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authorPaul Mundt <lethal@linux-sh.org>2012-05-25 16:34:48 +0900
committerPaul Mundt <lethal@linux-sh.org>2012-05-25 16:34:48 +0900
commit764f4e4e33d18cde4dcaf8a0d860b749c6d6d08b (patch)
tree1e498ea454a2392b557a0f562170946838dece39 /drivers/sh/clk
parent0fa22168e00106797f28b2655aaefd0d16a6e67b (diff)
sh: clkfwk: Use shared sh_clk_div_enable/disable().
This introduces a new flag for clocks that need to have their divisor ratio set back to their initial mask at disable time to prevent interactivity problems with the clock stop bit (presently div6 only). With this in place it's possible to handle the corner case on top of the div4 op without any particular need for leaving things split out. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'drivers/sh/clk')
-rw-r--r--drivers/sh/clk/cpg.c77
1 files changed, 34 insertions, 43 deletions
diff --git a/drivers/sh/clk/cpg.c b/drivers/sh/clk/cpg.c
index 29ee5f7072a4..06537f2b2fb8 100644
--- a/drivers/sh/clk/cpg.c
+++ b/drivers/sh/clk/cpg.c
@@ -14,6 +14,8 @@
#include <linux/io.h>
#include <linux/sh_clk.h>
+#define CPG_CKSTP_BIT BIT(8)
+
static unsigned int sh_clk_read(struct clk *clk)
{
if (clk->flags & CLK_ENABLE_REG_8BIT)
@@ -122,6 +124,30 @@ static int sh_clk_div_set_rate(struct clk *clk, unsigned long rate)
return 0;
}
+static int sh_clk_div_enable(struct clk *clk)
+{
+ sh_clk_write(sh_clk_read(clk) & ~CPG_CKSTP_BIT, clk);
+ return 0;
+}
+
+static void sh_clk_div_disable(struct clk *clk)
+{
+ unsigned int val;
+
+ val = sh_clk_read(clk);
+ val |= CPG_CKSTP_BIT;
+
+ /*
+ * div6 clocks require the divisor field to be non-zero or the
+ * above CKSTP toggle silently fails. Ensure that the divisor
+ * array is reset to its initial state on disable.
+ */
+ if (clk->flags & CLK_MASK_DIV_ON_DISABLE)
+ val |= clk->div_mask;
+
+ sh_clk_write(val, clk);
+}
+
/*
* div6 support
*/
@@ -174,44 +200,20 @@ static int sh_clk_div6_set_parent(struct clk *clk, struct clk *parent)
return 0;
}
-static int sh_clk_div6_enable(struct clk *clk)
-{
- unsigned long value;
- int ret;
-
- ret = sh_clk_div_set_rate(clk, clk->rate);
- if (ret == 0) {
- value = sh_clk_read(clk);
- value &= ~0x100; /* clear stop bit to enable clock */
- sh_clk_write(value, clk);
- }
- return ret;
-}
-
-static void sh_clk_div6_disable(struct clk *clk)
-{
- unsigned long value;
-
- value = sh_clk_read(clk);
- value |= 0x100; /* stop clock */
- value |= clk->div_mask; /* VDIV bits must be non-zero, overwrite divider */
- sh_clk_write(value, clk);
-}
-
static struct sh_clk_ops sh_clk_div6_clk_ops = {
.recalc = sh_clk_div_recalc,
.round_rate = sh_clk_div_round_rate,
.set_rate = sh_clk_div_set_rate,
- .enable = sh_clk_div6_enable,
- .disable = sh_clk_div6_disable,
+ .enable = sh_clk_div_enable,
+ .disable = sh_clk_div_disable,
};
static struct sh_clk_ops sh_clk_div6_reparent_clk_ops = {
.recalc = sh_clk_div_recalc,
.round_rate = sh_clk_div_round_rate,
.set_rate = sh_clk_div_set_rate,
- .enable = sh_clk_div6_enable,
- .disable = sh_clk_div6_disable,
+ .enable = sh_clk_div_enable,
+ .disable = sh_clk_div_disable,
.set_parent = sh_clk_div6_set_parent,
};
@@ -325,17 +327,6 @@ static int sh_clk_div4_set_parent(struct clk *clk, struct clk *parent)
return 0;
}
-static int sh_clk_div4_enable(struct clk *clk)
-{
- sh_clk_write(sh_clk_read(clk) & ~(1 << 8), clk);
- return 0;
-}
-
-static void sh_clk_div4_disable(struct clk *clk)
-{
- sh_clk_write(sh_clk_read(clk) | (1 << 8), clk);
-}
-
static struct sh_clk_ops sh_clk_div4_clk_ops = {
.recalc = sh_clk_div_recalc,
.set_rate = sh_clk_div_set_rate,
@@ -346,16 +337,16 @@ static struct sh_clk_ops sh_clk_div4_enable_clk_ops = {
.recalc = sh_clk_div_recalc,
.set_rate = sh_clk_div_set_rate,
.round_rate = sh_clk_div_round_rate,
- .enable = sh_clk_div4_enable,
- .disable = sh_clk_div4_disable,
+ .enable = sh_clk_div_enable,
+ .disable = sh_clk_div_disable,
};
static struct sh_clk_ops sh_clk_div4_reparent_clk_ops = {
.recalc = sh_clk_div_recalc,
.set_rate = sh_clk_div_set_rate,
.round_rate = sh_clk_div_round_rate,
- .enable = sh_clk_div4_enable,
- .disable = sh_clk_div4_disable,
+ .enable = sh_clk_div_enable,
+ .disable = sh_clk_div_disable,
.set_parent = sh_clk_div4_set_parent,
};