clk: Add a function to retrieve phase

[karo-tx-linux.git] / drivers / clk / clk.c

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b76fa69b44cb7eb625c65723862ebc37d963b494..113d75db371da3cd6fb9026cf0b36a219833aef2 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -117,11 +117,11 @@ static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
        if (!c)
                return;
 
-       seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu\n",
+       seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
                   level * 3 + 1, "",
                   30 - level * 3, c->name,
                   c->enable_count, c->prepare_count, clk_get_rate(c),
-                  clk_get_accuracy(c));
+                  clk_get_accuracy(c), clk_get_phase(c));
 }
 
 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
@@ -143,8 +143,8 @@ static int clk_summary_show(struct seq_file *s, void *data)
        struct clk *c;
        struct hlist_head **lists = (struct hlist_head **)s->private;
 
-       seq_puts(s, "   clock                         enable_cnt  prepare_cnt        rate   accuracy\n");
-       seq_puts(s, "--------------------------------------------------------------------------------\n");
+       seq_puts(s, "   clock                         enable_cnt  prepare_cnt        rate   accuracy   phase\n");
+       seq_puts(s, "----------------------------------------------------------------------------------------\n");
 
        clk_prepare_lock();
 
@@ -180,6 +180,7 @@ static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
        seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
        seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
        seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
+       seq_printf(s, "\"phase\": %d", clk_get_phase(c));
 }
 
 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
@@ -264,6 +265,11 @@ static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
        if (!d)
                goto err_out;
 
+       d = debugfs_create_u32("clk_phase", S_IRUGO, clk->dentry,
+                       (u32 *)&clk->phase);
+       if (!d)
+               goto err_out;
+
        d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
                        (u32 *)&clk->flags);
        if (!d)
@@ -1738,6 +1744,77 @@ out:
 }
 EXPORT_SYMBOL_GPL(clk_set_parent);
 
+/**
+ * clk_set_phase - adjust the phase shift of a clock signal
+ * @clk: clock signal source
+ * @degrees: number of degrees the signal is shifted
+ *
+ * Shifts the phase of a clock signal by the specified
+ * degrees. Returns 0 on success, -EERROR otherwise.
+ *
+ * This function makes no distinction about the input or reference
+ * signal that we adjust the clock signal phase against. For example
+ * phase locked-loop clock signal generators we may shift phase with
+ * respect to feedback clock signal input, but for other cases the
+ * clock phase may be shifted with respect to some other, unspecified
+ * signal.
+ *
+ * Additionally the concept of phase shift does not propagate through
+ * the clock tree hierarchy, which sets it apart from clock rates and
+ * clock accuracy. A parent clock phase attribute does not have an
+ * impact on the phase attribute of a child clock.
+ */
+int clk_set_phase(struct clk *clk, int degrees)
+{
+       int ret = 0;
+
+       if (!clk)
+               goto out;
+
+       /* sanity check degrees */
+       degrees %= 360;
+       if (degrees < 0)
+               degrees += 360;
+
+       clk_prepare_lock();
+
+       if (!clk->ops->set_phase)
+               goto out_unlock;
+
+       ret = clk->ops->set_phase(clk->hw, degrees);
+
+       if (!ret)
+               clk->phase = degrees;
+
+out_unlock:
+       clk_prepare_unlock();
+
+out:
+       return ret;
+}
+
+/**
+ * clk_get_phase - return the phase shift of a clock signal
+ * @clk: clock signal source
+ *
+ * Returns the phase shift of a clock node in degrees, otherwise returns
+ * -EERROR.
+ */
+int clk_get_phase(struct clk *clk)
+{
+       int ret = 0;
+
+       if (!clk)
+               goto out;
+
+       clk_prepare_lock();
+       ret = clk->phase;
+       clk_prepare_unlock();
+
+out:
+       return ret;
+}
+
 /**
  * __clk_init - initialize the data structures in a struct clk
  * @dev:       device initializing this clk, placeholder for now
@@ -1856,6 +1933,16 @@ int __clk_init(struct device *dev, struct clk *clk)
        else
                clk->accuracy = 0;
 
+       /*
+        * Set clk's phase.
+        * Since a phase is by definition relative to its parent, just
+        * query the current clock phase, or just assume it's in phase.
+        */
+       if (clk->ops->get_phase)
+               clk->phase = clk->ops->get_phase(clk->hw);
+       else
+               clk->phase = 0;
+
        /*
         * Set clk's rate.  The preferred method is to use .recalc_rate.  For
         * simple clocks and lazy developers the default fallback is to use the