the code more future proof even if they include clk-private.h. * Simplifies the generic clk_register() function and allows adding optional fields in the future without modifying the function signature. * Simplifies the static initialization of clocks on all platforms by removing the need for forward delcarations or convoluted macros. Signed-off-by: Saravana Kannan <skannan@codeaurora.org> [mturquette@linaro.org: kept DEFINE_CLK_* macros and __clk_init] Signed-off-by: Mike Turquette <mturquette@linaro.org> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergman <arnd.bergmann@linaro.org> Cc: Paul Walmsley <paul@pwsan.com> Cc: Shawn Guo <shawn.guo@freescale.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Jamie Iles <jamie@jamieiles.com> Cc: Richard Zhao <richard.zhao@linaro.org> Cc: Saravana Kannan <skannan@codeaurora.org> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Linus Walleij <linus.walleij@stericsson.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Amit Kucheria <amit.kucheria@linaro.org> Cc: Deepak Saxena <dsaxena@linaro.org> Cc: Grant Likely <grant.likely@secretlab.ca>
2012-04-26 05:58:56 +00:00
struct clk_init_data init;
/* allocate the mux */
mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL);
if (!mux) {
pr_err("%s: could not allocate mux clk\n", __func__);
return ERR_PTR(-ENOMEM);
}
clk: Use a separate struct for holding init data. Create a struct clk_init_data to hold all data that needs to be passed from the platfrom specific driver to the common clock framework during clock registration. Add a pointer to this struct inside clk_hw. This has several advantages: * Completely hides struct clk from many clock platform drivers and static clock initialization code that don't care for static initialization of the struct clks. * For platforms that want to do complete static initialization, it removed the need to directly mess with the struct clk's fields while still allowing to statically allocate struct clk. This keeps the code more future proof even if they include clk-private.h. * Simplifies the generic clk_register() function and allows adding optional fields in the future without modifying the function signature. * Simplifies the static initialization of clocks on all platforms by removing the need for forward delcarations or convoluted macros. Signed-off-by: Saravana Kannan <skannan@codeaurora.org> [mturquette@linaro.org: kept DEFINE_CLK_* macros and __clk_init] Signed-off-by: Mike Turquette <mturquette@linaro.org> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergman <arnd.bergmann@linaro.org> Cc: Paul Walmsley <paul@pwsan.com> Cc: Shawn Guo <shawn.guo@freescale.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Jamie Iles <jamie@jamieiles.com> Cc: Richard Zhao <richard.zhao@linaro.org> Cc: Saravana Kannan <skannan@codeaurora.org> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Linus Walleij <linus.walleij@stericsson.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Amit Kucheria <amit.kucheria@linaro.org> Cc: Deepak Saxena <dsaxena@linaro.org> Cc: Grant Likely <grant.likely@secretlab.ca>
2012-04-26 05:58:56 +00:00
init.name = name;
init.ops = &clk_mux_ops;
init.flags = flags;
init.parent_names = parent_names;
init.num_parents = num_parents;
/* struct clk_mux assignments */
mux->reg = reg;
mux->shift = shift;
mux->width = width;
mux->flags = clk_mux_flags;
mux->lock = lock;
mux->hw.init = &init;
clk: Use a separate struct for holding init data. Create a struct clk_init_data to hold all data that needs to be passed from the platfrom specific driver to the common clock framework during clock registration. Add a pointer to this struct inside clk_hw. This has several advantages: * Completely hides struct clk from many clock platform drivers and static clock initialization code that don't care for static initialization of the struct clks. * For platforms that want to do complete static initialization, it removed the need to directly mess with the struct clk's fields while still allowing to statically allocate struct clk. This keeps the code more future proof even if they include clk-private.h. * Simplifies the generic clk_register() function and allows adding optional fields in the future without modifying the function signature. * Simplifies the static initialization of clocks on all platforms by removing the need for forward delcarations or convoluted macros. Signed-off-by: Saravana Kannan <skannan@codeaurora.org> [mturquette@linaro.org: kept DEFINE_CLK_* macros and __clk_init] Signed-off-by: Mike Turquette <mturquette@linaro.org> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergman <arnd.bergmann@linaro.org> Cc: Paul Walmsley <paul@pwsan.com> Cc: Shawn Guo <shawn.guo@freescale.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Jamie Iles <jamie@jamieiles.com> Cc: Richard Zhao <richard.zhao@linaro.org> Cc: Saravana Kannan <skannan@codeaurora.org> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Linus Walleij <linus.walleij@stericsson.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Amit Kucheria <amit.kucheria@linaro.org> Cc: Deepak Saxena <dsaxena@linaro.org> Cc: Grant Likely <grant.likely@secretlab.ca>
2012-04-26 05:58:56 +00:00
clk = clk_register(dev, &mux->hw);
if (IS_ERR(clk))
kfree(mux);
return clk;
}