[PATCH v2 2/5] clk: bcm281xx: implement prerequisite clocks
From: Mike Turquette <hidden>
Date: 2014-05-24 00:54:12
Also in:
linux-devicetree, lkml
Subsystem:
common clk framework, the rest · Maintainers:
Michael Turquette, Stephen Boyd, Linus Torvalds
Quoting Alex Elder (2014-05-20 05:52:39)
quoted hunk ↗ jump to hunk
@@ -743,11 +746,16 @@ struct clk *kona_clk_setup(struct kona_clk *bcm_clk) clk = clk_register(NULL, &bcm_clk->hw); if (IS_ERR(clk)) { pr_err("%s: error registering clock %s (%ld)\n", __func__, - init_data->name, PTR_ERR(clk)); + name, PTR_ERR(clk)); goto out_teardown; } BUG_ON(!clk); + /* Make it so we can look the clock up using clk_find() */
s/clk_find/clk_get/ ?
+ bcm_clk->cl.con_id = name; + bcm_clk->cl.clk = clk; + clkdev_add(&bcm_clk->cl);
This is not so nice. I'll explain more below.
quoted hunk ↗ jump to hunk
+ return clk; out_teardown: bcm_clk_teardown(bcm_clk);diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c index d8a7f38..fd070d6 100644 --- a/drivers/clk/bcm/clk-kona.c +++ b/drivers/clk/bcm/clk-kona.c@@ -1195,6 +1195,48 @@ static bool __peri_clk_init(struct kona_clk *bcm_clk) return true; } +static bool __kona_clk_init(struct kona_clk *bcm_clk); +static bool __kona_prereq_init(struct kona_clk *bcm_clk) +{ + struct clk *clk; + struct clk_hw *hw; + struct kona_clk *prereq; + + BUG_ON(clk_is_initialized(bcm_clk)); + + if (!bcm_clk->p.prereq) + return true; + + clk = clk_get(NULL, bcm_clk->p.prereq);
The clkdev global namespace is getting polluted with all of these new prereq clocks. If there was an associated struct device *dev with them then it wouldn't be a problem, but you might get collisions with other clock drivers that also use NULL for the device. It would be a lot nicer for the clocks that require a prereq clock to just use clk_get(dev, "well_known_name"); in the same way that drivers use it, without considering it a special case.
+ if (IS_ERR(clk)) {
+ pr_err("%s: unable to get prereq clock %s for %s\n",
+ __func__, bcm_clk->p.prereq, bcm_clk->init_data.name);
+ return false;
+ }
+ hw = __clk_get_hw(clk);
+ if (!hw) {
+ pr_err("%s: null hw pointer for clock %s\n", __func__,
+ bcm_clk->init_data.name);
+ return false;
+ }
+ prereq = to_kona_clk(hw);
+ if (prereq->ccu != bcm_clk->ccu) {
+ pr_err("%s: prereq clock %s CCU different for clock %s\n",
+ __func__, bcm_clk->p.prereq, bcm_clk->init_data.name);
+ return false;
+ }
+
+ /* Initialize the prerequisite clock first */
+ if (!__kona_clk_init(prereq)) {
+ pr_err("%s: failed to init prereq %s for clock %s\n",
+ __func__, bcm_clk->p.prereq, bcm_clk->init_data.name);
+ return false;
+ }
+ bcm_clk->p.prereq_clk = clk;The above seems like a lot effort to go to. Why not skip all of this and just implement the prerequisite logic in the .enable & .disable callbacks? E.g. your kona clk .enable callback would look like:
diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c
index d603c4e..51f35b4 100644
--- a/drivers/clk/bcm/clk-kona.c
+++ b/drivers/clk/bcm/clk-kona.c@@ -987,6 +987,12 @@ static int kona_peri_clk_enable(struct clk_hw *hw) { struct kona_clk *bcm_clk = to_kona_clk(hw); struct bcm_clk_gate *gate = &bcm_clk->u.peri->gate; + int ret; + + hw->prereq_bus_clk = clk_get(hw->ccu, hw->prereq); + ret = clk_enable(prereq_bus_clk); + if (ret) + return ret; return clk_gate(bcm_clk->ccu, bcm_clk->init_data.name, gate, true); }
@@ -997,6 +1003,9 @@ static void kona_peri_clk_disable(struct clk_hw *hw) struct bcm_clk_gate *gate = &bcm_clk->u.peri->gate; (void)clk_gate(bcm_clk->ccu, bcm_clk->init_data.name, gate, false); + + clk_disable(hw->prereq_bus_clk); + clk_put(hw->prereq_bus_clk); } static int kona_peri_clk_is_enabled(struct clk_hw *hw)
I guess it might take some trickery to get clk_get to work like that. Let me know if I've completely lost the plot. Regards, Mike