Add the clock notifier infrastructure. The external function exposed here
is omap_clk_notify_downstream(). This is intended to be used by
architecture-specific clk_set_rate() and clk_set_parent() functions, e.g.,
omap2_clk_set_rate().
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
---
arch/arm/plat-omap/clock.c | 81 +++++++++++++++++++++++++++++++
arch/arm/plat-omap/include/mach/clock.h | 1
2 files changed, 82 insertions(+), 0 deletions(-)
diff --git a/arch/arm/plat-omap/clock.c b/arch/arm/plat-omap/clock.c
index 4c2ed56..73bef03 100644
--- a/arch/arm/plat-omap/clock.c
+++ b/arch/arm/plat-omap/clock.c
@@ -173,6 +173,64 @@ void omap_clk_del_child(struct clk *clk, struct clk *clk2)
}
}
+/**
+ * omap_clk_notify - call clk notifier chain
+ * @clk: struct clk * that is changing rate
+ * @msg: clk notifier type (i.e., CLK_POST_RATE_CHANGE; see mach/clock.h)
+ * @old_rate: old rate
+ * @new_rate: new rate
+ *
+ * Triggers a notifier call chain on the post-clk-rate-change notifier
+ * for clock 'clk'. Passes a pointer to the struct clk and the
+ * previous and current rates to the notifier callback. Intended to be
+ * called by internal clock code only. No return value.
+ */
+static int omap_clk_notify(struct clk *clk, unsigned long msg,
+ unsigned long old_rate, unsigned long new_rate)
+{
+ struct clk_notifier *cn;
+ struct clk_notifier_data cnd;
+ int ret = NOTIFY_DONE;
+
+ cnd.clk = clk;
+ cnd.old_rate = old_rate;
+ cnd.new_rate = new_rate;
+
+ list_for_each_entry(cn, &clk_notifier_list, node) {
+ if (cn->clk == clk) {
+ ret = atomic_notifier_call_chain(&cn->notifier_head,
+ msg, &cnd);
+ break;
+ }
+ }
+
+ return ret;
+}
+
+/**
+ * _do_clk_notifier - callback function for clock change notification
+ * @clk: struct clk * to start the notifications with
+ * @msg: notifier msg - see "Clk notifier callback types"
+ * @param2: unused
+ *
+ * Notify callbacks associated with @clk that a clock change will or has
+ * occurred. If @msg is CLK_PREPARE_RATE_CHANGE, then actually pay attention
+ * to the notifier return value.
+ */
+static int _do_clk_notifier(struct clk *clk, unsigned long msg, u8 param2)
+{
+ int ret;
+
+ ret = omap_clk_notify(clk, msg, clk->rate, clk->temp_rate);
+ if (ret && msg == CLK_PREPARE_RATE_CHANGE)
+ return ret;
+
+ if (omap_clk_has_children(clk))
+ return omap_clk_notify_downstream(clk, msg);
+ else
+ return 0;
+}
+
/*-------------------------------------------------------------------------
* Standard clock functions defined in include/linux/clk.h
*-------------------------------------------------------------------------*/
@@ -440,6 +498,27 @@ void recalculate_root_clocks(void)
_do_propagate_rate(clkp, 0, CURRENT_RATE);
}
+/**
+ * omap_clk_notify_downstream - trigger clock change notifications
+ * @clk: struct clk * to start the notifications with
+ * @msg: notifier msg - see "Clk notifier callback types"
+ *
+ * Call clock change notifiers on clocks starting with @clk and including
+ * all of @clk's downstream children clocks. Returns NOTIFY_DONE if
+ * the notifiers ran successfully, or when msg is CLK_PREPARE_RATE_CHANGE,
+ * NOTIFY_BAD if one of the notifiers denied the change.
+ */
+int omap_clk_notify_downstream(struct clk *clk, unsigned long msg)
+{
+ if (clk == NULL || IS_ERR(clk))
+ return -EINVAL;
+
+ if (!clk->notifier_count)
+ return 0;
+
+ return omap_clk_for_each_child(clk, msg, 0, _do_clk_notifier);
+}
+
int clk_register(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
@@ -529,6 +608,8 @@ void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
EXPORT_SYMBOL(clk_init_cpufreq_table);
#endif
+/* Clk notifier implementations */
+
/**
* clk_notifier_register - add a clock parameter change notifier
* @clk: struct clk * to watch
diff --git a/arch/arm/plat-omap/include/mach/clock.h b/arch/arm/plat-omap/include/mach/clock.h
index d08f16c..2faf4c4 100644
--- a/arch/arm/plat-omap/include/mach/clock.h
+++ b/arch/arm/plat-omap/include/mach/clock.h
@@ -183,6 +183,7 @@ extern void clk_init_cpufreq_table(struct cpufreq_frequency_table **table);
#endif
void omap_clk_add_child(struct clk *clk, struct clk *clk2);
void omap_clk_del_child(struct clk *clk, struct clk *clk2);
+extern int omap_clk_notify_downstream(struct clk *clk, unsigned long msg);
/* Clock flags */
#define RATE_CKCTL (1 << 0) /* Main fixed ratio clocks */
--
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