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clk: mux: add CLK_MUX_HIWORD_MASK

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In both Hisilicon & Rockchip Cortex-A9 based chips, they don't use the
paradigm of reading-changing-writing the register contents.
Instead they use a hiword mask to indicate the changed bits.

When b01 should be set as switching mux, it also needs to indicate
the change by setting hiword mask (b11 << 16).

The patch adds mux flag for this usage.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
This commit is contained in:
Haojian Zhuang 2013-06-08 22:47:17 +08:00 committed by Mike Turquette
parent f3aab5d614
commit ba492e9007
2 changed files with 20 additions and 2 deletions
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13
drivers/clk/clk-mux.c
View File

@ -86,8 +86,12 @@ static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
if (mux->lock)
spin_lock_irqsave(mux->lock, flags);
if (mux->flags & CLK_MUX_HIWORD_MASK) {
val = mux->mask << (mux->shift + 16);
} else {
val = readl(mux->reg);
val &= ~(mux->mask << mux->shift);
}
val |= index << mux->shift;
writel(val, mux->reg);
@ -111,6 +115,15 @@ struct clk *clk_register_mux_table(struct device *dev, const char *name,
struct clk_mux *mux;
struct clk *clk;
struct clk_init_data init;
u8 width = 0;
if (clk_mux_flags & CLK_MUX_HIWORD_MASK) {
width = fls(mask) - ffs(mask) + 1;
if (width + shift > 16) {
pr_err("mux value exceeds LOWORD field\n");
return ERR_PTR(-EINVAL);
}
}
/* allocate the mux */
mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL);

5
include/linux/clk-provider.h
View File

@ -299,6 +299,10 @@ struct clk *clk_register_divider_table(struct device *dev, const char *name,
* Flags:
* CLK_MUX_INDEX_ONE - register index starts at 1, not 0
* CLK_MUX_INDEX_BIT - register index is a single bit (power of two)
* CLK_MUX_HIWORD_MASK - The mux settings are only in lower 16-bit of this
* register, and mask of mux bits are in higher 16-bit of this register.
* While setting the mux bits, higher 16-bit should also be updated to
* indicate changing mux bits.
*/
struct clk_mux {
struct clk_hw hw;
@ -312,6 +316,7 @@ struct clk_mux {
#define CLK_MUX_INDEX_ONE BIT(0)
#define CLK_MUX_INDEX_BIT BIT(1)
#define CLK_MUX_HIWORD_MASK BIT(2)
extern const struct clk_ops clk_mux_ops;