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ARM: imx: add shared gate clock support
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>
+23
-3
+12
-1
arch/arm/mach-imx/clk-gate2.c
+12
-1
arch/arm/mach-imx/clk-gate2.c
···
33
33
u8 bit_idx;
34
34
u8 flags;
35
35
spinlock_t *lock;
36
+
unsigned int *share_count;
36
37
};
37
38
38
39
#define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
···
46
45
47
46
spin_lock_irqsave(gate->lock, flags);
48
47
48
+
if (gate->share_count && (*gate->share_count)++ > 0)
49
+
goto out;
50
+
49
51
reg = readl(gate->reg);
50
52
reg |= 3 << gate->bit_idx;
51
53
writel(reg, gate->reg);
52
54
55
+
out:
53
56
spin_unlock_irqrestore(gate->lock, flags);
54
57
55
58
return 0;
···
67
62
68
63
spin_lock_irqsave(gate->lock, flags);
69
64
65
+
if (gate->share_count && --(*gate->share_count) > 0)
66
+
goto out;
67
+
70
68
reg = readl(gate->reg);
71
69
reg &= ~(3 << gate->bit_idx);
72
70
writel(reg, gate->reg);
73
71
72
+
out:
74
73
spin_unlock_irqrestore(gate->lock, flags);
75
74
}
76
75
···
100
91
struct clk *clk_register_gate2(struct device *dev, const char *name,
101
92
const char *parent_name, unsigned long flags,
102
93
void __iomem *reg, u8 bit_idx,
103
-
u8 clk_gate2_flags, spinlock_t *lock)
94
+
u8 clk_gate2_flags, spinlock_t *lock,
95
+
unsigned int *share_count)
104
96
{
105
97
struct clk_gate2 *gate;
106
98
struct clk *clk;
···
116
106
gate->bit_idx = bit_idx;
117
107
gate->flags = clk_gate2_flags;
118
108
gate->lock = lock;
109
+
gate->share_count = share_count;
119
110
120
111
init.name = name;
121
112
init.ops = &clk_gate2_ops;
+11
-2
arch/arm/mach-imx/clk.h
+11
-2
arch/arm/mach-imx/clk.h
···
28
28
struct clk *clk_register_gate2(struct device *dev, const char *name,
29
29
const char *parent_name, unsigned long flags,
30
30
void __iomem *reg, u8 bit_idx,
31
-
u8 clk_gate_flags, spinlock_t *lock);
31
+
u8 clk_gate_flags, spinlock_t *lock,
32
+
unsigned int *share_count);
32
33
33
34
struct clk * imx_obtain_fixed_clock(
34
35
const char *name, unsigned long rate);
···
38
37
void __iomem *reg, u8 shift)
39
38
{
40
39
return clk_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT, reg,
41
-
shift, 0, &imx_ccm_lock);
40
+
shift, 0, &imx_ccm_lock, NULL);
41
+
}
42
+
43
+
static inline struct clk *imx_clk_gate2_shared(const char *name,
44
+
const char *parent, void __iomem *reg, u8 shift,
45
+
unsigned int *share_count)
46
+
{
47
+
return clk_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT, reg,
48
+
shift, 0, &imx_ccm_lock, share_count);
42
49
}
43
50
44
51
struct clk *imx_clk_pfd(const char *name, const char *parent_name,