On Thursday 28 June 2012 11:58 PM, Mike Turquette wrote:
On 20120628-16:07, Prashant Gaikwad wrote:
Add Tegra platform specific clock structure clk_tegra and
some helper functions for generic clock framework.
struct clk_tegra is the single strcture used for all types of
clocks. reset and cfg_ex ops moved to clk_tegra from clk_ops.
Signed-off-by: Prashant Gaikwad<pgaikwad@xxxxxxxxxx>
Hi Prashant,
I'm happy to see Tegra getting ported over to the common clk framework.
Thanks Mike!! It will help to get in-line with recent developments.
<snip>
+void tegra_clk_add(struct clk *clk)
+{
+ struct clk_tegra *c = to_clk_tegra(__clk_get_hw(clk));
+
+ mutex_lock(&clock_list_lock);
+ list_add(&c->node,&clocks);
+ mutex_unlock(&clock_list_lock);
+}
+
+struct clk *tegra_get_clock_by_name(const char *name)
+{
+ struct clk_tegra *c;
+ struct clk *ret = NULL;
+ mutex_lock(&clock_list_lock);
+ list_for_each_entry(c,&clocks, node) {
+ if (strcmp(__clk_get_name(c->hw.clk), name) == 0) {
+ ret = c->hw.clk;
+ break;
+ }
+ }
+ mutex_unlock(&clock_list_lock);
+ return ret;
+}
+
Are you planning to continue using an internal list of struct clk_tegra?
OMAP had a similar list for the legacy clock framework but that was
since removed and now lookups are done solely through clkdev.
No, will move to clkdev later.
<snip>
+void tegra_periph_reset_deassert(struct clk *c)
+{
+ struct clk_tegra *clk = to_clk_tegra(__clk_get_hw(c));
+ BUG_ON(!clk->reset);
+ clk->reset(__clk_get_hw(c), false);
+}
+EXPORT_SYMBOL(tegra_periph_reset_deassert);
+
+void tegra_periph_reset_assert(struct clk *c)
+{
+ struct clk_tegra *clk = to_clk_tegra(__clk_get_hw(c));
+ BUG_ON(!clk->reset);
+ clk->reset(__clk_get_hw(c), true);
+}
+EXPORT_SYMBOL(tegra_periph_reset_assert);
+
+/* Several extended clock configuration bits (e.g., clock routing, clock
+ * phase control) are included in PLL and peripheral clock source
+ * registers. */
+int tegra_clk_cfg_ex(struct clk *c, enum tegra_clk_ex_param p, u32 setting)
+{
+ int ret = 0;
+ struct clk_tegra *clk = to_clk_tegra(__clk_get_hw(c));
+
+ if (!clk->clk_cfg_ex) {
+ ret = -ENOSYS;
+ goto out;
+ }
+ ret = clk->clk_cfg_ex(__clk_get_hw(c), p, setting);
+
+out:
+ return ret;
+}
We had some discussions in the past on your clock reset and external
line request operations which you've had to put into struct clk_tegra.
Do you need to expose those ops to code in drivers/*? I consider that a
reasonable litmus test to start considering if something should be moved
into the generic clk.h api.
Yes, we need these ops in drivers. Peter has sent a patch proposing to
move these ops to generic clk.
In addition, we also need mechanism/ops to change rate and parent from
clk_ops implementation. There was some discussion but I do not know the
latest status.
<snip>
+enum clk_state {
+ UNINITIALIZED = 0,
+ ON,
+ OFF,
+};
How is clk_state used? Might it be helpful to you if that was in the
generic code in drivers/clk/clk.c?
clk_state is used to store the clock state. I am planning to remove this
since is_enabled ops should work.
<snip>
+struct clk_tegra {
+ /* node for master clocks list */
+ struct list_head node; /* node for list of all clocks */
+ struct clk_lookup lookup;
+ struct clk_hw hw;
+
+ bool set;
+ unsigned long fixed_rate;
+ unsigned long max_rate;
+ unsigned long min_rate;
+ u32 flags;
+ const char *name;
+
+ enum clk_state state;
+ u32 div;
+ u32 mul;
+
+ u32 reg;
+ u32 reg_shift;
+
+ struct list_head shared_bus_list;
+
+ union {
+ struct {
+ unsigned int clk_num;
+ } periph;
+ struct {
+ unsigned long input_min;
+ unsigned long input_max;
+ unsigned long cf_min;
+ unsigned long cf_max;
+ unsigned long vco_min;
+ unsigned long vco_max;
+ const struct clk_pll_freq_table *freq_table;
+ int lock_delay;
+ unsigned long fixed_rate;
+ } pll;
+ struct {
+ u32 sel;
+ u32 reg_mask;
+ } mux;
+ struct {
+ struct clk *main;
+ struct clk *backup;
+ } cpu;
+ struct {
+ struct list_head node;
+ bool enabled;
+ unsigned long rate;
+ } shared_bus_user;
+ } u;
+
+ void (*reset)(struct clk_hw *, bool);
+ int (*clk_cfg_ex)(struct clk_hw *, enum tegra_clk_ex_param, u32);
+};
I know this is an initial effort but I hope in time that struct
clk_tegra can be broken up into separate clk types. It would be even
better if some of the Tegra clocks code be converted over to the common
clk types in drivers/clk/clk-*.c
Yes, that is next in my action list. One approach I am working on is to
model the clock as Mux -> Divider -> Gate by which we can use some of
common clock types.
But this will take time.
Regards,
Mike
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