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ARM: imx: add shared gate clock support

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It's quite common on i.MX that one gate bit controls the gating of
multiple clocks, i.e. this is a shared gate.  The patch adds the
function imx_clk_gate2_shared() for such case.  The clocks controlled
by the same gate bits should call this function with a pointer to a
single share count variable, so that the gate bits will only be
operated on the first enabling and the last disabling of these shared
gate clocks.

Thanks to Gerhard Sittig <gsi@denx.de> for this idea.

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
This commit is contained in:
Shawn Guo 2014-04-19 10:58:22 +08:00
parent 94b5c02882
commit f9f28cdf21
2 changed files with 23 additions and 3 deletions
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13
arch/arm/mach-imx/clk-gate2.c
View file

@ -33,6 +33,7 @@ struct clk_gate2 {
u8 bit_idx;
u8 flags;
spinlock_t *lock;
unsigned int *share_count;
};
#define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
@ -45,10 +46,14 @@ static int clk_gate2_enable(struct clk_hw *hw)
spin_lock_irqsave(gate->lock, flags);
if (gate->share_count && (*gate->share_count)++ > 0)
goto out;
reg = readl(gate->reg);
reg |= 3 << gate->bit_idx;
writel(reg, gate->reg);
out:
spin_unlock_irqrestore(gate->lock, flags);
return 0;
@ -62,10 +67,14 @@ static void clk_gate2_disable(struct clk_hw *hw)
spin_lock_irqsave(gate->lock, flags);
if (gate->share_count && --(*gate->share_count) > 0)
goto out;
reg = readl(gate->reg);
reg &= ~(3 << gate->bit_idx);
writel(reg, gate->reg);
out:
spin_unlock_irqrestore(gate->lock, flags);
}
@ -91,7 +100,8 @@ static struct clk_ops clk_gate2_ops = {
struct clk *clk_register_gate2(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
void __iomem *reg, u8 bit_idx,
u8 clk_gate2_flags, spinlock_t *lock)
u8 clk_gate2_flags, spinlock_t *lock,
unsigned int *share_count)
{
struct clk_gate2 *gate;
struct clk *clk;
@ -106,6 +116,7 @@ struct clk *clk_register_gate2(struct device *dev, const char *name,
gate->bit_idx = bit_idx;
gate->flags = clk_gate2_flags;
gate->lock = lock;
gate->share_count = share_count;
init.name = name;
init.ops = &clk_gate2_ops;

13
arch/arm/mach-imx/clk.h
View file

@ -28,7 +28,8 @@ struct clk *imx_clk_pllv3(enum imx_pllv3_type type, const char *name,
struct clk *clk_register_gate2(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
void __iomem *reg, u8 bit_idx,
u8 clk_gate_flags, spinlock_t *lock);
u8 clk_gate_flags, spinlock_t *lock,
unsigned int *share_count);
struct clk * imx_obtain_fixed_clock(
const char *name, unsigned long rate);
@ -37,7 +38,15 @@ static inline struct clk *imx_clk_gate2(const char *name, const char *parent,
void __iomem *reg, u8 shift)
{
return clk_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT, reg,
shift, 0, &imx_ccm_lock);
shift, 0, &imx_ccm_lock, NULL);
}
static inline struct clk *imx_clk_gate2_shared(const char *name,
const char *parent, void __iomem *reg, u8 shift,
unsigned int *share_count)
{
return clk_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT, reg,
shift, 0, &imx_ccm_lock, share_count);
}
struct clk *imx_clk_pfd(const char *name, const char *parent_name,